MAPK8 and cancer: Liu et al. [85] also concluded that JNK is essential for maintaining stemness and tumor-initiating ability in chemoresistant human cancer cells, whereas Xie et al. [49] found that knockdown of JNK1 or JNK2 or the addition of pan-JNK inhibitor JNK-IN-8 could reduce ALDH1+ and CD44+/CD24− CSC subpopulations, and mammosphere formation in triple-negative breast cancer.