ROS1 and cancer: However, fusions with CD74 were detected in almost half of the cases,228 fusions with EZR in not more than 24%,229 with SDC4, TPM3 and SLC34A2 in less than 15%.228–230 Such rearrangements were also reported in cholangiocarcinoma, in 8.7% of the samples that were analyzed.231 ROS1 acts like a driver in various cancers, including NSCLC.232,233 It activates signaling pathways like Ras/MAPK, PI3K/Akt, and JAK/STAT, which contribute to its role in oncogenesis.