We recently reported that p38, especially the γ and δ isoforms of p38, suppresses the expression and reduces the stability of the stemness-related proteins SOX2, OCT4, NANOG, KLF4, and c-Myc and CSC properties via MK2-mediated HSP27 phosphorylation in NSCLC cells.25 Supporting a role of p38 in suppressing NSCLC development by inhibiting CSCs in vivo, we previously observed reduced levels of phosphorylated/activated p38 (p-p38), along with increased expression of SOX2, in NSCLC tissue samples compared with normal lung tissue samples. The gene discussed is KLF4; the disease is non-small cell lung carcinoma.