Castle Biosciences

What Castle Biosciences does

Castle Biosciences, Inc. is a publicly traded (NASDAQ: CSTL) molecular diagnostics company founded in 2008 by Derek J. Maetzold and headquartered in Friendswood, Texas. The company develops and commercializes proprietary gene expression profiling (GEP) tests and AI-driven spatialomics assays that provide prognostic, diagnostic, and therapy-guidance information for cancer and inflammatory skin disease. Its core technology platform uses qRT-PCR-based gene expression measurement and an AI-derived spatialomics classifier, with proprietary assays including a 31-gene profile (DecisionDx-Melanoma), 40-gene profile (DecisionDx-SCC), 15-gene profile (DecisionDx-UM), and 487-gene profile (AdvanceAD-Tx), alongside the TissueCypher AI spatialomics test for Barrett's esophagus. All testing is processed in the company's CAP-accredited, CLIA-certified laboratory, with results delivered through a secure clinician portal.

The company generates revenue by performing laboratory diagnostic tests ordered by healthcare providers, which are billed to insurance payers including Medicare, Medicaid, commercial insurers, and the Veterans Affairs system. Castle distributes its tests via a domestic direct sales force of area managers targeting dermatologists, gastroenterologists, and ophthalmologists, supplemented by an online clinician portal and fax-based ordering. Cumulative volume exceeds 300,000 test reports since 2008, including 220,000+ DecisionDx-Melanoma orders, 100,000+ TissueCypher orders (June 2026), and adoption by 3,000+ clinicians for TissueCypher alone. Full-year 2025 revenue was $344.2 million (4% year-over-year growth), with Q1 2026 revenue of $83.7 million and 36% year-over-year growth in core test report volumes; management has guided full-year 2026 revenue to $345–355 million.

Castle has built its portfolio through an aggressive inorganic strategy, acquiring Myriad myPath (2021, $32.5M), Cernostics (2021, up to $80M), AltheaDx (2022, $65M plus up to $75M earn-out), and Previse (2025), and recently opened a new 23-acre purpose-built headquarters in March 2026 to support a workforce of approximately 800 employees. The customer base is highly fragmented across U.S. specialty practices, with named research collaborators including Mayo Clinic, and the company has not pursued international commercialization.

Name

Castle Biosciences

Legal name

Castle Biosciences, Inc.

Website

https://castlebiosciences.com

Company type

Public

Founded year

2008

Operating status

Operating

Headcount range

501–1,000 employees

Short description

Castle Biosciences is a publicly traded molecular diagnostics company that develops gene expression profiling and AI-driven spatialomics tests for cancer prognosis, diagnosis, and therapy guidance, serving dermatologists, gastroenterologists, and ophthalmologists across the United States.

Ownership category

akta.pro rank

Product category

Molecular Diagnostics

NAICS

Medical Laboratories (621511)

SIC

Services-Medical Laboratories (8071)

akta.pro primary industry

Molecular & Genetic Testing (PCR/NGS/qPCR) (HLAGADAF)

akta.pro secondary industries

Oncology Diagnostics (tumor profiling, MRD, liquid biopsy) (HLAAALAE), Laboratory Developed Tests (LDTs) & Specialized Clinical Lab Assays (HLAAALAN), Clinical Biomarker Testing Services (central labs, trial enrollment/monitoring assays) (HLAAAMAC)

Keywords

• Molecular diagnostic tests
• Gene expression profiling
• Oncology prognostic tests
• Spatial tissue analysis
• Dermatology diagnostics

Headquarters

HQ city

Friendswood

HQ country

United States

HQ region

North America

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Technology or R&D, Marketing or Sales, Operations, Infrastructure

Revenue model

1. Laboratory Diagnostic Testing Services: Castle Biosciences generates revenue primarily through providing molecular diagnostic and prognostic laboratory testing services. Tests are ordered by healthcare providers and billed to insurance (Medicare, Medicaid, commercial insurers, VA). The company operates a CAP-accredited, CLIA-certified laboratory.

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels6 records

Core offering

Castle Biosciences develops and commercializes proprietary molecular diagnostic and prognostic tests that use gene expression profiling and AI-driven spatialomics to inform cancer and dermatologic disease management decisions. Tests are ordered by healthcare providers and processed in the company's CLIA-certified, CAP-accredited laboratory, with results delivered through a secure clinician portal. Core offerings include DecisionDx-Melanoma, DecisionDx-SCC, DecisionDx-UM, TissueCypher, MyPath Melanoma, AdvanceAD-Tx, and adjunct DecisionDx-PRAME and DecisionDx-UM*Seq* tests.

Product overview

Castle Biosciences operates as a molecular diagnostics company offering a portfolio of innovative gene expression profiling (GEP) tests across dermatology, gastroenterology, and ophthalmology. The product portfolio includes prognostic tests (DecisionDx-Melanoma for cutaneous melanoma recurrence risk, DecisionDx-SCC for squamous cell carcinoma metastasis risk, DecisionDx-UM for uveal melanoma metastasis risk, and TissueCypher for Barrett's esophagus cancer progression risk), diagnostic tests (MyPath Melanoma for differentiating melanoma from benign lesions), and therapy guidance tests (AdvanceAD-Tx for atopic dermatitis treatment selection). Additional offerings include DecisionDx-PRAME and DecisionDx-UM*Seq* as adjunct tests for uveal melanoma. Tests are processed in the company's CAP-accredited and CLIA-certified laboratory, with results delivered via secure online clinician portal.

