Analysis of MED12 Mutation in Multiple Uterine Leiomyomas in South Korean patients

Uterine leiomyomas are one of the most common benign gynecologic tumors, but the exact causes are not completely understood. In 2011, through DNA sequencing, MED12 mutation was discovered in approximately 71% of uterine leiomyomas. Several recent studies confirmed the high frequency of MED12 mutation in uterine leiomyoma. Nevertheless, no study has been done on MED12 mutation in the case of patients with multiple leiomyomas in a patient. The purpose of this study was to investigate the frequency of MED12 mutations in uterine leiomyomas of South Korean patients. In addition, we examined MED12 mutation in multiple leiomyomas in the same patients. Uterine leiomyoma tissues were obtained from symptomatic women who underwent hysterectomy or myomectomy for medically indicated reasons. We collected 60 uterine leiomyomas from 41 women. Tumor size ranged from 1 to 12cm. Patients' ages ranged from 25 to 55 years with an average of 38.4 years. Of the 60 tumors, 40 (66.67%) displayed MED12 mutation. Among the 41 patients, 14 patients had multiple leiomyomas and we analyzed those multiple leiomyomas. Three of them had the same mutations. Five of them, each leiomyoma had a different mutation. Two of them did not have mutation. Four of them had both mutation-positive and mutation-negative leiomyomas. In conclusion, we confirmed the high frequency of the MED12 mutation in uterine leiomyomas of South Korean patients. We also identified various MED12 mutation status in patients with multiple leiomyomas. This suggests that in a given patient, different tumors may have arisen from different cell origins and therefore it is supposed that occurrence of multiple leiomyoma in a single patient may not be caused by intrauterine metastasis or dissemination.