Helicobacter pylori: an evolutionary perspective.

Since the description of Helicobacter pylori (HP) as the most common cause of gastritis and its neoplastic complications, numerous articles have been written about the epidemiology, clinical features, diagnostic methods, histopathology, pathogenesis, molecular biology and treatment of this infection. This review focuses on those aspects of the infection that challenge the universality of the medical implications through the lens of evolutionary science applied to medicine. The divergent epidemiological and clinical outcomes observed in different populations and the possible beneficial aspects of the infection are discussed. Also reviewed are Correa's seminal contributions to our understanding of gastric cancer in particular and postinflammatory tumours in general, and the renewed interest in intestinal metaplasia and its clinical implications.