Abstract: BACKGROUND ＆ AIM: To study protein kinase C(PKC) expression in breast cancer cells at differentiation stage and their sensitivity to TNFα. MATERIALS AND METHODS: Protein immunoblot and MTT analysis were used to determine the expression profile of PKC isoforms in 12 breast cancer cell lines in various differentiation stages. RESULTS: The results suggested that expression of PKCε increased in stagesⅢ ＆ Ⅳ cell lines differentiations, compared to those in stages I and II. There was no association between differentiation stage of breast cancer cells and expression of PKCα、η、δ and μ. IC50 of breast cancer cell lines to TNFα at stage IV was higher than cells at other stages. CONCLUSION: PKCε might be useful markers to evaluate the differentiation in human breast carcinoma.

Key words: protein kinase C, breast cancer cell, TNFα