Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk

Table 1

Genetic classification of CRC.

Sporadic CRC	Familial CRC	Hereditary CRC
Occurs entirely by chance throughout life without any previous family history	Occurs when there are two or more family members with a history of CRC	When people inherit a high penetrant gene mutation from either of their parents
	No specific inherited gene mutation has been identified to explain the cancer yet.
~60%–80%	~15%–30%	~5%