SLC44A4 and non-small cell lung carcinoma: Currently, the blockade of PD-1 signaling and CTL4 signaling utilizing the PD-1/PD-L1 antibody and CTL4 antibody, respectively, has shown promising therapeutic effects in a variety of cancers, such as melanoma, non-small-cell lung cancer, renal cell cancer, and lymphoma (28–30).