It could be supposed that in patients with extra GI neoplasms, such as breast cancer, the FEC60 protocol induces alterations in the intestinal permeability associated with modifications in the levels of those hormones regulating the growth and physiology of intestinal membranes (such as GLP-2, ghrelin and, to a less extent, EGF). This evidence concerns the gene GCG and digestive system neoplasm.