Author: Dr Ian Katz, Southern Sun Pathology, New South Wales, Australia. DermNet New Zealand Editor in Chief: Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy editor: Gus Mitchell. November 2017.
At present, many clinical diagnoses in dermatology depend on histopathologic confirmation, which is subjective and requires surgical biopsy.
Gene expression analysis is more objective and is expected to improve management of tumours and inflammatory dermatoses.
Molecular analysis techniques currently depend on tissue obtained from surgical biopsies. They include:
These tests can help predict the behaviour of melanocytic neoplasms, including melanoma.
Tape stripping can be used to remove epidermal cells from the skin surface.
The entire human genome has been screened to determine differing gene expression between melanoma and other pigmented skin lesions.
PRAME (PReferentially expressed Antigen in MElanoma) has a role in oncogenesis, and LINC00518 (Long Intergenic Non–protein Coding RNA518) is a member of a newly described class of regulatory RNA molecules; both are elevated in melanomas compared to the other lesions. The four other genes provide normal values for laboratory processes.
Based on expression profiles of LINC00518 and PRAME in skin tissue samples obtained via adhesive patch biopsies, a pigmented lesion assay (PLA; DermTech, Inc) was developed.
Gene expression assays are being developed to identify cytokine inflammatory profiles from samples collected using adhesive patches.
A “Response TNF” product has been proposed that would help monitor patients on biologic therapy for psoriasis and determine when a change in therapy is needed.
A “Cytokine Ex 17” product measures gene expression changes of the IL–17 pathway, including TNF–alpha and IL–23, and could be used as a biomarker for clinical trials and to assess the cytokine status of a patient’s skin.
Clinical trials are underway to validate a gene expression test to detect cutaneous squamous cell carcinoma and basal cell carcinoma by using skin samples collected with an adhesive patch skin biopsy kit.
More applications of the technology are under development.
Differential gene expression can be detected via skin surface tape stripping to assist in the diagnosis of melanoma, non-melanoma skin cancer and inflammatory skin disease.
See the DermNet NZ bookstore.
© 2018 DermNet New Zealand Trust.
DermNet NZ does not provide an online consultation service. If you have any concerns with your skin or its treatment, see a dermatologist for advice.