Although they do not readily fit into any of the other categories of G protein-coupled receptor (GPCR), the receptors listed here have diverse and important physiological and pathological roles. Some examples include GPER, an estrogen receptor with physiological roles in the reproductive, nervous, endocrine, immune, and cardiovascular systems. It also exhibits potential as therapeutic target and prognostic indicator for breast cancer. FPR1 binds bacterial N-formyl-methionyl peptides, which leads to the recruitment of neutrophils to sites of infection and causes degranulation. In addition, the thrombin receptors PAR1-PAR3 are protease-activated GPCRs involved in hemostasis and thrombosis, inflammation, and tumorigenesis.