PECAM1 and ovarian cancer: This hypothesis is supported by the following data: 1) the regions expressing high levels of GRB7 and CD31 in ovarian cancer tissues were different; 2) knockdown of GRB7 decreased extracellular levels of VEGFA in SKOV-3 cells; 3) knockdown of GRB7 in SKOV-3 cells decreased the protein levels of VEGFR2 in co-cultured HUVECs; and 4) Knockdown of GRB7 in SKOV-3 cells decreased the protein levels of p-MEK1 and ERK1/2.