CDKN2A and cancer: The most parsimonious explanation of these changes is that a t(9;21)(9p13.3;21tel) reciprocal translocation occurred in the ABC lineage, with concomitant loss of a copy of 9p (and a copy of CDKN2A) early in cancer evolution, presumably because the 9p fragment liberated by the t(9;21) translocation lacked a centromere (Fig. 7c).