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

BACKGROUND

HER2/neu expression and fluorescence in situ hybridisation (FISH) amplification have therapeutic significance.

AIMS

To compare 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 two 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.