The expression of variant isoforms of CD44 (CD44v) correlates with the 
metastatic potential of various carcinomas. In endometrial cancer, however, the 
significance of CD44v-expression as a prognostic indicator has not been fully 
investigated, nor has it been compared with that of p53, estrogen receptor or 
Ki67. Surgical material consisted of 14 atypical endometrial hyperplasias (AEH) 
and 163 endometrial carcinomas (EC). Expression of CD44s, v3 and v6 in carcinoma 
tissue, and other prognostic markers were immunohistochemically evaluated. The 
expression in the squamous differentiation was strictly excluded for the 
evaluation of immunohistochemistry, because the significance was different from 
that in the adenocarcinoma component. CD44s was frequently expressed in AEH and 
EC. On the other hand, CD44v3- and v6-positivities were rare or nonexistent in 
AEH, but were observed in 8 and 35% of EC, respectively. CD44v3-expression 
correlated significantly with histologic grade and lymph node metastasis. 
However, there was no correlation between CD44v6 expression and any 
clinicopathologic factor, nor were other prognostic markers expressed. 
Univariate analysis revealed that each CD44 was a prognostic determinant in the 
patients with EC. However, employing multivariate analysis, there were only 
three independent factors: p53 overexpression, CD44v6 expression and myometrial 
invasion. CD44v6 expression in the adenocarcinoma component may directly affect 
the behavior of carcinoma and the prognosis of patients with EC.