polysomy


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

polysomy

[päl·ē‚sō·mē]
(genetics)
The occurrence in a nucleus of an extra copy of one or more individual chromosomes.
References in periodicals archive ?
Acquired cystic disease-associated renal cell carcinoma with a focal sarcomatoid component: report of a case showing more pronounced polysomy of chromosomes 3 and 16 in the sarcomatoid component.
Polysomy 17 in HER-2/neu status elaboration in breast cancer: effect on daily practice.
Two of these had polysomy 17 and thus a false positivity by IHC18; whereas, the reasons for the other case could be due to one of the following reasons, viz.
Polysomy and supernumerary isochromosomes in the grasshopper Omocestus bolivari (Chopard).
He stressed that only a small number of patients was analyzed and noted that trastuzumab did not improve progression-free survival or overall survival for the HER2-negative patients with polysomy of chromosome 17.
Central HER2 IHC and FISH analysis in a trastuzumab (Herceptin) phase II monotherapy study: assessment of test sensitivity and impact of chromosome 17 polysomy.
The rationale for assessing amplification status as a ratio to the centromeric region was to compensate for potential polysomy; however, detailed chromosomal analysis by comparative genomic hybridization and single-nucleotide polymorphism arrays have demonstrated that chromosome 17 polysomy is a rare event in breast cancer (7, 8).
Therefore, use of PPARG immunostaining as a surrogate for the PAX8/PPARG rearrangement will produce a larger number of false-positive results, because polysomy is often observed in FTC (17-20).
Increased CEP17 copy number may occur because of a focal gain in the centromeric region, polysomy (a duplication of the entire chromosome), a gain of a large portion of chromosome 17, or coamplification of the centromere and HER2.
HER-2 gene-amplified tumors were further subdivided into 3 categories: low amplification if no polysomy of chromosome 17 (mean of 2-5 signals per nucleus), moderate amplification (5-20 signals per nucleus), and high amplification (>20 signals per nucleus).