RB1 and cancer: It is noteworthy that CEN15 mimics the replication timing of RB1: (i) low SD values in cells of cancer-free patients, both with and without AZA; (ii) high SD values in the cells of the cancer patients, similar to those obtained for an imprinted region in normal cells; and (iii) a decrease in the abnormal (high) SD values in the cells of the cancer patients to normal low levels in the presence of AZA (Fig. 3c–f).