Immunohistochemical Expression of Lymphoid Enhancer-binding Factor 1 in Low-grade Endometrial Stromal Tumors.

Endometrial stromal tumors (ESTs) are uncommon uterine mesenchymal lesions. Nuclear expression of ß-catenin, an indication of activated Wnt/ß-catenin signaling pathway, was described in 50% to 92% of low-grade ESTs, including endometrial stromal nodule and low-grade endometrial stromal sarcoma. Activation of the Wnt/ß-catenin signaling pathway leads to the translocation of ß-catenin into the nucleus and interaction with the T-cell factor/lymphoid enhancer-binding factor-1 (LEF1) family of transcription factors to regulate cell proliferation, differentiation, migration, and survival. Immunohistochemical analysis of ß-catenin and LEF1 was performed in 2 endometrial stromal nodules and 20 low-grade endometrial stromal sarcomas and demonstrated 90.9% and 81.8% positive rates for ß-catenin and LEF1, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of ß-catenin and LEF1 were 90.9% versus 81.8%, 81.0% versus 85.7%, 83.3% versus 85.7%, 89.5% versus 81.8%, respectively, in the diagnosis of low-grade ESTs. There is no statistical significance of the performance of ß-catenin and LEF1 in all ESTs (P = 0.664) or in primary or metastatic/recurrent settings (P = 0.515 and 0.999, respectively). Only 3 smooth muscle tumors showed focal and weak positivity for LEF1. Our results indicate LEF1 can be a useful marker in aiding a diagnosis of low-grade EST and differentiating from smooth muscle tumors alone or in combination with ß-catenin.