Screening for genetic aberrations in papillary thyroid cancer by using comparative genomic hybridization

Background, Determination of the genetic composition of papillary thyroid c ancers may help explain differences in observed clinical behavior Comparati ve genomic hybridization (CGH) is a novel molecular cytogenetic assay that allows simultaneous detection of gains, losses, and amplification of geneti c information, making it an ideal screening tool. The aim of this study was to identify genetic aberrations occurring in papillary thyroid cancers by using CGH analysis. Methods, CGH analysis was performed on 21 individual cases of papillary thy roid cancers. Nonparametric statistical comparisons were performed with the Fisher exact test. Results. Genetic abnormalities were identified qv CGH ist 10 of 21 cases (4 8%). A recurrent pattern of aberrations was seen in cases where genetic cha nges were detected, involving losses at chromosome arms 1p and 9q and chrom osomes 17, 19, and 22, end gains at chromosome 4 and chromosome alms Sq, 6q , 9q, and 13q. The loss of chromosome 22 was unique to younger patients (P =. 05) and was associated with a higher rate of regional lymphatic metastas is (19% vs 80%, P =. 02). Conclusions. Two genetically unique groups of patients were identified by u sing CGH analysis. One group had no detectable aberrations; the other had a . recurrent pattern of aberrations, localizing to the identical chromosomal loci. This pattern of aberrations suggests that the involved loci may cont ain genes important in thyroid carcinogenesis. The clinical significance of the presence of copy number changes defected by CGH needs to be determined . In addition, molecular cloning of involved genes in each of the aberratio ns is warranted.