Dataset analysis revealed that PD-L2 expression in basal and triple-negative breast cancer (TNBC) patients, but not in luminal A or B patients, showed a very weak negative correlation with the expression of NDRG2, suggesting a minor role of PD-L2 expression in the progression of breast tumors (data not shown). Here, PDCD1LG2 is linked to triple-negative breast carcinoma.