In extended analysis of the other nine cancer cell lines, increase in Annexin V staining upon retroviral infection was detected not only in cancer cell lines defective in p53 function, either due to deletion (Saos-2 [26] and Calu-1 [27]), point mutation (Huh7 cells [28]) or human papilloma virus infection (SW756 [29]), but also in those with wild-type p53 (U2OS [30], Chang liver [31], and SK-Hep1 [32]). Here, TP53 is linked to human papilloma virus infection.