Yolk sac-derived malignant tumors develop in the absence of germ cells.

Abstract

Malignant tumors composed of extra-embryonic tissues are considered to be of germ cell origin. Since such tumors can also originate from displaced yolk sac we verified whether these neoplasms develop from germ cells possibly present in this fetal membrane. For this purpose we treated pregnant rats with Busulphan. This drug, which is known to destroy germ cells during their migratory phase, led to the complete absence of these cells in genital ridges of 12-day-old embryos removed during fetectomy. This treatment, however, did not influence the incidence or the latency period of yolk sac carcinomas or teratocarcinomas. Therefore, it is concluded that malignant yolk sac-derived tumors are not of germ cell origin.