An upregulation of ERK3 transcript and/or protein level was demonstrated in non-small cell lung cancers (NSCLCs) (in both lung adenocarcinomas and lung squamous cell carcinoma), chewing tobacco-induced oral squamous cell carcinoma, head and neck cancer and gastric cancer tissues as compared to normal tissues [36,37,38,39]. The gene discussed is MAPK6; the disease is squamous cell lung carcinoma.