CPNE1 and head and neck cancer: Corroborating the result we obtained from GEPIA gene expression studies, genes CTSB and CPNE1 are highly overexpressed in colorectal cancer and most of the other cancer types in the OncoMX database, such as head and neck cancer, liver cancer, stomach cancer, kidney cancer, esophageal, lung and thyroid (Figs. 7B and C).