ERBB2 and neoplasm: Even though HER2 overexpression without gene amplification was reported in 2.9–8.3% of cases (Kallioniemi et al, 1992; Persons et al, 1997; Couturier et al, 2000; Jimenez et al, 2000; Pauletti et al, 2000), discordant results between IHC and FISH were mainly observed for tumours that were scored 2+ by IHC (Persons et al, 1997; Bartlett et al, 2001; Tubbs et al, 2001).