EN2 and myalgic encephalomeyelitis/chronic fatigue syndrome: EN2 was most frequently identified in analogous secretory tissue carcinomas such as those in breast [47] and salivary glands [48], followed by congenital fibrosarcoma (CFS) and congenital mesoblastic nephroma (CMN), but was also reported in inflammatory myofibroblastic tumor (IMT), acute myeloid leukemia (AML) [49], acute lymphoblastic leukemia (ALL) [50,51], chronic eosinophilic leukemia (CEL) [52], sinonasal adenocarcinoma (SNAC) [53] and glioma [54].