Mitotic indexes as indicators of malignancy in human tumors

This review summarises recent prognostic results by mitotic indices in human tumours. The prognostic value of the mitotic indices is evaluated in breast carcinoma, in transitional cell bladder carcinoma, in ovarian carcinoma, in pancreatic carcinoma and in prostatic adenocarcinoma. The results show that mitotic indices can efficiently categorise particularly breast carcinomas, transitional cell bladder carcinomas and ovarian carcinomas into groups of distinctly different prognoses. The mitotic frequency 10 mitotic figures per mm2 of neoplastic tissue seems critical. The survival of patients with slowly proliferating tumours is significantly better than the survival of patients with a mitotic frequency over 10 mitotic fiqures per mm2 of neoplastic tissue. Methodological analyses also indicate that mitotic indices are reproducible and accordingly suitable for grading of tumours in clinical context. However, there are several variation factors related to mitosis counts like variation related to a delay in fixation, intratumoural variations, and variations related to observational reasons. Adequate standardization of fixation and measurement process probably improve the prognostic estimates based on mitosis counts.