While this sequence is demonstrable in lymphoma cells exposed to cyclophosphamide [91] and fibroblasts exposed to activated Ras [59], in other cases, such as human mammary epithelial cells exposed to suboptimal culture conditions [48], [92] and melanocytes which acquire B-RAF mutations [93], p16 activation and senescence occur independently of p53 activation. Here, TP53 is linked to lymphoma.