CDKN1A and clear cell adenocarcinoma: Moreover, an increase in either the fraction or the mean intensity of p-p21 positive cells was observed in three of the four tested cell lines, Kelly, SK-N-DZ, and BE(2)-C, indicating a preference for the anti-apoptotic function of p-p21 over its cell cycle regulatory function in NB cells, similar to findings in clear-cell carcinomas, testicular cancer, and ovarian cancer treated with cisplatin (11, 12, 46).