The endodermal origin of the endocrine cells of an adenocarcinoma of the colon of the rat.

A transplantable adenocarcinoma of the colon of the rat, which contained mucous, columnar, endocrine, and undifferentiated carcinoma cells, were cloned to see if each of the differentiated cell lineages had a common cell or origin. Four clonal lines were produced by the transplantation of single cells using micropipettes. Each tumor contained all four cell lineages but in markedly differing proportions. A confirmatory experiment was performed using a lung colony cloning assay. Seven tumors were obtained; each had mucous, columnar, endocrine, and undifferentiated cells. It is concluded that the endocrine cells of the colon are derived by differentiation from endoderm. They are not of neural crest origin.