CLDN2 and breast cancer: The individual ingredients of BC, viz., lactoferrin, immunoglobulins, fatty acids, and IGF-1, when given alone may not markedly improve the integrity of the intestinal wall thus preventing hyperpermeability; however, the combined administration of BC components appears to produce an additive or synergistic effect in tightening the junctions of the intestinal epithelium by stimulating the secretion of tight-junction proteins (e.g., Claudin-2) and Paneth cells as well as reducing gut inflammation, thereby collectively preventing the seepage of endo-toxins from the lumen into the bloodstream.