In studies investigating the cause of increased MDSC production in patients with uterine cervical and endometrial cancers, an increased number of MDSCs was found to be associated with increased serum E2 concentrations [33], serum PGE2 concentrations [29,30], leukocytosis [21,22,29], tumor G-CSF concentrations [21,22,28,29], IL-6 expression [29], or number of cancer stem-like cells in tumors [29,30]. This evidence concerns the gene CSF3 and cancer.