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Biomedical subjects

G L Clayman

Publications and source records attributed to G L Clayman.

At least 73 records · Page 4Linked to original sources
PubMed1996

Microsatellite instability in preinvasive and invasive head and neck squamous carcinoma.

To investigate the extent and significance of microsatellite instability in head and neck carcinogenesis we analyzed DNA extracted from normal squamous epithelium, severe dysplasia, and corresponding carcinoma specimens from 20 patients by multiplex polymerase chain reaction. Loci on chromosomes 3p, 5p, 5q, 8p, 9p, 9q, 11q, 17p, 17q, 18p, 18q were selected for analysis. Our results show that three of the dysplasias (15.0%) and six of the invasive carcinoma (30.0%) manifested instability at multiple loci. Two of the dysplastic lesions had identical alterations in the corresponding carcinomas and one showed instability differences in only two of eight loci. Normal squamous epithelium lacked microsatellite instability. No apparent association between smoking, alcohol use, or family history of cancer and instability was found in this small cohort. Invasive carcinomas with instability were relatively more poorly differentiated and had a higher stage and a high proliferative fraction. Our study indicates that microsatellite instability is 1) noted in a small subset of dysplastic lesions of head and neck squamous epithelium and 2) present in approximately one-third of invasive lesions, usually with aggressive characteristics, and may clinically be a late event associated with tumor progression.

Aged↗
PubMed1996

Evaluation of topical gene therapy for head and neck squamous cell carcinoma in an organotypic model.

The organotypic (raft) culture system has been shown to be a useful model for examining the effects of biochemical manipulations on various epithelial cell types, using in vitro conditions that simulate the in vivo environment of the tissue of origin. To investigate this method as a model for topical gene therapy, we cultured the oral head and neck squamous cell carcinoma cell line TR146 on fibroblast-containing collagen gels at the air-medium interface and assessed the efficiency of transduction of a topically applied adenoviral vector containing beta-galactosidase cDNA. Diffuse expression of -galactosidase activity in multiple cell layers demonstrated effective penetration of the vector. Transduction efficiency and therapeutic activity of a replication-defective recombinant adenovirus containing wild-type p53 cDNA linked to a FLAG marker (AdCMV-p53-FLAG) were then assessed in TR146 organotypic cultures transduced by topical application. Twenty-four, 48, and 72 h after transduction, the cultures were harvested, and residual cell number and FLAG peptide expression were determined. The number of cells in p53 transduced cultures was significantly reduced in comparison to controls at all three time points (P < 0.001), which resulted from the induction of apoptosis as determined by in situ DNA end labeling. In addition, the FLAG peptide was expressed diffusely in the residual cells, further confirming effective transduction and expression of the exogenous gene products throughout multiple layers. We conclude that the organotypic culture is an effective in vitro model for assessing the efficacy of topically applied gene therapy on head and neck squamous carcinomas and premalignancies.

Adenoviridae↗
PubMed1995

p53 mutations in nonmelanoma skin cancer of the head and neck: molecular evidence for field cancerization.

Multiple and distinct p53 mutations were detected by DNA sequence analysis in tumor and adjacent nonmalignant skin samples from eight patients with nonmelanoma skin cancer of the head and neck, providing unambiguous evidence for field cancerization. The mutations consisted of C-->T transitions at dipyrimidine sequences (30% of all single base substitutions), T-->C transitions (47%), and G-->T transversions (12%), suggesting that other carcinogens may act along with UV radiation in the development of nonmelanoma skin cancer. Patient interviews revealed that, in addition to substantial exposure to solar UV radiation, most had a history of smoking and were exposed to carcinogens from industrial or agricultural sources. These data show that extensive molecular epidemiological investigations are necessary to elucidate risk factors associated with the disease in localities where patients often report substantial exposure to environmental carcinogens.

Adult↗
PubMed1995

Apoptosis induction mediated by wild-type p53 adenoviral gene transfer in squamous cell carcinoma of the head and neck.

