PRL and cancer: These pathways mainly involved endocrine resistance, cancer pathways, chemical oncogenic-receptor activation, HIF-1 signaling pathway, estrogen signaling pathway, PD-L1 expression in cancer and PD-1 checkpoint pathway, relaxin pubis signaling pathway, the prolactin signaling pathway, and PI3K-AKT and other signaling pathways, and the results are shown in Fig. 2D.