Proliferation-associated Nuclear Antigen P105 As a Marker for Metastasis of Human Gastric Cancer

The expression of the proliferation-associated nuclear antigen p105 in 43 patients with advanced gastric carcinoma was studied by multiparameter flow cytometry. The p105 immunofluorescence intensity of tumor cells in the G0G1 phase was 1.8-14.5 times that in stromal cells, and the stromal cells could be separated by flow cytometry. The p105 intensity, which is the ratio of the mean fluorescence intensity of cancer cells to that of stromal cells in the G0G1 phase, was not correlated with the DNA index, the size of the S-phase fraction, or the histological type of the tumor. However, the intensity was significantly greater in patients with hepatic metastasis and significantly lower in patients with peritoneal metastasis. The patients with a p105 intensity of 4.0 or more had a significantly higher incidence of hepatic metastasis (8/22; 36%). The patients with a p105 intensity of less than 4.0 had a significantly higher incidence of peritoneal metastasis (8/21; 38%). These results suggest that the p105 intensity is a marker of metastasis useful in the treatment and follow-up of patients.