If a patient meets the above listed criteria, they should be referred immediately to a Family Cancer Clinic for genetic counselling and, if recommended, genetic testing.
Surgeons in some hospitals will routinely send a tumour sample for an Immunohistochemistry (IHC) test. This test looks for loss of proteins loss of proteins that indicate that a certain gene is not working in the tumour. Further testing will determine which mutations in the germline and which are only in the tumour. The germline mutations occur in one of the four-mismatch repair (MMR) genes associate with Lynch syndrome (i.e. MLH1, MSH2, MSH6, and PMS2). All patients whose tumours show this loss of staining (except as above) should be referred to a Family Cancer Clinic or Genetic Service without exception.