Fig. 4

Detection of anaplastic lymphoma kinase (ALK) gene abnormalities in circulating tumor cells (CTC) and tumor specimens of ALK-positive patients. a Examples of isolated or clusters of ALK-rearranged CTCs detected by filter-adapted fluorescent in situ hybridization (FISH) and of ALK-rearranged tumor cells in tumor specimens detected by FISH. Green arrows show an ALK rearrangement with a split 3′ and 5′ (red/green) signal. Red arrows show an ALK rearrangement with only the 3′ signal. b Examples of isolated CTCs with a gain of native ALK copies. In cells with a native ALK status, the overlapping of probes results in a fused (3′ 5′, yellow) signal. Scale: white bars correspond to 10 μm