Following irradiation, radiation-resistant tumor cells can inhibit apoptosis by modulating the interaction network of the Bcl family of proteins. This modulation involves upregulation of anti-apoptotic proteins such as Bcl-2 and Bcl-XL, as well as downregulation or inactivation of pro-apoptotic proteins such as Bax and Bak. This evidence concerns the gene BCL2 and neoplasm.