Cancer gene therapy strategies for inducing apoptosis in solid tumors may allow contemporary medicine to reassess its management of these cancers. We demonstrated previously that overexpression of the wild-type p53 gene in squamous cell carcinoma of the head and neck cell lines via adenovirus-mediated gene transfer suppressed growth both in vitro and in vivo. Here, we characterize the mechanism of the growth suppression by the exogenous p53 gene as a consequence of programmed cell death (apoptosis). One of the cell lines used in this study, Tu-138, harbors a mutated p53 gene, whereas the other cell line, MDA 686LN, possesses a wild-type p53 gene. DNA fragmentation was detected by electrophoresis in both cell lines after infection with the wild-type p53 adenovirus, Ad5CMV-p53. With the use of the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling method, 4.4% of the remaining viable Tu-138 cell population was identified as apoptotic as early as 15 h after inoculation with Ad5CMV-p53. The percentage of apoptotic cells increased to 31% at 22 h. In contrast, only 10% of the viable MDA 686LN cells (wt-p53) had undergone apoptosis 30 h after Ad5CMV-p53 infection, although the percentage of apoptotic cells rapidly increased to 60% at 48 h after infection. For in vivo analysis of apoptosis, nude mice in which squamous cell carcinoma of the head and neck cell lines had been implanted s.c. had exogenous wt-p53 transiently introduced to the tumor cells via Ad5CMV-p53 2 days later. In situ end labeling clearly illustrated apoptosis in the tumor cells. These results suggest that wt-p53 plays an important role in the induction of apoptosis in human head and neck cancer cell lines and that selective induction of apoptosis in cancer cells can be further explored as a strategy for cancer gene therapy.

Adenoviridae↗
PubMed1995

Expression of basic fibroblast growth factor in squamous cell carcinoma of the head and neck is associated with degree of histologic differentiation.

Basic fibroblast growth factor (bFGF) is a potent nitogen and angiogenic protein that may function as an autocrine growth regulator in a variety of malignancies. Expression of bFGF in squamous cell carcinoma of the head and neck (SCCHN) was characterized by Western blot and immunohistochemical analyses. We found that the levels of bFGF in tumors were the same or reduced relative to non-malignant adjacent mucosa. Reverse transcription-polymerase chain reaction and Southern blot transfer of mRNA derived from 7 SCCHN cell lines showed that the IIIb isoform of FGF-receptor 2 (FGFR2) was expressed at high levels, whereas the IIIc isoform and FGFRI were weakly expressed or not detected. No correlation was observed between levels of bFGF revealed by immunohistochemical staining and vascular counts in frozen sections derived from 11 different SCCHN tumors. Immunohistochemical analysis demonstrated that all differentiated tumors exhibited high levels of bFGF immunoreactivity, while all poorly differentiated tumors exhibited low to nondetectable levels. This expression pattern is consistent with that observed in non-tumoral mucosa and suggests that other angiogenic factors must play a predominant role in the development of poorly differentiated SCCHN.

Antibodies, Monoclonal↗
PubMed1995

In vivo molecular therapy with p53 adenovirus for microscopic residual head and neck squamous carcinoma.

Developing gene therapy strategies may allow contemporary medicine to reassess its management of solid malignancies. We have demonstrated previously that the wild-type p53 adenovirus (Ad5CMV-p53) suppressed the growth of established tumors of the head and neck. In this paper we develop a microscopic residual model which mimics the postsurgical environment of head and neck cancer patients with advanced disease. Using this squamous cell carcinoma of the head and neck model, we prevented the establishment of tumors in nude mice in which tumor cells had been s.c. implanted by transiently introducing exogenous wild-type p53 via an adenoviral vector 2 days following tumor cell implantation. These effects were vector dose dependent but independent on the endogenous wild-type or mutated p53 status of the cells. Importantly, karyotypically normal and nontumorigenic fibroblast cell lines are inert to the p53 adenovirus treatment. These results pave the ground work for further development of molecular therapy for head and neck cancer and other solid malignancies.

Adenoviridae↗
PubMed1995

Laryngeal preservation for advanced laryngeal and hypopharyngeal cancers.

