Molecular analysis of minimally invasive follicular carcinomas by gene profiling.

BACKGROUND

While the majority of minimally invasive follicular thyroid carcinoma (MIFTC) behave like follicular adenomas, some recur or metastasize. These studies were conducted to determine if molecular profiling can enhance our understanding of MIFTC and to perhaps offer a better classification schema.

METHODS

Microarray analysis was performed on 27 follicular neoplasms. Thirteen follicular adenomas (FAs) were compared with 7 widely invasive follicular thyroid carcinomas (WIFTCs) to generate a list of differentially expressed genes. Next, 7 MIFTCs were analyzed along with the other samples in a cluster analysis. The MIFTCs were then compared directly against both the adenoma and WIFTC groups to investigate genetic relatedness.

RESULTS

FAs and WIFTCs have distinct genetic profiles, with 401 differentially expressed genes. The 7 MIFTCs were added to the analysis. Six of 7 of the MIFTCs were grouped with the adenomas, 4 of which created their own subgroup. When analyzed directly, MIFTCs had 223 differently expressed genes, compared with FAs, and 365, compared with WIFTCs.

CONCLUSIONS

Molecular profiling illustrates that the majority of MIFTCs comprise a subclass of follicular neoplasms, and, while most MIFTCs are genetically similar to adenomas, our patient data suggest that these tumors may deserve greater suspicion of malignant potential. Gene profiling can provide insight into the molecular pathogenesis of MIFTC.