BRCA1 expression in leukoplakia and carcinoma of the tongue

Expression of BRCA1 was examined in patients with leukoplakia and carcinoma of the tongue. Its prognostic value was evaluated in patients with tongue cancer.

Expression of BRCA1 was studied by immunohistochemical localization. Cytoplasmic staining of BRCA1 was observed in both leukoplakia and carcinoma of the tongue.

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.

Subcellular localization of the BRCA1 gene product provided evidence of its involvement in the pathogenesis of tongue tumors.