Abstract

BACKGROUND
Controversy still remains concerning the criteria for the categorization of uterine smooth muscle tumors by conventional histologic examination. Various ancillary techniques have been used to improve diagnostic accuracy.
METHODS
Immunohistochemical study of MIB-1 and p53 was performed on 10 usual leiomyomas (UL), 13 cellular leiomyomas (CL), 5 bizarre leiomyomas (BL), 2 cases of intravenous leiomyomatosis (IL), 5 smooth muscle tumors of uncertain malignant potential (STUMP) and 8 leiomyosarcomas (LMS), to investigate the diagnostic value of MIB-1 and p53 in uterine smooth muscle tumors.
RESULTS
The MIB-1 labelling index was low in ULs and their variants (mean 5.67+/-5.53), but it was increased in STUMPs (17.67+/-6.51) and markedly increased in LMSs (35.71+/-11.35). In ULs and their variants, no immunostaining for p53 was noted except in one case of BL, while 2 (40%) of 5 STUMPs and 3 (38%) of 8 LMSs showed positive reactions for p53. There were significant differences among leiomyoma, STUMP and LMS in the MIB-1 labelling index and p53 expression.
CONCLUSIONS
These results suggest that both abnormal expressions of p53 and a high MIB-1 labelling index are frequently associated with leiomyosarcoma. Our data also indicate that the classification system of Kempson and Hendrickson is well correlated with the MIB-1 labelling index.

• Keywords: Uterine neoplasms;Smooth muscle tumor;Protein p53;Ki-67 antigen;Immunohistochemistry