Apolipoprotein E polymorphism and breast carcinoma: correlation with cell proliferation indices and clinical outcome

There is preliminary evidence that polymorphism of apolipoprotein E (apoE, protein; APOE, gene), one of the key regulatory proteins in cholesterol met abolism, influences the pathobiology of carcinoma of the colon, prostate an d breast and also primary tumours of the brain. This study was designed to determine whether APOE polymorphism is related to variation in the rate of tumour cell proliferation and clinical outcome in carcinoma of the breast. One hundred and eleven infiltrating ductal carcinomas, for which follow up data were available, were included in the study. Estrogen and progesterone receptor status (ER, PR) cell proliferation index (MIB-1) and APOE genotype s were determined from paraffin-embedded tissue by standard methods. Positi ve correlations were found between grade and tumour size, grade and presenc e of metastasis, grade and MIB-1 expression, as well as between ER and PR. Survival correlated inversely with tumour size and the presence of positive lymph nodes. Both steroid receptors correlated inversely with MIB-1 expres sion. PR positive status also correlated inversely with high histological g rade and presence of lymph node metastases. APOE allele frequencies resembl ed those of the general population. No significant associations were found between possession of either APOE epsilon2 or epsilon4 alleles and the para meters investigated. Although there is evidence to suggest that APOE epsilo n4 may predispose to the development of carcinoma of the breast our data do not support the hypothesis that APOE genotype influences the rate of tumou r cell proliferation or the clinical course.