PTGER1 and lung cancer: Only the expression of GPR54 was associated with CD8+ T cell infiltration in lung cancer, although Grin1 (glutamate receptor), Ptger1 (prostaglandin E receptor 1), Hrh2 (histamine receptor), Ghsr (growth hormone secretagogue receptor), and Tacr1 (substance P receptor) were detected (Panel B in Figure S1, Supporting Information).