OBJECTIVE: To compare a single institutional experience with combination chemotherapy and radiation for laryngeal preservation with historical age-, sex-, stage-, and site-matched controls who underwent laryngectomy for cancer of the larynx or hypopharynx. DESIGN: Fifty-five patients with stage III or IV laryngeal and hypopharyngeal squamous carcinoma were prospectively entered into a protocol to receive three cycles of cisplatin (+/- bleomycin sulfate) and fluorouracil and radiation therapy from 1986 to 1991 (group 1). Following two cycles of chemotherapy, the clinical tumor response was assessed and responders received a third cycle of chemotherapy followed by definitive radiation therapy. Nonresponders underwent surgical salvage. Two patients in the surgical control group were matched to each protocol patient (n = 110, group 2) regarding site, stage, sex, and age (+/- 7 years) without knowledge of patient outcome. SETTING: A tertiary cancer referral center, The University of Texas M. D. Anderson Cancer Center, Houston. RESULTS: Following chemotherapy, the tumor response rate for group 1 was complete in 38% and partial in 31%. With a median follow-up of 24 months (group 1) and 37 months (group 2), the Kaplan-Meier 2-year disease-specific survival for group 1 and 2 was 63% and 74%, respectively (P = .251). Among group 1 patients, 67% retained their larynges. Local recurrences were more frequent among the laryngeal preservation group (P = .001), whereas distant metastasis was more frequent among controls (P = .35). Thirty-three percent (18/55) of group 1 patients required total laryngectomy. Examining these subsets of patients showed that of the 67% (n = 37) of patients who retained their larynges, their 2-year survival was 56%, not significantly different from their respective controls (n = 74), 71%. Additionally, 2-year survival among the 18 group 1 patients who required salvage laryngectomy was 75% as compared with 80% for their matched controls (n = 36). CONCLUSIONS: These results document the results of chemotherapy and radiation therapy in the treatment of patients with advanced laryngeal and hypopharyngeal cancers in preserving the larynx. Although local control is significantly compromised among these patients, there is no compromise in overall survival when combined with prompt surgical salvage.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Outcome and complications of extended cranial-base resection requiring microvascular free-tissue transfer.

OBJECTIVES: To determine the complications of extensive cranial-base resection requiring free-tissue transfer (FTT) and the effect of these resections on local control and survival among patients with malignant neoplasms of the skull base. BACKGROUND: Before the advent of FTT, cranial-base surgery was often limited by our inability to adequately repair defects comprising communication between the central nervous system and upper aerodigestive tract. The use of FTT in cranial-base resections was therefore assessed to determine whether the improved procedure (ie, extensive resections) would improve local control and prolong survival. DESIGN: A retrospective review of 39 consecutive craniofacial resections with FTT reconstruction in patients with malignant neoplasms involving the cranial base. PATIENTS: All 39 patients had malignant neoplasms, including 20 squamous cell carcinomas, eight basal cell carcinomas, two melanomas, two neuroendocrine carcinomas, two adenoid cystic carcinomas, and various other malignant neoplasms. Resections involved the anterior, middle, or posterior cranial fossa in 19 patients (49%), 10 patients (26%), and three patients (8%) of cases, respectively. The remaining seven surgeries (18%) involved resection of more than one of these cranial base sites. RESULTS: Early (< 14 days after surgery) complications occurred in 14 (36%) of 39 patients. Major complications included failure of microvascular anastomosis (n = 1), pneumonitis (n = 3), perioperative myocardial infarction (n = 1), and cerebrovascular accident (n = 1). The microvascular anastomosis failure was promptly treated with surgical intervention. Two patients (5%) experienced late postoperative complications; one had cellulitis at the donor site, and the other had pneumonitis. No perioperative deaths or complications such as meningitis, epidural abscess, or tension pneumocephalus occurred. The 2-year disease-specific survival rate was 55%, and the 2-year local control rate, 49%; both were determined by the Kaplan-Meier method. The nine patients who died of their disease had a median survival of 9 months. Log-rank testing showed that pathologically positive margins and transdural pathology were the most significant predictors of local recurrence and death of disease. CONCLUSIONS: Contemporary surgical approaches provide an opportunity for wide surgical excision of dura and skull-base structures that normally separate the intracranial and extracranial cavities. These major skull-base resections can be reconstructed safely and effectively with FTT. Patients with malignant neoplasms of the dura and skull base should be approached with the understanding that transdural disease portends an increased risk of local recurrence and death of disease.

Adolescent↗
PubMed1995

HER-2/neu oncogene characterization in head and neck squamous cell carcinoma.

