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Biomedical subjects

R N Baergen

Publications and source records attributed to R N Baergen.

At least 19 recordsLinked to original sources
PubMed2001

h-Caldesmon, a novel smooth muscle-specific antibody, distinguishes between cellular leiomyoma and endometrial stromal sarcoma.

The difficulty in distinguishing between smooth muscle and endometrial stromal-derived neoplasms of the uterine corpus is a notorious and clinically relevant problem in pathology of the female genital tract. Immunohistochemistry offers some aid in resolving this difficulty, because the expression of smooth muscle markers is reputed to indicate smooth muscle derivation. This expression, however, is not entirely specific, and difficult cases may still present in which immunohistochemistry is of little help. To explore this problem, the authors evaluated the expression of traditional muscle markers and high-molecular-weight caldesmon (h-cal), an actin and tropomyosin binding protein that has recently been described as a useful muscle marker, in uterine leiomyosarcoma (LMS), cellular leiomyomata (CL), and endometrial stromal sarcoma (ESS). Formalin-fixed and paraffin-embedded tissue sections from nine LMSs, 11 CLs, and 12 ESSs were evaluated with commercially available monoclonal antibodies against smooth muscle actin (SMA), desmin, and h-cal. Established morphologic criteria were used to classify the neoplasms. We found that there was, as expected, a significant difference in the expression of traditional smooth muscle markers (SMA and desmin) between tumors derived from smooth muscle and those derived from endometrial stroma (p = 0.005 for LMS and 0.013 for CL). We further found that h-cal was most useful in distinguishing between CL and ESS (p = 0.01). A significant difference between h-cal expression in LMS versus ESS was not found. Of note, one ESS expressed both SMA and desmin but lacked h-cal expression. Our findings confirm the most useful immunohistochemical data to date; smooth muscle neoplasms are generally distinguishable from endometrial stromal tumors by the expression of conventional muscle markers. We also report here that h-cal is useful more specifically in the differentiation of CL from ESS.

Actins↗
PubMed2001

Early uterine serous carcinoma: clonal origin of extrauterine disease.

Uterine serous carcinoma (USC) is an uncommon but aggressive type of endometrial carcinoma that is frequently associated with extrauterine disease despite minimal or no myometrial invasion. The origin of the extrauterine tumors in this setting remains controversial. The majority of USCs (90%) and endometrial intraepithelial carcinomas (78%), the putative precursor of USC, have p53 mutations, suggesting that p53 alterations occur early in the pathogenesis of USC. To determine if the extrauterine tumors associated with minimally invasive USC and endometrial intraepithelial carcinoma (EIC) represent metastases or multifocal primary tumors, we examined the mutational pattern of the p53 gene in 3 cases of minimally invasive USC and 1 case of EIC and in the corresponding extrauterine tumors associated with each of the cases. In all 4 cases, the primary tumors and the associated extrauterine tumor foci had identical p53 mutations. Our results support the premise that extrauterine serous tumors found in association with EIC or minimally invasive USC represent a unifocal process and thus are early metastases.

Abdominal Neoplasms↗
PubMed2000

Tumor suppressor gene, cell surface adhesion molecule, and multidrug resistance in Müllerian serous carcinomas: clinical divergence without immunophenotypic differences.

