EXPRESSION OF CD44 AND ITS CLINICAL IMPLICATION IN DIFFUSE-TYPE AND INTESTINAL-TYPE GASTRIC ADENOCARCINOMAS

Knowing the differential expression of CD44 isoforms in intestinal- an d diffuse-type gastric carcinomas, we used antibodies against the stan dard form of CD44 (CD44s) and the domain encoded by exon v6 (CD44v6) i n 103 patients with primary gastric adenocarcinomas to explore the rol e of CD44 isoforms in metastases of both types of gastric cancer. Carc inomas of the intestinal type were more frequently CD44s and CD44v6 po sitive than carcinomas of the diffuse type (p = 0.034 for CD44s and p = 0.022 for CD44v6). The reactivity to these two antibodies did not co rrelate with histopathological and clinical prognostic factors in inte stinal-type carcinoma. In contrast, expression of CD44v6 was associate d with infiltrative tumor growth (p = 0.021), depth of invasion (p = 0 .012), lymph node involvement (p = 0.005) and a higher incidence of di stant metastasis (p = 0.069) in cancers of the diffuse type. CD44s-exp ressing diffuse-type tumors had a higher incidence of distant metastas is at presentation (p = 0.001), but expression of CD44s was not correl ated with other clinicopathologic indices. For all cases, there was a nonsignificant association between CD44s expression and poor survival. Unexpectedly, there was also no significant difference in survival re garding expression of CD44v6 for all cases or the diffuse-type subset. This study showed the role of CD44v6 in invasion and metastases of di ffuse-type gastric carcinoma and demonstrated the necessity of subclas sifying tumor types when studying the clinical significance of CD44 in human cancers.