due to improper biopsy collection and/or handling. Tumor biopsy collection is critical for the successful reporting of metastatic risk Class assignment following DecisionDx-UM testing. DecisionDx-UM Ordering and Reporting Castle Biosciences, Incorporated only accepts service orders for DecisionDx-UM from licensed physicians (most commonly ocular oncologists, ophthalmologists, or retina specialists) who care for patients diagnosed with uveal melanoma. Physicians who are first time customers must contact Castle’s for information and to establish an account. Sample submission requires submission of a DecisionDx-UM Requisition Form to be completed and faxed to Castle. FNAB specimens require use of a specimen collection kit, provided by Castle, to stabilize the sample and reduce the chance of technical failure. This kit must be received by the ordering physician prior to sample collection. Castle staff is available to assist with logistics concerning sample collection and shipping. Castle provides a report to the ordering physician that will classify the tumor as Class 1A, Class 1B, or Class 2. The report will also describe the statistics associated with the classification, and provide a discriminant value that reflects the confidence regarding the classification. The information provided in the report from Castle identifies how likely a tumor is to metastasize (spread) with this risk being categorized as low (Class 1A), intermediate (Class 1B), or high (Class 2). Other UM Metastasis Prognostic Factors Histopathologic Factors and Imaging Techniques Historically there are several clinical and pathologic features that have been statically associated with metastasis. Tumor size, tumor location, patient age and vascular structure have all been reported to correlate with metastatic onset and patient survival. While generalities regarding the UM patient population at large can be made based on these factors, none, alone or collectively, has demonstrated predictive accuracy with regard to metastatic activity. Imaging techniques used to detect metastatic activity also have limitations. Systemic metastases are detected by Positron Emission Tomography (PET) imaging at the time of the original diagnosis in less than 4% of UM patients Magnetic Resonance Imaging (MRI) has recently been reported more sensitive than PET for identifying metastasis from choroidal melanoma, but MRI requires tumor mass greater than 5mm in size. Thus, current imaging technology lacks the sensitivity for detecting micrometastases that may be present at the time of primary diagnosis of uveal melanoma. Genetic Factors Genetic analysis techniques have led to the identification of chromosomal abnormalities associated with metastatic tumor progression in uveal melanoma. Loss of heterozygosity, loss of