Biomedical subjects

S D Finkelstein

Publications and source records attributed to S D Finkelstein.

At least 37 records · Page 2Linked to original sources

PubMed1999

Max interacting protein 1: loss of heterozygosity is frequent in desmoplastic melanoma.

Max interacting protein 1 (MXI1), a negative regulator of myc oncoprotein with tumor suppressor properties, has been mapped to chromosome 10q24-25. MXI1 gene loss, demonstrated by loss of heterozygosity (LOH) analysis (allelic imbalance), is a frequent event in astrocytomas and other forms of glial neoplasia. Development and progression of malignant melanoma likely involves several cooperative oncogene/tumor suppressor gene alterations, many of which remain to be elucidated. We sought to discover whether desmoplastic melanoma (DM) exhibited MXI1 LOH. Archival fixative treated tissue was used for genotyping; this necessitated a microdissection-based molecular approach uniquely designed for minute tissue samples. Nineteen formalin-fixed tissue samples from 11 patients representing primary, locally recurrent, and metastatic DM were available for study. In each case, normal and neoplastic tissue was microdissected under stereomicroscopic observation as a basis for genetic analysis. We identified MXI1 LOH in neoplastic tissue by observing allelic imbalance for a microsatellite repeat polymorphism in the 3' nontranslated region of the MXI1 gene in subjects shown to be informative. Colorectal adenocarcinoma (n = 21) and astrocytomas (n = 19) were similarly analyzed, serving as negative and positive controls, respectively, for MXI1 LOH. Five of 11 DMs in subjects informative for the MXI1 microsatellite manifested MXI1 allelic imbalance consistent with tumor suppressor LOH. Genotype fidelity with respect to MXI1 status was present in two patients from whom primary and recurrent tumor was available for comparative analysis. We found that MXI1 LOH was independent of tumor stage and survival. MXI1 LOH seems to be a relatively frequent and early event in DM development and progression, consistent with neuroectodermal histogenesis of the neoplasm.

Adult↗

PubMed1999

Comparative immunohistochemical and molecular analysis of uterine and extrauterine leiomyosarcomas.

Histologic criteria defining malignancy in smooth muscle tumors are currently site specific. This study was undertaken to determine whether, in leiomyosarcomas (LMS) occurring in different anatomic locations, there were differences in patterns of expression of molecules that have been demonstrated to be associated with biologically aggressive behavior in malignant neoplasms, and also to determine their diagnostic utility. Formalin-fixed paraffin-embedded tissue blocks were selected from 16 extrauterine leiomyosarcomas (EULMS), 14 cases of uterine leiomyosarcomas (ULMS) and from five cases each of uterine and extrauterine leiomyomas (LM). Utilizing immunohistochemical (ABC) techniques with antigen retrieval, we assessed serial sections of each tumor for immunoreactivity with Glut1, CD44s, bcl2, cyclin D1, and estrogen receptor. Molecular genotyping for detecting k-ras-2 point mutation, p53 gene loss, and mdm2 gene amplification was performed on microdissected tumor samples from the same histologic sections. All of the uterine and extrauterine LM were diffusely positive for CD44s, bcl2, and cyclin D1, and uniformly negative for Glut1. In contrast, 50% of the ULMS and 25% of EULMS were Glutl positive. Moreover, Glut1 positivity closely correlated with aggressive biologic behavior reflected by distant metastatic spread. Eighty-percent of LM and 70% of the ULMS were estrogen receptor positive, whereas only one retroperitoneal tumor had focal weak positivity. Over 80% of the extrauterine and 50% of the uterine sarcomas showed absence of CD44s immunoreactivity. Percentage of cyclin D1 immunoreactivity was independent of tumor grade and inversely proportional to the percent of bcl2 positivity. An LMS of the male breast contained k-ras-2 exon 1 point mutation (codon 12 aspartate substitution of glycine). P53 allelic imbalance was present in 29% of ULMS and 57% EULMS. Mdm2 amplification was present in three of six EULMS but not in ULMS. In addition to clinical staging, Glut1 positivity together with patterns of immunoreactivity of CD44 and bcl2 may be helpful in identifying aggressive smooth muscle tumors of the uterus and some EULMS. The presence of estrogen receptor staining may be helpful in identifying uterine versus nonuterine LMS. Although sample numbers are too small for definite conclusions, this study suggests that there are differences in glucose transport, expression of adhesion molecules, and estrogen receptors in ULMS and EULMS, which in part may be due to the estrogen dependency of the ULMS. P53 mutations and mdm2 amplifications appear to be more frequent in EULMS.

