Table 1
Clinical criteria for diagnosis of hereditary nonpolyposis colorectal cancer (HNPCC)

Model	Criteria
Amsterdam criteria I	At least three relatives with colorectal cancer; all of the following criteria should be present:
	1. One affected individual is a first degree relative of the other two.
	2. At least two successive generations involved.
	3. At least one of the relatives with colorectal cancer diagnosed before the age of 50 years.
	4. Familial adenomatous polyposis should be excluded.
Amsterdam criteria II	Each of the following criteria must be fulfilled:
	1. Three or more relatives with an HNPCC-associated cancer.
	2. Two or more successive generations affected.
	3. One or more diagnosed before the age of 50 years.
	4. One should be a first-degree relative of the other two.
	5. Familial adenomatous polyposis should be excluded.
	6. Tumors should be verified by pathologic examination.
Revised Bethesda guidelines	Tumors from individuals should be tested for microsatellite instability in the following situations; Requires at least one of the following:
	1. Colorectal cancer diagnosed in a patient who is less than 50 years of age.
	2. Presence of synchronous, metachronous colorectal, or other HNPCC-associated tumors, regardless of age.
	3. Colorectal cancer with the high level of microsatellite instability histology diagnosed in a patient who is less than 60 years of age.
	4. Colorectal cancer diagnosed in one or more first-degree relatives with an HNPCC-related tumor, with one of the cancers being diagnosed under age 50 years.
	5. Colorectal cancer diagnosed in two or more first- or second-degree relatives with HNPCC-related tumors, regardless of age.