EFTs
Meaning of EFTs: The unifying feature is molecular rather than anatomic, which is why a bone tumor and a chest wall tumor sit in the same group.
Definition of EFTs
EFTs stands for the Ewing sarcoma family of tumors, a group of cancers that share a characteristic gene rearrangement rather than a single location. It covers Ewing sarcoma of bone, Ewing tumors arising outside bone, peripheral primitive neuroectodermal tumors, and Askin tumors of the chest wall. Newer classifications treat them as one disease.
What holds the group together?
Nearly all these tumors carry a rearrangement that fuses a gene called EWSR1 to a partner from the ETS family, most often FLI1. The fusion produces a protein that switches other genes on abnormally and drives the tumor. Detecting it in a sample confirms the diagnosis wherever the tumor was found, and it is what allowed these tumors, which appear under the microscope as sheets of small round blue cells, to be separated from several other cancers with the same appearance. What the group does not have is a settled cell of origin. Whether these tumors begin in a mesenchymal stem cell or in a cell of neural crest lineage is unresolved, so the grouping rests on the molecular finding rather than on a proven common ancestor.
What names fall inside it?
| Name | Where it arises |
|---|---|
| Ewing sarcoma of bone | Bone, most often the pelvis, thigh bone or ribs |
| Extraosseous Ewing tumor | Soft tissue outside bone |
| Peripheral primitive neuroectodermal tumor | Bone or soft tissue, with features suggesting nerve differentiation |
| Askin tumor | The chest wall |
One exclusion matters. Primitive neuroectodermal tumors of the central nervous system are a separate group of brain tumors and do not belong here despite the shared wording, and that label has itself been retired from brain tumor classification. Only the peripheral form carries the Ewing fusion.
Why does the grouping matter?
Because tumors in the family behave alike, they are approached with related strategies: treatment aimed at disease throughout the body, combined with local control of the primary site by surgery, radiation or both. That contrasts with much of oncology, where the organ of origin drives the plan. During the workup of a soft tissue sarcoma, finding the Ewing fusion changes the pathway substantially. Location still shapes an individual case, since a tumor in the pelvis poses different surgical problems from one in the forearm, and the extent of disease at the time of diagnosis remains the strongest single factor in outlook.
Also known as
Used in a sentence
Genetic testing of the tumor sample helped confirm a diagnosis within the Ewing sarcoma family of tumors.
Good to know
Tumors within the Ewing sarcoma family are unified by a characteristic gene rearrangement rather than by a single anatomic location or by a proven common cell of origin, which is why tumors in bone and in soft tissue are classified together.