Personalis, Inc. Reports Data Breach Affecting 650 Individuals On February 4, 2026, Personalis, Inc., a Fremont, California-based biotechnology company specializing in cancer genomics and sequencing, disclosed a data breach to the U.S. Department of Health and Human Services (HHS). The incident, classified as a hacking/IT breach, impacted 650 individuals across the United States. While the exact method of intrusion and responsible party remain undisclosed, the exposed data may have included personally identifiable information (PII) and protected health information (PHI), such as names, addresses, dates of birth, contact details, and potentially medical or genetic data. No specific data types have been officially confirmed. Personalis has not released further technical details about the breach but has advised affected individuals to monitor accounts for suspicious activity, review healthcare statements, and remain cautious of phishing attempts or identity theft risks. The company may provide additional notifications or support services, including credit monitoring, as part of its response.