Reassessment of microarray expression data of porokeratosis by quantitative real-time polymerase chain reaction.

Background: Porokeratosis (PK) is a heterogeneous group of keratinization disorders that exhibit similarities with psoriasis at both the clinical and molecular levels. Methods: The transcript levels of keratin (KRT) 6A, 16, 17, S100A7, A8, A9, p53 and three candidate genes (i.e. SART3, SSH1 and ARPC3) were reassessed in pairwise lesional and uninvolved skin from nine patients with PK by real-time quantitative polymerase chain reaction (RTQ-PCR). Results: The results of RTQ-PCR confirmed that KRT6A, 16, S100A7, A8 and A9 (p = 0.008) were mostly up-regulated in the lesional skin when compared with uninvolved skin. Different from the microarray data, there was no significant difference observed in KRT17 expression patterns between lesional and normal-appearing skin (p = 0.066). No statistical difference was observed in p53 and three candidate genes' expression patterns between lesional and uninvolved skin. Conclusions: In the present study, 9 of the 10 gene expression measured by RTQ-PCR in PK were statistically comparable to microarray data. KRT6A was identified as specific biomarker for porokeratotic keratinocytes, as it was the most significantly up-regulated gene in the nine patient samples.