Expression of steroid receptors, Ki-67, and p53 in uterine leiomyosarcomas

The expression of estrogen receptor (ER), progesterone receptor (PR), tumor suppressor oncogene p53, and Ki-67 was compared in uterine smooth muscle t umors, including leiomyosarcoma (LMS), tumor of uncertain malignant potenti al (UMP), cellular leiomyoma (CL), bizarre leiomyoma (BL), and usual leiomy oma (UL). ER and PR were expressed in all ULs. PR was expressed in UL irres pective of the phase of the menstrual cycle; this staining was also observe d in CL, UMP, and BL, although BL showed variable staining for ER. Compared to these tumors, the expression of both ER and PR was markedly reduced in LMS. The results of ER and PR transcripts by reverse transcription-polymera se chain reaction were compatible with those of immunohistochemistry. The n umber of Ki-67 positive cells in LMS was significantly higher than in UMP, BL, CL, and UL. p53 immunoreactivity was seen in 10 of 14 LMSs, and missens e mutation in the p53 gene was found in 4 of 10 LMSs. These results suggest that abnormal expression of ovarian steroid receptors, p53, and Ki-67 is f requently associated with LMS of the uterus.