ESR1 and glioblastoma: Despite knowledge of the influential role of age and sex in the aggressiveness of glioma, the risk factors associated with the development of this disease are not defined.3 There is a greater incidence in men versus women (1.6:1), suggesting a hormonal influence during the development and progression of the disease.34 Although the role played by estrogen and its receptors (ESR1 and ESR2), during the development of GBM is still not clear, here we have been able to identify an association of ESR1 with the tumor microenvironment.