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How It Works

DecisionDx Squamous Cell Carcinoma

Informs risk appropriate patient management

DecisionDx-SCC is a qRT-PCR assay of 6 control and 34 discriminant genes (40 in total) that uses a validated, proprietary neural network algorithm comprised of two gene expression signatures to classify patients into risk categories. The more personalized risk stratification or prognosis helps guide the most appropriate and individualized care for patients with SCC.

More biological insight, more appropriate patient management


  • 40 genes
  • 34 discriminating and 6 endogenous control genes


Precise and personalized risk classification, complementing  traditional risk factors 


Patient management decisions including appropriateness of adjuvant radiation therapy and frequency of surveillance 

DecisionDx-SCC testing process

DecisionDx-SCC is performed in Castle Biosciences’ CLIA certified, CAP-accredited and NY state approved laboratory using formalin-fixed, paraffin embedded (FFPE) primary tumor tissue from either a biopsy or excision.

Tissue biopsy submitted

Tissue blocks or slides from the primary tumor tissue biopsies are sent to our laboratory for testing.

RNA/DNA preparation

Once tissue is received in our laboratory, RNA is isolated from the tissue and converted to cDNA. The cDNA for each of the 40 genes is amplified and the gene signature recorded. 

Signature interpretation

Using an independently validated algorithm, the individual patient's gene expression signature is assessed and a class score is provided. 

DecisionDx-SCC reporting

The DecisionDx-SCC report provides a class score based on a patient's biological risk: 

  • Class 1: Low biological risk 
  • Class 2A: Higher biological risk 
  • Class 2B: Highest biological risk 

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Provides precise, personalized risk of metastasis to inform patient management

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