TTN and cholangiocarcinoma: In CCA tissues, an inverse correlation between expression levels of TTN-AS1 and miR-320a (Fig. 1d) and between miR-320a and NRP-1 mRNA (Fig. 1e) and a positive correlation between TTN-AS1 and NRP-1 mRNA (Fig. 1f) were found by using Pearson correlation analyses.