OBJECTIVES: We hypothesize that differences in the expression of selected tumor suppressor genes, cell surface adhesion molecules, and multidrug resistance glycoproteins could account for some of the reported differences between uterine serous carcinoma (USC) and extrauterine serous carcinomas (ESC), including ovarian and primary peritoneal carcinoma (OSC and PSC, respectively). METHODS: We studied the expression of the following antigens in 20 USCs, 20 OSCs, and 10 PSCs: p53 and mdm-2 (tumor suppressor genes), CD44 and CD44v6 (cell surface adhesion molecules), and the p-glycoprotein (a multidrug resistance protein recognized by two antibodies, C494 and JSB1). We further studied chemotherapeutic drug resistance by examining reports prepared using the Oncotech Extreme Drug Resistance Assay from 24 of the 50 study patients. Clinical data were obtained from medical record review. RESULTS: USC, OSC, and PSC patients were similar with respect to mean age at diagnosis, mean gravidity, mean parity, personal history of breast cancer, percentage treated with chemotherapy, and survival at 3 and 5 years postdiagnosis. Significant clinical differences included a high prevalence of nulliparity in OSC (P = 0.05), a low prevalence of Caucasian race in USC (P = 0.008), a paucity of stage I patients in OSC and PSC (P = 0.03), a high prevalence of familial breast cancer in OSC (P = 0.06), and superior 2-year survival in OSC (P = 0.02). Seventy-five percent of USCs, 52% of OSCs, and 60% of PSCs expressed p53. Five percent of USCs, 19% of OSCs, and 0% of PSCs expressed mdm-2. Forty percent of USCs, 33% of OSCs, and 10% of PSCs expressed CD44. None of the USCs, OSCs, or PSCs expressed CD44v6. Sixty-one percent of USCs and OSCs and 82% of PSCs expressed C494 while 17% of USCs, 19% of OSCs, and 20% of PSCs expressed JSB1. None of these apparent differences was statistically significant. USC, OSC, and PSCs patients did not demonstrate significant differences with respect to extreme drug resistance. However, the following trends were noted (P = 0.06): more prevalent low drug resistance for cyclophosphamide in OSC compared with USC and more prevalent extreme drug resistance for etoposide in OSC compared with USC. CONCLUSIONS: Therefore, despite significant clincial differences, the USCs and ESCs in our series do not differ significantly with respect to the expression of the tumor suppressor genes, cell surface adhesion molecules, and drug resistance proteins studied. It is premature, however, to recommend that USCs and ESCs should be treated identically.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2000

Cyclin D1 expression in high-grade endometrial carcinomas--association with histologic subtype.

Endometrial endometrioid adenocarcinoma (EC) and serous carcinoma (ESC) are associated with different epidemiologic risk factors, precursor lesions, morphology, and survival outcomes. They also possess distinct molecular profiles. We investigated the expression of cyclin D1, a member of the G1 cyclin family that regulates the G1/S transition in the cell cycle, and estrogen and progesterone receptors (ERs and PRs, respectively) in a group of ECs and ESCs matched for histological grade. We also sought to correlate the expression of cyclin D1 with ER and PR because cyclin D1 has been reported to stimulate transcription of ER- and PR-regulated genes (1,2). We hypothesize that cyclin D1 expression covaries with histologic subtype and is related to the expression of ER and PR. Twenty ESCs and 21 ECs were examined histologically and evaluated immunohistochemically for cyclin D1, ER, and PR using commercially available monoclonal antibodies in archival, formalin-fixed, and paraffin-embedded tissue. Three ESCs (15%) and 10 ECs (48%) expressed cyclin D1 (p = 0.02). Twelve ESCs (60%) and 16 ECs (76%) expressed ER, which is not significantly different. ER-positive ECs were significantly more likely to express cyclin D1 compared with ER-positive ESCs (p = 0.03), but a relationship between cyclin D1 and ER expression in EC was not found. We also did not find a significant relationship between cyclin D1 and PR expression. Therefore, cyclin D1 expression in poorly differentiated endometrial carcinomas is associated with endometrioid histology. This is consistent with pathobiologic divergence in poorly differentiated endometrial carcinomas.

Adenocarcinoma↗
PubMed1999

B-lineage lymphoblastic lymphoma is a clinicopathologic entity distinct from other histologically similar aggressive lymphomas with blastic morphology.

BACKGROUND: The authors present clinical, histopathologic, and immunophenotypic data regarding B-lineage lymphoblastic lymphoma (B-LBL), a rare entity that has not been extensively studied. To emphasize some of its unique clinical characteristics, the authors compare B-LBL with a group of histologically similar, very aggressive lymphomas, T-lineage lymphoblastic lymphoma (T-LBL) and the blastoid variant of mantle cell lymphoma (BVMCL); all were evaluated concurrently. METHODS: Clinical data were obtained on 29 patients with very aggressive lymphomas (12 B-LBLs, 10 T-LBLs, and 7 BVMCLs) from whom paraffin-embedded material was available. The diagnoses were confirmed on review of the hematoxylin and eosin-stained slides and the immunophenotype data. RESULTS: The mean age of patients with B-LBL was 39 years. Patients presented with both lymph node and extranodal disease, although involvement of the mediastinum and bone marrow was infrequent. Four were Stage I, 3 were Stage II, 2 were Stage III, and 3 were Stage IV. B-LBL patients were treated primarily with cyclophosphamide, hydroxydaunomycin, vincristine, and prednisone (CHOP), and one patient underwent allogeneic bone marrow transplantation. The mean follow-up time was 30 months. Seven of 11 had no evidence of disease at 48 months, whereas 4 patients were dead of disease at 5.6 months. The overall median survival was 24 months. The clinical characteristics of B-LBL patients differed significantly from those of T-LBL patients; there was more frequent bone marrow and mediastinal involvement in T-LBL cases (P = 0.03 and 0.04, respectively). T-LBL patients were also less likely to achieve a complete remission than B-LBL patients (P = 0.02). The mean age of BVMCL patients significantly exceeded that of B-LBL patients (P = 0.03). CONCLUSIONS: The authors believe that the distinction of B-LBL from its histologic mimics, T-LBL and BVMCL, has important clinical implications. Patients with B-LBL present differently from those with the other very aggressive lymphomas studied, and they achieve complete remissions more often than T-LBL patients.

