Novel cellular markers in breast cancer.

Epidemiological studies have revealed that Parsi women have a higher incidence of breast cancer than non-Parsis and that they are more susceptible to breast cancer. We have studied the cellular distribution of two prosomal proteins p23K in parallel to the p30.33K and proliferation marker Ki-67 as potential markers to identify high risk population for breast cancers. Flow cytometry data demonstrated that the Parsi benign and non-Parsi malignants have a higher number of cells labelled with these two prosomal protein antibodies than the non-Parsi benign and European 'normals'. Using immunohistochemical methods, p23 K was found to be significantly higher in Parsi and non-Parsi malignants as well as in non-Parsi benigns. In our FCM analysis, intergroup comparison showed, interestingly, a significantly higher expression of both p23K and p30.33K in Parsi benigns as compared to non-Parsis, raising the possibility that benign tumors of Parsis represent already premalignant lesions. The present study, in addition, proposes the prosomal antigens as likely cell proliferation markers comparable to Ki-67.