FURIN and colon carcinoma: Furin expression varies widely among the cell lines evaluated in the Human Protein Atlas (www.proteinatlas.org; Karlsson et al., 2021), but naturally furin-deficient cell lines, such as the CHO-derived RPE.40 (Moehring and Moehring, 1983; Watson et al., 1991) and colon carcinoma line LoVo (Takahashi et al., 1995, 1993), are rare.