Table 3

FISH versus MLPA results forEGFR
Tumor EGFR/CEP 7 ratios in FISH assays on FFPE EGFR’s tumor/NB DNA ratios (normalized CN) Average of 2 MLPA probe sets ± SD
Total EGFR/Total CEP 7 signals Median ratio CUSA FFPE
GBM1 7.3 7.2 8.8 ± 0.2 21.1 ± 2.0
GBM2 8.6 9.3 22.5 ± 7.9 19.3 ± 7.2
GBM3 10.3 9.0 10.5 ± 3.8 33.1 ± 17.2
GBM4 11.1 11.6 19.5 ± 9.3 26.7 ± 6.5
LCM1 1.0 1.0 1.2 ± 0.5 1.2 ± 0.4
LCM2 1.1 1.0 2.3 ± 0.9 2.3 ± 1.4
EP1 1.0 1.0 1.7 ± 0.7 2.9 ± 2.6

Although amplification of EGFR seen in individual cells of GBMs varied greatly and MLPA provided collective results of numerous cells, both techniques demonstrated corresponding large elevations in copy number for this oncogene in GBMs. Polysomy may have accounted for low-level amplifications found with MLPA in LCM2 and EP1. Median ratios were derived from the distributions of signal ratios in individual cells. EGFR = Epidermal Growth Factor Receptor. CEP 7 = Centromere of chromosome 7, FISH = Fluorescence in situ hybridization. SD = Standard deviation. CUSA = Cavitronic ultrasonic surgical aspiration. FFPE = Formalin-fixed, paraffin embedded tissue.

Truong et al.

Truong et al. Diagnostic Pathology 2012 7:66   doi:10.1186/1746-1596-7-66

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