ESR1 and meningioma: Previous studies have found that meningiomas tend to express progesterone receptors more frequently (32.1%–86.3%) than estrogen receptors (7.1%–50%) (Lieu et al., 2003; Wahab and Al-Azzawi, 2003; Korhonen et al., 2010), suggesting that progesterone and estrogen may influence tumor growth.