For example, exogenous treatment with recombinant APLP2 of chick sympathetic neurons promoted neurite outgrowth [31], whilst elevated levels of cellular APLP2 were associated with increased cellular growth of several cancer types including pancreatic cancer [74, 75], colon cancer [76], breast cancer [77] and Ewing’s sarcoma cell lines [78, 79]. This evidence concerns the gene APLP2 and breast cancer.