CD274 and cancer: Both PD-L2 and PD-L1 are B7 family members, and binding of these ligands to the receptor PD-1 results in inhibition of T- and B-cell responses.6 Although there are many similarities between PD-L2 and PD-L1, some differences have been reported in regard to localisation,8 receptors,27 affinity with their receptor PD-121,22 and response to cytokines.28 The relationship between PD-L1 and PD-L2 expression in various types of cancers is still controversial.29–32 In this study, our results showed no significant relationship between PD-L1 and PD-L2 expression in oesophageal cancer.