Summary
The experimental production of mammary tumors by administration of 7,12-dimethylbenz(a)anthracene was confirmed. Light microscopic examination of the multiple tumors thus produced showed different histological patterns in the same animal, although all tumors behaved similarly and none metastasized. Both epithelial and myoepithelial cells participated in tumor formation; the stroma also participated actively in tumor formation and growth. Unlike the case in human myoepithelial carcinoma of the breast, the enzyme alkaline phosphatase continued to be reactive on the plasma membrane of the proliferating myoepithelial cells. It is suggested that the lack of metastasis is related to several factors, all of which need further study. These factors include the simultaneous proliferation of myoepithelial and epithelial cells, the persistence of alkaline phosphatase on the plasma membrane of myoepithelial cells, and the infiltration of the tumor by mast cells.
Footnotes
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↵1 Supported by Grant 3287-A1 from the Damon Runyon Memorial Fund and by Grant 3357-A1 from the American Cancer Society, Ohio Division.
- Received August 6, 1971.
- Accepted March 23, 1972.
- ©1972 American Association for Cancer Research.
