Recovery of transformed nodule and ductal mammary cells from carcinogen-treated C57BL mice.

Transformed nodule and ductal mammary cells were recovered by cell dissociation and transplantation of mammary cells from C57BL/Crgl mice treated with 7,12-dimethylbenz(a)anthracene. Four-week-old mice were divided into the following groups: Group A, not treated; Group B, 2 pituitary isografts under the kidney capsule; Group C, 1.0 mg 7,12-dimethylbenz(a)anthracene intragastrically at 5 and 6 weeks of age; and Group D, 2 pituitary isografts and 1.0 mg 7,12-dimethylbenz(a)anthracene intragastrically at 5 and 6 weeks of age. At 10, 14, 18, and 22 weeks of age, the mammary glands were enzymatically dissociated, and 10(5) cells were injected into the gland-free mammary fat pads of 3-week-old syngeneic mice. After 10 weeks, the outgrowths were examined and classified as ductal, ductal dysplasia, or hyperplastic alveolar nodule. Ductal dysplasias and hyperplastic alveolar nodule outgrowths were recovered from carcinogen-treated mice. Pituitary isografting enhanced the recovery of ductal dysplasia. Five serially transplanted dysplastic outgrowth lines were established and are their fifty and sixth transplant generations. The data demonstrate that transformed mammary gland cells can be removed from carcinogen-treated mice by means of cell dissociation and transplantation.