Adolescent↗
PubMed1999

Second-trimester molecular prenatal diagnosis of sporadic Apert syndrome following suspicious ultrasound findings.

Apert syndrome, an autosomal dominant disorder characterized by craniosynostosis, mid-facial malformations, symmetric bony syndactyly of hands and feet, and varying degrees of mental retardation, is most frequently caused by a de novo mutation. Two missense mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have been found to account for the disorder in approximately 98% of affected patients. Seven cases of prenatal ultrasound diagnosis have been reported. Although one earlier diagnosis has been made in a familial case, sporadic cases have not been definitively diagnosed until the third trimester when craniosynostosis is usually detected. We report a second-trimester molecular diagnosis of a sporadic case, based on the ultrasound observation of fetal 'mitten hands' and craniosynostosis. We discuss the approach to such ultrasound features, given the current availability of molecular diagnosis for Apert syndrome.

Abortion, Therapeutic↗
PubMed1999

Suppression of apoptosis does not foster neoplastic growth in Barrett's esophagus.

Esophageal adenocarcinoma often arises in association with metaplastic and dysplastic mucosa in Barrett's esophagus. Derangements in cell cycle control and apoptosis regulation might be responsible for the progression from metaplasia to dysplasia and adenocarcinoma We tested this hypothesis by performing cell cycle analysis, in situ detection of apoptosis, and evaluation for the immunohistochemical expression of proteins involved in proliferation (Ki-67), the control of apoptosis (bcl-2, bcl-x and bax), and cell cycle regulation (retinoblastoma and cyclin D1). We studied 17 randomly selected paraffin-embedded esophagectomy specimens that contained intestinal metaplasia without dysplasia, low-grade dysplasia, high-grade dysplasia, and esophageal adenocarcinoma Compared with gastric controls and intestinal metaplasia without dysplasia, high-grade dysplasia and esophageal adenocarcinoma demonstrated greater numbers of cells in S phase and G2 phase. Comparison of the proliferation index and the apoptotic rate in intestinal metaplasia without dysplasia, low-grade dysplasia, high-grade dysplasia, and esophageal adenocarcinoma showed a statistically significant trend that linked an increasing proliferation index and apoptotic rate with increasing histologic severity (P = .006 and P = .0002, respectively). A statistically significant linear association was found between bcl-x expression, bax expression, and the bcl-2-to-bax expression ratio versus increasing histologic severity (P = .0004, P = .007, and P = .03, respectively). These data support the hypothesis that neoplastic transformation of intestinal metaplastic epithelium in the esophagus might result from sequential changes in the expression of proteins involved in the control of apoptosis and the cell cycle. Furthermore, suppression of apoptosis does not seem to foster neoplastic growth in Barrett's esophagus. These observations will lead to a better understanding of the pathogenesis of esophageal adenocarcinoma and might contribute to enhancing the diagnostic accuracy when presented with dysplastic lesions.

Adenocarcinoma↗
PubMed1998

Enrichment for DNA mismatch repair-deficient cells during treatment with cisplatin.

