Characterization of microarray gene expression profiles of early stage thyroid tumours

Microarray analysis offers the opportunity of screening transcriptional expression profile of neoplastic cells on a genomic level. Defining consistent changes in gene expression pattern of tumours enables the detection of genes essential for tumorigenesis and might provide biomarkers to early recognition of malignant behaviour and new therapeutical targets.

A high-density oligonucleotide array with 20,000 human gene-specific oligonucleotide was used to analyze benign and early-stage malignant thyroid tumours of epithelial origin: follicular adenoma, follicular carcinoma and papillary carcinoma, compared to normal thyroid tissue.

Significant expression differences of 279 genes -- underexpression of 252 and overexpression of 27 genes -- were found. The overlapping genes of the different histological types were examined extensively. Among these genes a limited set acting on the same transcriptional pathway, through NF-kappaB, were found.

The role of overlapping genes in histologically different tumours has not been clarified, but might represent early or pivotal steps of carcinogenesis. All investigated histiotypes of tumours contained significantly modulated genes acting on the NF-kappaB regulatory pathway. Our findings suggest that modulation of NF-kappaB signalling plays a crucial role in early thyroid carcinogenesis.