Biomarker Models of Prostate Cancer Outcome After Radiotherapy

描述(申请人提供)：分子标记物与前列腺癌根治性切除或放射治疗(RT)的最终治疗结果有关，但没有包含此类标记物的模型在临床上被接受。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记物(Ki-67、p53、MDM2、bcl2、bax、p16和COX-2)通过免疫组织化学(IHC)检测，可预测参加放射治疗肿瘤组(RTOG)临床试验86-10和92-02患者的预后。RTOG进行的临床试验的力量在于，相当数量的男性已经接受了标准技术的治疗。这7个生物标志物分别用PSA、Gleason评分和T分期等标准临床因素进行了检测，并指定了治疗方案。假设通过将所有这些标记物和临床参数结合在一起，将开发出一个与远处转移(DM)和/或原因特异性死亡(CSM)更相关的模型，与目前仅使用临床因素的模型相比。对于这项资助的重点的7个生物标记物中的大多数，图像分析已被用于量化表达，并已被发现导致与人工测定一样重要或更重要的关联。因为这些是相对较新的生物标记物量化方法，例如使用平均强度评分，需要在独立的患者队列中进行确认。初步模型显示Ki-67、MDM2、p16和COX-2最有希望。该模型的改进正在进行中，计划在RTOG 94-13治疗的相似但不同的患者群体中进行验证。在蛋白质水平上测定档案组织中的基因表达有其局限性。根据我们以前的经验，高危前列腺癌患者的典型前列腺针刺活检标本可以对每个病例进行大约7个标记物的量化。我们关注的是凋亡途径中的基因，但在其他途径中还有许多其他基因具有潜力。扩大基因表达测量范围的一种方法是量化信使核糖核酸水平。我们的初步数据表明，从一个5？M厚的组织切片中提取的500个细胞就可以获得高质量的RNA。本研究的目的是：1)建立一个基于IHC分子标志物表达、临床因素和治疗的预测DM和/或CSM的模型，2)定量IHC在RTOG94-13样本中的生物标志物表达，将该模型应用于目标1，并建立一个新的模型来判断RT+短期雄激素剥夺后的不良预后；3)确认我们开发的用于前列腺癌针吸活检组织RNA微阵列分析的方法是可靠的，并开始将这项技术应用于RTOG 94中的选定病例-公共卫生相关性：在放射治疗肿瘤组(RTOG 86-10和92-02)的临床试验中，我们识别了7个生物标记物(Ki-67、p53、MDM2、bcl2、bax、p16和COX-2)，在这些标记物中，免疫组织化学(IHC)的异常表达与放射治疗后较差的患者预后有关。目的是开发一个预测远处转移的模型，其中所有的生物标记物都与临床因素一起考虑，将该模型应用于一个独立的人群(RTOG 94-13)，并将这些结果与福尔马林固定组织(RTOG 94-13)的mRNA基因表达谱进行比较。基于IHC的模型有望迅速进入临床，以更好地选择适当的治疗方法，而基于RNA的方法从长远来看具有更广泛的潜力。

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.