Validating the prognostic value of EGFR768 in neuroblastoma

描述(申请人提供)：神经母细胞瘤(NB)是儿童最常见的颅外实体瘤，占儿童恶性肿瘤的7%以上。尽管进行了积极的治疗，患有高危神经母细胞瘤的儿童仍然表现不佳，只有不到一半的人幸存下来。幸存者还会遭受长期的副作用。迫切需要更有效的靶向治疗。近年来，表皮生长因子受体(EGFR)已成为肿瘤治疗的热门靶点。EGFR抑制剂已经在患有难治性NB的儿童中进行了测试。有趣的是，在这些患者中，有30%-40%的患者观察到部分缓解或病情稳定。由于EGFR突变是对抗EGFR药物反应的生物标志物，我们对62例原发NB肿瘤进行了EGFR突变筛查。我们不仅发现了32%的EGFR表达缺失突变，而且惊讶地发现了一个新的EGFR胞外缺失突变体EGFR 768。我们实验室的进一步研究发现，EGFR 768具有结构性活性，对EGFR抑制剂厄洛替尼具有敏感性，并增强癌细胞的生长和侵袭潜力。基于EGFR 768的这些生物学和生化特性，我们提出了以下假设：在神经母细胞瘤患者中，EGFR 768的表达显著降低了患者的无病生存率。我们计划用以下具体目标来证明这一假设。具体目的：利用参加儿童肿瘤组神经母细胞瘤临床试验的患者的原发神经母细胞瘤来确定表达EGFR768的神经母细胞瘤是否更具侵袭性，我们将确定表达EGFR768的神经母细胞瘤是否更有可能属于高危人群，因此5年无病生存率显著下降。有两个子目标。Subaim I：制备单抗EGFR 768。在这个子目标中，我们将开发和验证一种独特的分子诊断试剂来检测石蜡包埋肿瘤切片上的EGFR768突变蛋白。在用于结果分析之前，将对该抗体的敏感性和特异性进行严格的测试。苏巴伊姆II：生存分析。在这个子目标中，我们将进行临床生物学对照，以确定EGFR�768在NB中是否具有预后价值。该项目评估EGFR768作为神经母细胞瘤的预后生物标志物。如果成功，不仅将发现新的神经母细胞瘤预测因子，而且该突变也有可能成为新的治疗靶点。因此，EGFR768特异性诊断试剂的开发将允许在临床标本中快速鉴定这种突变，并有可能推进神经母细胞瘤患者的个性化抗EGFR768治疗，从而改善结果并将目前治疗的副作用降至最低。

DESCRIPTION (provided by applicant): Neuroblastoma (NB) is the most common extracranial solid tumor of childhood and accounts for more than 7% of childhood malignancies. Despite aggressive therapy, children with high risk neuroblastoma still fare poorly with less than half surviving the disease. The survivors also suffer long term side effects. More effective targeted therapy is urgently needed. Epidermal growth factor receptor (EGFR) has become a popular target for cancer therapy in recent years. EGFR inhibitors have been tested in children with refractory NB. Interestingly, partial response or stable disease was observed in 30 - 40% of these patients. Since EGFR mutations are biomarkers for response to anti-EGFR drugs, we screened for EGFR mutations in 62 primary NB tumors. We not only found that 32% expressed deletion mutations of EGFR, but were surprised to discover a novel EGFR extracellular deletion mutant, EGFR 768. Further studies in our laboratory found that EGFR 768 is constitutively active, confers sensitivity to the EGFR inhibitor, erlotinib, and enhances the growth as well as invasive potential of cancer cells. Based on these biological and biochemical properties of EGFR 768, we formulated the following hypothesis: EGFR 768 expression confers a significantly worse disease free survival in neuroblastoma patients. We plan to prove this hypothesis with the following specific aim. Specific Aim: Determine if neuroblastoma that express EGFR 768 are more aggressive Using primary NB tumors accrued from patients who participated in the Children's Oncology Group neuroblastoma clinical trials, we will determine if NB that expressed EGFR�768 are more likely to be in the high risk group and therefore have a significantly worse 5 year disease free survival. There are two subaims. Subaim I: Production of a monoclonal EGFR 768 specific antibody. In this subaim, we will develop and validate an unique molecular diagnostic reagent to detect the EGFR�768 mutant protein on paraffin embedded tumor sections. The sensitivity and specificity of this antibody will be vigorously tested before using it for the outcome analysis. Subaim II: Survival analysis. In this subaim, we will perform clinical biological correlation to determine if EGFR�768 has prognostic value in NB. This project evaluates EGFR�768 as a prognostic biomarker for neuroblastoma. If successful, not only will a new neuroblastoma prognosticator be identified, but there is a potential for this mutant to be a new therapeutic target as well. Thus, the development of a EGFR�768 specific diagnostic reagent will allow for rapid identification of this mutant in clinical specimen and has the potential to advance personalized anti-EGFR therapy for neuroblastoma patients, thereby improving the outcome and minimizing the side effects of the current therapy.