Abstract
Phosphorylation/activation of c‐jun NH~2~‐terminal kinase (JNK) has an ambivalent role, pro‐proliferation or antiproliferation, in human cancers, which is determined by different cell types and by its crosstalk with other kinases. So far, the role of phosphorylated JNK (p‐JNK) in breast cancer is mostly undefined. In this study, we analyzed the expression of p‐JNK, as well as p‐ERK1/2 and p‐38, in the pair of cancer and noncancer breast tissues, by using immunoblotting techniques. These results were further correlated with the clinicopathological characteristics and overall survival. Decreased p‐JNK1/2 expression in cancer tissues was observed in 48.5% of breast infiltrating ductal carcinoma (IDC) cases and was correlated significantly with the increased tumor grade and the decreased age at diagnosis (p = 0.030 and 0.029). Interestingly, the Kaplan–Meier survival curve showed that the decreased p‐JNK1/2 expression was associated with a better overall survival of IDC (p = 0.004). The expression of p‐JNK1/2 was positively correlated with p‐p38 (p = 0.002), but not p‐ERK1/2. Furthermore, co‐expressed p‐JNK1/2 and p‐p38 was associated with a poor overall survival of IDC (p = 0.007). In conclusion, our results indicate that the aberrant p‐JNK1/2 expression and the co‐expressed p‐JNK1/2 and p‐p38 in breast tissues may play a role in the carcinogenesis of breast IDC. © 2005 Wiley‐Liss, Inc.