Adult↗

PubMed1998

p53 sequence analysis predicts treatment response and outcome of patients with esophageal carcinoma.

BACKGROUND: The ability to predict biologic behavior and treatment responsiveness would be a valuable asset in the multimodality approach to esophageal carcinoma. The authors examined whether alterations of the p53 gene correlate with clinicopathologic parameters, response to preoperative chemotherapy/radiotherapy, and outcome in patients with esophageal carcinoma. METHODS. Histopathologic/genetic analysis of p53 was performed on formalin fixed, paraffin embedded tissues. Tissue sections were stained immunohistochemically for p53 protein followed by topographic genotyping comprised of polymerase chain reaction amplification and direct sequencing of p53 exons 5-8. All patients received induction chemotherapy (5-fluorouracil, cisplatin, and alpha-interferon) and concurrent external beam radiotherapy (4500 centigrays) followed by resection. RESULTS: p53 analysis performed on 42 tumors from patients with potentially resectable esophageal carcinoma revealed 25 of the 42 tumors (59.5%) to be p53 immunopositive; however, only 17 of the 42 tumors (40.5%) were proven to contain p53 point mutational damage in exons 8 (n=5), 5 (n=5), 7 (n=4), and 6 (n=3). Eight cases were weakly immunopositive and had no genotype mutation suggesting hyperexpression of normal wild-type p53. Genotyping also identified two immunonegative cases with deletion-type mutations (exons 5 and 6). Tissue samples collected before and after chemotherapy/radiotherapy exhibited fidelity in p53 mutational genotype in all cases. The presence of a p53 point mutation positively correlated with pTNM stage (P=0.003) and residual disease in the resected specimen (P=0.01). Moreover, survival of patients with p53 mutations was significantly lower than that of patients without mutations (overall survival of 21.6 months vs. 40 months; P=0.0038; and disease free survival of 14.1 months vs. 38 months; P=0.0004). CONCLUSIONS: Histopathologic/genetic analysis is a better determinant of p53 mutational damage than immunohistochemistry alone and can be used as a prognostic marker for esophageal carcinoma. p53 genotyping may define a subset of patients who respond to chemotherapy/radiotherapy and may predict who potentially benefits from multimodality therapy.

Adult↗

PubMed1998

Carcinosarcomas (malignant mixed mullerian tumors) of the female genital tract: comparative molecular analysis of epithelial and mesenchymal components.

Female genital tract carcinosarcomas (FGTCS) are biphasic neoplasms composed of an admixture of malignant epithelial and mesenchymal elements. Histogenesis of FGTCS centers on two theories: (1) simultaneous formation of independent tumors (biclonal theory), (2) multidirectional differentiation of a single neoplasm (monoclonal theory). In an attempt to resolve this histogenetic controversy, we determined the presence, specific genotype, and timing of p53 mutational change in each component of FGTCS using a topographic genotyping (TG) approach. We selected 43 FGTCS from the files of Magee-Womens Hospital, Pittsburgh, and initially immunostained them for p53 protein. Strong p53 immunopositivity was detected in 35 (82%) of 43 tumors. Subsequently, topographic genotyping (TG) was performed on a subset of nine immunopositive tumors with sufficiently distinct malignant components to enable effective sampling. All nine tumors showed point mutations in p53 exons 5 through 8. In each case, the identical point mutational genotype was present in both components. Furthermore, in all nine cases mutations were present with loss of the wild-type allele. P53 gene mutation is a frequent event in progression of FGTCS. Of importance, both p53 mutation and allelic loss occur before the differentiation into separate epithelial and mesenchymal malignant components. These molecular findings strongly support monoclonal, multidirectional histogenesis of FGTCS.

