Castle Biosciences’ Cutaneous Squamous Cell Carcinoma Prognostic Test Development Progress Highlighted in Oral Presentation at American Society for Dermatologic Surgery Annual Meeting

In this multi-center development study, more than 500 primary cSCC specimens were accrued from 14 centers, and gene expression analysis of candidate genes selected based on literature and pathway analysis was performed through reverse transcription polymerase chain reaction (RT-PCR). Predictive modeling with machine learning was performed on a preliminary development set that included both non-recurrent and recurrent cases with verified clinical data and outcomes.

Researchers successfully identified genes that exhibited significant differential expression between non-recurrent and recurrent cases, including several specific to regional/distant metastasis (p<0.05). An average of the top performing preliminary models for predicting metastasis or local recurrence had higher sensitivity and positive predictive value when compared to current staging methods, and maintained or improved comparable specificity and negative predictive value.

In addition to candidate genes selected from the literature, microarray analysis on 80 recurrent and non-recurrent cases permitted an unbiased, genome-wide approach for selection of additional genes through machine learning for validation.

“These study findings demonstrate continued progress in the development of a prognostic test for cSCC that can identify patients with a risk of metastasis more accurately than currently used staging systems,” commented Chrysalyne D. Schmults, M.D., Brigham and Women’s Hospital, Boston, an investigator in the study. “Successful validation and clinical application of a test such as this could help inform clinical decision-making regarding the potential need for adjuvant therapy.”

Based on demonstrated progress with initial development work, collaborative site recruitment and clinical study activities are actively continuing.

About Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC), a non-melanoma skin cancer, is one of the most common cancers with an estimated incidence of more than 1,000,000 cases in the U.S. each year. Approximately 20% of patients have high-risk features based on tumor depth, histology, anatomic location and/or immunosuppression. Most patients have a favorable prognosis, but a subset of patients will develop metastasis and up to 15,000 patients each year die from their disease. As current staging parameters have a low positive predictive value, many more patients are considered high risk than actually develop metastatic disease. Conversely, many patients that develop metastatic disease are misidentified as low risk. This leads to over and undertreatment of a substantial number of cSCC patients. To address this clinical need, Castle Biosciences is developing a gene expression profile test to improve upon current staging systems and identify patients with cSCC at high risk for metastasis and death, enabling more informed clinical decisions regarding adjuvant therapy and other management options.

About Castle Biosciences

Castle Biosciences is a molecular diagnostics company dedicated to helping patients and their physicians make the best possible decisions about their treatment and follow up care based on the individual molecular signature of their tumor. The Company currently offers tests for patients with cutaneous melanoma (DecisionDx^®-Melanoma, DecisionDx^®-CMSeq; www.SkinMelanoma.com) and uveal melanoma (DecisionDx^®-UM, DecisionDx^®-PRAME and DecisionDx^®-UMSeq; www.MyUvealMelanoma.com), with development programs in other underserved cancers. Castle Biosciences is based in Friendswood, Texas (Houston), and has laboratory operations in Phoenix, Arizona. More information can be found at www.CastleBiosciences.com.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are the trademarks of Castle Biosciences, Inc. Any other trademarks are the property of their respective owners.

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