MAP2K6 (mitogen-activated protein kinase kinase 6) is a dual-specificity protein kinase that serves as an essential component of the p38 MAPK signaling cascade, catalyzing phosphorylation of p38 MAPK family members (MAPK11-14) in response to cellular stresses and cytokines. MAP2K6 plays a major role in TNF-induced p38 MAPK activation and mediates stress responses through downstream transcription factors ATF2 and ELK1, as well as STAT4 activation by IL-12. 1 Mechanistically, MAP2K6 integrates multiple signaling inputs: mTORC1 increases MAP2K6 protein synthesis to drive intestinal stem cell aging via p38 MAPK-p53 pathway activation 1, while stress-activated kinases MKK3 and MKK6 activate the Mirk checkpoint kinase during cellular stress responses 2. The kinase is dysregulated in multiple malignancies, where it promotes cancer cell proliferation and radioresistance through LIFR/p70S6K signaling in nasopharyngeal carcinoma 3 and enhances paclitaxel sensitivity via autophagy induction in ovarian cancer 4. Clinically, MAP2K6 represents a therapeutic target in polycystic ovary syndrome and gastric cancer, where downregulation of regulatory microRNAs (miR-375, miR-324-3p, miR-1298-5p) leads to MAP2K6 overexpression and enhanced granulosa cell/cancer cell proliferation 567. In hepatocellular carcinoma, APEX1-mediated upregulation of MAP2K6 promotes malignant properties 8, suggesting MAP2K6 as a prognostic biomarker and therapeutic target across multiple cancer types.