Ki-67 expression in patients with uterine leiomyomas, uterine smooth muscle tumors of uncertain malignant potential (STUMP) and uterine leiomyosarcomas (LMS)

Abstract

Background:The aim of the current study was to evaluate the expression of Ki-67 in uterine smooth muscle tumors, comparing leiomyomas, uterine smooth muscle tumors of uncertain malignant potential (STUMP) and uterine leiomyosarcomas (LMS) and to prove the accuracy of a Ki-67 expression as a useful parameter in the diagnosis of LMS. Methods: Ki-67 was assessed using immunohistochemistry from paraffin-embedded tissue in 20 patients with uterine LMS, 22 cases of STUMP and 25 cases of leiomyomas. Results: Ki-67 was present in 10/20 (50%) LMS, in 0/22 (0%) STUMP and in 2/25 (8%) leiomyomas. Significant differences regarding the frequency of Ki-67 expression were observed between LMS and STUMP (p ¼ 0.0001) as well as between LMS and leiomyomas (p ¼ 0.002), but not between STUMP and leiomyomas (p ¼ 0.491). Likewise, the staining intensity differed significantly between LMS and leiomyomas (p ¼ 0.018) as well as between LMS and STUMP (p ¼ 0.002), but not between STUMP and leiomyomas (p ¼ 0.368). Conclusions: Our results demonstrate that the significantly elevated Ki-67 antigen expression in LMS, which correlates well with the rapid growth of these malignant tumors, may be a useful immunohistochemical parameter to distinguish between cases of malignant smooth muscle tumors and those of uncertain or borderline histology.

Immunohistochemical studies on uterine carcinosarcoma, leiomyosarcoma, and endometrial stromal sarcoma: expression and prognostic importance of ten different markers

“…In our series, positive Ki-67 staining was seen in 89% of CS cases, 67% of LMS cases, and 63% of ESS cases. Intense Ki-67 staining has been linked to malignant transformation [20,[24][25][26]. Accordingly, our results in CS and LMS cases are acceptable and in line with those of previous studies.…”

Analysis of Allelic Loss as an Adjuvant Tool in Evaluation of Malignancy in Uterine Smooth Muscle Tumors

“…13 In a study that evaluated Ki-67 expression, all of 22 STUMPs were, despite the presence of mitotic activity, Ki-67 negative and clinically benign. 18 Gokaslan et al reported similar findings in 2 STUMPs. 9 However, Ki-67 was positive in 8% and 35% of leiomyomas in each study, respectively.…”

Uterine leiomyosarcomas are characterized by high p16, p53 and MIB1 expression in comparison with usual leiomyomas, leiomyoma variants and smooth muscle tumours of uncertain malignant potential

“…have demonstrated a MIB1 proliferation index in excess of 15% in 93.5% of leiomyosarcomas, but in no STUMPs or cellular leiomyomas 18 . A low MIB1 proliferation index in STUMPs has also been found by Mayerhofer et al ., 29 in spite of considerable mitotic activity. In our study, all of the non‐sarcomatous lesions, except one usual leiomyoma, exhibited a MIB1 proliferation index of < 20%, while in 19 of 22 leiomyosarcomas this was in excess of 20%.…”