c-erbB-2 expression in FNAB smears and matched surgical specimens of breast cancer.

Most of the data regarding the significance of c-erbB-2 oncogene expression as a prognostic marker in breast cancer have been generated in many large retrospective studies by retrieving the corresponding oncoprotein in archival paraffin embedded sections. Recently, employing fresh breast cancer cells obtained by means of fine-needle aspiration biopsy, we found a rate of c-erbB-2 positive breast tumors (58\%) higher than that reported in paraffin-embedded tissue sections by others studies. The present analysis was undertaken to investigate the impact of routine tissue processing on the preservation of the c-erbB-2 immunoreactivity. This issue was addressed by assessing the relative rate of c-erbB-2 oncoprotein immunodetection on FNAB smears and matched surgical specimens of breast cancer. The expression of c-erbB-2 oncoprotein was evaluated using the alkaline phosphate-anti-alkaline phosphatase (APAAP) technique in 54 breast aspirates and corresponding surgical specimens of primary breast cancer. Twenty-six (48\%) smears and 23 (43\%) matched paraffin sections gave specific signal for c-erbB-2 oncoprotein. The slightly higher incidence of c-erbB-2 expression found on smears seems to be mainly due to the better antigen preservation in the fresh cytological preparations. We conclude that routine histological processing may affect c-erbB-2 immunoreactivity; therefore, in mounting prospective studies, it is advisable to assess c-erbB-2 status in fresh tissue. Moreover, the assessment of c-erbB-2 expression on aspirate samples may yield additional information to the pre-surgical prognostic evaluation of breast cancer diagnosed by FNAB.