Transcriptomic Study on Human Skin Samples: Identification of Two Subclasses of Actinic Keratoses

Area of Science:

• Dermatology
• Molecular Biology
• Genomics

Background:

• Actinic keratoses (AKs) are common sun-damaged skin lesions affecting a significant portion of the adult population, particularly the elderly.
• Current clinical and histological methods cannot reliably predict AK progression or regression.
• Transcriptomic analysis offers a potential method for characterizing AKs, but requires further investigation into molecular signatures.

Purpose of the Study:

• To identify objective biological features for distinguishing different AK molecular signatures.
• To conduct the largest patient study to date for AK characterization.
• To explore potential therapeutic targets for high-risk AK lesions.

Main Methods:

• Transcriptomic approach applied to a large cohort of patients.
• Differential gene expression analysis to identify molecular profiles.
• Connectivity map approach to identify potential therapeutic targets.

Main Results:

• Two distinct molecular profiles were identified: lesional AKs (AK_Ls) resembling squamous cell carcinomas (SCCs) and non-lesional AKs (AK_NLs) resembling normal skin.
• 316 differentially expressed genes (DEGs) were identified between AK_L and AK_NL.
• Upregulated genes in AK_L were linked to inflammation, while downregulated genes were associated with keratinization.

Conclusions:

• This study provides objective molecular criteria for classifying AKs into distinct subtypes.
• The identified molecular profiles offer insights into AK pathogenesis and progression.
• The VEGF pathway is highlighted as a potential therapeutic target for high-risk AK lesions.