Personalis Appoints Dr. Richard Chen as President to Further Accelerate MRD Adoption

Dr. Chen expands his leadership role to serve as President while continuing to serve as Chief Medical Officer (CMO), unifying R&D innovation with operational execution as Personalis defines the next era of ultrasensitive MRD testing

Personalis, Inc. (NASDAQ:PSNL), a leader in advanced genomics for precision oncology, today announced the promotion of Richard Chen, M.D., M.S., to the position of President. Dr. Chen will continue to serve as CMO of Personalis in addition to his new role.

The appointment comes at a critical inflection point as Personalis transitions from a pioneering R&D powerhouse into a market leader in Minimal Residual Disease (MRD) testing. Under Dr. Chen's scientific leadership, Personalis developed and accelerated adoption of the NeXT Personal® platform, which set a new industry benchmark for ultrasensitive MRD testing, detecting cancer at levels far below those previously achievable.

"Personalis is no longer just participating in the MRD market; we are defining its future," said Chris Hall, Chief Executive Officer of Personalis. "Rich has been the principal architect of our most significant product and technology leaps, including NeXT Personal, and designed the clinical evidence strategy that has accelerated adoption of our ultrasensitive MRD tests. By elevating him to President, we are aligning our visionary R&D with the need to integrate the technology into pharmaceutical drug trials and physician workflows to help patients fight cancer."

As President, Dr. Chen will oversee the integration of the company's R&D capabilities, biopharma services, reimbursement, quality systems and medical affairs to capitalize on the technical excellence of the Personalis platform and accelerate revenue growth.

"The work we have done with NeXT Personal has proven that ultra sensitivity is central to enabling earlier detection and intervention for cancer patients, and, just as important, more peace of mind for patients with a negative test result," said Dr. Chen. "We have pioneered a new path in the market and I am excited to step into this expanded role to help lead the scaling of the company. Our goal is clear: to make ultrasensitive MRD testing the standard of care for every cancer patient, ensuring earlier detection and better outcomes."

Dr. Chen's promotion reinforces the company's commitment to scientific rigor as it scales its commercial footprint. His deep expertise in genomic medicine and machine learning, and his track record of moving innovative R&D projects into high-growth clinical products, make him the ideal leader to help drive this next phase of the company's evolution.

About Personalis, Inc.

At Personalis, we are transforming the active management of cancer through breakthrough personalized testing. We aim to drive a new paradigm for cancer management, guiding care throughout the patient journey. Our highly sensitive assays combine tumor-and-normal profiling with proprietary algorithms to deliver advanced insights even as cancer evolves over time. Our products are designed to detect minimal residual disease (MRD) and recurrence at the earliest timepoints, enable selection of targeted therapies based on ultra-comprehensive genomic profiling, and enhance biomarker strategy for drug development. Personalis is based in Fremont, California. To learn more, visit www.personalis.com and connect with us on LinkedIn and X (Twitter).

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include all statements that are not historical facts and can generally be identified by terms such as "believe," "expect," "if," "may," "will" or similar expressions. These statements include those relating to: Personalis' role in defining the future of the MRD market; the expected benefits of aligning research and development capabilities with integration of Personalis' technology into pharmaceutical drug trials and physician workflows, including ultrasensitive MRD testing becoming the standard of care, earlier detection, better outcomes and future revenue growth; and Personalis' market leadership, performance, plans and expectations. Such forward-looking statements involve known and unknown risks and uncertainties and other factors that may cause actual results to differ materially from any anticipated results or expectations expressed or implied by such statements, including the risks, uncertainties and other factors that relate to Personalis' ability to demonstrate attributes, advantages or clinical validity or utility of the NeXT Personal test, including the NeXT Personal MRD assay remaining unique in its ability to detect traces of cancer in the ultrasensitive range; the integration of R&D capabilities, biopharma services, reimbursement, quality systems and medical affairs under Dr. Chen's leadership translating into accelerated revenue growth; the rate of adoption and use of the NeXT Personal test; changes in health care policy, which could increase Personalis' costs, decrease Personalis' revenue, and impact sales of and reimbursement for Personalis' tests; the impact of competition and macroeconomic factors on Personalis' business; having a limited number of suppliers; and customer concentration. These and other potential risks and uncertainties that could cause actual results to differ materially from the results predicted in these forward-looking statements are described under the captions "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" in Personalis' Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission on February 26, 2026. All information provided in this release is as of the date of this press release, and any forward-looking statements contained herein are based on assumptions that we believe to be reasonable as of this date. Undue reliance should not be placed on the forward-looking statements in this press release, which are based on information available to us on the date hereof. Personalis undertakes no duty to update this information unless required by law.

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