AN ADHESIVE PATCH BIOPSY BASED GENE EXPRESSION TEST TO NONINVASIVELY 
DIFFERENTIATE BASAL CELL �AND SQUAMOUS CELL CARCINOMAS FROM ACTINIC 
KERATOSES AND OTHER SKIN LESIONS OF SIMILAR APPEARANCE�

INTRODUCTION
A data-driven evolution from subjective image recognition strategies to 
objective gene expression changes (that precede morphological changes) 
may contribute to a paradigm shift in how we practice dermatology and 
differentiate various skin conditions. A qRT-PCR-based non-invasive gene 
expression test that differentiates primary melanomas from similar looking 
benign pigmented lesions with high accuracy became available to 
dermatologists in the US recently.1-4  It may become a tool to improve 
patient care and contribute to such a development.  Demand by patients 
and clinicians for a similar test to non-invasively differentiate 
non-melanoma skin cancers (generally excised) from benign or precursor 
lesions (generally treated via non-surgical modalities such as cryotherapy or 
chemical and immunological destruction) has been growing. 

RESULTS
With a robust qRT-PCR strategy utilizing a novel 13-target gene panel, we 
successfully differentiated BCC and SCC cases from AK and other 
non-cancerous skin lesions of similar clinical appearance with a sensitivity of 
91% (95% CI 86% - 95%) and a specificity of 87% (95% CI 80% - 92%) based 
on 160 non-invasively collected adhesive patch skin biopsies (p<0.001).   An 
area under the curve (AUC) value of 0.95 was observed (Figure 1).

CONCLUSION
The described approach of non-invasive gene expression testing 
differentiates primary cutaneous BCC and SCC cases from benign and 
precursor lesions such as AK with high sensitivity and specificity. Once fully 
validated in an ongoing large prospective study, such a test has the 
potential to reduce the number of avoidable surgical procedures while 
missing fewer cases of non-melanoma skin cancer.

REFERENCES

STUDY APPROACH 
We initiated the development of such a qRT-PCR gene expression test based 
on targets identified through microarray screening of human transcriptomes 
from adhesive patch skin biopsy samples and literature searches. The 
identified target candidates were evaluated in prospectively collected basal 
(BCC) and squamous cell carcinoma (SCC) as well as actinic keratosis (AK) 
and other control samples, also obtained via non-invasive adhesive patch 
biopsies. Cycle threshold (Ct) values from qRT-PCR analyses were used to 
demonstrate changes in target gene expression. Algorithms were developed, 
trained and subjected to primary validation in 160 histopathologically 
confirmed cases. 

Supported by DermTech, Inc.

Gerami et al., Development and validation of a non-invasive 2-gene molecular assay for 
cutaneous melanoma; JAAD-D-16-00647R1, 2016.
Ferris et al., Utility of a noninvasive 2-gene molecular assay for cutaneous melanoma and 
effect on the decision to biopsy. JAMA Dermatology, 153(7)675-680, 2107.
Yao et al., Analytical characteristics of a noninvasive gene expression assay for 
pigmented skin lesions. ASSAY and Drug Development Technologies, 14(6)355-363, 2016.
Yao et al., An adhesive patch-based skin biopsy device for molecular diagnostics and skin 
microbiome studies. Journal of Drugs in Dermatology, 16(10)611-618, 2017.

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 JAMES E SLIGH 1, MD, ZUXU YAO 2, PHD, AND BURKHARD JANSEN 2,  SOUTHERN ARIZONA VA HEALTHCARE SYSTEM AND UNIVERSITY OF ARIZONA 1, TUCSON, AZ AND DERMTECH INC 2, LA JOLLA, CA 

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0.95 (95% CI:0.92-0.97)
AUC

Figure 1. Receiver operating characteristic curve demonstrating the BCC and SCC samples from AK and other non 
cancer skin lesions. AUC, Area under the curve. 


	FC17PosterDermTechSlighAdhesivePatch.pdf