Importantly, phosphorylated HSP27 seemed to confer resistance to caspase-dependent apoptosis induced by hypoxia or serum depletion in CD(133+) CSCs from colorectal, lung, brain, and oral cancer; this HSP27 phosphorylation-mediated adaptive mechanism was based on the p38 MAPK/MAPKAPK2/HSP27 pathway while being suppressed by protein phosphatase PP2A, which dephosphorylates HSP27 [146]. The gene discussed is HSPB1; the disease is lip and oral cavity carcinoma.