Base Sequence↗

PubMed1998

Chemotherapy in experimental brain tumor, part 2: pretreatment with leukotriene C4 prolongs survival.

Previous work in our laboratory has shown a correspondence between the chemosensitivity of C6 rat glioma and that of human glioblastoma (GBM) to a panel of chemotherapeutic agents in vitro, as determined by the MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide] colorimetric assay. In the present study, an in vivo model of intracerebral C6 glioma in Sprague-Dawley rats was used to determine if a correlation exists between in vitro chemosensitivity and in vivo survival of the animals, and post-mortem histopathological changes in the tumor. Cisplatin (CDDP) and methotrexate (MTX), agents previously shown to demonstrate high and low in vitro cytotoxicity, respectively, against C6, were administered by intra-carotid infusion over the course of two days. In a separate series of animals, LTC4 was administered prior to infusion of CDDP or MTX; LTC4 was used in view of its known, selective, vasogenic effect on the permeability of brain tumor capillaries. It was found that survival of animals treated with CDDP alone was increased, although this did not reach statistical significance; histopathologically, CDDP-treated animals showed significant tumor necrosis. However, in CDDP-treated animals, pre-treatment with LTC4 increased survival to a statistically significant degree. When administered alone, LTC4 (not followed by CDDP) had no effect on either survival or histology. The survival-enhancing effect of CDDP, when combined with LTC4, was probably not due to any cytotoxic effect of LTC4; this is based on our finding that, on the in vitro MTT colorimetric assay, LTC4 showed low cytotoxicity for C6 glioma cells. By contrast with CDDP, MTX -- with or without pretreatment with LTC4 -- affected neither survival nor tumor histology. With respect to the question of correspondence between the MTT colorimetric in vitro assay and in vivo effect, MTX showed a clear correlation: low cytotoxicity in vitro and poor in vivo response. In the case of CDDP, the correspondence was not clear-cut: there was a high level of in vitro chemosensitivity of the C6 cell line to CDDP as well as post-mortem tumor necrosis, but in vivo testing showed no significant prolongation of survival. However, pre-treatment with LTC4 did significantly extend survival in animals treated with CDDP.

Animals↗

PubMed1997

K-ras gene mutations in normal colorectal tissues from K-ras mutation-positive colorectal cancer patients.

K-ras gene mutations have been reported as early events in colorectal tumorigenesis, but their role in tumor initiation and development is still unclear. To analyze and compare K-ras mutational patterns between colorectal tissues at different stages of tumor progression in individual patients, 65 colorectal tissue samples, including carcinoma, adenoma, histologically normal mucosa, submucosal muscularis propria, and histologically normal mucosa distant from tumor, were obtained from 13 patients with colorectal cancer. In addition, normal mucosal tissues obtained from four normal individuals were analyzed. Each of the 13 tumors was shown previously to harbor a mutation in either codon 12 or 13 of the K-ras gene by direct sequencing. These tissues were reanalyzed, using the recently established mutant allele enrichment + denaturing gradient gel electrophoresis method, which can detect one mutant allele in 10(4)-10(5) normal alleles, thus allowing for the analysis of infrequent cells bearing mutations against the background of wild-type cells. No K-ras codon 12 mutation was detected by this method in the histologically normal mucosal tissues sampled at the margin of resection distant from the tumor or in those obtained from four normal individuals. On the other hand, these mutations were detected in 9 of 10 adenoma and 6 of 10 mucosa samples from 10 patients with known K-ras codon 12 mutations, and also in 2 of 3 carcinoma, 2 of 3 adenoma, and 1 of 3 mucosa samples obtained from 3 patients with known K-ras codon 13 mutations. Thus, K-ras codon 12 mutations were found to occur with a high frequency (53.8%) in histologically normal mucosa adjacent to tumors of patients with K-ras mutation-positive colorectal cancer, suggesting that they may be useful biomarkers for early detection of colorectal cancer. Furthermore, multiple K-ras mutations were found in tissues of nearly half of the 13 patients, indicating that distinct evolutionary subclones may be involved in the development of tumor in some patients with colorectal cancer.

