FOXD1 and pachyonychia congenita: The downregulated levels of SPP1 mRNA were observed to be reversed by the introduction of antagomiR-570-3p into PC cells with suppression of lncRNA FOXD1-AS1, as depicted in Figs. 4K, L. Furthermore, Pearson correlation analysis demonstrated a positive relationship between the levels of lncRNA FOXD1-AS1 and the expression of SPP1 in tumor cells derived from primary PC tissues.