Blood Test Detects Gene Mutation Associated with Lung Cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and NSCLC tumors may shed tumor DNA into a patient's blood, making it possible to detect specific mutations in blood samples.

Testing for tumor DNA using a blood sample is also called a liquid biopsy and approval for blood-based genetic test that can detect epidermal growth factor receptor (EGFR) gene mutations in NSCLC patients has been granted. Such mutations are present in approximately 10% to 20% of non-small cell lung cancers.


Lung cancer is the leading cause of cancer-related death among men and women in the USA, and though more common in men, the number of deaths from lung cancer in women is increasing. According to the US National Cancer Institute (Bethesda, MD, USA), an estimated 221,200 Americans will be diagnosed with lung cancer, and 158,040 will die from the disease this year. The US Food and Drug Administration (Silver Springs MD, USA) have approved a blood-based companion diagnostic for the cancer drug Tarceva (erlotinib).

The cobas EGFR Mutation Test v2 (Roche Molecular Systems, Pleasanton, CA, USA) detected the presence of specific NSCLC mutations exon 19 deletion or exon 21 (L858R) substitution mutations, in patients' blood samples in selecting those who may benefit from treatment with Tarceva. However, if such mutations are not detected in the blood, then a tumor biopsy should be performed to determine if the NSCLC mutations are present. Insofar as the test provides positive results, it may benefit patients who may be too ill or are otherwise unable to provide a tumor specimen for EGFR testing.

Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological Health, said, “Approvals of liquid biopsy tests make it possible to deliver highly individualized health care for patients. Liquid biopsies also have the potential to allow physicians to identify patients whose tumors have specific mutations in the least invasive way possible.”

Related Links:
US National Cancer Institute
US Food and Drug Administration
Roche