PTGDR2 and type 2 diabetes mellitus: Since the expression of GPR44/DP2 (PTGDR2) in the pancreas is restricted to the islets with similar protein expression in both healthy and T2DM [8] we decided to further characterize the expression of GPR44/DP2 and genes related to PGD2 synthesis in all islet cell types by mining a single cell sequencing data set [16].