Correlation of MDR1 expression and oncogenic activation in human epithelial ovarian carcinoma.

The expression of the MDR1 gene has been shown to correlate with tumor aggressiveness and oncogenic activation both in experimental tumor models and in human clinical specimens In order to verify whether this association also takes place in ovarian carcinoma, we studied tumor samples from 39 patients by means of immunohistochemistry for the overexpression of P-glycoprotein (MDR1), nm23, c-erb-B2 and p53. MDR1 (p = 0.023), nm 23 (p = 0.037) and c-erb-B2 (p = 0.015) were expressed significantly more in specimens from patients with advanced stage of disease. There were no differences in p53 expression between both groups of patients. Furthermore, we found a significant coexpression of MDR1 and nm23 (p = 0.028), and of MDR1 and c-erb-B2 (p = 0.0077). There was no association between the expression of the MDR1 gene and p53. These results parallel those previously reported by us for mammary carcinoma, and seem to indicate that expression of the multidrug resistance gene (MDR1) is inherent to the development of the malignant phenotype in several human tumors.