Decreased expression of phosphorylated JNK in breast infiltrating ductal carcinoma is associated with a better overall survival.

Phosphorylation/activation of c-jun NH2-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.