FZD6 and neoplasm: The WNT ligands and their receptors FZD5 and FZD6 are expressed at variable levels in PDAC tumour in the cancer cell subpopulations (collectively designated epithelial cells in Fig. 2c) but also in the surrounding stromal cell types, especially fibroblasts, and immune cells (Fig. 2c, d; Supplementary Fig. 2c).