Cáncer colorrectal: del laboratorio al paciente, un paso ya imprescindible

Colorectal cancer is the third most common cancer in men and the second in women worldwide, whereas gastric cancer is the fourth most frequent cancer in men and the fifth in women. In both cases, the differences in incidence among diverse geographic areas are very substantial and are clearly associated with dietary and environmental factors. Different Latin American registries show colorectal cancer incidence to be below that of other regions, particularly in the more developed countries. Unfortunately, whereas the incidence of this cancer is decreasing in the Western world, Latin American countries have registered significant increases in colorectal cancer mortality rates within the last few years. The incidence of gastric cancer is particularly elevated in some Latin American countries, such as Chile or Costa Rica, but it is much lower in other regions, such as Mexico or Puerto Rico; Helicobacter pylori infection rates and tobacco consumption have been determinants for explaining the majority of these differences. Fortunately, the incidence of gastric cancer is progressively decreasing in Latin America, as in many other parts of the world. Much has been learned in recent years about the molecular mechanisms involved in the carcinogenic processes of these tumors. This is of the utmost importance, given that such knowledge is revolutionizing therapeutic approaches, enabling targeted treatments that are more efficacious in determined groups of cancers with specific alterations in some pathways instead of others the so-called precision medicine. Colorectal cancer develops through a process of numerous stages, known as the adenoma-carcinoma sequence, proposed by Fearon and Vogelstein more than two decades ago. During this process, genetic and epigenetic alterations accumulate in genes that are crucial for controlling cell