Implication of Immune System in Colorectal Cancer

Abstract

C olorectal cancer ranks the third most common diagnosed cancer worldwide among men and women as well as occupying the third rank for causing cancer related mortality worldwide. However, most of the diagnosed cases and deaths were attributed to modifiable risk factors, such as unhealthy diet, smoking, alcohol consumption, obesity and physical inactivity which are potentially preventable. In Egypt CRC is ranked the seventh among Egyptian males or females with an increase in the estimated number of diagnosed cases due to the paucity of epidemiological studies performed on the Egyptian population and the deficiency of effective screening programs as well. Currently, the most widely used diagnostic approaches for CRC are the endoscopic procedures, such as colonoscopy and sigmoidoscopy with high sensitivity and specificity for identifying polyps and cancers. However, high cost, invasiveness and time-consuming procedures have resulted in poor compliance rates. Some inexpensive and non-invasive methods, such as the fecal occult blood test (FOBT) based screening, have also been developed, but with lower sensitivity and specificity. Also, the currently used tumor markers for diagnosis of CRC; CEA and CA19.9 were proven to have a low diagnostic applicability due to their relatively low sensitivity and limited specificity. This signifies the marked need for introduction of new biological markers for screening, diagnosis and prognosis of CRC.