HNRNPL and pachyonychia congenita: Reduced tRF-21 promoted AKT2/1-mediated heterogeneous nuclear ribonucleoprotein L (hnRNP L) phosphorylation, and then phosphorylated hnRNP L enhanced interaction with hnRNP L-DEAD-box helicase 17 (DDX17) and formed a complex of alternative splicing, promoting PC cell malignancy.