Rivers J K, Copley M R, Svoboda R, Rigel D S
Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC, Canada; Pacific Derm, Vancouver, BC, Canada.
Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC, Canada.
Skin Therapy Lett. 2018 Sep;23(5):1-4.
The Pigmented Lesion Assay (PLA) is a gene expression test that helps rule out melanoma and has the potential to reduce the need for surgical biopsies of atypical pigmented skin lesions. Utilizing a new technological platform for the non-invasive profiling of skin, the assay analyzes samples collected from adhesive patches for expression of two key genes (PRAME and LINC00518) known to be overexpressed in melanoma. The test result is binary (positive/negative) based on the detection of one or both genes. PLA positive cases are generally biopsied to establish the histopathologic diagosis, while PLA negative cases are considered for ongoing monitoring. The combination of visual inspection with histopathology, the current gold standard for melanoma diagnosis, has a relatively low negative predictive value (NPV) of approximately 83%, meaning that 17% of melanomas will be interpreted as benign lesions. In contrast, the PLA has a very high NPV (>99%). Further, with its high specificity (69-91%), use of the PLA can reduce the number of false positive samples subjected to histopathology review. By adding the PLA to the current care pathway, the number of surgical biopsies needed to find a melanoma (number needed to biopsy) is markedly reduced from 20-25 biopsies for dermatologists and 39 biopsies for physician assistants, to an average of 2.7. To date, unnecessary surgical procedures of benign lesions have been reduced by 88% based on a sample of more than 20,000 analyzed cases. This has resulted in fewer missed melanomas and significant cost savings to health care systems.
色素沉着病变检测（PLA）是一种基因表达检测方法，有助于排除黑色素瘤，并有可能减少对非典型色素沉着皮肤病变进行手术活检的需求。该检测利用一种用于皮肤无创分析的新技术平台，分析从粘贴片中收集的样本中两个已知在黑色素瘤中过表达的关键基因（PRAME和LINC00518）的表达情况。检测结果基于对一个或两个基因的检测分为二元结果（阳性/阴性）。PLA检测呈阳性的病例通常会进行活检以确定组织病理学诊断，而PLA检测呈阴性的病例则考虑进行持续监测。目前黑色素瘤诊断的金标准是视觉检查与组织病理学相结合，其阴性预测值（NPV）相对较低，约为83%，这意味着17%的黑色素瘤会被误诊为良性病变。相比之下，PLA具有非常高的NPV（>99%）。此外，由于其高特异性（69 - 91%），使用PLA可以减少需要进行组织病理学检查的假阳性样本数量。通过将PLA添加到当前的护理流程中，发现黑色素瘤所需的手术活检数量（活检所需数量）显著减少，皮肤科医生从20 - 25次活检减少到平均2.7次，医师助理从39次活检减少到平均2.7次。迄今为止，基于超过20000例分析病例的样本，良性病变的不必要手术程序减少了88%。这减少了黑色素瘤的漏诊，并为医疗保健系统节省了大量成本。
