RNA analysis of tape strips to rule out melanoma in lesions clinically assessed as cutaneous malignant melanoma: A diagnostic study

Background: Distinguishing cutaneous malignant melanoma (CMM) from nevi can be clinically challenging. Suspicious lesions are therefore excised, resulting in many benign lesions being removed surgically to find 1 CMM. It has been proposed to use tape strip derived ribonucleic acid (RNA) to distinguish CMM from nevi. Objective: To develop this technique further and validate if RNA profiles can rule out CMM in clinically suspicious lesions with 100% sensitivity.Methods: Before surgical excision, 200 lesions clinically assessed as CMM were tape stripped. Expression levels of 11 genes on the tapes were investigated by RNA measurement and used in a rule-out test. Results: Histopathology showed that 73 CMMs and 127 non-CMMs were included. Our test correctly identified all CMMs (100% sensitivity) based on the expression levels of 2 oncogenes, PRAME and KIT , relative to a housekeeping gene. Patient age and sample storage time were also significant. Simultaneously, our test correctly excluded CMM in 32% of non-CMM lesions (32% specificity). Limitations: Our sample contained a very high proportion of CMMs, perhaps due to inclusion during COVID-19 shutdown. Validation in a separate trial must be performed.Conclusion: Our results demonstrate that the technique can reduce removal of benign lesions by one-third without overlooking any CMMs. ( J Am Acad Dermatol 2023;89:537-43.)

Automated summary

Using tape strip derived RNA, this study developed a technique to differentiate cutaneous malignant melanoma (CMM) from nevi with 100% sensitivity. The technique reduced the unnecessary surgical removal of benign lesions by one-third without overlooking any CMMs.