Utility of bone marrow aspiration and biopsy in initial staging of Ewing sarcoma.

BACKGROUND: The current standard of care for initial staging of pediatric Ewing sarcoma (EWS) patients is to obtain a bilateral bone marrow aspiration and biopsy (BMAB). The incidence of bone marrow (BM) disease in patients deemed non-metastatic by conventional and metabolic imaging and the concordance of BM positivity with other clinical characteristics are not well established. PROCEDURE: This study is a multi-institutional retrospective review of newly diagnosed EWS patients less than 40 years of age with initial staging that included imaging and BMAB. RESULTS: A total of 116 patients were eligible with 85 patients considered non-metastatic and 31 considered metastatic by imaging. None of the 85 patients with non-metastatic disease were BMAB positive (0%; 95% CI: 0-4.2%); 13 of the 31 patients with metastases were BMAB positive (41.9%; 95% CI: 24.5-60.9%). Primary tumor size was significantly higher in patients with metastases (P = 0.017). Bone metastasis by imaging had high correlation with BMAB positivity (P = 0.0002). In addition, the number of bony metastatic sites was significantly higher in patients with a positive BMAB as compared to those with a negative BMAB (median 3.5 and 0.0, respectively; P < 0.001). CONCLUSIONS: BMAB may not be required for initial staging of pediatric and young adult EWS patients deemed non-metastatic by imaging. In patients with metastatic disease, there is a high correlation of BM involvement with multiple bone metastases.

BIRC5 expression is a poor prognostic marker in Ewing sarcoma.

BACKGROUND: BIRC5 (Survivin), an inhibitor of apoptosis protein (IAP), is over-expressed in several human cancers and increased expression is associated with poor prognosis. The goal of the current study was to evaluate the role of BIRC5 in Ewing sarcoma (ES), the second most common pediatric bone sarcoma. PROCEDURE: BIRC5 protein expression was determined in ES cell lines using Western Blot analysis. Functional role of survivin on growth and viability of ES cells was assessed by siRNA knockdown of BIRC5 and by using a small molecule inhibitor YM155. Immunohistochemical analysis for BIRC5 protein was performed on patient tumor samples using an anti-survivin antibody. The degree of BIRC5 protein expression was correlated with clinical parameters and patient outcome. RESULTS: BIRC5 is over-expressed in a panel of ES cell lines. Gene silencing of BIRC5 in the ES cell line TC-71 decreases cell growth by more than 50% for each BIRC5 siRNA construct compared to non-silencing siRNA control constructs. YM155 also reduces ES cell growth and viability with an EC(50) ranging from 2.8 to 6.2 nM. BIRC5 protein is expressed in majority of the ES tumor samples with minimal expression in normal tissue (P < 0.005). Tumors with more than 50% expression are associated with worse overall survival than tumors with less than 50% expression (Hazard Ratio: 6.05; CI: 1.7-21.4; P = 0.04). CONCLUSION: BIRC5 is over-expressed in ES cell lines and tumor samples. Further, it plays an important role in cell growth and viability in vitro. Higher degree of expression in patients is an independent poor prognostic factor.

Gemcitabine, docetaxel, and bevacizumab in relapsed and refractory pediatric sarcomas.

BACKGROUND: The outcome for patients with relapsed and refractory pediatric sarcomas remains dismal. Novel agents are needed to improve overall survival in these patients. OBSERVATIONS: We present 3 patients with relapsed/refractory sarcomas treated with gemcitabine, docetaxel, and bevacizumab in 3-week cycles. The combination was well tolerated with minimal toxicity. Two patients had a partial response and the third patient had stable disease for >6 months. CONCLUSIONS: These results are limited by small patient numbers but this strategy should be evaluated in prospective clinical trials.

ATF6α Activation Enhances Survival against Chemotherapy and Serves as a Prognostic Indicator in Osteosarcoma.

Patients with metastatic or relapsed/refractory osteosarcoma (OS) have a 5-year survival rate of <30%. This has remained unchanged over several decades. One of the factors contributing to lack of improvement in survival is the development of chemoresistance. Hence, elucidating and targeting the mechanisms that promote survival against chemotherapy and lead to chemoresistance is pivotal to improving outcomes for these patients. We identified that endoplasmic reticulum (ER) stress-activated transcription factor, ATF6α, is essential for the survival of OS cells against chemotherapy induced cell death. ATF6α cleavage and activity were enhanced in OS cells compared to normal osteoblasts and knockdown of ATF6α expression enhanced sensitivity of OS cells against chemotherapy induced cell death. This was in part due to increased Bax activation. Pharmacologic inhibition or knock-down of downstream targets of ATF6α, protein disulfide isomerases (PDI) and ERO1ß, a thiol oxidase that is involved in the re-oxidation of PDIs also independently induced pronounced killing of OS cells following chemotherapy. Analysis of primary tumors from OS patients reveals that patients with high levels of nuclear ATF6α: (1) also had increased expression of its downstream targets the chaperone BiP and enzyme PDI, (2) had a significant likelihood of developing metastasis at diagnosis, (3) had significantly poorer overall and progression free survival, and (4) had poorer response to chemotherapy. These findings suggest that targeting survival signaling by the ATF6α pathway in OS cells may favor eradication of refractory OS tumor cells and ATF6α could be a useful predictor for chemo-responsiveness and prognosis.