MEN1 and pituitary tumor: In addition, significantly more C57BL/6 female Men1+/- mice had pituitary tumours than 129S6/SvEv female Men1+/- mice (75.7% vs 38.0%, P < 0.0001) (Table 1), whereas there was no significant difference in the number of anterior pituitary tumours in male Men1+/- mice between the two strains (Table 1).