NPPA and colorectal cancer: Four endogenous cardiac hormones [vessel dilator, kaliuretic peptide (KP), atrial natriuretic peptide (ANP) and long-acting natriuretic peptide (LANP)] have anticancer effects in vivo(10–12), and in vitro have been reported to decrease the numbers of human renal carcinoma cells by up to 81% (13), human colorectal cancer cells by 89–97% (14) and pancreatic cancer cells by up to 65% (15).