Reduction of RGS4 protein in human breast carcinomas. A, sections of breast tissue stained for RGS4 protein with anti-RGS4 antibody. Scale bar, 50 μm. a, benign breast tissue; b, benign breast tissue with antibody preblocked by RGS4 protein; c, ductal carcinoma in situ; d and e, invasive carcinoma; f, breast cancer metastasis in lymph nodes. B, RGS4 protein levels in human breast tissues (n = 9 patients) determined by H-score analysis of immunohistochemically stained tissue sections. Columns, mean; bars, SD. *, P < 0.05 and **, P < 0.001 compared with nearby benign breast tissue by paired t test.