Bowel cancer isn’t just one thing. There are lots of bowel cancers.
Some of the differences between bowel cancers are due to types genetic mutations in the cell, some of the differences are Genomic – ie, due to the person’s own inherited genetic make-up, or Somatic – mutations that have occurred after you were born.
Biomarkers help to identify these genetic factors.
- Biomarkers are molecules that can be found in your body tissues, blood, or tumours.
- Biomarkers can indicate that normal cell processes are not working correctly.
- Biomarkers can be used to target treatment to make it more effective.
Important biomarkers for bowel cancer:
- MLHL (Lynch Syndrome)
- MSH2 (Lynch Syndrome)
- MSH6 (Lynch Syndrome)
- PMS2 (Lynch Syndrome)
- EPCAM (Lynch Syndrome)
- KRAS
- NRAS
- BRAF
- HER2
- MMR MisMatch Repair Gene
Testing
In the UK patient biopsies and tumours are typically tested for the Lynch, KRAS, NRAS, BRAF and MMR biomarkers.
A cancer diagnosis will usually include the important biomarkers and their status, either Mutation or Wild Type
- Wild Type – The normal variant of the gene as found in the general population.
- Mutation – A gene that has significant changes that affect how it works
National Genomic Test Directory has full details of which biomarker tests should be carried out.
A whole body genome test would show what genetic variations you have inherited, but not the genetic make up of the tumour. These genomic or germline variations may be important in how the cancer develops.
The tumour will have the somatic variations that caused the cancer.
Implications of Biomarkers
The presence of particular versions of biomarkers may indicate that the standard forms of chemotherapy may be ineffective for advanced cancer, and it may be more appropriate to use a targeted therapy including immunotherapy. Visit the Cancer Research UK page on Targeted Therapy
The Global Colon Cancer Association has a guide to biomarkers: Know your biomarker
Lynch Syndrome
- Lynch Syndrome involves several inherited genes which normally protect the body from cancer, but mutations in any of these genes may inhibit this function.
- Lynch Syndrome UK is a support group for people with these mutations.
KRAS
- An important ‘family’ of biomarkers are known as KRAS. Mutations in the KRAS gene can reduce the body’s own defence mechanisms against cancer.
- There are many possible sites for mutations on the KRAS. I diagnosis will often detail which mutation is present.
- KRAS Kickers is a US based group that provides support and detailed information about the KRAS biomarkers