Assessing the Impact of Melanin Content on the Reliability of the Idylla™ BRAF Mutation Test

Abstract

Aims: This study aims to investigate the potential influence of melanin content on the performance of the Idylla™ BRAF Mutation Test. Specifically, we assess whether melanin levels in samples impact the test’s reliability, thereby validating its clinical utility in accelerating melanoma diagnosis and potentially improving patient prognosis. Methods: We conducted a retrospective analysis of 98 confirmed melanoma samples collected between February 2020 and November 2020. Formalin-fixed paraffin-embedded (FFPE) slides were evaluated by two independent observers using light microscopy to categorise samples into three groups based on melanin content (no, low, or high) following a standardised system. The samples underwent the Idylla™ BRAF Mutation Test and were compared with results obtained from next-generation sequencing (NGS). Results: Quantification cycle (Cq) values were utilised to assess for interference from melanin levels on the Idylla™ BRAF Mutation Test results. Statistical analyses revealed no significant differences in Cq values based on melanin content categories. Furthermore, analysis of polymerase chain reaction PCR curves did not indicate any notable influence of melanin. Discordant results with NGS are discussed. Conclusions: The study demonstrates that melanin content in samples does not significantly affect the performance of the Idylla™ BRAF Mutation Test. These results provide robust evidence supporting the confident application of the test in clinical settings, even for samples with high melanin content. The ability to obtain rapid on-site results holds promising potential in guiding timely and appropriate treatment decisions, thereby contributing to improved patient prognosis. What is already known on this topic—Prior research conducted by Petty et al. (2020) including 23 melanoma samples suggested that melanin does not significantly interfere with the Idylla™ BRAF Mutation Test by stating they were concordant with reference laboratory testing. What this study adds—This current study builds upon prior research with a larger sample size of 98. In addition to examining concordance between the Idylla™ BRAF Mutation Test and next generation sequencing, this study examines PCR curves and effect on Cq values, providing more robust evidence that melanin content in FFPE samples does not have a significant impact on the accuracy of the Idylla™ BRAF Mutation Test. How this study might affect research, practice or policy—The additional evidence base provided by this study is valuable for researchers, clinicians, and policymakers, as it supports the integration of the Idylla™ BRAF Mutation Test as a rapid and accurate method for detecting these mutations in melanoma patients.

Keywords

• melanin content
• Idylla™ BRAF Mutation Test
• test reliability
• melanoma diagnosis