Establishment and characteristics of two new human mammary carcinoma lines in nude mice with special reference to the estradiol receptor status and the importance of stroma for in vivo and in vitro growth.

Two new human mammary carcinoma lines originating from surgical material were established in nude mice. According to the adopted criteria, the tumor 4049 has been classified as estradiol receptor positive and mammary carcinoma 4296 as estradiol receptor negative. Both tumors proved to be c-erbB-2 protein positive and EGF-receptor negative. In contrast to carcinoma 4296, the in vitro growth and the take rate of mammary carcinoma 4049 in nude mice seems to be dependent on stromal components. Pretreatment of mice with estradiol/peanut oil before tumor engraftment was an essential precondition for the growth of the primary tumor in nude mice. After successful establishment the tumor growth was significantly stimulated by estradiol. The growth rate of mammary carcinoma 4296 was independent of any supplementation of estradiol. The two breast tumors were characterized with regard to their growth behaviour, histology, and sensitivity to cytostatics and antihormones. They are considered suitable tumor models for the testing of antineoplastic substances and for biological experiments.