Adenoma↗

PubMed1997

Detection of infrequent and multiple K-ras mutations in human tumors and tumor-adjacent tissues.

A sensitive method was developed and applied to examine the distribution of K-ras gene mutations in histologically differing areas of lung tissues obtained from lung cancer patients. This method, which combines polymerase chain reaction (PCR), mutation allele enrichment (MAE), and denaturing gradient gel electrophoresis (DGGE), allows detection of one K-ras mutant allele present in 10(4) to 10(5) wild-type alleles. It was applied to analyze mutations in codon 12 of the K-ras gene in 43 tissue sites microdissected from paraffin-embedded sections obtained from 8 archival cases of lung cancer, all previously shown to have codon 12 K-ras mutations by direct sequencing. In four cases, mutations were detected only in the tumor, while in the other four cases, the same mutations were also found in tissues adjacent to tumors, using the MAE + DGGE method. No mutations were detected among normal-appearing cells in areas distant from the tumors in any of the cases studied. These findings demonstrate that K-ras mutations can be detected at low frequencies in normal-appearing cells from tissues adjacent to the tumor in some lung cancer cases. In addition, this approach also allowed detection of multiple mutations in colorectal tissues obtained from colorectal cancer patients. Thus, the MAE + DGGE method may be applicable to study of K-ras mutations in premalignant or morphologically suspicious lesions in bronchial mucosa or other types of human cancer.

Base Sequence↗

PubMed1997

A case-matched molecular comparison of extraovarian versus primary ovarian adenocarcinoma.

BACKGROUND: Extraovarian müllerian adenocarcinoma (EOM) resembles primary ovarian carcinoma (POC) both histologically and clinically, yet little is known regarding the molecular genetic characteristics of this entity. The objective of this study was to compare the expression of three molecular markers of tumor behavior in EOMs and POCs. METHODS: Forty-four patients meeting strict criteria for EOM were identified and matched to POC controls for age, stage, tumor histology and grade, cytoreductive surgery, and survival. Immunohistochemistry was used to determine overexpression of p53 and HER-2/neu. DNA content was evaluated by flow cytometry. Direct DNA sequencing of exons 5-8 of the p53 gene was performed in nine EOM tumors. Statistical comparisons were made using chi-square, Kaplan-Meier, and Mantel-Cox log rank methods. RESULTS: Overexpression of HER-2/neu was demonstrated in 59% (26 of 44) of the EOM group versus 36% overexpression (16 of 44) in the POC controls (P = 0.05). Overexpression of p53 was noted in 48% of the EOM cases, similar to the 59% incidence observed in the control group (P = 0.29). Missense mutations were found in 9 of 9 EOM tumors showing strong p53 nuclear immunostaining. No significant difference in the incidence of aneuploidy was observed when EOM cases were compared with POC controls (65% vs. 63%). High tumor grade was strongly associated with HER-2/neu overexpression in the EOM group (P = 0.002). None of the parameters studied were predictive of prognosis within the EOM and POC groups. CONCLUSIONS: Although overexpression of p53 protein, p53 gene mutations, and abnormal DNA content were similar between EOMs and POCs, EOMs demonstrated almost twice the rate of HER-2/neu overexpression. This result suggests that distinct genetic events may be responsible for malignant transformation in EOMs versus POCs.

Adenocarcinoma, Clear Cell↗

PubMed1997

The relationship between TP53 mutations and overexpression of p53 and prognosis in malignant gliomas of childhood.

