Herceptin plus anti-estrogen decreases proliferation in some endometrial cancers

Combining Herceptin (trastuzumab) with anti-estrogen agents may benefit patients with malignant endometrial tumors with a positive estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status, German investigators report.

Herceptin, a recombinant anti-HER2 antibody, is used in the treatment of breast cancers that overexpress the oncogene HER2, and it is being investigated for treatment of endometrial carcinomas. Dr. O. Treeck and associates at the University of Lubeck examined the effect of Herceptin on HER2-mediated growth of endometrial cancer cell lines, in the presence and absence of estradiol. One cell line was ER-positive and the other was ER-poor, according to their report in the June issue of the European Journal of Cancer, and both expressed moderate levels of HER2. Dr. Treeck’s group treated the cells with heregulin-beta-1 to produce a model of HER2 overexpression, since overexpression is associated with poor survival.Herceptin inhibited HER2 signaling and the proliferation of both lines in the absence of estradiol. It was also effective when HER2 was upregulated by heregulin. In both cell lines, estradiol treatment counteracted the effects of Herceptin regardless of ER status.However, only in the ER-positive cell line was estradiol-induced proliferation blocked by the pure anti-estrogen ICI 182,780.’These findings suggest that combined treatment with Herceptin and ICI 182,780 may be useful for the treatment of patients with endometrial cancer expressing both ERs and HER2,’ the authors conclude.(Source: Eur J Cancer 2003;39:1302-1309: Reuters Health: June 27, 2003: Oncolink)