CD274 and squamous cell carcinoma: NA, not available; CHOP, cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisolone; R-CHOP, rituximab-CHOP; M, male; F, female; FISH, fluorescence in situ hybridization; MALT, mucosa-associated lymphoid tissue; PD-L1, programmed death-ligand 1; SCC, squamous cell carcinoma