GPR4 and ovarian carcinoma: The family of GPCR includes the ovarian cancer G protein-coupled receptor 1 (OGR1, also known as GPR68), the G protein-coupled receptor 4 (GPR4) [88], the T cell death-associated G protein 8 (TDAG8, also known as GPR65) [91], and the G2 accumulation protein (G2A, also known as GPR132) [92].