C-ERB-B2 INT-2 AMPLIFICATION APPEARS FASTER IN BREAST-CANCER PATIENTSRECEIVING 2ND-LINE ENDOCRINE TREATMENT/

We have examined the appearance of c-erb-b2 and int-2 amplification in 2 different groups of breast-cancer patients. The groups differed wit h regard to their clinical status in that one group was receiving firs t-line endocrine treatment (tamoxifen) whereas the second was receivin g second-line endocrine treatment (after failing on tamoxifen). The la tter group of patients showed clinically a more advanced disease (high er frequency of stage-IV as compared to stage-III disease). Consecutiv e tumor samples were obtained using fine-needle biopsies from individu al tumor lesions of each patient every second or third month. Median t ime from diagnosis to the last biopsy for patients receiving tamoxifen was 25 months and, for patients receiving second-line treatment, 55 m onths. The presence of amplification was determined using semi-quantif icative PCR. We found that both genes developed amplification during t umor progression. The appearance of amplification was more pronounced in the clinically more advanced patients receiving second-line treatme nt (p = 0.018). (C) 1996 Wiley-Liss, Inc.