Fig. 2

Determination of ALK gene copy number by fluorescence in situ hybridization. Copy number variation was further validated by an independent method of quantitative PCR in ALK amplified and non-amplified breast cancer samples. Tissues were screened on an Olympus BX 51 microscope (Olympus America Inc, Center Valley, PA, USA) under 100× magnification. a Breast cancer ALK amplified sample hybridized with ALK break-apart probe showing ten red and green fused signals. b Breast cancer ALK non-amplified sample hybridized with ALK break-apart probe showing normal tissue with two red and green fused signals. c Breast cancer ALK amplified sample hybridized with BAC probe RP11-328L16 and CEP2 probe showing two red CEP2 signals and seven to eight green signals representing the ALK gene amplification. d Breast cancer ALK non-amplified sample hybridized with BAC probe RP11-328L16 and CEP2 probe showing two red CEP2 signals and two green signals representing normal ALK copy number. e Verification of the ALK gene copy number by real-time quantitative PCR. Histogram showing ALK gene copy number obtained from normal breast samples 1–3 with two normal copies of ALK gene and samples 4–8 are amplified breast cancer samples. ALK anaplastic lymphoma kinase, PCR polymerase chain reaction