However, emerging studies have shown that inhibitory IC receptors PD-1 [13], [14], [15], [16], TIM-3 [17,18], TIGIT [19] and A2aR [20] are also expressed on lung, melanoma, colorectal [19], cervical [17] and gastric [18,20] cancer cells. The gene discussed is HAVCR2; the disease is melanoma.