2 COLONS - 2 CANCERS - PROXIMAL OR DISTAL ADENOCARCINOMA - ARGUMENTS FOR 2 TYPES OF CARCINOGENESIS

The purpose of this review is to study the literature concerning norma l colon and colorectal cancer for evidencing that the location of the primary proximal or distal tumor may determine two categories of carci nogenesis. The proximal or distal normal colon can be considered as tw o different organs. Their embryologic origins are different, the splen ic flexure starts the distal segment. Antigenic pattern as well as the use of metabolic pathways, such as that of glucose, butyrate and poly amines differ Epidemiologic, macroscopic and histological features and the inherited and acquired genetic abnormalities allow in some cases to distinguish between two types of cancer according to their proximal or distal location. These two forms are not entirely different and th ese features can overlap. However the recognition of these two differe nt forms of colon cancer, must be taken in account for clinical or bas ic research and evaluation of data.