Prognostic score of gastric cancer determined by cDNA microarray

Purpose: To estimate gastric cancer patients' prognosis more comprehensively, we tried to develop a prognostic scoring system using a cDNA microarray. Experimental Design: RNA was extracted from tumor/normal paired samples of 43 patients with gastric cancer, and cDNA microarray hybridization was performed. Results: We selected 78 genes that were differentially expressed between aggressive and nonaggressive groups with respect to five conventional pathological factors. Next, we determined a coefficient for each gene. Thereafter a prognostic score was calculated by summing-up the value for each gene. It ranged from -47 to 201 with a median of 114. There were two peaks in its distribution. Ten of 11 patients who were alive with no evidence of recurrence >5 years after the operation showed a score of <100 points, whereas all 19 patients who died of disease showed >100 points. In 13 patients who were alive but the follow-up time was <5 years, 2 of the 3 patients with >100 points revealed recurrent disease during the follow-up. Conclusions: These findings demonstrate that such a system with cDNA microarray can contribute to the comprehensive analysis of malignant behavior of the tumor and may provide accurate information on prognosis.