CCND1 and cervical cancer: In conclusion, this is the first study to demonstrate that GDF15 activates the PI3K/AKT and MAPK/ERK signaling pathways in a complex with ErbB2, which then alters the expression of cell cycle regulators including p21, CDK2/4 and CyclinD1/E1, and ultimately promotes cell proliferation in human cervical cancer (Fig. 8).