IMMUNOHISTOCHEMICAL EXPRESSION OF PS2 AND CATHEPSIN-D IN BREAST-CANCER - RELATIONSHIP WITH ER, PGR IMMUNOSTAININGS AND CLINICOPATHOLOGICAL ASPECTS

Fifty patients with breast cancer were studied to examine the relationship between the immunohistochemical tumour expression of pS2 and 52 kilodalton-cathepsin D (52K-CD) proteins and several biological and clinical parameters. Our aim was to verify whether these two proteins may provide additional information for the management of breast cancer patients. By using a cut-off point of 10% for pS2 and 15% for 52K-CD valuations, we found that 24 of 50 (48%) carcinomas were pS2+ and 26 of 50 (52%) were 52K-CD+. A statistically significant positive association was found between pS2 positivity and ER presence (p=0.05), though 36% of ER-patients were pS2+. We did not find any correlation between the 52K-CD expression and other parameters studied, neither pS2. Although our findings confirm previous data correlating significantly the ER presence with pS2+ cases, we emphasise the necessity to standardize the use of a clinically significant cut-off point in further immunohistochemical studies to evaluate this protein and, therefore, to explain its role also in tumours lacking ER. As regard the 52K-CD, our results agree with those of other studies, though the association of this enzyme with ER status is controversial in both cytosol and immunohistochemical studies, the use of monoclonal antibodies on frozen sections and polyclonal antibodies on paraffin section can explain this controversy. Our experience indicate the use of an immunohistochemical method in detection of this enzyme and the use of M1G8 (morioclonal antibody) on paraffin sections to make clear the possible role of 52K-CD in breast cancer.