Isolation of a sarcoma virus from a spontaneous chicken tumor.

A spontaneous tumor was obtained from a hen of White-Leghorn stock raised in a local farm in Yamaguchi City, in December 1973. The tumor had characteristics of fibro- or myxofibro-sarcoma and could be maintained by transplantation in chickens of similar flocks. This tumor was proved to produce sarcoma virus at 33rd passage and the transforming virus was designated as Y73 sarcoma virus. Biological studies suggested that the virus recovered from the tumor belonged to avian leukosis-sarcoma complex having subgroup A specificity. The possibility of defectiveness of this virus will be discussed.