Western blot analysis of p16^INK4a in indolent (A) and aggressive (B) lymphomas. Two transformed FCLs (3834 and 1700), one LBL (2286), and two diffuse large B-cell lymphomas (9630 and 15136) show a loss of protein expression. The Southern blot analysis of cases 17000 (T-FCL), 2286 (LBL), 9630 (DLCL), and 15136 (DLCL) is shown in Fig 1. Tumors 2286 and 9630 showed a homozygous deletion of p16^INK4a gene (Fig 1), whereas tumors 17000 and 15136 with germline configuration in the Southern blot analysis had a stop codon (Fig 2) and hypermethylation of the gene (Fig 4), respectively.