Biomarker Models of Prostate Cancer Outcome After Radiotherapy

描述（由申请人提供）：分子标志物与前列腺癌患者在根治性前列腺切除术或放疗（RT）的确定性治疗后的结局相关，但没有纳入此类标志物的模型在临床上获得认可。我们一直在研究与细胞凋亡和细胞周期相关的蛋白质的表达，并发现使用免疫组织化学（IHC）测量的7种前列腺癌组织生物标志物（Ki-67、p53、MDM 2、bcl-2、bax、p16和考克斯-2）可预测参加放射治疗肿瘤学组（RTOG）临床试验（86-10和92-02）的患者的结局。RTOG进行的临床试验的力量在于，大量的男性已经接受了标准技术的治疗。7种生物标志物中的每一种都已经用PSA、Gleason评分和T分期的标准临床因素单独测试，并分配方案治疗。假设是，通过将所有这些标志物与临床参数组合在一起，将开发与仅使用临床因素的当前模型相比与远处转移（DM）和/或原因特异性死亡率（CSM）更强相关的模型。对于作为该资助重点的7种生物标志物中的大多数，已使用图像分析来量化表达，并发现与手动测定相比，其相关性同样显著或更显著。由于这些是相对较新的生物标志物定量方法，例如使用平均强度评分，因此需要在独立患者队列中进行确认。初步模型表明Ki-67、MDM 2、p16和考克斯-2最有希望。模型的完善正在进行中，计划在RTOG 94-13中治疗的相似但不同的患者人群中进行验证。在存档组织中蛋白质水平上测定基因表达具有局限性。根据我们以前的经验，高危前列腺癌患者的典型前列腺穿刺活检标本允许每个病例定量约7种标志物。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。拓宽基因表达测量的一种方法是定量mRNA水平。我们的初步数据表明，高质量的RNA可以从一个5 μ M厚的组织切片中提取的500个细胞中获得。该提案的目的是1）基于通过IHC的分子标志物表达、临床因素和治疗构建DM和/或CSM的预测模型; 2）通过IHC定量来自RTOG 94-13的样品中的生物标志物表达，应用目标1中的模型并开发用于确定RT+短期雄激素剥夺后的不良预后的新模型;和3）确认我们已经开发的用于从档案前列腺癌针吸活组织检查组织中进行RNA微阵列分析的程序是稳健的，并开始将该技术应用于从RTOG 94-公共卫生相关性：我们已经确定了7个生物标志物（Ki-67、p53、MDM 2、bcl-2、bax、p16和考克斯-2），其中使用免疫组织化学（IHC）的异常表达与放疗后患者结局较差相关，伴或不伴雄激素剥夺，放射治疗肿瘤组（RTOG 86-10和92-02）临床试验。目的是开发一种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）进行对比。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.