Abstract: Objective: To investigate the effect of infiltrated mast cells on the biological characteristics of uterine tumors. Methods: Twelve leiomyomas, ten uncertain malignant uterine leiomyomas, and seven uterine leiomyosarcomas had been studied with light microscopy for the morphometry about their histological feature, mast cell particle and factor Ⅷ-related antigen (FⅧRAg); Cell apoptosis had been measured by flow cytometry. The correlative analysis had been carried out between the mast cell and others factors. Results: Comparing with smooth muscle tumors of uncertain malignant potential (4209.9±273.0), the count of tumor cell was the highest in leiomyosarcoma (3557.6±346.3, P<0.01), lowest in leiomyoma (5182.3±245.6, P<0.01). The ratio of mast cell's particles to whole tissue was the smallest in leiomyosarcoma (1.81±0.13%, P<0.01), largest in leiomyoma (4.51%±0.63%, P<0.01) vs smooth muscle tumors of uncertain malignant potential (3.41%±0.16%). Positive FⅧRAg of endothelia was the most scant in leiomyo- sarcoma (668.98±180.87μm2, P<0.01), the most abundant in leiomyoma (164.50±57.33 μm2, P<0.01) vs smooth muscle tumors of uncertain malignant potential (231.93 ± 65.37 μm2). The apoptosis ratio in leiomyosarcoma was the highest (15.38%±0.58%, P<0.01), the lowest in leiomyoma (3.31%±0.26%, P<0.01) vs smooth muscle tumors of uncertain malignant potential (8.36%±0.52%). Negative correlation had been confirmed between the ratio of mast cell's particles to whole tissue and the cell count, the ratio of particles in mast cells, or the apoptotic ratio in all uterine tumors. Conclusions: It suggested that there is a negtive correlation between the remained area ratio of mast cell and the atypical degree of neoplasm from uterine smooth muscles.

Key words: uterus, neoplasm, mast cell