Figure 2.

Fluorescence in situ hybridization (FISH) images of sections of non-small cell lung cancer hybridized with the ALK Break-Apart (A), the EGFR/CEP 7 (B and C) and the MET/CEP 7 (C) probe sets. ALK Break-Apart and the EGFR/CEP 7 probe are commercially available (Abbott Molecular), MET/CEP 7 is a “homebrew” probe. In each panel, the chromatin from the nuclei is stained with DAPI (blue color). In (A), the ALK Break Apart FISH probe includes DNA sequences contiguous to the 3′ end of ALK labeled in red and sequences of the 5′ end of ALK labeled in green. (A) Shows an adenocarcinoma specimen harboring the EML4-ALK fusion that is detected as split red and green signals (red and green arrows). The fused red/green signals (yellow arrows) indicate native status of the ALK gene. In (B and C), DNA sequences encompassing the EGFR gene are labeled in red and the centromere 7 control is labeled in green. In normal copies of chromosome 7, these two signals are physically close since EGFR maps at 7p12. (B) Shows a lung adenocarcinoma specimen harboring amplification of the EGFR gene (clusters of red spots indicated by the white arrows). (C) Shows a squamous cell carcinoma exhibiting copy number gain for both the EGFR gene and the control CEP 7. In (D), sequences encompassing the MET gene were labeled in red and the centromere 7 control is in green. (D) Shows an adenocarcinoma specimen exhibiting amplification of the MET gene (clusters of red spots indicated by the white arrows).