Refined Deletion Mapping Of Loss Of Heterozygosity In Sporadic Colorectal Cancer

Background & Objective: Colorectal cancer is one of the leading causes of cancer-associated death in western countries. In England and Wales, it is the second most common cancer in women and the third most common in men; the same trend occours in China in recent years. In the carcinogenesis of colorectal cancer, the concept of adenoma-carcinoma sequence is widely accepted. In this pathway, polypoid adenoma develops into early polypoid cancer and then progresses to advanced cancer.Colorectal cancer is characterized by genomic instability, the accumulation of multiple genetic alterations, and allelic imbalance throughout the genome. Loss of heterozygosity (LOH) is a common form of allelic imbalance, and the detection of LOH has been used to identify genomic regions that harbor tumor suppressor genes and to characterize different tumor types, pathological stages and progression. Global patterns of LOH can be discerned by allelotyping of tumors with polymorphic genetic markers. Identification of molecular markers associated with colorectal adenoma may uncover critical events involved in the initiation and progression of colorectal cancer. Inactivation of tumor suppressor genes is one of the major events involved in carcinogenesis and the most common representation is loss of heterozygosity (LOH). So, We made refined deletion mapping on 6 high LOH luci and 3 LOH luci involved in tumor stage and differentiation to make further study conveniently.