In pyrvinium-treated MCC cells, we observed not only the expected inhibition of canonical Wnt signaling (Figure 5B and Supplemental Figure 9C) but also a significant mRNA upregulation of WNT5A and WNT5B, which are Wnt ligands known to activate the noncanonical Wnt signaling pathway, which we confirmed with RT-qPCR analysis (Supplemental Figure 9, D and E). This evidence concerns the gene WNT5B and Merkel cell skin cancer.