Immunohistochemical analysis of p16 expression in uterine smooth muscle tumors

The expression of p16 as a tumor suppressor protein was evaluated in a retrospective analysis of paraffin-embedded tissue specimens of leiomyosarcoma (LMS), leiomyoma (LM) and normal myometrium. In this study, we investigated by immunohistochemistry p16 expression in 15 LMSs, 15 LMs and ten normal myometrium. Strong expression of p16 was found in 12 of the 15 LMSs and in three cases weak expression; three LMs had focal and weak p16 staining but none of the normal myometrium. A statistically significant difference regarding the frequency of p16 protein expression was observed between LMS and LM (p: 0.0001). We concluded that the results of this study confirm the overexpression of p16 in LMS. Therefore, the present study suggests that p16 might be a useful immunohistochemical marker which could help in distinguishing uterine LMS from LM and its benign variants.