Biomarkers in the Ewing sarcoma family of tumors

Figures & data

Figure 1 (A) Histopathology of conventional Ewing sarcoma; hematoxylin and eosin (H&E), 20×. (B) Primitive neuroectodermal tumors with rosette formation; H&E, 20×. (C) Atypical Ewing sarcoma with spindle cells; H&E, 40×. (D) Atypical Ewing sarcoma with large cells; H&E, 40×.

Figure 2 (A) Strong CD99 immunoexpression with predominant membranous pattern in Ewing sarcoma, 40×. (B) Strong caveolin 1 immunoexpression in Ewing sarcoma, 40×. (C) Fli-1 nuclear expression in Ewing sarcoma, 20×. (D) HNK-1 cytoplasmic positivity in Ewing sarcoma, 20×.

Abbreviations: Fli-1, Strong friend leukemia integration 1; HNK-1, Poor human natural killer 1.

Table 1 Potential use of morphological, immunohistochemical and molecular biomarkers in the diagnosis of ESFT

Diagnosis	Biomarkers
Confirmed	• CD99, caveolin 1-positive
Ewing sarcoma	Fluorescent in situ hybridization and/or reverse-transcriptase polymerase chain reaction positive for EWSRI/ETS, EWSRI/ non-ETS gene fusion or other less-frequent translocations without EWSRI rearrangement (FUS/FEV, FUS/ERG) Desmin- and myogenin-negative (absence of muscular differentiation) Can reveal immunoreactivity for cytokeratin and/or carcinoembryonic antigen; epithelial membrane antigen can be positive (poor and focal) Neural and/or neuroendocrine markers are positive Conventional/primitive neuroectodermal or atypical variant
Ewing-like sarcomas	Histopathology similar to atypical ewing sarcoma CD99, caveolin 1-positive Fluorescent in situ hybridization and/or reverse-transcriptase polymerase chain reaction negative or noninformative for EWSRI or FUS rearrangement Presence of CIC/DUX4 or BCOR/CCNB3 gene fusion Absence of specific translocations of other SRCT (synovial sarcoma, rhabdomyosarcoma, congenital fibrosarcoma, etc) Desmin- and myogenin-negative (absence of muscular differentiation) Can reveal immunoreactivity for cytokeratin; epithelial membrane antigen can be positive (poor and focal)
Ewing sarcoma or Ewing-like sarcomas excluded	CD99, caveolin 1-negative Fluorescent in situ hybridization and/or reverse-transcriptase polymerase chain reaction negative or noninformative for EWSRI or FUS rearrangement CIC/DUX4 and BCOR/CCNB3 are negatives Muscular differentiation, strong epithelial membrane antigen immunoreactivity, or any other immunohistochemical profile or molecular findings specific for non-Ewing sarcoma family of tumors, even with CD99 and/or caveolin 1 positivity Tumors corresponding to undifferentiated small round cell sarcomas or pediatric/adult small round cell tumors with non- Ewing sarcoma family of tumors profile (undifferentiated synovial sarcoma, small cell osteosarcoma, rhabdomyosarcoma, wilms tumor, undifferentiated carcinoma, Merkel cell carcinoma, lymphomas/leukemia, rhabdoid tumors, neuroblastoma, epithelioid sarcoma, malignant peripheral nerve sheath tumors)

Abbreviations: ESFT, Ewing sarcoma family of tumors; SRCT, small round cell tumors.

Figure 3 (A) Strong cytokeratin (AE1/AE3) immunoexpression in primitive neuroectodermal tumors, 20×. (B) Moderate epithelial membrane antigen immunoexpression in Ewing sarcoma, 20×. (C) Desmin negativity in Ewing sarcoma, 20×. (D) Strong nuclear Ki-67 expression in Ewing sarcoma, 10×.

Table 2 Potential biomarkers in Ewing sarcoma

		References
Clinical and phenotypic markers	<img/>
Metastatic disease at diagnosis		1–5
Tumor size .8 cm		1–5, 12
Poor histological response after computed tomography		5, 12
Central tumor site		5, 12
Increasing patient age		5, 12
Atypical histological variant		10
CD99, caveolin 1, friend leukemia integration 1, human natural killer 1		9–11, 14–18
NKX.2, ERG		19–23
Neural/neuroendocrine markers (S100, crom-A, syn)		10, 11, 13, 24–27
Epithelial markers (cytokeratin, epithelial membrane antigen, carcinoembryonic antigen)		9–11, 17, 18, 28–30
Muscular differentiation		14, 15, 31–33
Biological markers
Gene fusion type or specific gene rearrangement (EWS versus non-EWS)		34–37
Cell cycle biomarkers (p16, p53, Ki-67)		8, 40–49
Growth signalling pathway  AKT, p-AKT, p-mTOR, IGFBP-3, MAPK, p27KIP1, p70S6 kinase		50, 51
CD117		52, 53
NOTCH		54, 55
ERRB4		56, 57
GD2		58
Biomarkers relate to angiogenesis (VEGF)		59–62
Biomarkers related to epithelial mesenchymal transition
Adhesion molecules (desmoplakin, ZO-1, snail)		18
ZEB2		63
Ezrin		64
TPD52		65, 66
Biomarkers related to tumor microenvironment
CXCR4/CXCL12 axis		67–70
Papillomavirus binding factor		71
CCN3		72, 73
Lectin galactoside-binding soluble binding protein (LGALS3BP)		74
Xg		75
Connexins		76, 77
LSD1		78
STEAP1		79–81
Copy number alterations
Trisomy of chromosome 8 and gain of chromosome 1q		8, 82
Minimal residual disease		8, 83–85
Predictive biomarkers to chemotherapy response
CD133		86
Biological target
Insulin growth factor receptor 1		87–96
Poly(ADP-ribose)polymerase 1		97–99

Notes: Green, diagnostic support; red, prognostic significance; gray, prognostic significance requires validation.

Abbreviations: AKT, protein kinase B; MAPK, MAP-Kinase; p-mTOR, phosphorylated mTOR; VEGF, vascular endothelial growth factor; ADP, adenosine diphosphate; ZO-1, zona occludens 1.