CASP4 and cancer: In order to investigate the effects of CASP4 modulation on cell growth, apoptosis and cell migration, cancer cell lines were transfected with small interfering RNA (siRNA) targeting CASP4. All siRNA targeting exons coding for the pro-domain (#3) or the large p20 (#2) or the small p10 (#1) subunits strongly decrease CASP4 expression in A431 cells (Fig. 1a).