PDCD1 and breast cancer: Interestingly, analysis of publically available patient databases with breast cancer, and in particular with triple negative patients, tends to suggest that high expression of interactors of PD-1, e.g. PD-L1 and PD-L2 and of CTLA-4, e.g. CD80 and CD86, generally expressed in the tumor microenvironment [24,25], are strongly correlated with the prognosis for patients.