Clear cell carcinoma of the ovary: Characterization of its CD44 isoform repertoire

Objective. CD44 is a cell surface receptor implicated in tumor metastases. We have previously shown that there is a loss of CD44 splice control in cle ar cell carcinoma (CCCa) of the ovary. Our aim is to characterize the expre ssion of CD44-3v, -5v, -7v, and -10v in clear cell ovarian tumors and to de termine their prognostic value. Methods. Twenty-two cases of ovarian CCCa were studied for CD44-3v, -5v, -7 v, and -10v expression by immunocytochemistry, Results. The primary tumors showed expression of CD44-3v, -5v, -7v, and -10 v in 44, 55, 61, and 39% of the cases, respectively. We were able to compar e the expression of CD44 in the primary tumor and metastatic sites from the same patient in 7 cases (metastatic sites n 16). We observed decreased imm unoreactivity of CD44-3v, -5v, -7v, and -10v in 67, 100, 93, and 92% of the sites, respectively. CD44-3v and -10v expression was absent in 100% of the nonaffected contralateral ovaries while -7v and -10v were expressed in 1/1 1 (9%) of them. When CD44-10v was not expressed in the primary tumor, only 18% of the women recurred or died of disease; in contrast, of the cases whe re it was present, 71% of the women recurred or died of disease (P = 0.049) . Conclusions. There is aberrant alternative mRNA splicing in the development of CCCa of the ovary when compared to the contralateral nonaffected ovary. The expression of CD44-10v correlates with survival. Larger series are nee ded to further understand the role of CD44 isoforms in ovarian cancer metas tases. (C) 2000 Academic Press.