polysomy


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polysomy

 [pol″e-so´me]
an excess of a particular chromosome.

pol·y·so·my

(pol'ē-sō'mē),
State of a cell nucleus in which a specific chromosome is represented more than twice. Cells containing three, four, or five homologous chromosomes are referred to, respectively, as trisomic, tetrasomic, or pentasomic. Compare: polyploidy.
[poly- + G. sōma, body (chromosome)]

pol·y·so·my

(pol'ē-sō'mē)
State of a cell nucleus in which a specific chromosome is represented more than twice. Cells containing three, four, or five homologous chromosomes are referred to, respectively, as trisomic, tetrasomic, or pentasomic.
Compare: polyploidy
[poly- + G. sōma, body (chromosome)]
References in periodicals archive ?
Myelomonocytic/monocytic lineage involvement is also a characteristic of polysomy 8 cases.
Determining true HER2 gene status in breast cancers with polysomy by using alternative chromosome 17 reference genes: implications for anti-HER2 targeted therapy.
Since the current clinical guidelines for amplification and polysomy are defined by the cut-off values for MP data, the AD cannot be readily used for decision support without proper validation.
Determination of HER-2 status and chromosome 17 polysomy in breast carcinomas comparing HercepTest and PathVysion FISH assay.
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).
Chromosome 17 polysomy: a unifying hypothesis underlying benefit from adjuvant anthracyclines?
Within this group, the new investigation determined that 25 patients (19%) had polysomy (defined as 2.2 copies or more per cell) of chromosome 17.
(25-31) Given the evidence that some group 3 cases have true HER2 amplification rather than polysomy for chromosome 17, particularly when the HER2 copy number is high, the Expert Panel ultimately favored continuing to classify these cases as HER2 positive unless the concurrent IHC result is clearly negative (0 or 1+).
For EGFR, samples were grouped as normal disomy, [less than or equal to] 2 centromere signals in [greater than or equal to] 40% of cells; low polysomy/trisomy, [greater than or equal to] 3 centromere signals in [greater than or equal to] 40% of cells, excluding cases with high polysomy or gene amplification; high polysomy, [greater than or equal to] 4 centromere signals in [greater than or equal to] 40% of cells, excluding cases with gene amplification; and gene amplification, ratio of gene/chromosome [greater than or equal to] 2 or clusters of probes (>10 copies per tumour cell) in [greater than or equal to] 40% of cells.
A lung adenocarcinoma without ROS1 fusion showing (C) patchy ROSI IHC staining and (D) FISH exhibiting polysomy but no evidence of rearrangement (original magnifications X200 [A and C] and X630 [B and D]).