Although each alteration is infrequent, ROS1 fusions with many kinds of 5′ partner genes (CCDC6, CD74, EZR, FIG, KDELR2, LRIG3, SDC4, SLC34A2 and TPM3) have been reported in lung, brain, biliary tract, and ovarian cancers [9]–[16], [26]–[28]. The gene discussed is CD74; the disease is ovarian cancer.