The possible explanations are (1) lnc-PKD2-2-3 upregulate CD133 and OCT4, to increase the cell growth and invasion in CCA (19); (2) lnc-PKD2-2-3 targets anti-oncogene miR-328 to realize the CCA proliferation and invasion (31); (3) lnc-PKD2-2-3 may show similar oncogene role as its parent gene PKD2 does, to promote CCA proliferation and invasion (32, 33). Here, PKD2 is linked to cholangiocarcinoma.