[Extracellular nucleic acid in ascitic experimental tumors].

By using the phenol method, employed for obtaining RNA, the factor possessing electrophoretic mobility close to that of more rapidly migrating conformomer 5 S p-RNA and resistant to the action of pancreatic RNA-s was isolated from noncellular ascitic fluid, Ehrlich and NK/Ly tumors, hepatoma 22a, Zajdela hepatoma, ovarian ascites tumor in rats. This factor is suggested to participate in suppression of antitumor immunity in cancer.