[Study on the clinical usefulness of NCC-ST-439 in cases of digestive tract cancer].

NCC-ST-439 is a monoclonal antibody established from human stomach cancer xenografted nude mice. The values of NCC-ST-439 were measured in 139 cases with various digestive tract cancers and 294 cases with benign digestive tract diseases with the NCC-ST-439 EIA kit (Nihon Kayaku Co., Ltd.), and its clinical usefulness was compared with those of CA19-9 and CEA. The positive rates of NCC-ST-439 in cases of digestive tract cancer were high, i.e., 66.7% for cancer of the bile duct, 58.3% for pancreatic cancer and 52.9% for colorectal cancer. In the benign digestive tract diseases, the overall positive rate seen in case of cholelithiasis and cholangitis, chronic gastritis, benign colorectal diseases and hepatitis, was only 3.7%. The positive rate of NCC-ST-439 was lower than those for CA19-9 and CEA in cases of stomach cancer, colorectal cancer and liver cancer, but it was the same as that of CA19-9 and higher than that of CEA in cases of biliary tract cancer and pancreatic cancer. The false positive rate of NCC-ST-439 in benign diseases of the digestive tract was the lowest among the three markers. With respect to sensitivity, specificity and efficiency, CA19-9 showed the highest sensitivity, but NCC-ST-439 and CEA showed better specificity than CA19-9, and NCC-ST-439 showed the highest efficiency. In combination assays using combinations of NCC-ST-439, CA19-9 and CEA, the positive rates for ST-439 alone were 22.1% for stomach cancer, 52.9% for colorectal cancer, 15.0% for liver cancer and 58.3% for pancreatic cancer, while the combined rates increased to 51.9%, 70.6%, 75.0% and 66.7%, respectively. In an investigation of changes with time in NCC-ST-439 values during chemotherapy of various types of digestive tract cancer, there was a decrease in PR cases, no change in NC cases and a tendency to increase in PD cases. These results suggested that it was possible to apply NCC-ST-439 clinically.