Somatic Genomic Testing
What Is Somatic Genomic Testing?
Somatic Genomic Testing is a type of genomic analysis used to identify genetic changes that have developed within tumour cells during a person’s lifetime. These changes, known as somatic or acquired genetic alterations, are found in the tumour rather than being inherited from a parent.
Unlike Cancer Genetic Testing, which may investigate inherited genetic variants associated with an increased susceptibility to certain cancers, Somatic Genomic Testing examines the genetic characteristics of the tumour itself. This distinction is important because genetic changes found in tumour cells do not necessarily indicate that a person has an inherited genetic condition or that their relatives have the same genetic change.
Depending on the tumour type, clinical question and testing approach, Somatic Genomic Testing may examine different types of genomic alterations, including changes within individual genes, copy number alterations, gene fusions or other molecular findings. The aim is to identify genomic information that may help clinicians better understand the molecular characteristics of a tumour.
Somatic Genomic Testing may be considered when molecular information could provide additional clinically relevant information alongside pathology, imaging and other aspects of a person’s medical history. In appropriate circumstances, identified genomic alterations may have relevance to treatment discussions, further clinical assessment or potential eligibility for specific clinical trials.
The results of Somatic Genomic Testing require careful clinical interpretation. Finding a genetic alteration does not automatically mean that a particular treatment will be effective or appropriate, and some findings may have limited or uncertain clinical significance. Similarly, a test may not identify an alteration that currently has an established clinical application.
Somatic Genomic Testing is therefore best understood as a way of analysing the molecular features of a tumour rather than as a test that predicts an individual’s health outcomes. Its findings can provide additional genomic information that may be considered alongside the wider clinical picture when appropriate.
Somatic Genomic Testing examines acquired genetic changes within tumour cells. By analysing the genomic characteristics of a tumour, it can provide molecular information that may contribute to clinical interpretation and cancer care when considered alongside other relevant clinical evidence.
What Can Somatic Genomic Testing Examine?
Somatic Genomic Testing can examine different types of genetic and genomic alterations within tumour cells. The specific findings assessed depend on the testing method, tumour type, sample quality and the clinical question being investigated.
| Genomic Finding | What It Means | Why It May Be Relevant |
|---|---|---|
| Gene Mutations | Changes in the DNA sequence of a gene within tumour cells. | Some mutations may provide information about the molecular characteristics of a tumour and may have clinical relevance. |
| Insertions and Deletions | Small sections of DNA that have been added or removed from a tumour cell's genetic sequence. | Depending on the gene and alteration, these changes may contribute to understanding tumour biology or have potential clinical significance. |
| Copy Number Alterations | Gains or losses affecting sections of DNA, which can result in abnormal numbers of copies of particular genes or genomic regions. | Copy number changes can provide additional information about the molecular profile of a tumour. |
| Gene Fusions and Rearrangements | Structural changes in DNA that can bring parts of different genes together or alter their normal arrangement. | Some gene fusions or rearrangements can act as clinically relevant molecular markers in particular tumour types. |
| Other Genomic Alterations | Depending on the test, other clinically relevant genomic changes or molecular biomarkers may also be assessed. | Additional findings may help provide a more complete picture of the tumour's molecular characteristics. |
Somatic Genomic Testing can examine several types of acquired genomic alterations. The significance of an individual finding depends on the tumour, the alteration identified and the available clinical evidence, so results need to be interpreted in the wider clinical context.
How Is Somatic Genomic Testing Different From Cancer Genetic Testing?
Somatic Genomic Testing and Cancer Genetic Testing both involve analysing genetic information, but they answer different clinical questions. Somatic Genomic Testing examines genetic changes that have developed within tumour cells, whereas Cancer Genetic Testing may investigate inherited genetic variants that can increase a person’s susceptibility to certain cancers.
The main difference is whether the genetic change is acquired or inherited. Somatic alterations arise in cells during a person’s lifetime and may be present specifically within a tumour. They are generally not present in every cell of the body and are not automatically passed from a person to their children.