OBJECTIVE: To characterize the HER-2/neu oncogene in head and neck squamous cell carcinoma (HNSCC) cell lines and tumor tissue specimens. DESIGN: Molecular analysis of HER-2/neu oncogene amplification and expression in HNSCC cell lines by Southern, Northern, and Western blot techniques, and HER-2/neu oncoprotein expression in HNSCC tumor tissue sections by immunohistochemical analysis. SPECIMENS: Eleven HNSCC cell lines, eight paired samples of frozen HNSCC tumor tissue specimens and adjacent nonmalignant mucosa, and 38 paraffin-embedded slides derived from HNSCC tumor specimens (including those from which the cell lines were derived) were analyzed. RESULTS: Southern blot analysis showed twofold HER-2/neu gene amplification in two (18%) of the 11 HNSCC cell lines, MDA-1386 and Tu-167. Northern blot analysis showed messenger RNA overexpression in the same two cell lines, and to a lesser degree in MDA-1483. Western blot analysis showed high levels of HER-2/neu oncoprotein expression in two (18%) of the 11 cell lines (MDA-1386 and Tu-167), a moderate level of protein expression in one cell line (9%) (MDA-1483), and low levels of protein expression in eight cell lines (73%). Some HER-2/neu protein expression was seen in all of the HNSCC cell lines. Immunohistochemical analysis of the tumor tissue sections from which the cell lines were derived corroborated the Western blot results. Western blot analysis of frozen primary tumor specimens showed HER-2/neu oncoprotein overexpression in two (25%) of eight specimens. Immunohistochemical analysis showed high levels of protein expression in six (16%) of the 38 tumor tissue slides, moderate levels in 12 (31%), and low levels in 20 (53%). CONCLUSIONS: The HER-2/neu oncogene is overexpressed in a subset of HNSCC tumors and cell lines. The results from Western blot and immunohistochemical analyses underscore a variable HER2/neu oncoprotein expression in HNSCC. Gene amplification was observed in a few of the cell lines, suggesting a potential mechanism of oncoprotein overexpression. Messenger RNA overexpression, however, can be seen in the absence of gene amplification, indicating that transcriptional or posttranscriptional control mechanisms must be involved. Further studies are indicated to determine the biologic role of HER-2/neu expression in the clinical progression of these lesions and to further define the molecular basis regulating its expression.

Aged↗
PubMed1995

Glutathione s-transferase genotypes as risk factors for head and neck cancer.

BACKGROUND: Several enzymatic systems, including glutathione S-transferases, are involved in the metabolism of environmental agents. The absence of glutathione S-transferases mu (GSTM1) and theta (GSTT1) results in decreased detoxification of carcinogens, for example, chemicals in cigarette smoke. These metabolic deficiencies may predispose individuals to the development of smoking-related tumors, such as cancers of the lung, head and neck, and bladder. METHODS: The glutathione S-transferase genotypes of 186 previously untreated patients with squamous cell carcinoma of the head and neck and 42 healthy controls were determined with polymerase chain reaction (PCR) methodologies. Lymphocytes separated from heparinized peripheral blood or whole blood extracts served as sources of genomic DNA. The presence or absence of the gene-specific PCR products revealed the positive or negative genotypes, respectively. RESULTS: The absence of the GSTM1 genotype conferred an odds ratio of 2.37, and the 95% confidence interval (CI) was 1.20 to 4.67. The absence of the GSTT1 gene conferred an odds ratio of 1.47 (CI 0.71 to 3.02). In the population of 42 patients and their matched 42 controls, the absence of the GSTM1 and GSTT1 genotypes conferred odds ratios of 3.10 (CI 1.24 to 7.75) and 2.18 (CI 0.91 to 5.23), respectively. CONCLUSIONS: Despite the small study size, our preliminary data suggest that genetically determined factors of carcinogen metabolism may be associated with increased risk for head and neck cancer.

Base Composition↗
PubMed1995

Screening at a health fair to identify subjects for an oral leukoplakia chemoprevention trial.

