CASP4 and cancer: To examine if this correlation is also found in human cancer cells, a panel of 20 human cancer-derived cell lines (17 lung, 2 colon, and 1 cervix) were analyzed for the constitutive expression of mRNA encoding SDC1 and CASP4 (CASP4 and CASP5 are the human equivalent of CASP11 in mice) (Fig. 1A–C).