Inherited, or germline, genetic variants are present throughout the body because they are carried in the genetic material inherited from a biological parent. When a variant is associated with hereditary cancer susceptibility, it may have implications not only for the individual but also for biological relatives. This is why the purpose and interpretation of inherited cancer testing differ from tumour-focused genomic analysis.
Somatic Genomic Testing focuses on the molecular characteristics of an existing tumour. Depending on the test and tumour type, it may identify mutations, gene fusions, copy number alterations or other genomic findings that could provide clinically relevant information about the tumour. These findings may sometimes be relevant to treatment discussions or further clinical investigation.
By contrast, Cancer Genetic Testing focuses on whether a person carries an inherited genetic variant associated with an increased risk of developing particular cancers. The results may therefore contribute to assessment of hereditary cancer risk and, where relevant, consideration of implications for family members.
The two approaches can sometimes be considered alongside one another. For example, a genomic alteration identified in a tumour may raise a question about whether an inherited genetic factor could also be relevant. In such circumstances, additional clinical assessment may be considered rather than assuming that a tumour finding is inherited.
It is therefore important not to interpret a genetic change found through Somatic Genomic Testing as evidence of hereditary cancer risk without appropriate clinical assessment. The origin and significance of a finding depend on the type of sample tested, the genomic alteration identified and the wider clinical context.
Somatic Genomic Testing examines acquired genetic changes within tumour cells, while inherited cancer testing investigates genetic variants that may be present throughout the body and associated with hereditary cancer susceptibility. Understanding this distinction helps ensure that genomic findings are interpreted in the appropriate clinical context.
How Can Tumour Genomic Changes Affect Cancer Cells?
Somatic genomic changes can alter how tumour cells function, grow and interact with their surrounding environment. The effect of an acquired change depends on the gene or genomic region affected and the biological role it has within the tumour.
Some acquired genomic changes can affect genes involved in regulating cell growth and division. When these biological controls are altered, tumour cells may behave differently from healthy cells.
Genomic changes can affect molecular pathways that transmit signals within cells. Alterations in these pathways may influence how tumour cells respond to signals that normally regulate their behaviour.
The combined effect of genomic alterations can contribute to the molecular characteristics of a tumour. Different cancers can therefore develop distinct genomic profiles even when they arise in the same type of tissue.
Some genomic changes may have recognised clinical significance in particular cancers. Where relevant evidence exists, these findings can contribute to further assessment or discussions about available treatment approaches.
Acquired genomic changes can influence the biological behaviour of tumour cells. Understanding their potential effects helps place genomic findings in context, although the significance of an individual alteration depends on the tumour type and available clinical evidence.
Who May Consider Somatic Genomic Testing?
Somatic Genomic Testing may be considered for people who have a confirmed cancer diagnosis when information about the tumour’s genomic characteristics could provide additional clinically relevant information. Whether testing is appropriate depends on the type of cancer, the available tumour sample, previous investigations and the specific clinical question being considered.
People with advanced, metastatic or recurrent cancer may be considered for Somatic Genomic Testing when understanding the molecular features of the tumour could contribute to further clinical assessment. In some circumstances, identifying specific genomic alterations may provide information that can be considered when discussing treatment options or other approaches to care.
Somatic Genomic Testing may also be relevant when a tumour has unusual clinical or pathological features. Where the molecular characteristics of a tumour could help provide additional information alongside pathology and other investigations, genomic analysis may be considered as part of the wider diagnostic or clinical assessment.
Testing can sometimes be considered when standard treatment options have been limited or when further molecular information is clinically relevant. Depending on the tumour type and findings, genomic analysis may identify alterations that have established or emerging relevance to particular treatments, clinical trials or additional specialist assessment.
A suitable tumour tissue sample is also an important consideration. Testing may be possible using previously collected tissue when the sample contains sufficient tumour material and is suitable for the intended analysis. In some circumstances, another sample or an alternative testing approach may need to be considered.
Somatic Genomic Testing is not necessarily appropriate for every person with cancer. The potential value of testing depends on the individual clinical circumstances, the tumour being investigated and whether the results are likely to provide information relevant to the clinical question. A specialist can consider these factors before recommending whether genomic analysis should be pursued.
