APOBEC3B and cancer: Because abrogated FHIT activity may increase the levels of mutagenesis both as a standalone mechanism and synergistically with APOBEC3B [7, 9, 32], we note that cell lines from several cancer types including head and neck (4.85) and sarcoma (4.87) had a considerably lower mean FHIT expression than the pan-cancer average (5.74).