Number of mitotic figures in microscopic picture of nephroblastoma histologic types--estimation of the value of the oldest known prognostic factor.

There are two main widely accepted prognostic factors in nephroblastoma group of tumors--histological type of tumor and clinical stage of disease. However nuclear anaplasia, one of the elements of Wilms' tumor microscopic picture was found as a new prognostic marker in this group of tumors. Estimation of nuclear anaplasia is an obligatory procedure in currently used therapeutic protocols. In our work we compared another element of nephroblastoma microscopic picture--number of mitoses as the oldest known indicator of activity of tumor cells with prognostic markers estimated in routine histologic examination according SIOP Protocols (histological risk, nephroblastoma type and the presence of diffuse anaplasia) and with CD44 expression--widely known marker of discussed prognostic value. We found statistically important correlation between number of mitoses and all the examined features. We believe that mitotic figure counting may become in future a helpful tool in the qualification of prognosis for individual patients in doubtful cases.