Peroxidase activity and estradiol receptors in human breast cancer

In order to establish the relation between peroxidase activity in human breast carcinoma and its estrogen-dependency, estradiol receptors and their peroxidase activities were determined by a very sensitive fluorimetric method in 61 carcinomas. The geometrical mean of peroxidase activity in the 34 estradiol receptor negative carcinomas, 12.8 mU/g tissue, was significantly higher (p less than 0.05) than that of the 27 estradiol receptor positive cases, with a mean of 10.57 mU/g tissue. Necrosis and/or inflammation were found more frequently in the estradiol receptor negative carcinomas (p less than 0.01) than in the estradiol receptor positive. It is concluded that peroxidase activity is linked more to the typical biological behavior of the tumor than to tumoral estrogen-dependency. Thus, the estradiol receptor negative tumors, which showed a more aggressive behavior associated with frequent necrosis and intratumoral inflammatory signs, had a greater peroxidase activity.