Studies with knockout mice have shown that the absence of XIAP does not adversely affect the development of normal tissues (Harlin et al, 2001), whereas antisense knockdown (KD) of the protein in a non-small-cell lung cancer (NSCLC) xenograft (H460) produces significant antitumour activity (Hu et al, 2003). The gene discussed is XIAP; the disease is non-small cell lung carcinoma.