The prognosis for children with high-grade gliomas remains somewhat unpredictable. Although prolonged disease control is sometimes achieved after surgery, radiotherapy, and chemotherapy, most patients exhibit rapid disease progression. Because p53-dependent apoptosis mechanisms are involved in the cytotoxic effects of irradiation and chemotherapy, we questioned whether p53 status might be associated with outcome in childhood malignant gliomas. Therefore, we examined p53 status, both immunohistochemically and by direct sequencing of exons 5-8, in a series of 29 archival pediatric malignant non-brainstem gliomas treated consecutively at our institution between 1975 and 1992. Eighteen tumors had dense p53 staining in the majority of cells, although only 11 had mutations of the p53 gene (TP53). On univariate analysis, there was a significant association between p53 overexpression and a shorter progression-free survival (PFS) and overall survival (OS; P = 0.019 and 0.013, respectively; rank sum test). In addition, there was a significant association between TP53 mutations and a poorer PFS (P = 0.04), and a strong trend toward a shorter OS among patients with TP53 mutations (P = 0.06). Median PFS and OS for patients with TP53-mutated tumors were 6 months and 16 months, respectively, and for those with p53 overexpression 5.5 months and 14 months, respectively, versus 16 months and 25 months, respectively, for those without TP53 mutations and 25 months and >4 years, respectively, for those without p53 overexpression. The percentage of patients in this series with TP53 mutations (37.9%) was substantially higher than in previous studies of childhood gliomas and comparable to the frequency of mutations noted in adult gliomas. However, both TP53 mutation and p53 overexpression were significantly less frequent in tumors from children younger than 4 than from older children (P = 0.02 and 0.01, respectively). These results indicate that p53 mutation and expression status may be associated with prognosis in childhood malignant gliomas, and thus may provide a basis for stratifying patients biologically in future malignant glioma studies.

Adolescent↗

PubMed1997

Mutated p53 gene is an independent adverse predictor of survival in colon carcinoma.

OBJECTIVE: To evaluate the impact of p53 gene mutations on long-term survival in patients with intermediate stage carcinoma of the colon. DESIGN: Retrospective cohort study; median follow-up of 87 months. SETTING: Tertiary care academic medical center. PATIENTS: Mutational analysis was conducted in a single institution in 141 consecutive patients with resected stage II (n = 71) and stage III (n = 70) colon carcinoma. Archival pathology specimens were analyzed for point mutations of exons from the p53 gene by means of amplification and direct sequencing by polymerase chain reaction. MAIN OUTCOME MEASURES: The impact of p53 mutations and of adverse histopathologic features (i.e., poor differentiation, lymphovascular invasion, or mucin production) on patient survival. RESULTS: Median overall survival was 64 months (95 months for patients with stage II and 34 months for patients with stage III colon carcinoma; P = .001). Presence of a p53 mutation was the single most important risk factor associated with poorer survival in both patients with stage II (P = .02) and stage III colon carcinoma (P = .006) throughout the follow-up period. A p53 mutation increased the risk of death by 2.82 times in patients with stage II and by 2.39 times in patients with stage III colon carcinoma. There was an additive effect on the cumulative risk of death between p53 mutations and adverse histopathologic variables. CONCLUSIONS: The presence of p53 mutations carries an independent adverse prognostic value in colon cancer. These findings imply that the applicability of mutational analysis in clinical practice is likely to affect therapeutic choices in the future.

Adult↗

PubMed1997

Extracellular matrix expression in metastasizing and nonmetastasizing adenocarcinomas of the lung.

