comparison of genetic, antigenic and clinical features of extra- osseous ewing sarcoma (eo- ews) and...

Comparison of genetic, antigenic and clinical features of extra-osseous Ewing Sarcoma (EO-EWS) and osseous Ewing sarcoma (O-EWS)

Amanda Rivera-Begeman; Carrye Cost; Stephen Lessnick; Richard Smith; Charles Timmons; Patrick Leavey

Annual CTOS Meeting; Seattle, Washington, November 2007

Background

Ewing's sarcoma family of tumors (EFT) Osseous EWS (O-EWS), Extraosseous ES

(EO-EWS), Peripheral primitive neuroectodermal tumor (pPNET) and Askin's tumor of chest wall (Carvajal,R. et al; Hematol Oncol Clin North Am 2005)

Cell surface protein MIC-2 (CD99) expressed on both O-EWS and EO-EWS (Ambros, IM; Cancer; 1991)

FLI-1 nuclear immunostain + ve in 70% of EWS and PNET cases (Folpe et al; Am J Surg Pathol; 2000)

Background

EWS/FLI-1 is seen in patients with EFT (O’Sullivan,MJ et al; Hum Pathol; 2001)

Prior reports of treatment for EO-EWS demonstrated no advantage to the addition of Doxorubicin (Raney RB et al.; J Clin Oncol; 1997)

EO-EWS should be treated with strategies used for O-EWS vs. malignant mesenchymal tumors (Castex,M.P.; J Clin Oncol; 2007)

Objective

To describe genetic, antigenic, and clinical features of patients with EO-EWS, primarily those of intra-abdominal origin

To compare genetic and antigenic features of EO-EWS to those of randomly chosen patients with O-EWS

Patients

Eligibility criteriaEFT treated at Children’s

Medical Center Dallas (1995 – 2005; n=52)

Availability of archival diagnostic material and clinical data

Patients

Clinical Characteristic

EO-EWS(n=11)

O-EWS(n=11)

Primary site

Abdominal: n=9 Pelvic: n=5

Brain: n=1 Long Bone: n=5

Nasopharynx: n=1

Rib: n=1

Mean tumor volume 1035 cm3 494 cm3

Metastases at diagnosis

2 5

Median age at diagnosis

14.9 11.4

Radiation 5 7

Surgery 8 3

Died 2 5

MethodsAE1/AE3

CytokeratinCAM5.2

CK8

CK7

CEA Carcino-embryonic antigen

Vimentin Mesenchymal

FLI-1 Nuclear stain

CD99 MIC2

CD56 Neuro-ectodermal

Synaptophysin

NeuronalNSE

Chromogranin

MyogeninMuscle

Desmin

All immunostains were independently reviewed by 2 pathologists (CT, ARB)

Interpretation was subjective +ve vs. –ve No grading was

attempted

Fli-1weak positive

Fli-1strong positive

CD99 (O13)Weak positive

CD99 (O13)strong positive

Results – positive staining

Immunohistochemistry EO-EWS O-EWS

CK AE1/AE3 1 1

CAM5.2 1 0

CK7 0 0

CK8 0 1

CEA 2 2

Vimentin 8 8

FLI-1 9 9

CD99 11 11

Leu-7/CD56 4 8

Synaptophysin 4 4

NSE 11 10

Chromogranin 0 0

Myogenin 0 0

Desmin 0 0

Cytokeratin Cam 5.2positive

Carcinoembryonic antigen (CEA)positive

Results – positive staining

Immunohistochemistry EO-EWS O-EWS

CK AE1/AE3 1 1

CAM5.2 1 0

CK7 0 0

CK8 0 1

CEA 2 2

Vimentin 8 8

FLI-1 9 9

CD99 11 11

Leu-7/CD56 4 8

Synaptophysin 4 4

NSE 11 10

Chromogranin 0 0

Myogenin 0 0

Desmin 0 0

Methods

RT-PCR RNA extracted from formalin fixed,

paraffin embedded tumor (Roche high pure RNA paraffin kit)

PCR was performed for EWS/FLI-1• EWS/FLI-1 fusion type identified by melt

curve analysis• EWS-FLI-1 fusion type confirmed by agarose

gel electrophoresis Alternate partners were examined as

necessary (ews/fev, etv1, etv4 and erg)

Results – EWS-FLI-1 type

EO-EWS

O-EWS

EWS-FLI-1

10 10

Type 1 7 10

Type 2 3 0

Non Type 1 or 2

1 1

Not type 1 or 2 EO-EWS: confirmed

t(11:22)(q24;q12) but no translocation products amplified

O-EWS: PCR product melting curve between types 1 and 2 but failed sequencing

Summary

Negative FLI-1 nuclear staining does not exclude EWS-FLI-1 translocation positive EFT

While CEA +ve staining can be seen in EO-EWS it does not differentiate this from O-EWS

More type 2 fusions noted in patients with EO-EWS

Conclusion

Variability may occur in immunostaining and genotype analysis of patients with extra-osseous Ewing sarcoma vs. osseous Ewing sarcoma.

comparison of genetic, antigenic and clinical features of extra- osseous ewing sarcoma (eo- ews) and...

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