TY - JOUR
T1 - Loss of heterozygosity at the RB-1 locus and pRB immunostaining in epithelial ovarian tumors: A molecular, immunohistochemical, and clinicopathologic study
AU - Gras, Esther
AU - Pons, Cristina
AU - Machin, Pilar
AU - Matias-Guiu, Xavier
AU - Prat, Jaime
PY - 2001/1/1
Y1 - 2001/1/1
N2 - 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.
AB - 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.
KW - 13q
KW - Immunohistochemistry
KW - Loss of heterozygosity
KW - Mixed endometrioid-serous carcinomas
KW - Ovarian tumors
KW - RB-1
KW - Serous carcinomas
KW - Sporadic ovarian cancers
U2 - 10.1097/00004347-200110000-00004
DO - 10.1097/00004347-200110000-00004
M3 - Article
VL - 20
SP - 335
EP - 340
JO - International Journal of Gynecological Pathology
JF - International Journal of Gynecological Pathology
SN - 0277-1691
IS - 4
ER -