Interestingly, it is worth mentioning that among the three types of receptors involved in estrogen-receptor signaling, such as estrogen receptor-α, estrogen receptor-β and G protein-coupled estrogen receptor (GPER), estrogen receptor-α in terms of mRNA expression and protein content was significantly correlated with malignancy grade of tumor morphology and could be used as a prognostic biomarker of low-grade astrocytoma patients [13]. This evidence concerns the gene ESR1 and neoplasm.