REPRODUCIBILITY OF LSI(R) HER-2 NEU SPECTRUMORANGE(TM) AND CEP-17 SPECTRUMGREEN(TM) DUAL-COLOR DEOXYRIBONUCLEIC-ACID PROBE KIT - FOR ENUMERATION OF GENE AMPLIFICATION IN PARAFFIN-EMBEDDED SPECIMENS - A MULTICENTER CLINICAL VALIDATION-STUDY/

Overexpression and/or amplification of HER-2/neu gene L-ave been found to be prognostic and predictive in breast and other cancers. Fluoresc ence in situ hybridization (FISH) assay, with its sensitivity and spec ificity, can be a superior method of detection when its performance ch aracteristics are demonstrated. A multicenter study was initiated, to evaluate the reproducibility of the LSI HER-2/neu SpectrumOrange and C EP 17 SpectrumGreen Dual Color DNA Probe for enumeration of both the H ER-2/neu gene and chromosome 17 (signals) in interphase cells. Section slides were prepared from four cell lines (H, E. R, and N) with known ratios of the HER-2/neu to CEP 17 copy numbers (approximately H = 1.1 0, E = 1.70, R = 4.50, N = 9.0). The study variable was the ratios of the HER-2/neu to chromosome 17 copy numbers. Reproducibility with resp ect to assay, site, lot, day and reader was evaluated at 3 centers. Ou t of 120 specimen slides, 100 pet-cent were successfully assayed. Ther e were no significant differences among: (li four repeated assays: of the same specimen (p = 0.99), (2) the four probe lots (p = 0.33), or ( ) the four study days (p = 0.54). There were statistically significant , but not important differences among centers and between readers. The ratios of the HER-2/neu to chromosome 17 copy numbers were estimated with accuracy and precision; the mean ratios land sd) for specimens, H , E, R, and N were 1.05 (0.06), 1.81 (0.12), 4.48 (0.28), and 8.60 (1. 23), respectively. In summary, assays with the LSI HER-2/neu and CEP 1 7 Dual Color DNA Probe Kit, conducted at three sites by 6 different te chnicians, over 8 assay days, using kits from four lots; were performe d with a high success rate in paraffin-embedded specimens. The signal enumeration was also accurate and precise. This study demonstrated tha t the results obtained by using the LSI HER-2/neu SpectrumOrange and C EP 17 SpectrumGreen Dual Color DNA Probe Kit are reliable and reproduc ible.