Reduction of endogenous p65 by siRNA treatment in HCT-116 colon cancer cells significantly impaired CPT-11-mediated NF-κB activation, enhanced apoptosis, decreased colony formation in soft agar and when administered in vivo, reduced HCT-116 tumour formation in the presence but not in the absence of CPT-11 (Guo et al, 2004). This evidence concerns the gene NFKB1 and neoplasm.