In addition to playing a role in tumorigenesis, loss of DNA mismatch repair results in low-level intrinsic resistance to cisplatin and carboplatin. We used a mismatch repair-deficient (clone B) and -proficient (clone B/rev) pair of Chinese hamster ovary sublines to determine the ability of cisplatin to enrich for repair-deficient cells during growth in vitro and in vivo. Clone B cells were 1.8-fold resistant to cisplatin as measured by a clonogenic assay. These cells were molecularly engineered to express constitutively the green fluorescent protein, and changes in the fraction of these repair-deficient cells were monitored by flow cytometric analysis. A single 1-hr exposure to cisplatin at an IC50 concentration enriched populations initially containing either 5 or 10% clone B cells by 81 and 75%, respectively, when measured at 5 days. Enrichment increased as a function of drug concentration to 158 and 169%, respectively, following an IC90 exposure. When grown as a xenograft, a single LD10 dose of cisplatin enriched the tumors by 48% from 4.6 to 6.8% repair-deficient cells (p = 0.04). To determine whether similar enrichment occurs during the treatment of human ovarian cancer patients, paired tumor samples were obtained from 38 patients before and after treatment with a minimum of 3 cycles of platinum drug-based primary chemotherapy and analyzed immunohistochemically for changes in the fraction of tumor cells expressing hMHL1. Following treatment there was a reduction in hMLH1 staining in 66% of the cases (p = 0.0005). Our results demonstrate that, despite the fact that loss of mismatch repair yields only modest levels of cisplatin resistance, even a single exposure to cisplatin produces quite a marked enrichment for repair-deficient cells in vitro and in vivo. Our results are consistent with the concept that treatment with cisplatin or carboplatin selects for preexisting mismatch repair-deficient cells, and that this contributes to the frequent development of clinical resistance.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Field cancerization: why late "recurrent" ovarian cancer is not recurrent.

OBJECTIVE: Late "recurrence" of ovarian cancer may result from either regrowth of dormant tumor cells or from development of a new cancer caused by the phenomenon of field cancerization. Clinically, some recurrent ovarian cancers show the same therapeutic sensitivities to chemotherapy and surgery as did the primary disease, whereas others are refractory to all therapy. We hypothesize that recurrent ovarian cancers are distinguishable on the basis of a molecular genetic fingerprint and that some are actually new primary cancers of the peritoneum rather than recurrent ovarian cancer. STUDY DESIGN: We constructed molecular genetic fingerprints of 13 paired primary and late recurrent ovarian cancers to study their clonal relationships. The tumor pairs were analyzed for p53 mutations and allelotypes, patterns of X-chromosome inactivation, loss of heterozygosity, and microsatellite instability at 12 different loci on 6 different chromosomes. Techniques used included single-strand conformational polymorphism mutation screening and polymerase chain reaction-based sequence analysis of the p53 locus, restriction digestion of the androgen receptor locus to determine X-chromosome inactivation, and polyacrylamide gel electrophoresis of highly polymorphic dinucleotide, trinucleotide, and tetranucleotide repeats. RESULTS: The average age at initial diagnosis for this cohort was 54.7 years (range 45.3 to 65.5). Mean interval to recurrence was 42.7 months (range 28 to 62). Molecular fingerprints were characterized for 4 to 8 informative loci per tumor pair. The fingerprints of 10 (77%) differed significantly, strongly suggesting that a second primary cancer had developed. The remaining 3 tumor pairs demonstrated identical allelotypes consistent with regrowth of dormant tumor cells. CONCLUSION: Our results are consistent with the "field cancerization" hypothesis of ovarian carcinogenesis but could also be explained by a polyclonal tumor origin, which contrasts with the currently accepted monoclonal theory of ovarian carcinogenesis. Late development of a new primary cancer may herald the proband as a member of a familial cancer phenotype. These studies provide a molecular genetic rationale that both explains and prognosticates the clinical course of recurrent ovarian cancer.

Aged↗
PubMed1998

Placental site trophoblastic tumor: human placental lactogen and pregnancy-associated major basic protein as immunohistologic markers.

Placental site trophoblastic tumor (PSTT) consists of a neoplastic proliferation of intermediate or extravillous trophoblast (also known as X cells). Pregnancy-associated major basic protein (pMBP) is a marker for placental intermediate trophoblast. We compared the distribution of pMBP and human placental lactogen (hPL) in 24 PSTT and 3 exaggerated placental site (EPS) specimens using two distinct immunohistologic methods. Statistical analyses were used to compare staining intensities in metastatic and nonmetastatic lesions. By immunofluorescence, 77% of the PSTT specimens and 100% of the EPS specimens stained with antibodies to pMBP, and the pMBP was localized in intermediate trophoblast and surrounding extracellular areas. By immunohistochemistry, 78% of the PSTT specimens and 100% of the EPS specimens stained for pMBP with a pattern comparable with that of immunofluorescence. Likewise, by immunohistochemistry, hPL stained 96% of the PSTT specimens and 100% of the EPS specimens. Immunohistochemical staining intensities for pMBP and hPL correlated (r2 = +.24; P = .013), but hPL staining was mainly confined to intermediate trophoblast and was more intense. Anti-pMBP tended to stain metastatic PSTT weakly. Thus, pMBP is a useful marker for intermediate trophoblast tumors and could help distinguish these from other forms of trophoblastic disease.

