SERIAL TRANSPLANTATION OF CEA PRODUCING HUMAN GASTRIC CARCINOMAS IN NUDE MICE

Abstract

Carcinoembryonic antigen (CEA) producing human gastric carcinoma (NSC-4, NSC-5) were transplanted into BALB/c Ajcl-nu nude mice. The original tumor of NSC-4 was obtained from a 61-year-old patient, and the tumor has been transplanted serially 18 passages in nude mice. The tumor of NSC-5 was obtained from a 45-year-old patient, and the tumor has been transplanted serially 11 passages. The transplantability was 100%. The doubling time of NSC-4 in the first passage was 4.6 weeks, and that of NSC-5 was 3.5 weeks. The doubling time of NSC-4 was ranged from 1.0 to 1.9 weeks, and that of NSC-5 was from 0.9 to 2.2 weeks in the serial transplantation. CEA was appeared in the serum of nude mice after transplantation and plasma CEA level of mice was elevated as a function of time. Positive correlation was observed between plasma CEA level and tumor size. The histology of original tumor, poorly differentiated adenocarcinoma, was retained in each passage. CEA was stained positively with immunochemical technique in the original and transplanted tumors, and it was located in the cytoplasms of the tumor cell. These results indicate that CEA producing human gastric carcinomas transplanted into nude mice provide a usefull experimental model for CEA producing gastric carcinomas.