MAPK6 and cancer: As BMI1 is an oncogenic transcriptional factor for cancer cell growth and migration (Cao et al., 2011) and both BMI1 and ERK3 are overexpressed in head and neck cancers (Rai et al., 2004; Song et al., 2006), we were interested in investigating the molecular regulation of ERK3 by BMI1 and the functional significance of this axis in head and neck cancer cells.