Alterations in extracellular matrix, cell-cell and cell-matrix adhesion, and oncogenes are thought to be important in tumor progression and metastasis. Adenocarcinomas of the lung from 31 patients were studied for immunohistochemical expression of basement membrane molecule type IV collagen, type IV collagenase, and integrins alpha2,3,v adhesion molecules to assess their diagnostic and prognostic importance in pathological stage T2 tumors. The results indicate that with decreasing tumor differentiation, there is a progressive loss of type IV basement membrane collagen (P = .06) and decreased integrin alpha2 expression (P = .03). Type IV collagenase expression was significantly associated with the presence of lymph node metastases, with moderate to strong expression present in 53% T2N1 tumors compared with none (0%) of the T2N0 tumors (P = .008). Integrin alpha(v) was increased in tumors with nodal metastases compared with those without (P = .08). Loss of alpha2 and alpha3 integrins was associated with increased alpha v expression (P = .03). Median survival was 48 months for T2N0 and 20 months for T2N1 (P = .07). In correlating expression of the immunohistochemical markers and survival, type IV collagenase expression was found to be a predictor of survival at a level of P = .07. Measurable alterations in integrins and extracellular matrix, and in particular, expression of matrix-degrading enzyme type IV collagenase may be of prognostic importance in resectable adenocarcinoma of the lung.

Adenocarcinoma↗

PubMed1997

Granulomatous hepatitis in a patient with chronic hepatitis C treated with interferon-alpha.

Common adverse effects of IFN-alpha include flulike symptoms, headache, irritability, and bone marrow suppression. Hepatic side effects are unusual except in patients with pretreatment autoimmune hepatitis. Granuloma formation in the liver as a result of IFN-alpha therapy has never been reported. We described a 48-year-old female with chronic hepatitis C infection who developed granulomatous hepatitis following treatment with IFN-alpha. The granulomatous inflammation resolved after discontinuation of IFN-alpha treatment. Possible mechanisms for this unusual occurrence are discussed.

Antiviral Agents↗

PubMed1997

The origin and molecular characterization of adenoid basal carcinoma of the uterine cervix.

Five cases of adenoid basal carcinoma (ABC) of the uterine cervix were examined for the presence of p53 tumor suppressor gene, K-ras-2 oncogene, and human papillomavirus (HPV). A topographic genotyping approach was used to search for point mutations in K-ras-2 (exon 1 and 2) and p53 (exons 5 to 8) in archival formalin-fixed tissue blocks. Minute target sites were selected from polymerase chain reaction (PCR) amplified and directly sequenced tissue sections. Tissue sections were additionally subjected to immunohistochemical staining for p53 and WAF-1 protein. Because wild type p53 induces WAF-1 gene expression, immunohistochemical staining for WAF-1 protein using monoclonal antibodies may serve as an indirect means to test for p53 mutational damage. Mutational genotype was compared to histopathologic features and immunohistochemical staining. To study the role of HPV, L1 region consensus primers were used to amplify topographic samples, followed by HPV genotyping by direct sequencing and comparison to known viral strains. ABC was found to contain HPV in all cases, proven by genotyping to be HPV type 16 in each case. The virus showed no evidence of genomic variation from prototype HPV type 16 in the L1 segment examined. No K-ras-2 point mutations were identified. p53 immunopositivity was present in all tumors, being weak and focal in 4 and strong and diffuse in 1. WAF-1 immunostaining was positive in two tumors showing weak focal p53 immunopositivity. The single strong and diffuse p53 immunopositive tumor was negative for WAF-1 and was shown to contain a missense p53 point mutation (exon 7-codon 248 tryptophan). In conclusion, ABC is characterized by the presence of HPV type 16. K-ras-2 point mutation appears to play no role in the development of this tumor. p53 gene alterations are common including wild type hyperexpression (weak focal p53 immunopositivity, WAF-1 positivity, no mutational change) and p53 point mutational damage.

Adult↗

PubMed1997

Prognostic value of p53 and K-ras-2 topographic genotyping in endometrial carcinoma: a clinicopathologic and molecular comparison.

