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]. This evidence concerns the gene SDC4 and ovarian cancer.