Non-Invasive Diagnosis of Sun Damaged Skin: Actinic Keratosis Vs Squamous Cell Carcinoma.

IMPORTANCE

Actinic keratosis (AK) is a premalignant lesion that has a1% to 10% potential of progression to squamous cell carcinoma (SCC), but it is not possible to determine which lesions are at higher risk.

OBJECTIVE

This study examined the epidermal genetic profiles of actinic keratosis and SCC through non-invasive techniques seeking to develop a biopsy-free method for AK monitoring and aid in the early diagnosis of developing SCC.

DESIGN

Ribonucleic acid (RNA) was collected from adhesive tape strips and gene expression levels were measured. A threshold fold change >2 and adjusted P-value <0.05 were used to determine differentially expressed genes.

SETTING

Single center dermatology clinic.

PARTICIPANTS

Patients who presented to the clinic with lesions suspicious of non-melanoma skin cancer that had never been previously biopsied.

MAIN OUTCOME AND MEASURE: RNA was extracted via non-invasive biopsy and sequenced. Low quality samples were filtered out and the remaining samples underwent differential gene expression analysis by DESeq2 in R package. A threshold of fold change >2 and adjusted P-value <0.05 was used for determination of differentially expressed genes. The differentially expressed genes that overlapped between the corrected and uncorrected groups were the most significant for analysis.

RESULTS

From 47 lesions, 6 significant differentially expressed genes were found between AK and SCC, and 25 significant differentially expressed genes between in-situ SCC and invasive SCC. Individual samples showed similarities based on diagnosis, suggesting mutations were specific to the disease and not the individual.

CONCLUSIONS AND RELEVANCE: These findings highlight which genes may play a role in AK progression to SCC. The genomic differences between in-situ and invasive squamous cell carcinoma open an opportunity for early diagnosis of squamous cell carcinoma and risk prediction of actinic keratosis. J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.7097.