It is also important to distinguish tumour genomic analysis from testing for inherited cancer susceptibility. A somatic finding is generally a change that has developed within tumour cells and does not automatically indicate an inherited genetic risk. Where the clinical history or tumour findings raise a separate question about hereditary risk, that question may require a different form of genetic assessment.
Somatic Genomic Testing may be considered when tumour genomic information could contribute to clinical assessment. The decision depends on the cancer type, tumour sample, available evidence and the specific clinical question rather than on the cancer diagnosis alone.
What Samples Are Used for Somatic Genomic Testing?
Somatic Genomic Testing can be performed using different types of samples depending on the tumour, the information available and the genomic analysis required. Tumour tissue is commonly used, while blood-based testing may be considered in appropriate circumstances.
| Sample Type | What It May Provide | Important Considerations |
|---|---|---|
| Tumour Tissue | DNA and other genomic information from tumour cells can be analysed to identify acquired genetic alterations. | The amount and quality of tumour tissue can affect whether sufficient material is available for genomic analysis. |
| Preserved Tumour Tissue | Previously collected and appropriately preserved tumour tissue may sometimes be suitable for genomic testing. | Suitability depends on factors such as tissue quality, tumour content, sample age and the requirements of the test. |
| Blood Sample | In appropriate circumstances, a blood sample can be analysed for circulating tumour DNA released into the bloodstream. | The amount of circulating tumour DNA can vary, and a blood-based test may not detect every genomic alteration present in a tumour. |
| Other Clinical Samples | Depending on the tumour and clinical circumstances, other appropriately collected material may occasionally be available for molecular analysis. | The appropriate sample depends on the tumour type, available material and the specific genomic test being considered. |
The sample used for Somatic Genomic Testing depends on the clinical circumstances and the genomic question being investigated. Tumour tissue is commonly analysed, while blood-based testing may provide an alternative approach in appropriate situations when circulating tumour DNA can be detected.
How Does Somatic Genomic Testing Work?
Somatic Genomic Testing involves analysing genetic material from a tumour or, in appropriate circumstances, a blood sample containing circulating tumour DNA. The process is designed to identify acquired genomic alterations that may provide clinically relevant information about the molecular characteristics of a tumour.
The process usually begins with the selection of an appropriate sample. Where tumour tissue is available, previously collected tissue may be assessed to determine whether it contains sufficient tumour material and is suitable for the planned analysis. In some circumstances, a blood-based sample may be considered when circulating tumour DNA is an appropriate source for testing.
Once a suitable sample has been identified, DNA is extracted and prepared for genomic analysis. The testing method used depends on the clinical question, tumour type and genomic alterations being investigated. Different approaches can examine specific genes or broader panels of genomic regions.
The genomic analysis then looks for acquired alterations within the tumour DNA. Depending on the test, this may include mutations, insertions or deletions, copy number alterations, gene fusions and other relevant genomic findings. The ability to identify a particular alteration depends on the characteristics of the sample and the analytical method used.
Identified findings are subsequently reviewed and interpreted in their clinical context. A genomic alteration is not automatically clinically significant, so its potential relevance may be considered alongside the tumour type, pathology, clinical history and available scientific evidence.
The final results are provided in a genomic testing report, which may describe the alterations identified, their potential clinical significance and relevant supporting information. Depending on the findings, the results may contribute to discussions about treatment options, further investigations or clinical trial opportunities where appropriate.
Somatic Genomic Testing is therefore not simply a process of identifying genetic changes. The value of the test depends on the quality of the sample, the scope of the genomic analysis and the appropriate interpretation of the findings within the wider clinical picture.
Somatic Genomic Testing follows a process of sample assessment, DNA analysis, genomic finding and clinical interpretation. The resulting information can provide additional insight into the molecular characteristics of a tumour and may contribute to clinical decision-making when interpreted alongside other relevant evidence.
How Can Somatic Genomic Testing Inform Cancer Care?
