Clinical significance of serum levels of CD44 variant exons 8–10 protein in colorectal cancer

We examined serum levels of a CD44 splice variant that contained variant exons 8–10 (CD44v8–10) as a tumor marker in colorectal cancer patients. We performed enzyme-linked immunosorbent assays in 81 sera obtained from 71 colorectal cancer patients and 10 healthy controls. Serum CD44v8–10 levels were significantly higher in the colorectal cancer patients than in the healthy controls (0.209 ± 0.098 versus 0.114 ± 0.019 OD; P < 0.01). There was a close correlation between immunohistochemical expression and serum CD44v8–10 levels. Surgical resection of the tumors resulted in a reduction of serum CD44v8–10 levels. There was no significant correlation between serum CD44v8–10 level and serosal invasion or histologic type. However, a significant correlation was observed between serum CD44v8–10 level and lymphatic or venous invasion. In addition, serum CD44v8–10 levels were significantly higher in carcinomas associated with lymph node or liver metastasis than in those without metastasis. These findings suggest the usefulness of serum CD44v8–10 level in the prediction of colorectal cancer metastasis. (Received July 25, 1997; accepted Nov. 28, 1997)