Biomarker Models of Prostate Cancer Outcome After Radiotherapy

描述（由申请人提供）：分子标记物与前列腺癌患者根治性前列腺切除术或放疗（RT）最终治疗后的预后相关，但尚未有纳入此类标记物的模型在临床中获得认可。我们一直在研究与细胞凋亡和细胞周期相关的蛋白的表达，并发现7种前列腺癌组织生物标志物（Ki-67, p53, MDM2, bcl-2, bax， p16和cox-2）使用免疫组织化学（IHC）测量，可以预测放射治疗肿瘤组（RTOG）临床试验患者的预后，86-10和92-02。RTOG进行的临床试验的力量在于，大量男性接受了标准技术的治疗。7种生物标志物分别与PSA、Gleason评分和t分期等标准临床因素进行了测试，并分配了治疗方案。我们的假设是，通过将所有这些标志物与临床参数结合在一起，与目前仅使用临床因素的模型相比，将开发出与远处转移（DM）和/或致因特异性死亡率（CSM）相关性更强的模型。对于本次拨款重点关注的7种生物标记物中的大多数，图像分析已被用于量化表达，并已发现与人工测定相比，其关联同样重要，甚至更重要。由于这些是相对较新的生物标志物量化方法，例如使用平均强度评分，因此需要在独立的患者队列中进行确认。初步模型表明Ki-67、MDM2、p16和cox-2最有希望。模型的改进正在进行中，计划在RTOG 94-13治疗的类似但不同的患者群体中进行验证。档案组织中蛋白水平基因表达的测定存在局限性。根据我们之前的经验，高危前列腺癌患者的典型前列腺穿刺活检标本允许每个病例量化约7个标记物。我们关注的是凋亡途径中的基因，但其他途径中的许多其他基因也有潜力。扩大基因表达测量的一种方法是量化mRNA水平。我们的初步数据表明，从单个5¿M厚的组织切片中提取的500个细胞中可以获得高质量的RNA。本研究的目的是：1)基于免疫组化、临床因素和治疗的分子标志物表达，构建预测糖尿病和/或CSM的模型；2)通过免疫组化定量RTOG 94-13样本中生物标志物的表达，将该模型应用于Aim 1，建立RT+短期雄激素剥夺后不良预后的新模型；3)确认我们开发的用于从档案前列腺癌针活检组织中提取RNA的微阵列分析程序是可靠的，并开始将该技术应用于RTOG 94-公共卫生相关性中的选定病例；在放射治疗肿瘤学组（RTOG 86-10和92-02）的临床试验中，我们确定了7种生物标志物（Ki-67、p53、MDM2、bcl-2、bax、p16和cox-2），其中免疫组织化学（IHC）的异常表达与放疗后患者预后较差有关，无论是否剥夺雄激素。目的是建立一个预测远处转移的模型，其中所有生物标志物与临床因素一起考虑，将该模型应用于独立人群（RTOG 94-13），并将这些结果与福尔马林固定组织的mRNA基因表达谱（RTOG 94-13）进行比较。基于免疫细胞的模型有望迅速进入临床，以更好地选择合适的治疗方法，而基于rna的方法在长期内具有更广泛的潜力。

DESCRIPTION (provided by applicant): Molecular markers have been associated with prostate cancer patient outcome after definitive therapy with radical prostatectomy or radiotherapy (RT), but no model incorporating such markers has gained acceptance in the clinic. We have been investigating the expression of proteins related to apoptosis and the cell cycle, and have found 7 prostate cancer tissue biomarkers (Ki-67, p53, MDM2, bcl-2, bax, p16 and cox-2) measured using immunohistochemistry (IHC) that are predictive of outcome in patients enrolled in Radiation Therapy Oncology Group (RTOG) clinical trials, 86-10 and 92-02. The power of the clinical trials performed by the RTOG is that substantial numbers of men have been treated with standard techniques. Each of the 7 biomarkers has been tested individually with the standard clinical factors of PSA, Gleason score and T-stage, and assigned protocol treatment. The hypothesis is that by combining all of these markers together, along with clinical parameters, a model will be developed that is more strongly associated with distant metastasis (DM) and/or cause specific mortality (CSM), as compared to current models using clinical factors alone. For most of the 7 biomarkers that are the focus of this grant, image analysis has been used to quantify expression and has been found to result in associations that are as significant, or more so, as compared to manual determinations. Because these are relatively new methods of biomarker quantification, such as using mean intensity score, confirmation in an independent patient cohort is needed. A preliminary model indicates that Ki-67, MDM2, p16 and cox-2 have the most promise. Refinements in the model are in progress, with planned validation in a similar, but distinct, patient population treated in RTOG 94-13. The determination of gene expression at the protein level in archival tissue has limitations. Based on our prior experience, typical prostate needle biopsy specimens in patients with high-risk prostate cancer allow for about 7 markers to be quantified per case. We have focused on genes in the apoptotic pathway, but there are many other genes in other pathways that have potential. One way to broaden measurement of gene expression is to quantify mRNA levels. Our preliminary data show that high quality RNA may be obtained from as few as 500 cells extracted from a single 5¿M thick tissue section. The aims of this proposal are to 1) construct a model predictive of DM and/or CSM based on molecular marker expression by IHC, clinical factors and treatment; 2) quantify biomarker expression by IHC in samples from RTOG 94-13, apply the model in Aim 1 and develop a new model for determining poor prognosis after RT+ short term androgen deprivation; and 3) confirm that the procedure we have developed for microarray analysis of RNA from archival prostate cancer needle biopsy tissue is robust and to begin to apply this technology to selected cases from RTOG 94- PUBLIC HEALTH RELEVANCE: We have identified 7 biomarkers (Ki-67, p53, MDM2, bcl-2, bax, p16 and cox-2) in which abnormal expression using immunohistochemistry (IHC) has been associated with worse patient outcome after radiotherapy, with or without androgen deprivation, in Radiation Therapy Oncology Group (RTOG 86-10 and 92-02) clinical trials. The objectives are to develop a model predictive of distant metastasis in which all of the biomarkers are considered together with clinical factors, apply the model to an independent population (RTOG 94-13) and contrast these results with mRNA gene expression profiles from formalin-fixed tissue (RTOG 94- 13). The IHC-based model has promise to be brought rapidly into the clinic to better select appropriate treatment, while the RNA-based approach has broader potential in the long-term.