Comprehensive genomic profiling (CGP) is an advanced medical test that examines an individual’s DNA to uncover specific genetic alterations. Its primary purpose is to understand diseases, particularly cancers, at a molecular level. By analyzing these changes, medical professionals can gain insights into how a disease might behave and potentially respond to different treatments.
Understanding Comprehensive Genomic Profiling
Comprehensive genomic profiling (CGP) involves simultaneously detecting all classes of genomic alterations across hundreds of genes with a single test. This broad scope differentiates CGP from traditional single-gene tests or smaller genetic panels, which typically analyze only one or a limited number of genes. CGP’s ability to interrogate vast quantities of genetic information at once provides a more complete picture of a patient’s unique genetic profile.
The “comprehensive” aspect means looking for various types of genomic alterations. These can include single nucleotide variants (SNVs), which are changes in a single DNA building block, and insertions or deletions (indels), where small pieces of DNA are added or removed. CGP also identifies copy number variations (CNVs), such as gene amplifications (too many copies of a gene) or deletions (missing copies), and gene fusions, which occur when two genes incorrectly join together. This detailed analysis helps in characterizing the specific genetic drivers of a disease.
The Process of Genomic Profiling
The process of comprehensive genomic profiling begins with sample collection. For cancer patients, this often involves obtaining tumor tissue through a biopsy or surgical procedure. A blood sample, known as a liquid biopsy, can also be used, offering a less invasive option. These samples contain the genetic material needed for analysis.
Once collected, DNA is extracted from the cells. This extracted DNA then undergoes next-generation sequencing (NGS). NGS technology allows for the rapid and simultaneous sequencing of hundreds of genes, providing a detailed readout of their genetic code. The raw sequencing data is analyzed using specialized computational tools to identify any genomic alterations present. The output is a detailed report that lists the specific genomic alterations found, which medical experts then interpret.
How Genomic Insights Guide Treatment
The information from comprehensive genomic profiling guides medical decisions, especially in cancer care. Identified genomic alterations can directly point towards specific targeted therapies. For example, if a tumor exhibits a particular gene mutation, there may be a drug designed to inhibit the activity of the protein produced by that mutated gene, slowing or stopping cancer growth. This approach minimizes harm to healthy cells, potentially leading to fewer side effects compared to traditional treatments.
Genomic insights also inform decisions regarding immunotherapy, a treatment that harnesses the body’s immune system. Certain genomic signatures, such as tumor mutational burden (TMB) or microsatellite instability (MSI), can indicate a higher likelihood of response to immunotherapy. CGP results can also determine a patient’s eligibility for specific clinical trials, offering access to investigational treatments tailored to their unique genetic profile.
Important Considerations for Patients
Patients considering comprehensive genomic profiling should be aware of several practical aspects. Genetic counseling is often recommended both before and after testing to help individuals understand the potential implications of the results. A genetic counselor can explain what the test can reveal, the likelihood of finding actionable alterations, and how these findings might impact treatment decisions and family members.
The turnaround time for CGP results can vary, typically ranging from a few weeks to a month, depending on the laboratory and the complexity of the analysis. While CGP is comprehensive, not all identified genomic findings may have immediate actionable treatments or an approved therapy. Genomic medicine is an evolving field, and new discoveries are constantly being made. Therefore, even if a treatment is not available today for a particular alteration, research may lead to new options in the future.