Somatic Genomic Testing can provide additional information about the molecular characteristics of a tumour that may be relevant to cancer care. By identifying acquired genetic alterations within tumour cells, testing can sometimes add information to pathology, imaging and other clinical investigations.
One potential role is to identify genomic alterations with established clinical relevance. Depending on the cancer type and the alteration identified, certain findings may be relevant when clinicians are considering available treatment approaches. However, the presence of a particular alteration does not automatically mean that a specific treatment will be suitable or effective for an individual.
Somatic genomic findings may also contribute to treatment discussions when there is an established association between a molecular alteration and a particular therapeutic approach. The relevance of a finding depends on factors such as the tumour type, the specific alteration, the available clinical evidence and the person’s overall clinical circumstances.
In some cases, testing may identify findings that are relevant to clinical trials or further specialist assessment. Where an alteration is being investigated in relation to an emerging therapy or research study, genomic information may help determine whether further discussion or assessment is appropriate.
Somatic Genomic Testing can also provide a more detailed view of the molecular profile of a tumour. This information may help clinicians understand certain biological characteristics of the cancer and consider them alongside other findings when assessing the disease.
Importantly, not every genomic alteration has a known clinical application. Some findings may have uncertain or limited significance, while a test may fail to identify an alteration that is currently relevant to treatment. The absence of an actionable finding therefore does not mean that there are no treatment options available.
The value of Somatic Genomic Testing ultimately depends on how its findings are interpreted within the wider clinical picture. Results are considered alongside the cancer diagnosis, pathology, previous and current treatments, imaging, symptoms and other relevant clinical information rather than being used in isolation.
Somatic Genomic Testing can add molecular information to cancer care. In appropriate circumstances, identified genomic alterations may contribute to treatment discussions, further specialist assessment or consideration of clinical trials, while their significance must always be interpreted in the context of the individual tumour and wider clinical evidence.
What Information Can Somatic Genomic Testing Provide?
Somatic Genomic Testing can provide information about the genetic and molecular characteristics of a tumour. The information available depends on the type of test, the tumour sample and the genomic alterations detected.
| Information Provided | What It May Show | Potential Clinical Relevance |
|---|---|---|
| Tumour Genomic Profile | Genetic alterations and molecular features identified within the tumour. | Can provide additional information about the molecular characteristics of the cancer. |
| Specific Genetic Alterations | Mutations, insertions, deletions or other changes affecting particular genes. | Some alterations may have established or emerging clinical relevance depending on the tumour type and available evidence. |
| Gene Fusions and Structural Changes | Changes in the structure or arrangement of genetic material within tumour cells. | Certain findings may be relevant to further clinical assessment or treatment discussions in specific cancers. |
| Molecular Biomarkers | Genomic or molecular features that can be assessed as part of the tumour profile. | Depending on the cancer and test, some biomarkers may contribute to decisions about further investigation or available treatment approaches. |
| Findings Relevant to Clinical Trials | Genomic alterations that may be investigated in relation to specific therapies or research studies. | In appropriate circumstances, findings may support consideration of whether further specialist or clinical trial assessment is relevant. |
Somatic Genomic Testing can provide a detailed view of the genetic and molecular features of a tumour. The information may contribute to clinical assessment, treatment discussions or consideration of further investigation, but its significance depends on the specific findings and the wider clinical context.
What Are the Limitations of Somatic Genomic Testing?
Somatic Genomic Testing can provide valuable information about the molecular characteristics of a tumour, but it has important limitations. The results depend on the quality and amount of tumour material, the genomic alterations included in the test and the available clinical evidence for interpreting individual findings.
One limitation is that not every genomic alteration can be detected. Different tests examine different genes and types of genomic changes, while some alterations may be outside the scope of the analysis. A test may therefore provide useful information without identifying every genetic change present within a tumour.
The quality and quantity of the sample can also affect the results. Tumour tissue may contain a mixture of cancerous and non-cancerous cells, and there may be insufficient tumour material for certain analyses. In blood-based testing, the amount of circulating tumour DNA can also vary, which may affect the ability to detect particular alterations.
