Background and objectives: Expression of BRCA1 was examined in patients with leukoplakia and carcinoma of the tongue. Its prognostic value was evaluated in patients with tongue cancer.
Methods: Expression of BRCA1 was studied by immunohistochemical localization. Cytoplasmic staining of BRCA1 was observed in both leukoplakia and carcinoma of the tongue.
Results: In leukoplakia, 61% and 39% of the patients expressed BRCA1 expression with a staining intensity of 1+ and 2+, respectively. In patients with hyperplasia (67%), BRCA1 expression with a staining intensity of 1+ was 67%; BRCA1 expression with a staining intensity of 2+ was 33%. In patients with dysplasia (33%; mild and moderate), BRCA1 expression with a staining intensity of 1+ and 2+ was 50% each. In carcinoma of the tongue, only 34% of the patients showed BRCA1 expression. In this group, 33% of the tumors exhibited 1+ staining, and only 1% of the tumors expressed 2+ staining. Moreover, BRCA1 expression with a staining intensity of 2+ was significantly higher in patients with dysplasia (50%) than in those with hyperplasia (33%), followed by patients with squamous cell carcinoma of the tongue (1%). The percentage positivity of BRCA1 expression in tongue cancer patients was significantly lower (34%), as compared with patients with leukoplakia (100%; P = 0.000001). A significant positive correlation was noted between BRCA1 and c-myc (P = 0.012). Univariate survival analysis by log-rank test and multivariate survival analysis by Cox regression showed that BRCA1 expression was the most significant prognostic factor predicting relapse-free survival of early-stage patients.
Conclusions: Subcellular localization of the BRCA1 gene product provided evidence of its involvement in the pathogenesis of tongue tumors.
Copyright 2003 Wiley-Liss, Inc.