Clinical Utility

MSI occurs in approximately 15% of CRC patients and more frequently in stage II (~20%) compared to stage III (~11%) and stage IV (~3.5%) CRCs. Nevertheless, MSI has also been observed in other types of cancer as shown in the following table.

Cancer MSI Prevelance Histology
Breast <%1, unless occuring in young women with HNPCC -
Cervical %5 Advanced Cancers
Colorectal cancer %15 All cancers
Endometrial Up to %33' 40% of endometrioid tumours and 2% of serous tumours.
Gastric %15 All cancers
Glioma %0-33 Controversial data. Pediatric, young adults
Head and Neck Cancer None -
Hepatocellular <%1 -
Lung Cancer <%1 -
Melanoma %2-77 Inconsistent data
Ovarian %10 All cancers
Pancreatic and Periampullary %1 in sporadic PDAC, %10 in cancers of periampullary area All cancers
Prostate Cancer Up to %12 Advanced stage cancers
Renal cell carcinoma None -
Sarcoma None -
Sebaceous skin tumors %25 All cancers
Thyroid %1 All cancers

The knowledge of the MSI status is valuable for:

  • Determination of prognosis of Stage II Colon Cancer patients.
  • Identification of patients with a higher risk of developing Hereditary Non Polyposis Colorectal Cancer (Lynch Syndrome). 
  • Identification of patients eligible for OncotypeDX® Colon.
  • Prediction of 5-FU treatment.
  • Response to immunotherapy.