What Is NGS?

Next-Generation Sequencing (NGS) is a modern genetic testing technology that can analyze large amounts of DNA or RNA very quickly. Unlike older sequencing methods that read one gene at a time, NGS can sequence hundreds of genes simultaneously, providing a detailed picture of genetic changes in cancer cells.

NGS is a cornerstone of precision oncology — helping doctors match patients to treatments based on the unique genetic profile of their tumor.

How NGS Is Used in Cancer

1. Diagnosis

• Identifies genetic mutations that confirm certain cancer types (e.g., leukemias, lymphomas).
• Helps differentiate between cancer subtypes.

2. Treatment Selection (Precision Medicine)

• Detects actionable mutations that guide targeted therapy or immunotherapy.
• Examples:
  • EGFR, ALK, ROS1 mutations in lung cancer.
  • HER2 amplification in breast cancer.
  • BRCA1/2 mutations for PARP inhibitor therapy.

3. Prognosis

• Provides information on how aggressive a cancer might be.
• Helps assess likely outcomes based on genetic drivers.

4. Monitoring & Resistance Tracking

• Detects new mutations after treatment that may cause drug resistance.
• Guides switching therapies when cancer evolves.

5. Hereditary Cancer Testing

• Identifies inherited mutations (e.g., BRCA, Lynch syndrome genes) that increase cancer risk in families.

 

What to Expect During the Test

• Usually requires a tumor tissue biopsy or a liquid biopsy (blood sample).
• DNA/RNA is extracted and sequenced in a laboratory.
• Results typically take 1–3 weeks.
• The report highlights genetic mutations and possible treatment options.

 

Benefits

• Comprehensive: tests many genes at once.
• Enables personalized treatment plans.
• May qualify patients for clinical trials.
• Can detect rare mutations missed by standard single-gene tests.

 

Risks & Limitations

• Requires adequate tumor sample (sometimes a challenge).
• Not all mutations have available targeted treatments.
• Results can be complex and need expert interpretation.
• May reveal incidental findings (hereditary mutations not directly related to cancer).
• Cost and insurance coverage vary.

 

Alternatives & Related Tests

• Single-Gene Testing: Focuses on one mutation (e.g., EGFR, KRAS).
• Immunohistochemistry (IHC): Detects protein expression (e.g., HER2, PD-L1).
• Fluorescence In Situ Hybridization (FISH): Detects specific chromosomal changes.
• Liquid Biopsy: A non-invasive blood test version of NGS.

 

Questions to Ask Your Doctor

• Why do I need NGS, and how will it affect my treatment?
• Will my insurance cover the test?
• Is a liquid biopsy an option instead of tissue biopsy?
• How often should NGS be repeated during my treatment?
• Could this test reveal hereditary cancer risk for my family?

 

Patient Tips

• Keep copies of your NGS report for future treatment planning.
• Ask your doctor to explain which mutations are actionable versus just informational.
• If a hereditary mutation is found, consider genetic counseling for family members.
• Explore clinical trial options based on your genetic profile.

 

References

• National Cancer Institute (NCI): Next-Generation Sequencing
• American Cancer Society: Genetic Testing for Cancer Treatment
• FDA: NGS and Oncology