Sarcomas Perspectives and Background

Sarcomas: Themes Sarcomas are a heterogeneous collection of diseases and families of diseases –Individual diseases/families may be defined molecularly and a molecular derangement characterizes each tumor type (usually) –Molecular derangement supersedes histomorphology in defining disease –Unlikely that characteristic molecular derangement is the entire story Prototypic diseases which span the child/young adult age range

Distribution of Common Pediatric Malignancies

The Sarcomas Osteosarcoma Ewing family of tumors –Ewing sarcoma of bone and soft tissue –Peripheral Primitive neuroectodermal tumor Soft tissue sarcomas –Non-rhabdomyosarcoma STS –Rhabdomyosarcoma Embryonal rhabdomyosarcoma Alveolar rhabdomyosarcoma Other variants

Five Year Survival Rates Among Children with Sarcomas: Improvement Over Time From: Arndt C and Crist W. N Engl J Med 341: , 1999

Osteosarcoma: Distribution by Site, Age, and Sex From: Dahlin DC, Unni KK. Bone Tumors: General Aspects and Data on 8542 Cases (ed 4). Springfield, IL: Charles C Thomas; 1986

Molecular Derangements in Osteosarcoma Mutations in RB gene (inactivation) Mutations in p53 (inactivation) MDM2 amplification (and thus inactivation of p53) Over-expression of HER2/erbB-2 No single molecular derangement defines osteosarcoma

Multi-Institutional Osteosarcoma Study ( ): Outcome of All Patients Treated with Chemotherapy

Intergroup Osteosarcoma Study ( ): Event-Free Survival for all Patients

Event-free survival Survival Probability (%) Years followed Metastatic Osteosarcoma: Outcome 80

Ewing Sarcoma: Distribution by Site, Age and Sex From: Dahlin DC, Unni KK. Bone Tumors: General Aspects and Data on 8542 Cases (ed 4). Springfield, IL: Charles C Thomas; 1986

Molecular Pathogenetic Mechanisms in Rhabdomyosarcoma and Ewing’s Sarcoma From: Arndt C and Crist W. N Engl J Med 341: , 1999

The 11;22 Translocation And The Family of Ewing’s Sarcomas Reciprocal translocation t(11;22)(q24;q12) Found consistently in bone and soft tissue Ewings, PNET, Askin tumors Unifying diagnostic criterion for Ewing’s family of tumors EWS (RNA binding protein) fused to FLI-1 or ERG (transcription factors of the ETS family) Translocation results in a tumor-associated fusion gene –Fusion transcript present in > 95% of tumors of Ewings family

Effect of Presence of Metastases on EFS

EFS for All Non-Metastatic Patients by Location

EFS for Non-Metastatic Patients by Age

Rhabdomyosarcoma

Age

Common Histiotypes of Rhabdomyosarcoma

Survival by Histology

Gene Fusions with Novel Chimeric Protein Products t(2;13)(q35;q14) PAX3FKHR Chromosome 2Chromosome 13 Activation of aberrant gene program Malignant transformation

Genetic Features of Rhabdomyosarcoma Embryonal rhabdomyosarcoma –Associated with inactivation of tumor suppressor gene located at 11p15.5 –Cases with hyperdiploid DNA content associated with better outcome Alveolar rhabdomyosarcoma –Cases with tetraploid DNA content fare poorly –Characteristic reciprocal translocation t(2;13)(q35;q14) Results in fusion of PAX3 (transcriptional regulatory protein expressed during embryogenesis) to FKHR (member of the forkhead family of transcription factors) Infrequently, t(1;13)(p36;q14) involving PAX7 and FKHR

Global : p = PAX3 vs PAX7: p = Overall Survival: Metastatic Patients Only Proportion Overall survival (years) PAX7 Negative PAX3

