Differential gene expression profiling of XXXX .

@entity1 @entity21510 @entity73037 @entity25261 @entity146 @entity5 @entity4938 @entity34548 @entity73036 @entity189 @entity3 @entity652 @entity259 @entity2513
The classification of follicular @entity259 requires surgical resection for histologic evaluation of @entity5 . Because variable clinical behavior exists, genomic expression profiling may lead to the identification of novel markers that facilitate better biologic classification. We performed for the first time gene expression analysis on clinically @entity146 ( @entity189 ) from @entity1 for whom long-term follow-up data were available. We examined matched fresh-frozen tissue from 15 histopathologically diagnosed @entity189 (7 @entity1 with documented distant @entity3 and/or death from disease and 8 @entity1 without recurrence). For categorical comparison, we analyzed 4 @entity652 ( @entity652 ). The biologic control comprised 11 normal thyroid tissue specimens. High-quality RNA was extracted from the tissues, labeled, and hybridized to an Affymetrix (Santa Clara, CA) oligonucleotide microarray (HG-U133A). With the exceptions of 1 follicular @entity2513 , unsupervised hierarchical cluster analysis revealed 2 distinct groups--one containing normal thyroid tissue and @entity652 and another containing @entity189 . We identified 421 genes that were differentially expressed between histologically normal thyroid tissues and all @entity5 (P < 0.01; fold-change >2), 94 genes that distinguished @entity189 from @entity652 (including @entity4938 and @entity25261 ), and 4 genes that @entity146 from @entity189 ( @entity21510 , @entity34548 , @entity73036 , and @entity73037 ). Comparative genomic groupings identified differentially expressed genes that may lead to better classification of follicular @entity259 . Such genes may be used in future prospective validation studies to establish clinically useful and complementary diagnostic markers.
