Amsterdam II criteria:

1. Three of more relatives with histologically verified Lynch syndrome-associated cancer, one of whom is a first-degree relative of the other two*
2. Cancer involving at least two generations
3. One or more cancer cases diagnosed before 50 years old of age

Revised Bethesda guidelines:

1. Diagnosis of colorectal cancer or endometrial cancer in a patient younger than 50 years age
2. Presence of synchronous colorectal cancers, metachronous colorectal cancers, or other Lynch syndrome-associated tumors, regardless of patient age
3. Diagnosis of colorectal cancer with a high frequency of microsatellite instability on the basis of histologic findings (Crohn’s-like lymphocytic reaction, mucinous or signet-ring cell differentiation, or medullary growth pattern) in a patient younger than 60 years of age
4. Diagnosis of colorectal cancer in one or more first-degree relatives with a Lynch syndrome-related tumor, with one of the diagnoses occurring before 50 years of age
5. Diagnosis of colorectal cancer in two or more first- or second-degree relatives with Lynch syndrome-related tumors, regardless of patient age