Following the recent finding that PD-L1 protein expression correlated with PTEN loss [14], we came to the hypothesis that tumour progression and PD-L1 expression are independently related to PTEN loss, and that the clinical effect of PD-L1 may, at least in part, be attributed to the correlation between PTEN loss and PD-L1 expression. Here, PTEN is linked to neoplasm.