Another important limitation is that not every finding has an established clinical significance. Some genomic alterations may have a recognised association with a particular cancer or treatment approach, while others may have limited, emerging or uncertain evidence. A genetic alteration identified through testing does not automatically indicate that a specific treatment will be appropriate or effective.
Somatic genomic findings also need to be interpreted in the context of the individual tumour and wider clinical information. The same genomic alteration may have different implications depending on the cancer type, disease stage, pathology, previous treatment and other clinical factors.
A further limitation is that Somatic Genomic Testing generally examines acquired changes within tumour cells rather than inherited genetic risk. A finding in tumour DNA does not by itself establish that a person carries an inherited genetic variant or that their biological relatives have an increased risk of developing cancer.
Genomic information can also change as scientific and clinical knowledge develops. An alteration that has limited significance today may become better understood as new evidence emerges, while the clinical relevance of particular findings can depend on evolving treatment options and research.
Somatic Genomic Testing provides additional molecular information but does not provide a complete picture of a cancer. Results may be limited by the sample, the scope of the test and the available evidence, and findings should be interpreted alongside pathology, clinical history and other relevant investigations.
Somatic Genomic Testing and Personalised Cancer Care
Somatic Genomic Testing can provide molecular information about a tumour that may contribute to a more individualised approach to cancer care. By identifying acquired genomic alterations, testing can add information to pathology, imaging and other clinical findings when appropriate.
Understanding the Tumour's Molecular Profile
Somatic genomic analysis can identify acquired genetic alterations within tumour cells, providing additional information about the molecular characteristics of an individual cancer.
Identifying Clinically Relevant Alterations
Some genomic findings have established or emerging clinical relevance. Identifying these alterations may provide information that can be considered alongside other factors during cancer care.
Supporting Treatment Discussions
Where a genomic alteration has a recognised association with a particular treatment approach, the finding may contribute to discussions about available options and their suitability for the individual.
Considering Further Investigation
Genomic findings may sometimes raise questions that require additional specialist assessment, further molecular testing or investigation of other clinical factors.
Exploring Clinical Trial Opportunities
In appropriate circumstances, particular tumour alterations may be relevant when considering clinical trials or emerging therapies being investigated for specific molecular features.
How Are Somatic Genomic Testing Results Interpreted?
Somatic Genomic Testing results are interpreted by considering the genetic alterations identified in a tumour alongside the cancer type, clinical history, pathology and available scientific and clinical evidence. As one approach within the wider field of Genetic Testing, its purpose is to understand whether a tumour finding has potential clinical relevance rather than simply identifying whether a genetic change is present.
The first step is to determine which genomic alterations have been detected. Depending on the test, the report may identify mutations, insertions or deletions, copy number alterations, gene fusions or other molecular findings. The significance of each alteration depends on its specific characteristics and the context in which it occurs.
Findings may then be assessed according to the strength and relevance of the available evidence. Some alterations have well-established associations with particular cancers or treatment approaches, while others may have emerging evidence or uncertain clinical significance. A finding should therefore be interpreted in light of the evidence supporting its potential clinical relevance.
The type of cancer and its molecular context are also important. The same genomic alteration may have different clinical implications in different tumour types, meaning that interpretation requires consideration of the diagnosis and other characteristics of the individual cancer.
Where appropriate, the results may be considered alongside available treatment options and clinical trials. A genomic finding may contribute to a discussion about a particular therapeutic approach or further investigation when there is relevant clinical evidence. However, identifying an alteration does not automatically mean that a specific treatment will be suitable or effective.
The interpretation also considers the limitations of the test and the sample analysed. Factors such as tumour content, sample quality, the sensitivity of the testing method and the genes or genomic regions included can influence which alterations are detected. A negative result therefore does not necessarily mean that no genomic changes are present.
It is also important to distinguish somatic findings from inherited genetic variants. An alteration identified in tumour tissue generally represents an acquired change within the cancer cells and does not by itself establish an inherited genetic condition or hereditary cancer risk. Where an inherited cause is clinically suspected, a separate genetic assessment may be appropriate.
