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Gad Singer

Publications and source records attributed to Gad Singer.

22 records · Page 2Linked to original sources
PubMed2002

Diverse tumorigenic pathways in ovarian serous carcinoma.

This study was undertaken to analyze genetic alterations in 108 sporadic serous ovarian neoplasms to elucidate ovarian serous carcinogenesis. Our results demonstrate that K-ras mutations occur in approximately 50% of serous borderline tumors (SBTs), non-invasive micropapillary serous carcinomas (MPSCs), and invasive micropapillary serous carcinomas, which represent a morphological continuum of tumor progression. Moreover, progressive increase in the degree of allelic imbalance of chromosomes 1p, 5q, 8p, 18q, 22q, and Xp was observed comparing serous borderline tumors to noninvasive and invasive micropapillary serous carcinomas. In contrast, high-grade (conventional serous carcinoma) tumors contained wild-type K-ras in all 23 cases studied and a high frequency of allelic imbalance even in small (early) primary tumors similar to that found in advanced stage tumors. Based on these findings, we propose a dualistic model for ovarian serous carcinogenesis. One pathway involves a stepwise progression from SBT to noninvasive and then invasive MPSC. The other pathway is characterized by rapid progression from the ovarian surface epithelium or inclusion cysts to a conventional (high-grade) serous carcinoma.

Allelic Imbalance↗
PubMed2002

HLA-G immunoreactivity is specific for intermediate trophoblast in gestational trophoblastic disease and can serve as a useful marker in differential diagnosis.

HLA-G is a nonclassical MHC class I antigen that has been shown to be a specific marker for normal intermediate trophoblast (IT). In this study HLA-G immunoreactivity assessed with an HLA-G specific antibody (4H84) was detected in all 14 cases of choriocarcinoma, 14 placental site trophoblastic tumors, 13 epithelioid trophoblastic tumors, 16 placental site nodules, and nine exaggerated placental sites. In contrast, HLA-G immunoreactivity was not detected in 34 nontrophoblastic uterine neoplasms. HLA-G immunoreactivity was present in all the IT cells of exaggerated placental sites and placental site trophoblastic tumors and in 70-100% of IT cells in placental site nodules and epithelioid trophoblastic tumors. The pattern of distribution of HLA-G in different subpopulations of IT confirms the relationship of various trophoblastic lesions to different types of IT (exaggerated placental site and placental site trophoblastic tumor to implantation site IT and placental site nodule and epithelioid trophoblastic tumor to chorionic-type IT) and suggests that choriocarcinoma is related to villous-type IT because the majority of mononucleate cells in this neoplasm were HLA-G immunoreactive. In conclusion, HLA-G immunoreactivity appears to be specific for IT in gestational trophoblastic disease and can serve as a useful marker in the differential diagnosis of these lesions.

Antibodies↗
PubMed2002

Genotype analysis using human hair shaft.

Analysis of genotypes for genetic predisposition of diseases has profound and widespread clinical application and has become a fundamental tool in the study of molecular epidemiology. In this study, we report a convenient and completely noninvasive approach to perform genotyping using terminal cephalic hair shaft. The average and median DNA amounts purified from the hair shaft are 112 +/- 180 (1 SD) pg/mg and 66 pg/mg of hair shaft, respectively. Using hybridization with molecular beacons that can reliably distinguish single nucleotide polymorphisms at different alleles, we are able to analyze the genotypes of APO-E and G-protein beta3 (GNB3) subunit C825T loci in DNA samples obtained from hair shaft in a high throughput format. The amount of DNA obtained from 20 mg of hair shaft is sufficient for multiple independent genotyping assays. These findings demonstrate that terminal hair shaft provides a convenient and reliable genomic DNA source for an analysis of genotypes.

DNA↗