Epidermal differentiation complex (EDC) comprises a number of genes associated with human
skin diseases including
psoriasis,
atopic dermatitis and hyperkeratosis. These genes have also been linked to numerous
cancers, among them skin, gastric, colorectal, lung, ovarian and
renal carcinomas. The involvement of EDC components encoding
S100 proteins, small
proline-rich
proteins (SPRRs) and other genes in the
tumorigenesis of head and neck
squamous cell cancer (
HNSCC) has been previously suggested. The aim of the study was to systematically analyze the expression of EDC components on the transcript level in
HNSCC. Tissue specimens from 93 patients with HNC of oral cavity and 87 samples from adjacent or distant grossly normal oral mucosawere analyzed. 48 samples (24
tumor and 24 corresponding surrounding tissue) were hybridized to Affymetrix GeneChip Human 1.0 ST Arrays. For validation by quantitative real-time PCR (QPCR) the total
RNA from all180 samples collected in the study was analyzed with Real-Time PCR system and fluorescent amplicon specific-probes. Additional set of samples from 14 patients with laryngeal
carcinoma previously obtained by HG-U133 Plus 2.0 microarray was also included in the analyses. The expression of analyzed EDC genes was heterogeneous. Two transcripts (S100A1 and S100A4) were significantly down-regulated in
oral cancer when compared to normal mucosa (0.69 and 0.36-fold change, respectively), showing an opposite pattern of expression to the remaining S100 genes. Significant up-regulation in
tumors was found for S100A11, S100A7, LCE3D, S100A3 and S100A2 genes. The increased expression of S100A7 was subsequently validated by QPCR, confirming significant differences. The remaining EDC genes, including all encoding SPRR molecules, did not show any differences between
oral cancer and normal mucosa. The observed differences were also assessed in the independent set of
laryngeal cancer samples, confirming the role of S100A3 and LCE3D transcripts in HNC. In HNC of oral cavity only one family of EDC genes (
S100 proteins) showed significant
cancer-related differences. A number of other transcripts which showed altered expression in HNC require further validation.