Abstract

In 38 women with breast carcinoma who had locally advanced cancer without distant metastasis, the expression of P-glycoprotein was evaluated, using JSB-1 monoclonal antibody by ABC-immunoperoxidase method, P-glycoprotein was detected in 35 of 38 tumor samples(91.4%). Result were expressed in a semiguantitative manner, taking into account the number of posi- tive tumor cells(N index) and the specific staining index(I index). The frequencies of higher expression(N+I+2 or I+3) were detected in 0% of grade I, 33% of grade II and 90.9% of grade III in infiltrating duct carcinoma. Recurred cases were 4 out of 38(10.5%), of which 3 cases showed high histologic grade and more advanced stage with strong P-glycoprotein expression (N+I+3). Strong P-glycoprotein-positive staining in a majority of tumor cells(N-/I+3) was significantly correlated with histoiogic group with poor prognosis hi#gh histologic grade and recurrence. Thus, the pretreatment evaluation of P-glycoprotein expression may be of prognostic value in patients with locally advanced breast cancer. The possiblity that Mdrl enhances the invasiveness of cancer was suggested.

• Keywords: P-Glycoprotein, Breast Ca.