Failure-free Survival of Patients with Local/Regional Rhabdomyosarcoma on IRS-IV by Chemotherapy Regimen Log Rank Test: p= Years VAC VAI VIE Failure-free Survival

7%Orbit 28%Head & Neck 11%Trunk 2%Intrathoracic 2%GI-Hepatic 6%Retroperitoneum 18%GU 2%Perineum-Anus 24%Extremities Sites

Log Rank Test: p<0.001 Extremity GU B/P GU non-B/P H & N Orbit Other PM Failure-free Survival, IRS-IV for Patients with Local/Regional Tumors by Primary Site Years Failure-free Survival

Tumor Histologic Subgroup Distribution by Age Group p<0.001

Disease Stage Distribution by Age Group p<0.001

Results of Univariate Analysis Adolescents (>10 years) more often have*: –alveolar tumors (p<0.001) –tumors arising in extremity or paratestis sites (p=0.001) –large tumors (>5 cm, p<0.001) –invasive tumors (i.e. T 2, p=0.007) –+ regional nodes (i.e. N 1, p<0.001) –metastatic disease (p<0.001) –unfavorable tumor stage (p<0.001) *compared to children (1 to 9 yrs of age)

Estimated Relative Risk of Failure by Age Group (Cox Proportional Hazards Model)

The Common Soft Tissue Sarcomas in Children Rhabdomyosarcoma Soft tissue Ewing/PNET Synovial Sarcoma Malignant Peripheral Nerve Sheath Tumor Malignant Fibrous Histiocytoma Sarcoma NOS Leiomyosarcoma Fibrosarcoma Clear cell sarcoma Epithelioid sarcoma Liposarcoma

Molecular Diagnosis of Sarcomas TumorTranslocationFusion Gene Ewing/PNETt(11;22)(q24;q12)EWS/FLI1 t(21;22)(q22;q12)EWS/ERG Alveolar Rhabdomyosarcomat(2;13)(q35;q14)PAX3/FKHR t(1;13)(p36;q14)PAX7/FKHR Desmoplastic small round cell tumor t(11;22)(p13;q12)EWS/WT1 Synovial Sarcomat(X;18)(p11.2;q11.2)SYT/SSX1+2 Congenital Fibrosarcomat(12;15)(p13;q25)ETV6/NTRK3 Clear Cell Sarcomat(12;22)(q13;q12)EWS/ATF1

Outcome of Children with Localized Non-Rhabdomyosarcoma Soft Tissue Sarcomas From Pratt C et al J Clin Oncol 17:1219, 1999

Considerations of Linking Studies of Sarcomas Diseases occur in children, adolescents and young adults (excluding non-rhabdo STS) –Diseases in adults and children may be similar on a molecular level –But, heterogeneity even within major subclasses of sarcomas Histopathological Biological Other significant molecular derangements and differences in gene expression likely Limited numbers of patients Relatively high cure rate with current therapy limits subjects available for experimental therapies Therefore: Combine efforts among adult and pediatric patients where the disease appears to be a continuum encompassing pediatric and young adults

Challenges in Linking Studies in Children and Adults Older patients fare less well in all varieties of sarcoma –?True age-related biological differences Older age associated with higher risk features and more advanced disease Age remains independently prognostic –?Differences in host tolerance for therapy –?Difference in compliance with intensive therapies –?Differences in physician compliance with intensive therapies Mindset of medical v. pediatric oncologists

Novel Targets for Biological Agents in Sarcomas Osteosarcoma –Her2 via herceptin –PDGF signal transduction pathway blockade via STI-571 –Agents which target p53 and Rb Rhabdomyosarcoma –PAX/FKHR fusion gene products Ewing family –EWS/FLI1 and EWS/ERG fusion gene products –Stem cell factor/c-kit signal transduction pathway blockade via STI-571 Desmoplastic Small Round Cell tumor –PDGF signal transduction pathway blockade via STI-571 Other Soft Tissue Sarcomas –Products of associated fusion genes