Possibility of the prediction of metastasis using molecular biological examination of biopsy specimens in patients with gastric cancer -clinical study of CD44 variant mRNA expression in gastric cancer-

CD44 is a cell surface adhesion molecule involved in cell-cell and cell-matrix interactions. CD44 exists in a standard form and in multiple isoforms, each generated by alternative splicing of up to 10 variant exons (termed v1-v11) encoding parts of the extracellular domain. Expressions of CD44 and its variants are associated with cancer progression and metastasis. We examined the expression of CD44 containing a segment encoded by variant exon 6 (CD44v6) mRNA in 73 cases of gastric cancer using molecular biological examination of surgical specimens. The level of CD44v6 mRNA expression was significantly higher in patients with lymph node metastasis and liver metastasis. In 48 curatively resected patients, the level of CD44v6 mRNA expression significantly correlated with recurrence. Furthermore, there was a significant survival advantage in patients iwth a low level of CD44v6 mRNA expression as compared to those with high expression. We also examined the level of CD44v6 mRNA expression in endoscopic biopsy specimens from 25 cases of gastric cancer. The expression of CD44v6 mRNA in biopsy specimens was similar to that in surgical specimens from the same patient. These results suggest that the level of CD446 v mRNA expression is a potential prognostic indicator and may be useful as a preoperative predictor of distant metastasis and recurrence in patients with gastric cancer.