Moreover, in view of the fact that both PD-L1 and PD-L2 were found to be expressed by breast tumor cells in patients and to be associated with each other [50,51,52,53,77], we have also analyzed the proportions of TNBC cells that co-expressed PD-L1 and PD-L2 together. This evidence concerns the gene PDCD1LG2 and breast neoplasm.