Copper uptake occurs mainly through the small intestine, the small intestine epithelium took up copper ions via copper transporter 1 (CTR1) or called solute carrier family 31 member 1(SLC31A1), the transporter encoding by slc31a1 on the cell surface.
The uptake of copper ions by tumor cells also requires the involvement of CTR1, and the elevated and decreased expression levels of SLC31A1 directly affect intracellular copper ion levels.