A number of different isoforms of CD44 generated by alternative splicing have 
been isolated and sequenced. There have been several reports that CD44v plays a 
role in the steps of the metastatic process. We examined the role of the variant 
CD44v8-10 in metastases of human colon cancer cell line HT29m using a monoclonal 
antibody reactive with the v9 product (mAb 44-1V). Pretreatment with mAb 44-1V 
prevented the formation of liver metastases. In addition, we found that the 
attachment of HT29m cells to the basement membrane matrix was inhibited by mAb 
44-1V. Several reports have shown correlations between metastatic potential and 
expression of CD44v in human colorectal cancer. We demonstrated that CD44v8-10 
and CD44v6 RNA expression was higher in carcinomas associated with liver 
metastases than in those without by Northern blotting. We analyzed the 
expression of the CD44v8-10 product in colorectal cancer immunohistochemically 
using mAb 44-1V, and evaluated its prognostic significance. There were 
significant correlations between CD 44v8-10 immunoreactivity and both lymph node 
and liver metastases. Patients with CD44v8-10-positive tumors had a greater 
relative risk of death compared with those whose tumors were CD44v8-10 negative. 
These results suggest that CD44v8-10 may play an important role in the adhesion 
of tumor cells to the capillaries of distant organs in the metastatic process, 
and that immunohistochemical detection of CD44v8-10 may be a biologic marker of 
prognostic significance.