Oncology – Hereditary predisposition to colorectal cancer (HNPCC)
Colorectal cancer (CRC) affects 1 in 20 people during their lifetime. An estimated 25% of all CRC cases present a familial clustering of the disease suggesting a contribution of genetic factors among other risk factors, while approximately 5% of all CRC cases are purely hereditary.
Hereditary non-polyposis colorectal cancer, also known as Lynch syndrome (LS) accounts for the majority of these hereditary CRC cases (2-3% of overall CRC cases).
But diagnostic criteria are complex and several studies have reported a lack of sensitivity and specificity for the Amsterdam criteria and the revised Bethesda guidelines, which are typically used for the identification of LS patients. In addition, heterogeneous and overlapping phenotypes make it difficult to distinguish from other type of hereditary CRCs and decide which genes should be analyzed first.
Our next generation sequencing panel for CRC therefore aims at facilitating patient referral for molecular screening, while keeping costs at a reasonable level.
How does it work ?
- Stage 1: Patient identification – Discussion of personnal and family history Eplanation of genetic testing options
- Stage 2: Sample submission -The patient’s sample and necessary paperwork are sent to the laboratory
- Stage 3: Genetic testing – At the laboratory, genetic testing for most genes includes next-generation sequencing and/or exon aray analysis
- Stage 4: Genetic test results – Contains information on the results of the genetic test and available medical management options. The final report is sent to the ordering Incorpore specialist
- Stage 5: Post-test discussion – Incorpore specialist discusses the test resutls, medical management options, and implication for family members with the patient
To whom it is recommended?
The CRC gene panel is recommended for patient whose diagnosis and/or family history is indicative of a suspicion of hereditary CRC. Such indications include :
Early age of cancer onset:
- Patient diagnosed with CRC or endometrial cancer at an age < 50
- Patient diagnosed with CRC at an age < 60 and MSI-H histology
Patient presenting multiple cumulative polyps:
- >10 colorectal adenomatous polyps
- Multiple gastrointestinal hamartomatous polyps
Patient with multiple related primary CRCs or other associated LS cancers
Patient fulfilling the revised Bethesda guidelines or from a family meeting the Amsterdam II criteria
- Patient with a family history of hereditary CRC, with or without a known mutation
- Multiple close family members with CRC or other associated LS cancers
What is investigated?
- Targeted capture of all coding exons and exon-intron boundaries followed by NGS.
- Deletion and duplication assessed by MLPA (Multiplex ligation-dependent probe amplification)
5-6 weeks in average. Urgent testing is available upon request.