TGFA and ovarian cancer: It is worth noting that almost of all the hub genes and node genes were present in the ErbB signaling pathway, such as TGFA, ErbB2, and MYC. Accordingly, we propose the hypothesis that hypoxia promotes the proliferation of ovarian cancer cells mainly by the HIF-1α-TGFA-EGFR-ErbB2-MYC regulation axis and is dependent on the ErbB signaling pathway (Additional file 4: Figure S4).