Screening examinations were conducted at a Chinese community health fair in Houston, Texas, to identify individuals with oral leukoplakia for a chemoprevention trial of oral-cavity squamous cell carcinoma. All 161 volunteer participants were interviewed regarding age, smoking habits, and betel-nut and alcohol use. The screening included an examination of the oral cavity, oropharynx, and neck. One participant had a 1-mm area of oral leukoplakia on the right lateral surface of the oral tongue. Eighteen participants had other head and neck abnormalities. Only 12 participants (7.5%) were active smokers, and eight (5%) reported a prior history of smoking. One participant reported prior betel-nut use. The mean age was 55 years. The authors conclude that a venue such as this has a low yield for screening and recruitment of high-risk individuals for chemoprevention of oral-cavity squamous cell carcinoma, that generally health-conscious individuals attend health fairs, and that only a small percentage volunteer for oral screening.

Adult↗
PubMed1995

Transduction of normal and malignant oral epithelium by an adenovirus vector: the effect of dose and treatment time on transduction efficiency and tissue penetration.

We tested an adenovirus vector that carries a beta-D-galactosidase marker gene for its ability to transduce normal oral mucosa and oral carcinoma cells. Topical application of adenovirus to normal oral mucosa of mice at 1 x 10(10) plaque-forming units (pfu)/mL for 1 minute did not result in transduction of epithelial cells. Similarly, topical application to human oral mucosa ex vivo was not successful. However, systemic administration by intracardiac injection of hamsters did transduce normal oral mucosa effectively. To evaluate transduction of carcinomas, the Tu138 human oral cancer cell line was used. A single application of virus at 1 x 10(8) pfu/mL in vitro resulted in 30% of oral carcinoma cells expressing the marker gene, and 2 x 10(8) pfu/mL transduced 60% of cells. After two applications of virus at 2 x 10(8) pfu/mL with an interval of 18 hours, 100% of oral carcinoma cells expressed the marker gene. Topical application to a raft culture of Tu138 cells for 1 hour produced gene expression that penetrated up to four layers of cells. To emulate the effect of treating a carcinoma, Tu138 cells were implanted subcutaneously in nude mice, allowed to grow to a tumor 1 cm in diameter, and then injected directly with virus. This produced diffuse transduction of around 30% of cells in the tumor, and expression was seen in cells at a significant distance from the injection site. Adenovirus vectors are therefore capable of transferring novel genetic information to both normal and malignant oral mucosa. They may have potential for use in gene therapy in the prevention or treatment of oral squamous carcinomas.

Adenoviruses, Human↗
PubMed1994

Growth suppression of human head and neck cancer cells by the introduction of a wild-type p53 gene via a recombinant adenovirus.

Mutations of the p53 gene constitute one of the most frequent genetic alterations in squamous cell carcinoma of the head and neck (SCCHN). In this study, we introduced wild-type p53 into two separate SCCHN cell lines via a recombinant adenoviral vector, Ad5CMV-p53. Northern blotting showed that following infection by the wild-type p53 adenovirus (Ad5CMV-p53), cells produced up to 10-fold higher levels of exogenous p53 mRNA than cells treated with vector only (without p53). Western blotting showed that the increased levels of p53 protein produced in the Ad5CMV-p53-infected cells were a reflection of p53 mRNA expression. In vitro growth assays revealed growth arrest following Ad5CMV-p53 infection as well as cell morphological changes consistent with apoptosis. In vivo studies in nude mice with established s.c. squamous carcinoma nodules showed that tumor volumes were significantly reduced in mice that received peritumoral infiltration of Ad5CMV-p53. These data suggest that Ad5CMV-p53 may be further developed as a potential novel therapeutic agent for SCCHN since introduction of wild-type p53 into SCCHN cell lines attenuates their replication and tumor growth.

Adenoviridae↗
PubMed1994

Human papillomavirus in laryngeal and hypopharyngeal carcinomas. Relationship to survival.

OBJECTIVE: To determine the relationship between human papillomavirus (HPV) DNA detection in upper aerodigestive tract malignancies and patient outcome. DESIGN: Archival paraffin-embedded specimens from 78 previously untreated patients with squamous carcinomas of the larynx and hypopharynx were pathologically verified and analyzed by polymerase chain reaction for detection of HPV DNA. Charts were independently reviewed and coded until final analysis. SETTING: The University of Texas M. D. Anderson Cancer Center, Houston, a tertiary cancer referral center. RESULTS: DNA was successfully extracted from 65 archival patient samples (83%). The mean (+/- SEM) duration of follow-up for these patients was 42 +/- 21 months. Thirty specimens (46%) exhibited detectable HPV DNA. Detection of HPV was significantly related to decreased survival, independent of disease stage. Log rank testing revealed that HPV detection, pathologic vascular invasion, and nodal status were the most significant predictors of death of disease. CONCLUSIONS: Laryngeal and hypopharyngeal carcinomas with detectable HPV may represent a biologically distinct subset of tumors that carry a poorer prognosis than do cancers with no detectable HPV.

