Marino FZ, Rossi G, Cozzolino I, et al. - Given the possible usefulness of multiplex ALK/ROS1 fluorescence in situ hybridization (FISH) approach in clinical practice to save cytological samples for further molecular analysis, researchers sought to ascertain its diagnostic performance in lung adenocarcinoma cytological series compared with classic single break apart probes. Sixty-one lung adenocarcinoma cytological specimens enriched in tumors harboring ALK-rearrangement and ROS1-rearrangement were collected. Using single break apart probes and immunohistochemistry, previous assessment of ALK and ROS1 status was done by classic FISH test. The study population was comprised of 6 ALK-positive, 2 ROS1-positive and 53 ALK/ROS1-wild type. Analysis of all specimens was done via multiplex FISH assay using FlexISH ALK/ROS1DistinguISH Probe Zytovision. Full concordance was observed between the results of the dual ALK/ROS1 FISH probe test and previous single ALK and ROS1 FISH tests on two different slides. Findings thereby support the utility of multiplex ALK/ROS1FISH probe test for simultaneously detecting ALK-rearrangement and ROS1-rearrangement on a single slide in cytological specimens with a small amount of biomaterial.