Epithelial origin of polyoma salivary tumors in mice: evidence based on chromosome-marked cells

Trypsin dissection of epithelium from mesenchyme of salivary gland rudiments allows reassembly of glands having either epithelium or mesenchyme selectively marked by T(6) chromosomes. Virus-induced tumors in such glands invariably bear the karyotype of the epithelial component. The method solves a specific example from a group of classical problems concerning epithelial as opposed to mesenchymal origin of neoplasms.