Clinical workflow for MyPath® Melanoma and DiffDx®-Melanoma provides a framework for use of the tests in clinical practice to reduce uncertainty in diagnoses

FRIENDSWOOD, Texas--(BUSINESS WIRE)--$CSTL #CSTL--Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today provided a proposed framework of the Company's diagnostic gene expression profile (GEP) tests, MyPath® Melanoma and DiffDx®-Melanoma, for use in clinical practice to help achieve personalized management and treatment plans. The data is being shared during the Maui Derm NP+PA Fall 2022 Conference, being held Sept. 18-21 in Nashville, Tennessee, and virtually, Sept. 19-21.

MyPath Melanoma and DiffDx-Melanoma are Castle's diagnostic GEP tests designed to provide objective, accurate results to aid in the diagnosis of ambiguous melanocytic lesions. The tests can provide clinically actionable information to help guide and potentially increase confidence in a diagnosis, if any uncertainty or discordance exists, to help clinicians deliver more informed patient management plans and provide their patients with more appropriate and individualized care.

"Using diagnostic GEP testing in clinical practice to alleviate ambiguous diagnoses, in terms of whether a lesion is benign or malignant melanoma, can have a significant impact on a patient's overall treatment plan," said Joanna Ludzik, M.D., Ph.D., dermatologist and Assistant Professor of Dermatology at Oregon Health & Science University's School of Medicine in Portland, Oregon. "The clinical plan that we proposed in the poster provides a framework for how clinicians can use MyPath Melanoma and DiffDx-Melanoma to potentially increase confidence in their diagnoses and ensure the treatment intensity for each patient is better aligned to those diagnoses."

The poster, titled "Clinical Utility and a Guide for Using Gene Expression Profile Ancillary Diagnostic Testing for Cutaneous Melanocytic Neoplasms" and available here, provides a proposed post-biopsy clinical workflow for the use of Castle's diagnostic GEP tests to achieve more personalized management and treatment plans compared to diagnoses based on histopathology alone. Additionally, the poster shares impactful data demonstrating how benign and malignant diagnostic GEP test results can alter patient management plans, including:

• a 76.7%-80.5% reduction in excisions for patients with benign test results, and a 75% increase in excisions for patients with malignant results; and
• 74.1% of dermatologists reducing office visits for patients with benign test results, and 95.2% of dermatologists increasing office visits for patients with malignant results.

About MyPath® Melanoma and DiffDx®-Melanoma

MyPath Melanoma and DiffDx-Melanoma are Castle's two gene expression profile tests designed to provide an accurate, objective result to aid dermatopathologists and dermatologists in characterizing difficult-to-diagnose melanocytic lesions. Of the approximately two million suspicious pigmented lesions biopsied annually in the U.S., Castle estimates that approximately 300,000 of those cannot be confidently classified as either benign or malignant through traditional histopathology methods. For these cases, the treatment plan can also be uncertain. Obtaining accurate, objective ancillary testing can mean the difference between a path of overtreatment or the risk of undertreatment. Interpreted in the context of other clinical, laboratory and histopathologic information, MyPath Melanoma and DiffDx-Melanoma are designed to reduce uncertainty and provide confidence for dermatopathologists and help dermatologists deliver more informed patient management plans.

More information about Castle's tests can be found at .

About Castle Biosciences

Castle Biosciences (Nasdaq: CSTL) is a leading diagnostics company improving health through innovative tests that guide patient care. The Company aims to transform disease management by keeping people first: patients, clinicians, employees and investors.

Castle's current portfolio consists of tests for skin cancers, uveal melanoma, Barrett's esophagus and mental health conditions. Additionally, the Company has active research and development programs for tests in other diseases with high clinical need, including its test in development to predict systemic therapy response in patients with moderate-to-severe psoriasis, atopic dermatitis and related conditions. To learn more, please visit and connect with us on LinkedIn, Facebook, Twitter and Instagram.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-SCC, MyPath Melanoma, DiffDx-Melanoma, DecisionDx-UM, DecisionDx-PRAME, DecisionDx-UMSeq, TissueCypher and IDgenetix are trademarks of Castle Biosciences, Inc.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the "safe harbor" created by those sections. These forward-looking statements include, but are not limited to, statements concerning: the potential of our diagnostic GEP tests to (i) provide clinically actionable information to help guide and potentially increase confidence in a diagnosis; (ii) have a significant impact on a patient's overall treatment plan; and (iii) potentially increase confidence in clinical diagnoses and ensure the treatment intensity for each patient is better aligned to those diagnoses. The words "can," "potential" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements that we make. These forward-looking statements involve risks and uncertainties that could cause our actual results to differ materially from those in the forward-looking statements, including, without limitation: subsequent study or trial results and findings may contradict earlier study or trial results and findings or may not support the results obtained in this study, including with respect to the discussion of our diagnostic GEP tests in this press release; actual application of our tests may not provide the aforementioned benefits to patients; and the risks set forth under the heading "Risk Factors" in our Quarterly Report on Form 10-Q for the three months ended June 30, 2022, and in our other filings with the SEC. The forward-looking statements are applicable only as of the date on which they are made, and we do not assume any obligation to update any forward-looking statements, except as may be required by law.

Investor Contact:
Camilla Zuckero
czuckero@castlebiosciences.com

Media Contact:
Allison Marshall
amarshall@castlebiosciences.com