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Photo Courtesy of the National Institute of Health
For those of us who have been diagnosed with cancer, time is a precious commodity. The time and distance from the scientist's lab bench to the patient's bedside must be shortened. ~ Larry Lucchino
Characteristics of Lynch Syndrome:
Autosomal dominant inheritance pattern
Earlier average age of onset of colorectal cancer than in the general population (45 years in Lynch syndrome v. 63 years in the general population)
Proximal (right sided) colonic cancer predilection (70%-85% of colorectal cancers in Lynch syndrome are proximal to the splenic flexure)
Accelerated carcinogenesis (tiny adenomas can develop carcinoma within 2-3 years in Lynch syndrome v. 8-10 years in the general population)
High risk of additional colorectal cancers (25%-30% of patients who have surgery for a Lynch syndrome-associated colorectal cancer within 10 years of surgical resection if they received a less than subtotal colectomy) Starts at an earlier age than the general population. Average onset is 44 years old. Lifetime risk is 60% to over 80%.
Increased risk of malignant disease at certain extracolonic sites
Endometrium (20-65% lifetime risk for female mutation carriers)
Ovary (9%-12% lifetime risk for female mutation carriers)
Stomach (11% - 19% lifetime risk. Higher risk in individuals of Asian descent. Average age of presentation at 56)
Small Bowel ( Lifetime risk is 1% to 4%.)
Hepitobilliary Tract ( Lifetime risk is 2% to 7% )
Pancreas ( Lifetime risk is 4%)
Upper Uroepithelial Tract (transitional cell carcinoma of ureter and renal pelvis. Lifetime risk is 4% to 10%. )
Prostate (two fold higher)
Sebaceous adenomas, sebaceous carcinomas and multiple keratoacanthomas in Muir-Torre syndrome (variant of Lynch syndrome)
Subset of Breast Cancer
Pathology of colorectal cancer is more often poorly differentiated, with an excess of mucoid and signet cell features, a Crohn-like reaction and an excess of infiltrating lymphocites within the tumor.
Increased survival from colorectal cancer
Germline mutation in a mismatch repair gene (most commonly MLH1, MSH2 or MSH6) that segregates in the patient's family (i.e., members who carry the mutation show a high rate of syndrome-related cancers than those who do not carry the mutation.)
In the MSH-6 mutation, most individuals have colorectal cancers located on the left side of the colon; including the descending colon, the sigmoid colon and the rectum, different from many of those with Lynch syndrome in which the cancers are proximal. There are more cases of endometrial cancer within those with an MSH-6 mutation.