The Diverse Forms of Lactose Intolerance and the Putative Linkage to Several Cancers.
Lactase-phlorizin hydrolase (LPH) is a membrane glycoprotein and the only β-galactosidase of the brush border membrane of the intestinal epithelium. Besides active transcription, expression of the active LPH requires different maturation steps of the polypeptide through the secretory pathway, including N- and O-glycosylation, dimerization and proteolytic cleavage steps. The inability to digest lactose due to insufficient lactase activity results in gastrointestinal symptoms known as lactose intolerance. In this review, we will concentrate on the structural and functional features of LPH protein and summarize the cellular and molecular mechanism required for its maturation and trafficking. Then, different types of lactose intolerance are discussed, and the molecular aspects of lactase persistence/non-persistence phenotypes are investigated. Finally, we will review the literature focusing on the lactase persistence/non-persistence populations as a comparative model in order to determine the protective or adverse effects of milk and dairy foods on the incidence of colorectal, ovarian and prostate cancers.
Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany. mahdi.amiri@tiho-hannover.de.
Mahdi
M
Amiri
Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany. lena.diekmann@tiho-hannover.de.
Lena
L
Diekmann
Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany. maren.von.koeckritz-blickwede@tiho-hannover.de.|The Research Center for Emerging Infections and Zoonosis (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany. maren.von.koeckritz-blickwede@tiho-hannover.de.
Maren
M
von Köckritz-Blickwede
Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany. hassan.naim@tiho-hannover.de.
Hassan Y
HY
Naim
D003611:Dairy Products / Q000009:adverse effects; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D043322:Lactase / Q000145:classification / Q000172:deficiency* / Q000235:genetics; D010694:Lactase-Phlorizin Hydrolase / Q000235:genetics / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism; D007787:Lactose Intolerance / Q000145:classification / Q000175:diagnosis / Q000201:enzymology / Q000453:epidemiology* / Q000235:genetics; D009154:Mutation; D009369:Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D010641:Phenotype; D015995:Prevalence; D065840:Protective Factors; D011487:Protein Conformation; D018570:Risk Assessment; D012307:Risk Factors; D013329:Structure-Activity Relationship
D043322:Lactase; D010694:Lactase-Phlorizin Hydrolase; D007785:Lactose
adult type of hypolactasia; alactasia; colorectal cancer; lactase-phlorizin hydrolase; lactose intolerance; ovarian cancer; prostate cancer