CK5 and p40 were positive in the squamous cell cancer cell lines HCC-95 and HCC-1588 (see Fig. 1), while SK-MES-1, B1203L, NCI-H520, and NCI-H1703 were negative for CK5 and p40 (occasional NCI-H520 cells, < 1%, expressed CK5 only, see Supplementary Fig. 1, also including images of control tissue). Here, KRT5 is linked to squamous cell carcinoma.