CDKN1A and cholangiocarcinoma: In summary, our study demonstrated the regulatory mechanism in tumorigenesis of SNHG1, by which SNHG1 could promote malignancy of CCA by binding to histone methyltransferase EZH2 (the catalytic subunit of the PRC2, a highly conserved protein complex that regulates gene expression by methylating lysine 27 on histone H3), and then specified the histone modification pattern on the target genes, including CDKN1A, thus explaining cell survival and metastasis of CCA (Fig. 7g).