title: Analysis of mammary tumors for cytochemical evidence of endogenous mammary peroxidase.
abstract: The purpose of this study was to determine whether or not endogenous mammary peroxidase can serve as a cytochemical marker to distinguish ovarian hormone-dependent from ovarian hormone independent mammary tumors. Spontaneous mammary tumors arising in virgin C3H and GR mice (hormone independent tumors) and hormone-dependent mammary tumors arising during pregnancy in GR mice were examined. None of these tumors contained mammary peroxidase. Mammary tumors induced in Sprague-Dawley rats with methylnitrousourea (MNU) and dimethylbenzanthracene (DMBA) were also examined. These tumors included hormone-dependent and hormone independent ones. Several of the DMBA-induced hormone-dependent tumors contained a few peroxidase-positive cells, but the hormone independent tumors were negative. All of the MNU-induced tumors examined were negative for mammary peroxidase. Twenty human breast tumors (malignant and non-malignant) removed from women at surgery, were also negative for mammary peroxidase. Our results indicate that endogenous mammary peroxidase cannot be used to distinguish hormone-dependent from hormone independent mammary tumors.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology; D005260:Female; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology*; D008770:Methylnitrosourea; D051379:Mice; D010544:Peroxidases / Q000032:analysis*; D011247:Pregnancy; D051381:Rats
chemical_list: D015127:9,10-Dimethyl-1,2-benzanthracene; D008770:Methylnitrosourea; D010544:Peroxidases