sample tube in female hands with pipette.

Why We Should Care About the Move from Saliva to Living Cells in Precision Medicine

By Adithi Iyer

The cultural, informational, and medical phenomenon that is 23andMe has placed a spotlight on precision medicine, which seeks to personalize medical care to each patient’s unique makeup. Thus far, advances in direct-to-consumer genetic testing have made saliva-sample sequencing services all the rage in this space, but regenerative medicine, which relies on cells and tissues, rather than saliva, now brings us to a new, increasingly complex inflection point.

While collecting and isolating DNA samples from saliva may offer a wealth of information regarding heredity, disease risk, and other outflows of the “instruction manual” for patients, analyzing cells captures the minutiae of patients that goes “beyond the book” and most closely informs pathology. Disease isn’t always “written in the stars” for patients. Epigenetic changes from environmental exposures, cell-to-cell signaling behaviors, and the mutations present in diseased cells all profoundly inform how cells behave in whether and how they code the instructions that DNA offers. These factors are critical to understanding how disease materializes, progresses, and ultimately responds to treatment. This information is highly personal to each patient, and reflects behavioral factors as well as genetics.

Regenerative medical technologies use cell- and tissue-based methods to recapitulate, bioengineer, and reprogram human tissue, making a whole suite of sci-fi-sounding technologies an ever-closer reality. With cell-based and other regenerative therapies entering the market (making up an entire FDA subgroup), it well worth considering how cell-based medicine can advance the world of personalized consumer testing. In other words, could a corporate, direct-to-consumer cell-based testing service be the next 23andMe? And what would that mean for patients?

“Next-Generation” is Closer Than We Think

The technology that would make cell-based testing services available is already here. For example, Moderna and Merck recently announced the commencement of a Phase III study testing a regimen for high-risk melanoma that combines immunotherapy and a personalized mRNA therapy, which has already obtained FDA Breakthrough Therapy approval. The process by which the treatment is personalized involves sampling the patient’s cancerous tissue and blood. The mRNA therapy is personalized to the patient’s own biomarkers, training the patient’s immune system to recognize and attack the unique mutations in the patient’s cancer.

While the Moderna-Merck intervention classifies as a regulated drug or therapy, it is not a stretch of the imagination to map this type of dynamic onto a non-therapeutic service offering like 23andMe. Swap out saliva samples for blood, cell, or tissue samples, and this type of testing service can offer a veritable health database for each patient with new, and more, data to explore.

Cells and Tissue Offer More of “You” Than Saliva—Or Anything We’ve Seen Before

The distinction between private companies collecting saliva and living tissue is more significant than we might think, especially for consumer privacy in a nascent era of privatized, direct-to-consumer medicine. A “yourtissueandyou” would be decidedly more informative — but also more invasive — than a 23andMe.

With living cells, the types and volume of information one can obtain about a patient are more varied and greater than what can be obtained from saliva. The Merck-Moderna treatment strategy of targeting the unique mutational structure of the patient’s individual cancer requires information (a profile of the patient’s specific biomarkers) that can only be sequenced from mutated cancer cells —  information that is not available from a saliva sample.

Collecting cells for testing using technologies that can analyze your personalized microenvironment and tissue structure therefore also means collecting an even greater amount of data than a saliva sample can offer (not just because cells also contain DNA). This highly precise information is powerful in that it is 1) invaluable to the patient seeking personalized, maximally effective treatment regimens or risk assessments and 2) informative of the deepest minutiae of how you as a human operate. Just short of owning you as a test subject, tissue-based direct-to-consumer services could get a type of access to you through your cells and tissue that substantively differs from accessing DNA. Companies don’t just have the playbook to you; they have your lifetime stats and in-depth analysis of every play you’ve ever made in every game you’ve ever played, or could play.

By not only collecting a vast amount of data, but also new and highly personal types of data, tissue-based medicine might simultaneously offer more tailored insights for patients and turbo-charge data privacy concerns.

Our Cells in Whose Hands?

Open questions abound for cell-based testing services, but perhaps the first among them would be: who would offer them? It seems, in the near term, that the “who” would probably be a venture-backed biotechnology company — a corporate actor. The notoriously capital-heavy biotech landscape has seen ups and downs in the past few years, to be sure, but emerging biotechnologies remain, at large, privately fueled and intimately connected to private capital from the start-up stage to market. 23andMe is itself a publicly held company from start-up beginnings, and so are its competitors in this space.

With such sensitive information in the hands of corporate entities, the burning question becomes: how do we protect our data? The corporate angle is particularly enticing for a potential cell-based direct-to-consumer offering because it appears as though fewer strings are attached. One of the most salient examples of this is that 23andMe, being a consumer service and not a covered provider, claims that it is not subject to HIPAA protections. Whether or not this is a sound argument, and whether there are other tools we might deploy to protect personal data in the age of regenerative medicine, are topics I’ll discuss in my next installment.

Adithi Iyer

Adithi Iyer is a law student (J.D. 2025). Her research interests include cell biology, regenerative medicine, and the law. She previously worked in biomedical research, healthcare analytics, and tech policy. At the law school, Adithi is interested in examining how emerging biotechnologies in intersect with privacy and legal/ethical rights. She also serves on the editorial board of the Harvard Journal of Law and Technology (JOLT).

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