Genonic coordinate (human 10:30,434,021 MAP3K8) & (mouse 18:4,331,325 Map3k8).
Cytoband (human 10p11.23 MAP3K8) & (mouse 18qA1 Map3k8).
Here I present: “Ewing Sarcoma“, Victor McKusick, Mendelian Inheritance in Man’, 1966. (MAP3K8) 尤文氏肉瘤。 icd10=C49.9
INTRODUCTION.
Ewing sarcoma is an aggressive type of cancer that most often affects bones or the soft tissue around bones. It primarily occurs in children, adolescents, and young adults, typically between ages 10 and 20, though it can appear at other ages. Here’s a detailed overview:
Origin and Biology
It is part of the Ewing sarcoma family of tumors (ESFT), which includes:
Classic Ewing sarcoma of bone
Extraosseous (soft tissue) Ewing sarcoma
Primitive neuroectodermal tumor (PNET)
Most cases are associated with a chromosomal translocation, usually t(11;22)(q24;q12), which fuses the EWSR1 gene with FLI1 gene, producing an oncogenic fusion protein that drives tumor growth.
Common Sites
Bones: pelvis, femur, tibia, humerus, ribs
Soft tissue: chest wall, paravertebral region
Rarely, other organs may be involved.
Symptoms
Pain and swelling at the affected site
Tender mass
Fever, fatigue, or weight loss (systemic symptoms in some cases)
Fractures may occur if the tumor weakens bone.
Diagnosis
Imaging
X-ray: often shows a “onion-skin” periosteal reaction
MRI: evaluates soft tissue involvement
CT scan: staging and chest evaluation (lungs are common metastasis site)
Biopsy
Confirms small, round, blue cell tumor
Immunohistochemistry: positive for CD99 (MIC2)
Genetic testing: detects EWSR1 translocations
Staging
Bone scan, PET scan, or MRI to check for metastases
Treatment
Ewing sarcoma requires multimodal therapy:
Chemotherapy
Usually started first (neoadjuvant) to shrink tumor and treat micrometastases.
Common drugs: vincristine, doxorubicin, cyclophosphamide, ifosfamide, etoposide
Local control
Surgery: complete removal when feasible
Radiation therapy: for inoperable tumors or as adjunct
Post-surgery chemotherapy (adjuvant) to reduce recurrence risk
Prognosis
Depends on metastasis and tumor response to therapy:
Localized disease: ~70% 5-year survival
Metastatic disease (lungs, bone, bone marrow): ~30% 5-year survival
Early detection and intensive therapy improve outcomes.
Key Points
Rare but serious; mainly affects youth.
Genetic hallmark: EWSR1-FLI1 fusion
Requires combination of chemo, surgery, radiation
Long-term monitoring is crucial for recurrence or late effects of treatment.
Mitogen-Activated Protein Kinase 8 (MAP3K8) in the context of Ewing sarcoma. Breaking this down and connect it to transformation.
1. MAP3K8 Overview
Gene/Protein: MAP3K8 (also called COT or TPL2)
Family: Part of the MAP kinase kinase kinase (MAP3K) family
Function:
Activates the MAPK signaling cascade (Raf → MEK → ERK).
Involved in cell proliferation, survival, and differentiation.
Plays a role in inflammatory signaling via NF-κB.
2. Ewing Sarcoma Background
Ewing sarcoma is a small round blue cell tumor of bone/soft tissue, mainly in children and young adults.
Characterized by a fusion oncogene, most commonly EWSR1-FLI1, which acts as an aberrant transcription factor.
Transformation in Ewing sarcoma is driven by oncogenic signaling pathways including MAPK, PI3K/AKT, and IGF1R.
3. MAP3K8 and Ewing Sarcoma
Experimental models have shown that overexpression of MAP3K8 (COT) can act as a transforming oncogene in fibroblasts and other cells.
In the context of Ewing sarcoma, MAP3K8 can:
Enhance ERK signaling, promoting proliferation and survival.
Potentially cooperate with EWSR1-FLI1 to drive tumorigenesis.
Be a potential therapeutic target, since inhibiting MAP3K8 can reduce MAPK-driven growth.
Reference Example:
A study using Ewing sarcoma transformants (cells engineered to express EWSR1-FLI1) found that MAP3K8 activity could further enhance anchorage-independent growth, a hallmark of transformation.
MAP3K8 can bypass upstream RAS mutations and directly activate MEK/ERK, which is why it can function as a potent oncogenic driver in certain sarcoma contexts.
4. Summary
MAP3K8 (COT/TPL2) is a MAP kinase kinase kinase that activates ERK signaling.
In Ewing sarcoma, it can act as a transforming oncogene, cooperating with EWSR1-FLI1 or other pathways to drive proliferation and survival.
Targeting MAP3K8 is of interest for potential therapeutic intervention in MAPK-driven tumors.
There is evidence that Ewing sarcoma can be caused by mutation of the mitogen-activated protein kinase-8 (MAP3K8) gene encoded on genomic coordinate 10:30,434,021 and cytoband 10p11.23 in humans.
