Immunohistochemical analysis of Ki-67, PCNA and S6K1/2 expression in human breast cancer.

Aim: To assess the correlation between the expression profiles of ribosomal protein S6 kinase (S6K1/2), Ki-67 nuclear antigen (Ki-67) and proliferating cell nuclear antigen (PCNA) in human breast adenocarcinomas.

Methods: The expression pattern of S6K1/2, Ki-67 and PCNA has been investigated by immunohistochemical analysis of formalin fixed paraffin embedded sections of 40 human breast adenocarcinomas. Analysis was performed using specific monoclonal and polyclonal antibodies directed against S6K2, Ki-67 and PCNA followed by semi-quantitative measurements.