Kinetics of carcinoembryonic antigen and carbohydrate antigen 19-9 production in a human pancreatic cancer cell line (SUIT-2).

Kinetics of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) production in a human pancreatic cancer cell line (SUIT-2) were investigated. Production of CEA reached a maximum, 31.0 ng/1 X 10(6) cells, in the late stationary phase with transient decline during the early exponential phase and 15.5% of the produced CEA was released into the medium, while production of CA19-9 reached a maximum, 421 U/1 X 10(6) cells, in the early stationary phase and 68.8% of the produced CA19-9 was released into the medium. Accordingly, the kinetics of CEA and CA19-9 production of SUIT-2 in vitro might be independent. CEA was stained immunohistochemically in the cytoplasm of the cells forming small buds above the monolayer cell sheet. On the contrary, CA19-9 positive cells were observed scattered in the monolayer cell sheet and CA19-9 was stained in the cytoplasm, predominantly at the projections of the cell surface. CEA and CA19-9 were also detected in the sera of nude mice bearing SUIT-2 tumors and their concentrations correlated well with tumor volume. Correlation coefficients between tumor markers and tumor volume were 0.79 (p less than 0.01) for CEA and 0.90 (p less than 0.01) for CA19-9.