Vysis 1p36 1q25 and 19q13 19p13 fish probe kit

Fluorescent in situ hybridization (FISH) was performed on formalin-fixed, paraffin-embedded tumor tissue to detect deletion of chromosome 1p and 19q [15 (link)]. 4-μm-thick sections were deparaffinized, treated with sodium thiocyanate and followed by digestion with pepsin solution at 37°C. Dual-color-probe hybridization was then performed using Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit (Abbott Molecular) and the spectrum-green-probe was labeled on chromosome 1q and 19p, respectively. Both probes and target tumor DNA were denatured in an 80°C oven for 30 minutes and followed by an overnight incubation at 37°C. Nuclei were counterstained with Vectashield mounting medium containing 4′, 6-diamidino-2- phenylindole (Vector Laboratories, Burlingame, CA, USA) and the number of FISH signals was assessed under a Zeiss Axioplan fluorescence microscope (Carl Zeiss Microscopy LLC, NY, USA) equipped with a triple-pass filter (DAPI/Green/Orange). Hybridizing signals of at least 100 non-overlapping nuclei were enumerated and a sample will be considered as 1p or 19q deleted when more than 25% of counted nuclei presented one target (orange) signal and two reference (green) signals [2 (link)].

Fluorescence in situ hybridisation was performed for each tumour to detect 1p/19q co-deletion (Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit; Abbott Molecular, De Plaines, IL, USA). For each probe, at least 100 non-overlapping nuclei were selected. When the proportion of missing nuclei was over 30%, the sample was defined as exhibiting chromosomal loss.