The predictive value of p53 and K-ras-2 mutational genotyping in determining tumor aggressiveness and survival in patients with endometrial carcinoma (EC) was retrospectively evaluated using a molecular genotyping approach on fixative treated tissue specimens. Two groups of patients with EC were selected based upon length of survival. Group A consisted of 14 patients that died within 3 years of initial diagnosis and treatment (mean survival of 1.1 years). Group B consisted of 18 patients that survived beyond 3 years (mean survival of 4.7 years). Clinicopathologic features including clinical stage, histologic type, and combined nuclear and architectural grade of each tumor were statistically analyzed with respect to oncogene/tumor suppressor gene alterations. The majority of carcinomas in group A were serous (57%), stage III or IV (93%), and high combined grade (93%). Group B consisted mostly of endometrioid (89%) and low-grade carcinomas (83%); 56.1% were stage III or IV. K-ras-2 point alterations were found in 2 (14%) and 4 (22%) patients from group A and B respectively; the spectrum of K-ras-2 genotypes was similar in both groups. p53 gene mutations were identified in 9 (64%) and 1 (6%) patient from group A and B respectively. p53 staining in group A tended to be of strong intensity and diffuse distribution, being associated with the presence of point mutations, mainly in exon 8. Only a single group B tumor exhibited point mutational change. The presence of p53 mutations strongly correlated with short survival (p <0.05) but the finding of K-ras-2 alterations did not. p53 genotyping has potential prognostic value in EC and can be used along with histopathologic type and histologic grade to identify subsets of more aggressive tumors and to guide the treatment.

Adenocarcinoma↗

PubMed1997

Sporadic and Thorotrast-induced angiosarcomas of the liver manifest frequent and multiple point mutations in K-ras-2.

Hepatic angiosarcoma (HA) is an uncommon neoplasm associated with known etiologic factors in 25% to 42% of cases. It is, however, one of the most common sarcomas found in the liver. The aim of this study was to find was to find mutations in the K-ras-2 oncogene in sporadic and Thorotrast (TT)-induced HA. Point mutations in K-ras-2 were sought in archival, formalin-fixed tissue blocks from 24 patients with angiosarcoma. Of these, 19 cases were sporadic and 5 were TT-induced. Mutational analysis was performed by topographic microdissection with PCR amplification followed by genotyping. Specific mutations were determined by two independent methods: (a) direct sequencing of the PCR product confirmed by rePCR and by using a different sequencing primer, and (b) PCR-based selective enrichment of mutant DNA by endonuclease digestion followed by heteroduplex DNA analysis using denaturing gradient gel electrophoresis. Eleven K-ras-2 point mutations were detected in 7 of 24 (29%) tumors, including 5 of 19 (26%) sporadic HA and 2 of 5 (40%) TT-induced HA. There were seven G:C > A:T and four G:C > T:A mutations. All seven mutated tumors contained a codon 12-aspartate amino acid substitution. In addition, a second codon 12-cysteine mutant cell population was present in one of two codon 12-aspartate mutated TT-induced HA and in three of five codon 12-aspartate sporadic tumors. Of these four tumors, three contained both aspartate and cysteine mutations and were composed of multiple nodules; the fourth was a single mass. Seventeen tumors had multiple nodules; whereas 5 had a K-ras-2 mutation, 12 were wild-type. The molecular pathology of both sporadic and TT-induced HA is characterized by a high rate of K-ras-2 mutations characteristic of oxidative damage (ie, G:C > A:T and G:C > T:A mutations) resulting in two mutated population sets: codon 12 GGT > GAT and GGT > TGT (glycine to aspartic acid and cysteine). This is, to date, the first study to characterize the K-ras-2 gene mutations within human sporadic and TT-induced HA by direct sequence analysis and denaturing gradient gel electrophoresis. These data further support the hypothesis linking adduct-forming vinyl chloride exposure to HA containing a much higher frequency of K-ras-2 mutations and a mutational spectrum characteristic of chloroethylene oxide, a carcinogenic metabolite of vinyl chloride.

Adult↗

PubMed1997

Osteoma of the base of the tongue.