Differentiator

Problem solved

Functional benefit

Brands

• DecisionDx-Melanoma: 31-gene expression profile test for cutaneous melanoma prognosis and SLNB decision guidance
• DecisionDx-SCC
• DecisionDx-UM
• TissueCypher
• MyPath Melanoma
• AdvanceAD-Tx
• DecisionDx-PRAME
• DecisionDx-UMSeq

Products and services

• DecisionDx-Melanoma

Quantifiable outcome

• TissueCypher test modified surveillance intervals in 55% of patients following testing (Mayo Clinic data at DDW 2026)
• +3 more outcomes

Named customers4 records

Segments4 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

AI capability4 records

Feature6 records

Partnerships

Six partnerships are on record, tiered core and minor.

• SciBasecoreStrategic or Co-development Partner · 10 June 2026Collaboration on DETECT-AD clinical study to assess Electrical Impedance Spectroscopy (EIS) technology for predicting flares in atopic dermatitis patients. Castle Biosciences expanded collaboration with license and loan agreement (SEK 20 million) to accelerate development and production of skin diagnostic tests. SciBase is a medical technology company specializing in dermatology diagnostics with FDA-approved Nevisense device for melanoma detection.
• PrevisecoreStrategic or Co-development PartnerCastle Biosciences acquired Previse in 2025 to expand its GI franchise and strengthen capabilities in gastroenterological disease diagnostics.
• AltheaDxcoreStrategic or Co-development PartnerCastle Biosciences acquired AltheaDx in April 2022 for $65 million initial consideration (plus $75 million contingent on milestones) to expand into pharmacogenomics testing for mental health conditions. AltheaDx specializes in the IDgenetix test for personalized mental health treatment guidance.
• CernosticscoreStrategic or Co-development PartnerCastle Biosciences acquired Cernostics in late 2021 for up to $80 million to expand into spatial biology and AI-driven tissue analysis for esophageal cancer diagnostics. Cernostics was a portfolio company of Pittsburgh Life Sciences Greenhouse.
• Myriad myPath, LLCcoreStrategic or Co-development PartnerCastle Biosciences acquired Myriad myPath, LLC from Myriad Genetics in May 2021 for $32.5 million in cash, adding MyPath Melanoma diagnostic test to its portfolio.
• Patient Advocacy OrganizationsminorGTM or Marketing PartnerCastle partners with multiple patient-focused organizations including AIM at Melanoma, Melanoma Research Foundation, The Skin Cancer Foundation, IMPACT Melanoma, Nevada Cancer Coalition and The Sun Bus for patient education, advocacy walks, and skin cancer screening initiatives during Skin Cancer Awareness Month.

Scale indicators8 records

Recent moves7 records

Expansion highlights7 records

Direct peers

• Myriad Genetics: Oncology molecular diagnostics leader offering hereditary cancer testing (BRCA), tumor profiling, and prenatal screening. Directly comparable as both operate CLIA-certified labs serving dermatologists and oncologists with proprietary genomic tests; Castle even acquired Myriad's MyPath Melanoma business.
• Veracyte: Molecular diagnostics company specializing in genomic tests for thyroid, prostate, breast, and lung cancers using RNA sequencing and machine learning. Directly comparable in business model (specialty lab-developed tests sold to clinicians via field sales) and clinical use case (urologic/oncology risk stratification).
• Natera: Molecular diagnostics company offering cell-free DNA tests including Signatera (tumor-informed MRD) and Empower (hereditary cancer). Comparable as a specialty oncology-focused diagnostics company with proprietary tests ordered by clinicians and reimbursed by payers.
• Lucid Diagnostics: Commercial-stage cancer diagnostics company focused on esophageal precancer detection with the EsoGuard test for Barrett's esophagus screening. Directly competes with Castle's TissueCypher test in the same GI/esophageal cancer risk stratification clinical workflow.
• Interpace Biosciences: Molecular diagnostics company offering tests for thyroid (ThyGeNEXT/ThyraMIR) and pancreatic cancer (PanDNA). Comparable as a smaller specialty diagnostics player offering proprietary molecular tests ordered by clinicians with similar field sales model and reimbursement dynamics.

Broad incumbents

• Exact Sciences: Larger molecular diagnostics company best known for Cologuard (colorectal cancer screening) and Oncotype DX (oncology). Comparable as a publicly traded diagnostics company operating specialty labs and commercializing proprietary cancer tests to clinicians, but operates at much greater scale.
• NeoGenomics: Oncology-focused clinical laboratory services company offering comprehensive cancer testing across solid tumors and hematologic malignancies. Comparable as a publicly traded cancer diagnostics lab, though it operates at much broader scale with both clinical trial and routine testing services.
• Guardant Health: Leading precision oncology liquid biopsy company offering Guardant360 and Reveal tests for tumor profiling and MRD monitoring. Comparable as a publicly traded molecular oncology diagnostics company operating CLIA-certified labs and reimbursed by payers.

Emerging players

• Adaptive Biotechnologies: Molecular diagnostics company leveraging immune receptor sequencing for clonoSEQ (MRD) and T-Detect (immune-based disease detection). Comparable as an oncology-focused molecular diagnostics business with proprietary GEP-style technology sold to clinicians, though at smaller scale.
• HTG Molecular Diagnostics: Molecular diagnostics company offering HTG EdgeSeq technology for gene expression profiling. Comparable as a smaller specialty molecular diagnostics player with proprietary gene expression-based profiling technology targeting oncology indications.

Market position

Strengths5 records

Weaknesses3 records

Competitive moat6 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/Castle_Biosci
• YouTubeyoutube.com/channel/UC7ShT1KUjwgxLJDWvxOE0ng
• Facebookfacebook.com/castlebiosciences
• LinkedInlinkedin.com/company/castle-biosciences-inc-
• Instagraminstagram.com/castlebiosciences

Compliance4 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles6 records

Subsidiaries4 records

Funding overview

Funding rounds16 records

Investors11 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A4 records

Investments1 record

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Castle Biosciences