Adult↗
PubMed1994

Keratinocyte transglutaminase expression varies in squamous cell carcinomas.

Type I transglutaminase (TGase I, keratinocyte or particulate transglutaminase) is a 92-kilodalton (kDa) protein expressed in abundance in cultured keratinocytes and in the hyperproliferative skin disorder psoriasis. To determine the expression of TGase I protein and mRNA, we studied tissue and established squamous carcinoma lines derived from different sources. Immunohistochemistry and Western blotting were used to detect TGase I protein with the B.C1 mouse monoclonal antibody. Only well-differentiated, skin-derived squamous carcinomas stained for TGase I. However, a precocious pattern of expression was seen overlying less-differentiated tumors. Compared to cultured human keratinocytes, squamous cell carcinoma (SCC) had many times less to 7.8 times more TGase I protein, greatest in the two most differentiated tumor lines 14-83 and ME-180. TGase I mRNA levels ranged from 0.010 to 0.00004 pg/microgram total RNA by reverse transcriptase-polymerase chain reaction using an internal standard. Protein expression correlated with mRNA levels in most SCC lines. When a human TGase I promoter was isolated and used to study genomic DNA, SCC1-83 was shown to have unique restriction enzyme fragments, including one indicative of methylation differences, also present within DNA from the KB line. These studies suggest that transcriptional control of TGase I gene expression in squamous carcinomas may be influenced both by cis elements in the promoter and by the degree of tumor squamous differentiation.

Alleles↗
PubMed1993

Serologic determinants of survival in patients with head and neck cancer: validating a clinical prediction model.

Quantitative measurements of serum C1q-binding macromolecules (C1qBM) and immunoglobulin A (IgA) were done on 162 patients using previously described methodology. The measurements were compared to a previously described head and neck cancer population. Using the Cox Proportional Hazards model, the prognostic implications regarding high C1qBM and subsequent death with disease (P = .02), and regional recurrence (P = .0094) were validated, but not our previous IgA-related prognostic implications. When both study populations were combined, C1qBM was predictive of survival in those patients treated with induction chemotherapy (P = .0001). C1qBM was not a significant predictor of survival in patients treated with surgery plus postoperative radiation therapy in either this second "test" population or in the original "training" population. The findings demonstrate the confounding influence of treatment modalities and the importance of model validation.

Age Factors↗
PubMed1993

Serum and acute phase protein modulation of the effector phase of lymphokine-activated killer cells.

An understanding of the role that immunomodulatory factors play in the effector phase of lymphokine-activated killer (LAK) activity is essential for the development of biologic response modifiers for use in the treatment of advanced carcinoma. Fifteen head and neck cancer patients were studied. Single-donor killer cells activated by recombinant interleukin-2 (10 U/mL) and induced in either a complete medium or complete medium plus a 10% autologous serum solution were used. Effector phase solutions of 25% autologous serum were used in chromium 51 release assays to determine sera immunomodulation of LAK cell cytotoxicity. Both K562 and squamous carcinoma (MDA686-Ln) tumor cell lines were tested. Significant effector phase inhibition (EPI) of cytotoxicity occurred in 40% of studied patients. Seventy percent of patients with stage III or IV or recurrent disease exhibited EPI, whereas only 20% of patients with stage I or II disease and 30% of controls did so. EPI of cancer patient serum correlated directly with alpha 1-antitrypsin, alpha 1-acid glycoprotein, and C-reactive protein (CRP) levels (MDA686-Ln targets) (r = 0.6, 0.7, and 0.6, respectively) (P < .02). Neither EPI against K562 targets nor EPI in control patients correlated with acute phase protein levels. These findings suggest that advances in in vivo immunomodulatory therapy will be dependent upon further elucidation of serologic inhibition of the effector phase of the LAK cell phenomenon. The relationship between LAK cell recognition and EPI requires further investigation.

Acute-Phase Proteins↗