This idea was prompted by literature data indicating elevatedlevels of copper ions and ROS in the tissues of patients with CRC., Furthermore, it has been suggested that (Fn) may have a major impact on the occurrenceof colorectal cancer. Taking this asa motivation, we took into consideration a few fragments (Ac-KGHGNG-NH2 (1L), Ac-PTVHNE-NH2 (2L), Ac-KGHGNGEEGTPTVHNE-NH2 (3L) and its cycliccounterpart, cyclo­(KGHGNGEEGTPTVHNE) (4L)), as well as Ac-PTVHNEYH-NH2 (5L) from loop no.4 (reach inHis residues) of the FomA protein from Fn and analyzedtheir interaction with Cu­(II) ions. This evidence concerns the gene FN1 and colorectal cancer.