Loss of heterozygosity at the RB-1 locus and pRB immunostaining in epithelial ovarian tumors: A molecular, immunohistochemical, and clinicopathologic study

Esther Gras, Cristina Pons, Pilar Machin, Xavier Matias-Guiu, Jaime Prat

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18 Citations (Scopus)

Abstract

Alterations in the retinoblastoma gene (RB-1) are common in human neoplasia. The frequency of loss of heterozygosity (LOH) at the RB-1 locus on chromosome 13q14 was studied in a series of 51 epithelial ovarian tumors (10 benign, 7 borderline, and 34 malignant). LOH was scored by the absence or reduction of the signal to < 50% of one of the alleles in tumor DNA compared with normal DNA. LOH results were correlated with retinoblastoma protein (pRB) immunostaining. LOH at the RB-1 locus was observed in 9 tumors (17.6%), specifically in 1 of 7 borderline tumors and 8 of 34 ovarian carcinomas (23.5%). Among the malignant tumors, LOH occurred more frequently in carcinomas with serous differentiation (7/23; 30%). A heterogeneous (10% to 70% cells) or diffuse (>70% cells) pRB immunostaining was less frequent in benign (1/10; 10%) and borderline (2/7: 28%) tumors than in ovarian carcinomas (15/34; 44%), an observation that correlated with the higher proliferative index in carcinomas than in benign and borderline tumors. However, lack or only focal (<10% cells) pRB immunostaining occurred in the vast majority of tumors with LOH at the RB-1 locus (7/9; 77%), a finding that may suggest a tumor suppressor role for RB-1 in these tumors. The results suggest that RB-1 may play a role in a subset of ovarian carcinomas, particularly those exhibiting serous differentiation.
Original languageEnglish
Pages (from-to)335-340
JournalInternational Journal of Gynecological Pathology
Volume20
Issue number4
DOIs
Publication statusPublished - 1 Jan 2001

Keywords

  • 13q
  • Immunohistochemistry
  • Loss of heterozygosity
  • Mixed endometrioid-serous carcinomas
  • Ovarian tumors
  • RB-1
  • Serous carcinomas
  • Sporadic ovarian cancers

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