Changes in casein sequence abundance in DNA of mouse mammary tumors

The casein gene content of mouse mammary tumor virus-induced mammary tumors was found to be elevated, apparently in proportion to the increase in MTV proviral copy number. Conversely, mammotropic hormone-induced mammary tumor DNA was deficient in casein genes in 2 of 3 tumors. Globin gene abundance, however, in both normal and malignant mammary tissues was unchanged, regardless of changes in casein gene content. These results suggest that perturbations have occurred in a common region of DNA from mammary tumors with 2 different etiologies.