THE PROLIFERATING CELL NUCLEAR ANTIGEN INDEX IN BREAST CARCINOMAS DOES NOT CORRELATE WITH MITOTIC INDEX AND ESTROGEN-RECEPTOR IMMUNOREACTIVITY

To investigate the expression of a marker of cell proliferation (PCNA/ Cyclin) and its putative relationship with histological grading, mitot ic index and estrogen receptor immunoreactivity, we studied twenty-sev en cases of invasive breast carcinoma in formalin-fixed, paraffin-embe dded tissue sections. The PCNA and estrogen receptor were detected by the PC10 and H222 monoclonal antibodies respectively, using an avidin- biotin-pernxidase method. The median value of PCNA index was 20.9% wit h a range from 1.4 to 84.2%. We did not find any significant relations hip between PCNA index anti the histological grading, mitotic index an d estrogen receptor immunoreactivity. We conclude that PCNA detected b y the monoclonal antibody PC10 in formalin-fixed material looks at pre sent unrealiable as a proliferation marker in breast carcinoma.