Fig. 1

EGFR FISH classifications and patterns of EGFR FISH amplification observed. Using dual colour FISH and fluorescent microscopy, EGFR gene copy number was determined in 160 patients with advanced oesophageal cancer. EGFR FISH negative cases are present in panels a-c, EGFR FISH positive cases in panels D-F and a heterogeneously amplified case in panel G. The EGFR FISH classification as follows: loss of chromosome 7 (a), disomy (b), trisomy (c), high polysomy (d), amplification (double minute type) (e), amplification (homogenous staining region type) (f) heterogeneous amplification (g). Blue = DAPI nuclear staining; red signal = EGFR; green signal = chromosome 7 centromere; white arrow = EGFR amplified cells in a heterogeneous amplified case