A large, prospective study in the UK General Practice Research Database identified a significantly increased risk of VS among women receiving menopausal hormone therapy.[23] While VS tumor cells are not typically observed to express estrogen receptors, a recent study observed progesterone receptor expression in ~20% of tumors.[24] Given age-dependent associations with sex observed in our analyses, where female sex conferred increased risk of VS from ages 10–59 years, the role of sex hormones in VS development likely merits further attention. This evidence concerns the gene PGR and neoplasm.