GJA1 and endometrial cancer: Genes in vicinity of risk variants at the two other genome-wide significant loci, 3q26.2 and 6q22.31, include MECOM whose mutation is known as a somatic driver of endometrial cancer,73HSF2 encoding an oestrogen-regulated heat-shock factor,74 and GJA1 encoding the gap junction protein connexin-43 which may regulate uterine decidualisation and whose expression decreases with increased grade of EC.75