CDKN2A and cancer: Similarly, using conditional oncogene K-rasV12 in a mouse model for human cancer initiation, Collada et al. [96] have shown that both in lung and in pancreas, premalignant tumor tissues displayed extensive senescent cells as indicated by the expression of different senescent markers including p16INK4a, p15INK4b, SA-β-gal, Dec1, DcR2 and SAHF, while these markers were rare or absent in the same tumors after they turned malignant; this could prove useful both in prognoss and diagnosis of cancer.