To identify the HER2 status and CEP17 copy number in each case, HER2 FISH (PathVysion assay, Abbott Molecular, Downers Grove, IL) was performed on TMAs of the first set and all tissue sections of the second set. FISH using CEP1 [Vysis CEP1 (D1Z5) SpectrumOrange Probe, Abbott Molecular], CEP8 [Vysis CEP8 (D8Z2) SpectrumGreen Probe, Abbott Molecular], CEP11 [Vysis CEP11 (D11Z1) SpectrumGreen Probe, Abbott Molecular], and CEP16 probe [Vysis CEP16 (D16Z3) SpectrumGreen Probe, Abbott Molecular] was performed on TMAs to assess CIN. These CEP probes around the centromere have been reported to show frequent copy number gains in breast cancer17 (link),23 (link),28 (link).
Briefly, 4 μm deparaffinized tissue sections were incubated in pretreatment solution (Abbott Molecular) at 80 °C for 30 min and then, in protease solution (Abbott Molecular) at 37 °C for 20 min. Probes were diluted in tDen-Hyb-2 hybridization buffer (Insitus Biotechnologies, Albuquerque, NM). The probes and the DNA from the tissue sections were denatured together by incubating them for 5 min at 73 °C in HYBrite™ (Abbott Molecular), and then hybridized for 16 h at 37 °C. Post-hybridization washes were performed according to the manufacturer’s protocol. The mounted slides were viewed using a fluorescence microscope.
Briefly, 4 μm deparaffinized tissue sections were incubated in pretreatment solution (Abbott Molecular) at 80 °C for 30 min and then, in protease solution (Abbott Molecular) at 37 °C for 20 min. Probes were diluted in tDen-Hyb-2 hybridization buffer (Insitus Biotechnologies, Albuquerque, NM). The probes and the DNA from the tissue sections were denatured together by incubating them for 5 min at 73 °C in HYBrite™ (Abbott Molecular), and then hybridized for 16 h at 37 °C. Post-hybridization washes were performed according to the manufacturer’s protocol. The mounted slides were viewed using a fluorescence microscope.