Let‐7 repression leads to HMGA2 overexpression in uterine leiomyosarcoma

Overexpression of HMGA2 is common in uterine leiomyomas (ULM). The expression of HMGA2 in its malignant counterpart – uterine leiomyosarcomas (ULMS) remains undetermined. Recently it has been shown that repression of HMGA2 by microRNA let‐7s is a critical molecular regulatory mechanism associated with tumour growth in many tumours and cell types, including leiomyomas. To test whether HMGA2 and let‐7s play a role in ULMS, we examined the levels of endogenous HMGA2 and let‐7 expression and found a significant correlation between these two molecules in a case‐matched cohort of human ULMS. We found that overexpression of HMGA2 and let‐7‐mediated HMGA2 repression is a relevant molecular alteration in ULMS. Disrupting the control of HMGA2 and let‐7 pairs promotes ULMS cell growth in vitro.