How Genomic Testing Works

Genomic testing analyzes DNA to help guide cancer treatment. A sample of tumor tissue is submitted to a laboratory for sequencing. Specialized machines can rapidly read the DNA sequence of a person’s entire genome. This process reveals any genetic mutations present in the tumor that are not found in normal cells. Some key steps in genomic testing include:

– Sample preparation: Tumor tissue is isolated from a biopsy or surgery and prepared for sequencing. This ensures only cancer cell DNA is analyzed.

– Sequencing: Advanced machines unravel the DNA sequence letter by letter, generating huge amounts of genetic data. Different techniques like whole genome sequencing or gene panels may be used.

– Data analysis: Bioinformatics specialists use powerful computers to compare the Genomic Cancer Testing genome to the known normal human genome sequence. They identify any mutations, missing or extra DNA, and other alterations unique to the tumor.

– Mutation interpretation: Genetic counselors and oncologists determine if identified mutations are likely drivers of cancer growth or progression. They assess potential associations with prognosis or drug targets.

– Results reporting: A comprehensive genomic profile is generated for the patient’s doctor. It details any clinically relevant mutations and lists targeted therapies or clinical trials the cancer may respond to based on its molecular profile.

Actionable Genomic Alterations

Through genomic profiling, targetable genomic changes can be uncovered that help guide personalized treatment selection. Some commonly assessed genomic alterations in cancer and their potential implications include:

– EGFR mutations in lung cancer: These identify patients likely to benefit from EGFR tyrosine kinase inhibitors like erlotinib or osimertinib rather than standard chemotherapy.

– BRAF mutations in melanoma: Mutations in the BRAF gene indicate immunotherapy with BRAF inhibitors like dabrafenib plus MEK inhibitors like trametinib.

– ALK fusions in lung cancer: An ALK gene rearrangement warrants treatment with ALK inhibitor crizotinib or others in this class over standard chemo.

– Tumor mutation burden: Cancers with a high number of mutations may respond preferentially to immunotherapy due to increased antigens stimulating the immune system.

– Microsatellite instability: If DNA repair defects create many small mutations, immunotherapy may work best for these mismatch repair-deficient tumors.

Understanding the Genomic Basis of Each Individual Cancer Helps Guide More Effective, Targeted Treatment Choices. Genomic Testing is Transforming Cancer Care.

The Limitations and Complexities of Genomic Testing

While genomic testing aims to offer the most optimized treatment selection, there are some limitations and complexities to be aware of:

– Genomic variations are complex: Even clinically actionable mutations may not always perfectly predict drug response since cancer genomes are heterogeneous. Development of resistance is also possible.

– Interpretation challenges: The functional role and effect of many genetic variants is uncertain. Interpretation requires specialized expertise and continuous re-evaluation as knowledge advances.

– Target availability: Not every identified genomic alteration has a matched, commercially available targeted drug. Clinical trials may provide access to promising experimental agents.

– Multifactorial disease nature: Most cancers arise due to multiple interacting genomic and non-genomic factors. Targeted treatment alone is often insufficient and requires combination therapy.

– Intratumor heterogeneity: Different areas of the same tumor may harbor varying mutations. A biopsy may not fully capture this complex genomic makeup.

– Changes over time: Acquired resistance usually emerges inevitably as years of targeted treatment exert selective pressure, driving new mutations. Periodic re-biopsy helps monitor changing tumor profiles.

With these complexities in mind, oncology providers and pathologists heavily rely on expert interpretation of genomic results in the context of each patient’s unique situation to maximize treatment benefit while avoiding unnecessary toxicity or costs from poorly matched therapies. Ongoing clinical validation of genomic testing is also needed given the rapidly evolving understanding of cancer genomics.

Overall, Genomic Cancer Testing profiling has transformed cancer treatment by enabling increasingly personalized, mechanism-driven care. While challenges remain, continued innovation is helping to realize the full potential of genomic medicine for improving outcomes. As testing becomes more widespread, it will be important for patients to discuss genomic testing options thoroughly with their medical team.

*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it