Genetics in Colorectal Cancer

Colorectal cancer are the third most commonly diagnosed form of cancer globally, which about 11% of all cancer diagnoses. Obesity, together with kind of sedentary lifestyle, red meat consumption, tobacco, and alcohol consumption are considered as predisposing factors of progression of CRC. In the development of colorectal cancer, genetic factors having a role in its incidence. The hereditary type of colorectal cancer was divided into two types is polyposis and Lynch syndrome which have each and different mechanism and genetic pattern. Lynch syndrome contributes for 3–5% of CRC cases and is caused by a germline mutation in one of four genes associated with the DNA mismatch repair (MMR) system: MLH1, MSH2, MSH6, or PMS2. In polyposis, there are some types such as Familial Adenomatous Polyposis (FAP) which mostly caused by APC mutation, MYH-associated polyposis, and the rare hamartomatous polyposis syndromes. Genetic testing and better family history documentation can enable those with a hereditary predisposition for the neoplasm to take preventive measures. Some genetic testing can be used such as Microsatellite instability (MSI), immunohistochemistry (IHC), DNA sequencing and protein truncation that used for each type of hereditary colorectal cancer.

Hamartomatous Polyposis Syndromes: Management and Surveillance Strategies

Introduction: Hamartomatous Polyposis Syndromes (HPS) are a rare group of dominant autosomal inheritance, which is characterized by the development of hamartomatous polyps in the gastrointestinal tract. This syndrome included Juvenile Polyposis syndrome (JPS), Peutz-Jeghers syndrome (PJS), and PTEN Hamartoma Tumour Syndrome (PHTS). PTEN Hamartoma Tumour Syndrome (PHTS) itself includes Cowden Syndrome, Bannayan-Riley-Ruvalcaba Syndrome (BRRS), and Proteus Syndrome.Diagnosis of Hamartum polyarthritis syndrome (HPS) is routinely made based on clinical criteria, but sometimes the diagnosis of this syndrome becomes problematic due to the varying severity of clinical symptoms even within a family.Therefore, today, genetic testing of germ-related mutations associated with this disease is used in the diagnosis process. Management strategy of the syndrome is different due to extra-intestinal symptoms and various cancers. Clinical awareness and early diagnosis of HPS is important, so it is recommended to patients and families at risk for genetic counseling and care. Surveillance in children with HPS might prevent intestinal and extra-intestinal disorders, and reduce the risk of intestinal cancer or breast cancer in adults.

Peutz-Jeghars’ syndrome, a rare genetic disorder: A case report

Hamartomatous polyposis syndromes or Peutz-Jeghers syndrome (PJS) is a hereditary autosomal dominant disease characterized by benign hamartomatous polyps and mucocutaneous pigmentation in the digestive tract. It occurs mostly in the small intestine during first decade of life but frequently in the colon and stomach. Only a few cases have been reported in the duodenum1. Polyposis syndromes are common cause of adult intussusceptions, with polyps acting as lead points. Adult intussusceptions are rare and is almost always associated with that lead point2. Although hamartomatous polyps are not pre-malignant, there is an increased risk of gastrointestinal and non-gastrointestinal malignancy, commonly involving the small bowel. Most patients of PJS presents with acute abdomen and diagnosed as intussusceptions, commonly entero-enteric type but colo-colic intussusceptions are rare in Peutz-Jeghers syndrome3. To the best of our knowledge, synchronous colo-colic intussusception association in Peutz-Jeghers syndrome has not been previously reported.