Colorectal cancer early screening: Dilemmas and solutions

Table 1 Familial high-risk diseases associated with colorectal cancer

Diseases	Mutation	CRC incidence	Risk	Description
Lynch syndrome[21]	mismatch repair genes such as MLH1, MSH2, MSH6, or PMS2	50%-80%	High	A hereditary condition linked to mutations in mismatch repair genes. It significantly increases the risk of colorectal cancer, often at a younger age, and is also associated with other cancers like endometrial and ovarian cancers
Familial adenomatous polyposis[22]	APC gene	100%	High	An autosomal dominant disorder caused by mutations in the APC gene, leading to the development of numerous adenomatous polyps in the colon and rectum. If untreated, nearly all individuals with familial adenomatous polyposis will develop colorectal cancer by the age of 40-50 years
MUTYH-associated polyposis[23]	MUTYH gene	43%-100%	High	A condition similar to familial adenomatous polyposis, but caused by mutations in the MUTYH gene, which also leads to the development of colorectal polyps and an increased risk of colorectal cancer
Peutz-Jeghers syndrome[24]	STK11 (LKB1) gene	NA	High	A genetic disorder characterized by the presence of hamartomatous polyps in the gastrointestinal tract and an increased risk of colorectal cancer, as well as other cancers such as breast and ovarian cancers
Juvenile polyposis syndrome[25]	SMAD4 or BMPR1A gene	17%-68%	High	A hereditary condition marked by the development of numerous juvenile polyps in the gastrointestinal tract, which can progress to colorectal cancer
Constitutional mismatch repair deficiency[26]	mismatch repair genes	NA	High	A rare, autosomal recessive condition caused by biallelic mutations in mismatch repair genes, leading to early-onset colorectal cancer and other cancers, often before the age of 20 years

NA: Not applicable.