A 14-year-old girl developed a firm mass at the base of the tongue. Computed tomography indicated marked density suggesting either a foreign body or bony tissue. A thyroid scan confirmed the presence of a normally sized and positioned gland. The mass was removed in toto and found to be an osteoma. This is the first report of a case in which the diagnosis of this rare developmental lesion of the tongue was achieved preoperatively based on clinical and radiologic information. This experience should lead to greater awareness of this entity in the future. Recognition of this entity in the pediatric age group is especially useful in avoiding misdiagnosis of other, potentially more aggressive types of tongue mass lesions. Our case demonstrates that it is possible to detect this entity using computed tomography. The dense calcification is truly characteristic of the tumor and may be relied upon to exclude alternative soft tissue mass lesions. While other forms of osseous and cartilagenous neoplasms, such as extraskeletal osteosarcoma and chondrosarcoma, have been reported arising in the tongue, their malignant nature should otherwise be readily apparent. Osteoma of the tongue is the favored diagnosis when mature bone tissue is imaged at the base of the tongue.

Adolescent↗

PubMed1996

Morphologic, histologic, and molecular similarities between adenocarcinomas arising in the gastric stump and the intact stomach.

BACKGROUND: Patients with gastric remnants resulting from partial resections have an increased risk for carcinoma. It is unclear whether adenocarcinoma arising in the gastric stump (GSca) differs from intact stomach carcinoma (Gca). The goal of this study was to examine the pathologic and molecular features of GSca and compare them with Gca. METHODS: Adjacent nonmalignant areas and tumors from 14 patients who were 19-55 years postgastrectomy (mean, 32.1 years) were compared with 14 Gca by pathologic and molecular analysis. Formalin fixed, paraffin embedded specimens were immunohistochemically stained for p53 followed by topographic genotyping. Exons 5-8 were amplified by the polymerase chain reaction and directly sequenced. RESULTS: No differences were noted between the two groups regarding gender, types of metaplasia, dysplasia, morphology, or histologic tumor type. However, a higher incidence of cystic dilatation and foveolar hyperplasia were present in GSca. p53 gene point mutations occurred in 5 of 14 (35.7%) GSca patients. GSca p53 mutations included missense point mutations (G:A transitions in four patients and G:C transversion in one patient) with allelic loss. In four of the five patients with p53 mutations, the same mutation was also observed in the adjacent area. p53 point mutations were present in 4 of 14 Gca (28.6%), in exons 5, 6, and 8. In one case, the same mutation was also detected in the adjacent nonmalignant mucosa. CONCLUSIONS: Similarities in clinical, pathologic, and molecular features between GSca and Gca suggest the possibility that they share similar mechanisms of carcinogenesis. p53 gene alterations in premalignant areas may denote a possible early role of this gene in gastric carcinoma.

Adenocarcinoma↗

PubMed1996

Effects of lambda-carrageenan induced experimental enterocolitis on splenocyte function and nitric oxide production.

A lambda-carrageenan induced rat model of inflammatory bowel disease (IBD) allowed evaluation of progressive histopathological changes over time and comparison with human disease. In addition, this model was used to test the hypothesis that the immunosuppression observed in IBD may be mediated in part by augmented production of nitric oxide by splenic lymphocytes. Male Sprague-Dawley rats were fed standard rat chow and a drinking solution of 2% lambda-carrageenan without prior sensitization to the compound. At 2, 4, 6, and 8 weeks, small and large intestines were removed for histological examination, and splenocytes were assayed for response to various mitogens and for nitrite production. Intestinal lesions gradually developed in lambda-carrageenan fed rats and were found to be morphologically similar to those observed in human ulcerative colitis. The proliferative response of splenocytes to known mitogens was significantly diminished in carrageenan fed rats, when compared with pair-fed controls, but was fully restored when cultured in the presence of NG-monomethyl-L-arginine, a specific inhibitor of nitric oxide synthase. Preliminary data suggest that overproduction of nitric oxide may provide a molecular mechanism for the immunosuppression observed during chronic inflammatory bowel disease. Further characterization of a reproducible rat model of IBD will allow further investigation into the pathogenesis of the human disease.

Animals↗