Recently, aberrant ERK5 signaling has been found in various malignancies, such as glioma, breast cancer, colorectal cancer, renal cancer, prostate cancer and lung cancer (Wu et al., 2016; Zhuang et al., 2016; Liu et al., 2017; Salinas-Sanchez et al., 2017; Won et al., 2017), and it is generally associated with poorer prognosis. Here, MAPK7 is linked to prostate cancer.