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Table 2 Results of molecular screening on tumor specimen and mutational analysis

From: Early-onset colorectal cancer patients without family history are “at very low risk” for lynch syndrome

Patients

Immunohistochemistry (lack of expression)

MSI status

Germline mutational analysis

Group A

1 PMS2

1 MSI-H

No deleterious mutation§

No family history

1 PMS2

1 MSI-H

No deleterious mutation*

3 MLH1, PMS2

3 MSS

No deleterious mutation

1 normal

1 MSI-H

No deleterious mutation*

Group B with Am.II Criteria

8 MLH1

8 MSI-H

7 MLH1 deleterious mutation

  

1 missense VUS**

7 MSH2

7 MSI-H

7 MSH2 deleterious mutation

1 MSH2***

1 MSI-H

1 MLH1 deleterious mutation

1 PMS2

1 MSI-H

1 MLH1 deleterious mutation

2 Normal

2 MSI-H

2 MSH2 deleterious mutation

1 NE****

1 MSI-H

1 MSH2 deleterious mutation

1 MSH2, MSH6

1 MSI-H

No deleterious mutation

4 MLH1

4 MSS

No deleterious mutation

1 MLH1, PMS2

1 MSS

No deleterious mutation

1 MSH2, MSH6

1 MSS

No deleterious mutation

Group C

7 normal

7 MSS

 

Family history without Amsterdam II Criteria

  1. §MLH1 promoter hypermethylation.
  2. *polymorphism MSH6 gene (c.116G > A) associated with slight increased risk of CRC in males.
  3. **VUS: variant of uncertain clinical significance.
  4. ***confirmed after repeating the test.
  5. ****NE: not evaluable.