A large proportion of tumor regression observed with X-ray treatment and chemotherapy is due to the induction of apoptosis. Among the candidate genes for this type of therapy are those of the Bcl-2 family that are important in the regulation of apoptosis. These are cellular homologs of the pro-apoptótic genes Bax, Bak and the antiapoptótic genes Bcl-2 and Bcl-XL.

The transfer of the genes Bak & Bax induces high levels of apoptosis in cancerous cells from the lung independently of the status of p53. Another gen that induces apoptosis is the gene fas, occurring in patients with NSCLC that have better survival with its overexpression mediated by adenovirus inducing apoptosis in tumor cells. Nuclear factor kappa B (NF-kB) is another inhibitor of apoptosis.

See also Ambrosini et al (Nat Med 3: 917-921, 1997) and Olie et al (Cancer Res 60: 2805-2809,2000).