Castle Biosciences(NASDAQ) CSTL

Castle Biosciences helps doctors treat skin and eye cancer. Their tests use genes to find the best patient care. They also help people with severe skin rashes.

Tests for Better Care Decisions

• Dermatology Gene Tests: Gene expression profile (GEP) tests—which look at how genes are active in a cell—help doctors predict if skin cancer will spread to other organs.
• Esophageal Health Tools: Risk-scoring tools identify the likelihood of cancer for patients with Barrett’s esophagus, a condition where the food pipe lining is damaged.
• Eye Cancer Diagnostics: Specialized genomic tests predict the risk of eye cancer spreading to other parts of the body.
• Skin Condition Analysis: Tests analyze immune pathways to help doctors select systemic treatments for patients with severe atopic dermatitis, or eczema.
• Diagnostic Support: Laboratory services help pathologists identify suspicious skin lesions that are difficult to diagnose under a microscope.

New Partnerships and Products

• Acquired Capsulomics, also known as Previse, in May 2025 to add new DNA-based testing technology for esophageal cancer.
• Partnered with SciBase Holding AB in June 2025 to develop diagnostic tools for inflammatory skin diseases.
• Released the AdvanceAD-Tx test in November 2025 to help clinicians guide treatment for patients with moderate-to-severe skin rashes.
• Purchased AltheaDx in April 2022 to enter the mental health diagnostic market, though this service was discontinued in May 2025.

Modern Lab Operations

The company runs high-complexity laboratories in Arizona and Pennsylvania that are certified to serve patients in all 50 states. It uses proprietary algorithms to turn complex gene data into guides that help clinicians decide on surgeries or drug therapies.

A Look at the Numbers

• Total revenue reached $344.2 million for the fiscal year ended December 31, 2025, up 3.6% from $332.1 million in 2024.
• Medicare coverage accounted for 44% of total revenue during the fiscal year ended December 31, 2025.
• Total test reports delivered reached 105,053 in 2025, up 9.3% from the 96,071 reports delivered in 2024.
• Operating income for Q4 2025 turned negative, worsening from a $4 million profit to a $3.8 million loss year-over-year.
• Free cash flow reached $19.7 million in Q4 2025, up 17.6% from the $16.8 million recorded in Q4 2024.

Bottom Line

Castle has grown from a specialized skin cancer tester into a provider of genomic data for several complex medical conditions. Its expansion into inflammatory skin diseases and advanced esophagus testing marks its evolution into a broader medical diagnostics business.