<unk>  (or FN-RMS) is the more common of two major sub-types of rhabdomyosarcoma, the other being alveolar rhabdomyosarcoma (ARMS) also known as Fusion Positive RMS (FP-RMS). Commonly, FN-RMS is driven by a mutation in the RAS family of proto-oncogenes, creating a powerful signal which is now known to promote tumor growth by preventing muscle lineage progression by blocking expression of the transcription factor MYOG. Inhibition of this signaling pathway with trametinib has been recently shown to overcome this differentiation block and reduce tumor progression in animal models of FN-RMS. FN-RMS has been informally classified as a "small round blue cell tumor" because of the characteristic microscopic appearance of its cells after histological staining with hematoxylin and eosin.
Embryonal rhabdomyosarcoma
Endodermal sinus tumor
Primitive neuroectodermal tumor
Malignant rhabdoid tumour
Immature teratoma
Germ cell tumor
Neurofibroma
Sclerosing rhabdomyosarcoma