In short, the upregulation of phospho-p53[S15] [18] and phospho-Chk1[S345] (Figure 1) combined with the reduced expression of p21 [17,18] in UV-induced affected dFb vs. unaffected and control dFb represent a striking irregularity that may play a key role in the onset of cancer. This evidence concerns the gene CDKN1A and cancer.