To determine if Bax and another pro-apoptotic BCL-2 family member, Bak, are necessary for p53-induced apoptosis, we transfected a BAX−/−;BAK−/− colorectal adenocarcinoma cell line (DLD-1) and the parental cell line that expressed wild type BAX and BAK with p53-R9. Here, BAK1 is linked to colorectal adenocarcinoma.