PTBP1 and cancer: Studies at the molecular level, using HCT116 and DLD-1 cell lines, have highlighted the involvement of miR-339-5p, upregulated by kaempferol, that target two different mRNAs, heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) and polypyrimidine tract-binding protein 1 (PTBP1) that, by alternative splicing of PKM mRNA, lead to M2 type-pyruvate kinase (PKM2) production, overexpressed in cancer cells compared with PKM1 expressed in normal cells.