Genetic Panel Testing: Points of View
An interview with Marilyn Bui
What are the main pros and cons of genetic panel testing?
The key benefit is that it allows us to test multiple genes simultaneously, thus cutting down the consumption of tissue or sample, and reducing associated costs of running multiple tests and the time needed to return results. It’s also important for guiding treatment decisions. For example, EWSR1 is a promiscuous gene with numerous partners. Different EWSR1 and partner combinations give rise to different types of tumors, so finding the translocation partner helps us to specify the diagnosis and to guide the most effective treatment. This is a clear example of how NGS panel testing can really make a difference to patient outcomes.
In spite of the above, there are some testing panels that are too large and include many genes which have no immediate diagnostic, prognostic and predictive value. And I feel that overall, the process of NGS panel testing still takes too long and is quite costly.
What are the main ethical issues surrounding NGS testing?
The main concern is what we should be doing with all of the data generated. There will be times when we won’t find what we are looking for; for example, we may be searching for a targetable and actionable marker to treat a cancer, but we don’t find it and instead we accidentally discover that the patient has certain genes that predispose them to Alzheimer’s or cardiovascular disease. Should we disclose that to the patient? And do we share the raw data with them or just what we think is applicable?
Traditionally, a pathology report is generated once and represents the best understanding of the disease at that point of time. However, with NGS raw data, we may be able to interpret results later in the day, once there has been further scientific advancement. What do we do in this scenario? There is currently no guideline on how often we should go back and review these data and how we should report new findings to the patient, nor is there a requirement for us to do so. This is unchartered territory for pathologists.
How should data from panel testing be used?
This is how I think the process should work… As pathologists, we are in the best position possible to help clinicians and patients to decide if a test is appropriate and if the tissue is adequate or suitable. So, we need to be involved in ordering tests and have full access to all of the results. We should then have a central role in multidisciplinary molecular tumor board-like settings, where we discuss the results, provide full interpretation and support the formulation of an action plan. In my opinion, if any new information comes to light as a result of scientific advancement, the patient should be made aware. As physicians and scientists, we have an obligation to advance our understanding of disease. As such, patients should consent to their data being used in studies that are regulated by Institutional Review Boards; the data will, of course, be de-identified.
What are the current unmet needs?
There is a need for further technological innovation so that the speed of panel testing is increased and the cost reduced. The lack of consensus guidelines that support use of the technology in practice is a problem too; it’s important that this gap is addressed. We also need guidance on the ethics of panel testing – how we should approach testing and how we should be using the data. The bottom line is that genetic panel testing is already making positive impact on patients’ care every day. It will be beneficial for us to all work together to maximizes these benefits moving forward.
Marilyn Bui is a Senior Member of the Department of Anatomic Pathology & Sarcoma, Section Head of Bone and Soft Tissue Pathology, and Scientific Director of the Analytic Microscopy Core at Moffitt Cancer Center. She is also a Professor and Director of the Cytopathology Fellowship Program at the University of South Florida Morsani College of Medicine Tampa, USA.
Marilyn Bui is a Senior Member of the Department of Anatomic Pathology, Section Head of Bone and Soft Tissue Pathology, and Scientific Director of the Analytic Microscopy Core at Moffitt Cancer Center. She is also a Professor and Director of the Cytopathology Fellowship Program at the University of South Florida Morsani College of Medicine Tampa, USA.