Microarray Technique, Analysis, and Applications in Dermatology

Jennifer Villaseñor-Park1

and Alex G Ortega-Loayza2

1Department of Dermatology, University of Pittsburgh Medical Center; 2Virginia Commonwealth University

Microarray: Introduction

• Used for– Assessing gene expression levels– Genome-wide studies and genotyping– Evaluating microRNA levels

How do microarrays work?• Microarray chips are created that contain many

thousands of small DNA segments (probes) • Probes are arranged in a known and orderly

fashion (the “array”)• Sample mRNA or its corresponding cDNA is

labeled and exposed to the DNA probe on the chip

• If a given gene is expressed, the mRNA hybridizes to the DNA segment on the chip and can be detected

Microarrays

• Types of array platforms:– Filter arrays (i.e., “macroarrays”)

• Lower probe density compared to spotted or oligonucleotide arrays

• Lower sensitivity (e.g., low-abundance sequences may be missed)

– Spotted glass slide arrays– In situ synthesized oligonucleotide arrays

• Common probes– Complementary DNA (cDNA)– Oligonucleotides

Oligonucleotide arraysControl

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cDNA arraysControl

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Applications in dermatology

• Melanoma• Cutaneous T-cell lymphoma• Psoriasis• Scleroderma• Lupus erythematosus• Others