As genomic research develops, the interpretation of some findings may also change. New evidence about a genetic alteration, cancer type or treatment can affect how a previous result is understood. This is one reason why genomic results may sometimes require review when there is a relevant clinical reason or when significant new evidence becomes available.
Somatic Genomic Testing results are interpreted in the context of the tumour, clinical evidence and the limitations of the test.
A detected alteration may provide useful information, but its significance depends on the available evidence and should be considered alongside the wider clinical picture rather than in isolation.
Frequently asked questions
In this section you can check frequently asked questions.
What is Somatic Genomic Testing used for?
Somatic Genomic Testing is used to identify acquired genetic changes within tumour cells. The findings may provide additional molecular information that can contribute to clinical assessment, treatment discussions or consideration of further investigations where appropriate.
Is Somatic Genomic Testing the same as genetic testing for inherited cancer risk?
No. Somatic Genomic Testing examines genetic changes that have developed within tumour cells, whereas testing for inherited cancer risk investigates genetic variants that may be present throughout the body and can be associated with hereditary cancer susceptibility.
What types of genetic changes can Somatic Genomic Testing identify?
Depending on the test, it may identify mutations, insertions and deletions, copy number alterations, gene fusions, rearrangements and other genomic or molecular findings.
What sample is needed for Somatic Genomic Testing?
Tumour tissue is commonly used. In appropriate circumstances, a blood sample may also be analysed for circulating tumour DNA. The most suitable sample depends on the tumour, available material and the genomic analysis being considered.
Can Somatic Genomic Testing help guide cancer treatment?
In some circumstances, genomic findings may provide information relevant to treatment discussions. However, identifying a particular alteration does not automatically mean that a specific treatment will be suitable or effective. Results need to be considered alongside the wider clinical picture.
What does a negative Somatic Genomic Testing result mean?
A negative result means that no relevant alteration included within the scope of the test was identified in the sample analysed. It does not necessarily mean that the tumour contains no genetic changes, as some alterations may be outside the test’s scope or below its detection threshold.
Can Somatic Genomic Testing identify inherited genetic changes?
A somatic test is primarily designed to identify acquired changes within tumour cells. A finding in tumour DNA does not by itself establish whether a genetic change is inherited. If hereditary cancer risk is a separate clinical concern, additional assessment may be appropriate.
How long does Somatic Genomic Testing take?
The timeframe can vary depending on the sample, laboratory, testing method and complexity of the genomic analysis. Additional time may also be required for clinical interpretation and reporting of the findings.
Can Somatic Genomic Testing results change over time?
The genomic findings in a particular tumour sample do not change simply because the result is reviewed. However, the clinical interpretation of a finding can change as new scientific evidence, treatments and clinical knowledge become available.
What is the difference between Somatic Genomic Testing and Tumour Profiling?
Somatic Genomic Testing and tumour profiling are closely related terms used to describe the analysis of genetic and molecular characteristics of tumour cells. The exact scope of testing can vary depending on the laboratory method, genes analysed and clinical purpose.
Discuss Somatic Genomic Testing With a Specialist
If you are considering Somatic Genomic Testing, a specialist consultation can help you understand whether tumour genomic analysis is relevant to your circumstances and what the testing process may involve.
When May a Consultation Be Helpful?
Considering Genomic Testing: You may wish to discuss Somatic Genomic Testing if you have a cancer diagnosis and want to understand whether genomic analysis of the tumour could provide additional information.
Understanding Your Testing Options: A consultation can provide an opportunity to discuss the type of genomic analysis being considered, the sample that may be required and the information the test is designed to assess.
Discussing Your Results: If you already have a Somatic Genomic Testing report, a specialist consultation can help you understand the findings and how they relate to your individual clinical circumstances.
Personalised Genomic Assessment
At London Genetics, we consider Somatic Genomic Testing in the context of your cancer diagnosis, available medical information and the reason for seeking genomic analysis.
The aim is to provide a clear explanation of the testing process and help you understand what genomic information may be relevant to your circumstances.
If you would like to discuss Somatic Genomic Testing with a specialist, arrange a consultation with London Genetics to explore whether genomic analysis may be appropriate for you.
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