Prognostic significance of c-erb-B2 amplification in fine-needle biopsies of breast cancer patients not operated at diagnosis.

Prognostication of breast cancer patients, not operated at diagnosis, poses a clinically difficult problem. To use gene amplification we examined cytological samples and determined c-erb-B2 gene copy number with semi-quantitative PCR. Control experiments showed the same gene-copy number in aliquots that were either air-dried (and MGG-stained), fixed in methanol (and air-dried), or snap-frozen in liquid nitrogen. Therefore we examined the prognostic value of c-erb-B2 amplification in 95 breast cancer patients that had not been operated at diagnosis (up to 12 years previously). Tumor cells were obtained from routine archival cytological smears. 15 patients (16%) had developed amplification. Univariate and multivariate analysis showed that c-erb-B2 amplification is a significant prognostic factor (p < 0.0001). Hence routine cytological MGG smears can be used for prognostic determination.