PTGS2 and breast carcinoma: Of the candidate genes tested, mRNA levels for CXCR4 (p < 0.001), survivin (p < 0.05), SLPI (p < 0.05) and EGP-2 (p < 0.05) were significantly lower in normal primary fibroblasts compared with breast cancer tissue, while COX-2 showed no significant difference.