Comparing subjective and digital image analysis HER2/neu expression scores with conventional and modified FISH scores in breast cancer

Abstract

Aims: HER2/neu expression and fluorescence in situ hybridization (FISH) amplification have therapeutic significance. We compared subjective HER2/neu expression scores with digital image analysis (DIA) and conventional and modified FISH scores in breast cancer.

Methods: Sixty HercepTest-immunostained breast carcinomas, prospectively scored as consensus 2+ and 3+ (DAKO protocol) by 2 observers, were analysed with DIA and conventional (Vysis) and modified FISH scoring protocols.

Results: With consensus scoring, 23 (38%) of the 60 cases were 2+ and 37 (62%) were 3+. Agreement with DIA scores was 100%. With conventional FISH scoring, 4 of the 3+ cases did not show amplification, but all of those negative cases had high HER2/neu copy numbers. With the modified FISH scoring protocol, all HercepTest immunohistochemical 3+ cases were amplified. Of the 2+ cases, 3 were amplified with the modified FISH protocol and 4 with the conventional FISH protocol.

Conclusions: Modified FISH scores were better correlated with HercepTest 3+ consensus and DIA scores than were conventional FISH scores. HER2/neu DIA scoring is a cost-effective supplementary tool in surgical pathology.