The majority of demographic and clinicopathologic characteristics did not differ by PD-L1 expression, PD-L2 expression, or coexpression; the exceptions to this included the stage of SCLC at diagnosis by PD-L1 expression only, and LDH level by PD-L1 expression, PD-L2 expression, and PD-L1/PD-L2 coexpression. This evidence concerns the gene PDCD1LG2 and small cell lung carcinoma.