Unlike mesotheliomas in adulthood, ALK-rearranged mesothelioma in children and young adults appears to be similar to the aforementioned mesothelioma harboring EWSR1/FUS-ATF1 fusions in terms of histology, but a significant predilection for peritoneum [22,27,28]. The gene discussed is EWSR1; the disease is mesothelioma.