BioProject

normal skin (no), actinic keratosis (ak), and squamous cell carcinoma (scc) of the skin were examined: Carcinogenesis is a multi-step process indicated by several genes up- or down-regulated during tumor progression. The type and number of genes involved in non-melanoma skin cancer (NMSC) are still unclear. This study examined and identified different expressed genes in NMSC. Fifteen snap-frozen biopsies of five immunosuppressed organ-transplanted recipients each normal skin, actinic keratosis (AK) and invasive squamous cell carcinoma (SCC) were analysed. Total RNA was extracted reverse transcribed and biotin-labeled cRNA was used for hybridization with Affymetrix HG-U133A gene expression cDNA-microarrays containing 22,283 known genes. Confocal scanner evaluated the signals twice and data analysis was performed by predicition analysis of microarrays (PAM) using nearest shrunken centroids with the threshold 3.5 to identify genes best characterizing normal skin and skin cancer. ANOVA analysis was performed as a second independent method to identify differentially expressed genes (p<0.05, and p<0.15). Quantitative verification of 13 up- or down-regulated genes was performed by real-time RT-PCR and genes were confirmed by sequencing. Broad coherent patterns in normal skin vs. AK and SCC were observed for 118 genes. Some of the genes (e.g. annexin, lamin, and metalloproteinases) up-regulated in carcinomas in our study have previously reported as over-expressed in NMSC. In total 42 genes were up-regulated and 76 genes were down-regulated in non-melanoma skin cancer. The majority of genes identified have not been previously reported different expressed during non-melanoma skin carcinogenesis. Keywords: ordered