Another important discoverywas reported in a study demonstrating that umbilical cord mesenchymalcells incubated with HL60 and K-562 leukemic cells increased p38 MAPKphosphorylation, thus inhibiting leukemic cell growth.41 In cancer stem cells isolated from the lung,p38 MAPK inactivation contributes to the maintenance of this populationin a more undifferentiated state.42 Allthese studies indicate that activated p38 MAPK functions as a growthsuppressor, highlighting its potential as a target for antitumor therapiesto eliminate LSCs and other types of cancer stem cells. This evidence concerns the gene MAPK14 and cancer.