CDKN2A and neoplasm: Class II included tumours that carried wild-type TP53, expressed p16 and was not amplified at 11q13, class III included tumours that also carried wild-type TP53 and expressed p16 but were amplified at chromosomal band 11q13 and class I tumours were those with all other combinations of TP53 mutation status, p16 expression and 11q13 amp status.