Surprising Discovery: Driver Mutations Are the Same Across All Metastases in a Patient

Most cancer deaths result from metastasis. Against metastases, developing targeted treatments depends on identifying specific mutationsin metastasizing cells. In September 2018, Sciencepublished a study discovering that driver mutations are the same across all metastases in a patient. This development may enable tumor mutations in metastases to be understood through a single biopsy.

Until now, cancer genetics studies (genetic diversity, heterogeneity) had focused on primary tumors. Identifying driver mutations in metastases is important for developing targeted treatments. Driver mutations are among the important mutations causing tumor formation. They usually occur in genes controlling cell proliferation. More than 100 driver mutations have been discovered so far. However, determining whether these mutations are drivers or passengers is very difficult.

To determine whether gene mutations are the same across all metastases in a patient, researchers examined, from 20 patients' 76 untreated metastases, DNA samples. Care was taken to obtain samples from 2 different metastases per patient. Cancer types included breast, colorectal (large intestine), endometrial (uterine), stomach, skin, pancreatic and prostate cancer.

More than 25.000 cancer sequence datasets were compared with the DNA samples. Analysis found that certain driver mutations important in disease development were the same across all metastases in a patient.

What Does This Study Mean for Us?

• Different metastases in a cancer patient were found to arise from the same “driver” mutation. A single biopsy may identify driver mutations in metastases and enable targeted treatments to be developed against them.
• This finding needs confirmation in studies involving more patients. Cancer cells can mutate very rapidly. Identifying these mutations may pave the way for effective cancer treatments.