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Molecular analysis of papillary thyroid carcinoma (PTC) by microarray techniques offers a valuable tool for identifying novel genes that can be used as diagnostic and prognostic markers, as well as for staging and monitoring the disease. In this study, we used high-density Affymetrix oligonucleotide arrays (GeneChip Human Genome U133 Plus 2.0 Array) that include 38,500 well-characterized human genes to analyze the gene expression profile of 7 papillary thyroid carcinoma samples compared to 7 paired normal samples. Analysis of the microarray data by Affymetrix and dChip software, revealed the significant altered expression of 186 genes, most of them present in all the seven patient’s samples. Real-time RT-PCR was used to validate microarray data for a selected set of genes. Grouping the genes according to Gene Ontology terms showed altered gene expression associated with cell adhesion and extracellular matrix, transport, metabolism, signal transduction and thyroid metabolism. Specifically, kallikrein 7, kallikrein 10, secretory leukocyte protease inhibitor (antileukoproteinase), STRA6, ATP-binding cassette sub-family C (CFTR/MRP) member 3, and secreted frizzled-related protein 2 were among the most highly overexpressed genes and, more significant, not previously reported in this type of cancer. Underexpressed genes in PTC include fibroblast growth factor receptor 2, leukemia inhibitory factor receptor, phospholipase A2 receptor 1, v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT), and peroxisome proliferative activated receptor gamma coactivator 1. We also found genes that were previously detected in PTC (overexpressed or underexpressed), including CITED1, MUC-1, thyroid peroxidase, deiodinase iodothyronine type I and type 2, and alpha-1 antiproteinase antitrypsin (SERPINA1), validating our study. In conclusion, we successfully detected new genes with increased expression in PTC that may be used as biomarkers in PTC.

[Proc Amer Assoc Cancer Res, Volume 46, 2005]