Diagnosis of HNPCC often involves a combination of family history assessment, genetic testing, and tumor testing. Individuals with a family history of colorectal cancer or other HNPCC-related cancers may undergo genetic testing to identify mutations in the DNA mismatch repair genes. Additionally, tumor testing methods such as microsatellite instability (MSI) testing and immunohistochemistry (IHC) can help determine whether a colorectal tumor is associated with HNPCC.
