On the origin of Ewing's tumor

A typical Ewing's tumor was grown in tissue culture for a prolonged period of time. The pattern of growth was that of a malignant mesenchymal tumor. Cell growth, in vitro, was accompanied by accumulation of glycogen and acquisition of hydrolytic enzyme activity, and some clones developed ultrastructural features characteristic of developing myelocytes. These findings suggest that Ewing's tumor is a neoplasm of myelogenous origin with a manner of growth and spread analogous to plasma cell myeloma.