PS2 protein in breast carcinomas: cut-off value of estrogen-regulated expression

This study includes 152 patients with histologically confirmed breast carcinoma. Steroid hormone receptors (SR), estrogen (ER) and progesteron (PR) receptors, and pS2 protein were assayed on the same cytosolic extract in accordance with the recommendation of EORTC. Our results showed menopausal- and histologic grade-related expression of pS2 protein. Unfavorable carcinoma subgroups, in relation to expression of pS2 protein were defined: postmenopausal carcinomas with histologic grade II, and pre-, as well as postmenopausal carcinomas with histologic grade III. There were overlappings of individual pS2 protein values between favorable and unfavorable carcinoma subgroups in relation to the expression of pS2 protein. Otherwise, no overlapping of pS2 protein values was obtained between ER-positive and ER-negative carcinomas within defined unfavorable menopausal - and histologic grade-related expression of pS2 protein subgroups. The highest pS2 protein level observed in ER-negative unfavorable subgroups (15 ng/mg) was considered as the cut-off value which defined estrogen-regulated expression of pS2 protein.