Adult↗
PubMed1998

Imaging of placental vasculature using three-dimensional ultrasound and color power Doppler: a preliminary study.

OBJECTIVE: To assess placental vasculature using color power Doppler and three-dimensional ultrasound techniques. DESIGN: A prospective study was performed in patients to correlate visualization of placental vessels in vivo with known anatomy. SUBJECTS: Fourteen normal patients and one patient with intrauterine growth restriction were recruited to the study. METHODS: Vessels were assessed with regard to, first, the number of vessels seen within the placenta, second, the branching pattern of the vessels within the placenta, third, the number of vessels seen along the surface of the placenta, and, last, the number of vessels seen in the maternal circulation. RESULTS: Our results show that the placental vessels seen with this technique correlate well with known anatomy. A progressive increase in the number of intraplacental vessels and the number of vascular branches observed was seen with increasing gestational age. Volume data review using three orthogonal planar images had two distinct advantages. First, they could be obtained from orientations not possible using two-dimensional ultrasound alone, and, second, they could be viewed in conjunction with volume-rendered images to allow for referencing and identification of specific vessels. Volume-rendered images were valuable in allowing the observer to acquire an improved overall understanding of placental anatomy. They also assisted the observer in following the continuity of vessels as they wrapped around and twisted through three-dimensional space. Stereo viewing was helpful in distinguishing overlapping vessels. CONCLUSIONS: Our study showed that sonographic volume imaging combined with color power Doppler imaging methods allowed for individual vessels in the placenta to be identified, both in the fetal and maternal circulations.

Arteries↗
PubMed1998

Features of cancer in nonagenarians and centenarians.

OBJECTIVE: To describe the incidence rates and sites of cancer, the causes of death, and gender and ethnic variations in patients with cancer in a population of people 90 years of age and older. DESIGN: Analysis of the 14,088 cases of cancer in this age group, accessioned by the California Cancer Registry from 1988 through 1993, and comparison with those less than age 90. MEASUREMENTS: Incidence rates and numbers and percents of cases with various features (gender, ethnicity, site of tumor, stage, causes of death). RESULTS: The peak age-specific incidence (ASI) of cancer is in the group 80 to 84 years of age. Those 90 to 94 years of age had a higher ASI than any group except those ages 75 to 89. There are ethnic variations in the sites of cancer in people aged 90 or older. Colorectal cancer accounts for more than one-fifth of the new cases of cancer in people 90 or older. In women aged 90 or older, the most common sites of cancers are colorectal, breast, and lymphoma/leukemia. In men of the same age, prostate, colorectal, and lung/bronchus are the most common sites. As age increases, fewer people have their cancers staged, and for lung/bronchus, prostate, and breast, more cancers are first diagnosed in the distant stage in people aged 90 and older. Of the people with cancer who die, the proportion dying of cancer decreases as age increases. CONCLUSION: Cancer is a common disease in nonagenarians and centenarians and will be an increasing healthcare problem. Knowledge of its features is essential to those planning, delivering, and financing health care.

Age Factors↗
PubMed1997

Endometrioid ovarian carcinoma in a premenarchal girl: report of a case.

In children and adolescents, ovarian neoplasms are predominantly germ cell and sex cord stromal tumors. Carcinomas are quite rare, and, in particular, endometrioid adenocarcinomas are extremely rare in this age group. We report the case of a 13-year-old girl with FIGO stage I, grade I endometrioid adenocarcinoma of the ovary. To our knowledge this is the first report of an endometrioid carcinoma of the ovary occuring in the premenarchal age group and only the second case reported before age 15. Our patient has been treated by conservative surgery without postoperative chemotherapy. Menarche occured 3 months after surgery. Twelve months after surgery she is free of disease.

Adolescent↗
PubMed1997

Maternal melanoma metastatic to the placenta: a case report and review of the literature.

