SLC46A1 and cancer: In contrast, in cancer cells, folic acid is preferentially taken up by a folate receptor (FR) which has a high affinity, but a low capacity (Nutt et al., 2010; Assaraf et al., 2014), while intestinal uptake is predominantly mediated by the proton-coupled folate transporter (PCFT/SLC46A1) (Zhao et al., 2008; Zhao et al., 2009; Matherly et al., 2018).