The ARC Registry is a large-scale, multi-site, prospective, observational registry. All patients with a solid tumor malignancy who receive Ataraxis testing as part of routine clinical care are eligible for enrollment, which will link Ataraxis test results with short- and long-term patient outcomes to evaluate the real-world performance and clinical utility of Ataraxis tests. The ARC Registry utilizes an adaptable design, where additional Sponsor-led analyses and investigator-initiated ancillary studies can be added after the initial study is opened.

The Ataraxis Real-World Clinical Outcomes (ARC) registry is a prospective, multi-site, non-interventional, observational registry designed to capture short- and long-term clinical outcomes of patients who undergo Ataraxis testing as part of routine clinical care. Ataraxis tests generate prognostic and predictive scores from digitized hematoxylin and eosin (H&E)-stained pathology slides and baseline clinical variables. Treatment is at the discretion of the treating physician in accordance with standard of care, and participation in the registry does not change or influence treatment selection.

Following enrollment, clinical data will be collected at multiple time points for up to 10 years. Data will be captured in Ataraxis AI's Portal.

Enrollment is planned over approximately two years, with follow-up extending up to 10 years per participant. Approximately 1,000 participants will be enrolled across participating U.S. sites.

Objectives:

• Establish a large-scale, multi-site registry of patients receiving Ataraxis tests, linking test results with short- and long-term clinical outcomes to evaluate their real-world prognostic and predictive performance and clinical utility
• Evaluate the performance and clinical utility of Ataraxis tests across diverse patient populations, including molecular subtypes, treatment regimens, and demographic and geographic strata
• Leverage the adaptable registry infrastructure to support downstream independent research by contributing site-investigators

Inclusion Criteria:

• Aged 18 years or older at the time of consent.
• Diagnosis of a solid tumor malignancy, confirmed histologically or cytologically.
• Patient is undergoing Ataraxis testing as part of their routine clinical care.
• Availability of a pathology specimen.
• Willing and able to provide written informed consent.

Exclusion Criteria:

• Unable or unwilling to provide informed consent.
• Patient for whom an Ataraxis test result was not successfully generated (e.g., due to sample quality, technical failure, or any reason resulting in a non-reportable result).

Study population will include adults (≥18 years) with a histologically or cytologically confirmed solid tumor malignancy who undergo Ataraxis testing as part of routine clinical care and have signed an informed consent. Patients will be excluded if an Ataraxis test result is not successfully generated.