Whole Genome Sequencing test (WGS test)

A very special type of molecular diagnostics is the analysis of the complete tumor DNA. This is called Whole Genome Sequencing, or a WGS test. 

In specific circumstances, your physician will request this type of DNA test for you. This diagnostic procedure maps out the complete DNA code of the tumor, showing all abnormalities at once.

What is a WGS test?

A WGS test analyzes all tumor DNA. This DNA is then compared to the healthy DNA taken from the patient's blood. This brings all mutations in the DNA of the tumor to light. 

When would your physician request a WGS test for you?

The WGS test can be used for two purposes:

  • if other diagnostic tests are not sufficient to reach a diagnosis. The complete DNA profile can help determine where the tumor originated and what type of tumor it is.
  • A WGS test can help us select the treatment that is right for you. Your tumor type will determine if and when a WGS test can be used for this purpose. 

Can a WGS test tell us anything about hereditary cancer?

A WGS test is not intended to detect hereditary illness. The test is intended to detect changes to the DNA of tumor cells that came about during life. These mutations are not hereditary. 

A WGS test can still detect hereditary mutations. This is because the computer compares the tumor DNA with the healthy DNA from your blood. In about 10% of cases, this healthy DNA shows a hereditary predisposition for cancer. Some patients knew about this, but some did not. 

It may be important to know that such a hereditary predisposition will only be included in the results of your WSG test if you have given us permission to do so. Your physician will discuss this with you before requesting the test. If a patient does not want to know if they have a hereditary factor in their DNA, the results of the test will still be complete. 

DNA Onderzoek Bij Kanker

More information

A WGS test, how does it work?

  • If your practicing physician is considering requesting a WGS analysis for you, he or she will discuss it with the patient. 
  • Your physician will ask you whether you want to be informed about any potential hereditary mutations that may be found in your healthy DNA. See point 3 for more information. 
  • We will take a biopsy for your WGS test. We may be able to use materials from earlier procedures (biopsy or surgery) if it has been stored correctly at the time. 
  • We will take some blood to analyze the healthy DNA and compare it to the tumor DNA.
  • After two or three weeks your practicing physician will receive your results. 

Is the test part of the diagnostics for patients with metastatic cancer?  

Until 2021, WGS tests were only used at the NKI as part of clinical trials.  Between 2019 and 2021, we have shown through a large study, the WIDE trial, that this type of diagnostics is applicable to regular hospital diagnostics at the NKI.

As of January 2021, whole genome sequencing is part of regular hospital diagnostics at the NKI for some patients with metastatic cancer.