SOX2 and leiomyoma: Leiomyoma stem cells, also called tumour‐initiating cells, express high levels of stemness markers including Nanog, Oct4, Sox2 and KLF4, while showing low levels of oestrogen receptor, progesterone receptor and smooth muscle actin, in line with their undifferentiated status.3, 4 UL stem cells also have a shorter doubling time than myometrial progenitor cells.3