Yolk sac carcinoma grown from rat egg cylinders.

Eight-day rat egg cylinders transplanted in toto under the kidney capsules of adult histocompatible recipients gave rise to small nodules composed of parietal yolk sac cells surrounded by Reichert's membrane-like material. These yolk sac cells could grow and give rise to malignant, transplantable tumors identical to mouse yolk sac carcinomas derived from teratocarcinoma. The sera of rats with yolk sac tumors contained elevated concentrations of alpha1 fetoprotein.