Differential expression of miRNAs in uterine leiomyoma and adjacent myometrium of different races

African American (black) women have a higher rate, larger size and worse morbidity of uterine leiomyomata (fibroids) than white women. The racial difference in gene expression may contribute to the high burden of fibroids in black women. Dysregulated miRNAs have been found to be significantly related to tumorigenesis of fibroids, but racial difference of miRNA expression in fibroids and matched myometrial tissue remains largely unknown. Here, we examined the differential miRNA expression in fibroids and myometrial tissue adjacent to a fibroid from black (n=20) and white (n=20) women. Forty-three miRNAs were significantly different in the fibroids from the two groups. Most importantly, we found that Twenty-three miRNAs were significantly different in myometrial tissues of black and white women. We further determined the expression of the five highly dysregulated miRNAs between the two groups by real-time RT-PCR. We confirmed that miRNAs of miR-10a, miR-10b, miR-21, miR-29b and miR-145 were differentially expressed in both fibroid tissue and adjacent myometrium. Our findings suggested that racial differences in miRNA expression in leiomyoma and adjacent myometrial tissue may have an important role in the tumorigenesis of fibroids.