Consistent with recent reports (15, 16), we found the E76 residue to be the most frequently mutated H2B residue in various cancers including breast and lung carcinoma, which contained either Glu76Lys (E76K) or Glu76Gln (E76Q) missense mutations in genes encoding H2B (Table S1). The gene discussed is H2BC21; the disease is lung carcinoma.