Upon review of the IHC (clone D5F3, Ventana, Oro Valley, AZ USA) results for this sample by a pathologist, it was determined that the ALK-positive status had previously been incorrectly assigned, as high signal foci were present in the normal mucosa while the tumor cells were unstained (Figure 4; additional high-resolution images are provided in Supplementary Figure S3). Here, ALK is linked to neoplasm.