FISH images of sequential hybridization with the Vysis ETV6 break-apart probe and the MetaSystems BCR-ABL1 dual-fusion probe. The left-hand images (A,C) show the first hybridization with the ETV6 probe. The signal pattern shows 1 normal ETV6 signal and separated 3 ′ETV6 and 5 ′ETV6 signals, indicating the ETV6 gene rearrangement (t(12;21)(p13;q22)). The right-hand images (B,D) show the same cells sequentially hybridized with the BCR-ABL1 probe. The signal pattern shows 2 copies of ABL1, 1 copy of BCR, and 1 BCR-ABL1 fusion signal consistent with the BCR-ABL1 gene rearrangement, as demonstrated by molecular techniques. Image captured using Zeiss microscope and MetaSystems image analysis software.