Precancerous Lesions in Colorectal Cancer

Table 1

Proposed categories of hereditary colorectal cancer syndromes for which genetic testing is possible.

Categories of hereditary colorectal cancer
	FAP	AFAP	HNPCC/Lynch	Juvenile polyposis	Peutz-Jeghers	Cowden syndrome
Mean age at diagnosis of CRC	32–39	45–55	42–49	34	64	20
No of polyps	>100	10–100	1 (ie tumors)	5–10 or  more jp	Two or more PJ polyps
Gene	∗ APC; MYH	APC; MYH	MHS2, MLH1,; PMS1, PMS2	SMAD4; BMPR1A	STK11/LKB	PTEN
Mode of inheritance	AD	∗∗AD; ∗∗∗AR		AD	AD	AD

∗Adenomatous polyposis Coli.
∗∗Autosomal dominant.
∗∗∗Autosomal recessive.