A Modification of YAMANAKA Test for the Diagnosis of Gastric Cancer

1.YAMANAKA test, a test for the diagnosis of gastric cancer using dithizone reaction for zinc in gastric juice, was applied to 100 patients with gastric cancer and 98 patients with gastric diseases other than cancer. There were 73 correct positive results (73.0 per cent) and 76 correct negative results (77.6 per cent). The accuracy of positive diagnosis was lower in the cancer patients with anacidity or hypoacidity. 2. The accuracy of YAMANAKA test was greately elevated by the previous addition of HCl prior to the test. In this modification, correct positive results were obtained in 92 of 100 (92.0 per cent) patients with gastric cancer. However, the accuracy of correct negative diagnosis was not elevated. 3. The present model experiments strongly suggest that YAMANAKA test is principally based on zinc originating in gastric cancer cells and that HCl accelerates the degenerative changes of cancer cells and transforms the released zinc-containing substances to react with dithizone easily. Thus the addition of HCl is a reasonable procedure. 4. In view of its simplicity and reliability, our modification of YAMANAKA test can be recommended as a valuable method of diagnosis of gastric cancer. Acknowledgements. The authors are indebted to Prof. Tokuoka for his interest and guidance in this investigation.