ALK and neoplasm: Since PD-L1 expression in tumor cells can be influenced by the aberrant activation of oncogenic signals, such as MYC, ALK, MEK-ERK, RAS and EGFR [36], and that miR-455-5p was reported to directly regulate the EGFR expression [37], we then investigated whether miR-455-5p could interfere with the EGF mediated PD-L1 expression.