Metastases of maternal cancer to the placenta and fetus are rare in cases of maternal primary malignancy. This report describes a case of malignant melanoma metastatic to the placenta, reviews the literature, and discusses the clinical significance. A 33-year-old woman presented at 30 weeks' gestation with multiple metastases from a malignant melanoma diagnosed 4 years previously. Rapid maternal deterioration necessitated premature cesarean delivery, and maternal death occurred 7 days later. The placenta showed multiple metastases of malignant melanoma. The infant, however, is alive and well at 7 months of age. Melanoma in pregnancy rarely results in metastasis to the conceptus, but when it does occur there may be fatal consequences to the fetus. Therefore, the placenta should be thoroughly examined for metastasis, which, if present, should alert the clinician to monitor the infant for development of malignant disease.

Adult↗
PubMed1997

Gestational choriocarcinoma.

The malignant transformation of trophoblast is interesting to contemplate, as trophoblast normally behaves in a manner that is interpreted as indicative of malignancy. First of all, trophoblasts show "controlled invasion" at the placental site as part of the normal process of implantation. Secondly, it is estimated that 100,000 syncytiotrophoblastic cells are deported to the maternal circulation daily and these are commonly identified in the pulmonary circulation of pregnant women (38). These trophoblastic cells do not ordinarily produce disease and presumably are rejected by the mother, unlike true metastases. When trophoblastic malignancy does develop, however, the trophoblast continues to invade and grow without limit, eventually metastasizing and ultimately leading to death. Choriocarcinoma is, therefore, unique in that it represents a malignant transformation of a tissue that inherently has "invasive" and "metastatic" properties. It is also the only tumor which contains DNA foreign to the host, as it is derived from a conception which contains paternal genetic material. Thus, choriocarcinoma is a complex neoplasm, and to study it, one must study and understand graft rejection, immunologic mechanisms and a multitude of genetic concepts in addition to the mechanisms of invasion and metastasis.

Carcinoma in Situ↗
PubMed1997

Trophoblastic lesions of the placental site.

The trophoblast of the chorionic villi as well as the hydatidiform mole and choriocarcinoma have been recognized and studied for many years. However, the trophoblast comprising the implantation site, chorionic plate, chorion laeve, cell islands and septa have only in recent years received attention in the literature. These "extravillous" trophoblastic cells were originally referred to as "X" cells due to doubt regarding their derivation from either maternal or fetal tissue (70). Subsequent studies determined that they were trophoblastic in origin (42), but the term X-cell is still in use today by some researchers (30, 4). Due to continued uncertainty regarding their nature and origin, many other terms have been used including syncytial wandering cells (21), placental site trophoblast, placental site giant cells (42), extravillous trophoblast (25), extravillous cytotrophoblast, nonvillous trophoblast, and intermediate trophoblast (49). Light microscopic and immunohistochemical studies have led to elucidation of specific morphologic and biochemical features of the extravillous trophoblast (48-50) which is commonly designated as the "intermediate trophoblast". Lesions of the "intermediate" or extravillous trophoblast of the placental site include the exaggerated placental site, the placental site trophoblast tumor and the recently described placental site nodule. This article will review the clinical and pathologic features of these lesions, their differential diagnosis, treatment, and prognostic factors after discussion of the origin, nature and definition of the "intermediate" trophoblast.

Adolescent↗
PubMed1996

Simultaneous assessment of loss of heterozygosity at multiple microsatellite loci using semi-automated fluorescence-based detection: subregional mapping of chromosome 4 in cervical carcinoma.

Detection of loss of heterozygosity (LOH) by comparison of normal and tumor genotypes using PCR-based microsatellite loci provides considerable advantages over traditional Southern blotting-based approaches. However, current methodologies are limited by several factors, including the numbers of loci that can be evaluated for LOH in a single experiment, the discrimination of true alleles versus "stutter bands," and the use of radionucleotides in detecting PCR products. Here we describe methods for high throughput simultaneous assessment of LOH at multiple loci in human tumors; these methods rely on the detection of amplified microsatellite loci by fluorescence-based DNA sequencing technology. Data generated by this approach are processed by several computer software programs that enable the automated linear quantitation and calculation of allelic ratios, allowing rapid ascertainment of LOH. As a test of this approach, genotypes at a series of loci on chromosome 4 were determined for 58 carcinomas of the uterine cervix. The results underscore the efficacy, sensitivity, and remarkable reproducibility of this approach to LOH detection and provide subchromosomal localization of two regions of chromosome 4 commonly altered in cervical tumors.

Chromosome Deletion↗