CLINICAL-THERAPY AND HER-2 ONCOGENE AMPLIFICATION IN BREAST-CANCER - CHEMOTHERAPY VS RADIOTHERAPY

One hundred and five breast cancer patients with stage T3/4, N+/-, Mo were treated at random either with a pre- and postoperative chemothera py (A) (5-drug-combination + tamoxifen) or with a pre- and postoperati ve radiotherapy (B). Paraffin embedded tissue samples were prepared fr om tumor material taken by biopsy prior to therapy as well as at surge ry from patients of both groups to estimate the HER-2 oncogene copy nu mbers before and after treatment. In 53 and 50% of the pretherapeutic samples the HER-2 gene was amplified in groups A and B, respectively. In the posttherapeutic group 60% of the chemotherapy and 48% of the ra diotherapy patients, respectively, had low or high HER-2 oncogene copy numbers. In addition, HER-2 amplification before and after therapy wa s estimated in 28 patients. An increase of oncogene copy numbers could be detected in 21% of the chemotherapy patients, and a decrease was n oted in 11%. No radiotherapy patient showed a rise, but 11% a loss of copy numbers. Although amplification of HER-2 oncogene was not found t o be associated with overall survival as it was in many studies before , it could still be a predictor of clinical outcome and the cause of m ammary carcinomas developing into stage T3/4.