PTEN and melanoma: At the light of recent data indicating loss of PTEN in aggressive melanoma, characterized by impaired immune responses, it is tempting to speculate that loss of PTEN may also be followed by loss of miR-17-5p, with the consequent lack of post-transcriptional regulation in PD-L1 and the described over-activation of the Wnt-β catenin Akt/PI3K pathways.