Identification of novel biomarkers associated with poor patient outcome in invasive breast carcinoma

Breast carcinoma (BC) is the leading cause of death in women worldwide, making up 23% of all cancers in women, with 1.38 million new cases worldwide annually and responsible for 460,000 deaths. Despite the significant advances in the identification of molecular markers and different modalities of treatment in primary BC, the ability to predict the metastatic behavior in breast cancer is still limited. The purpose of this study was to help identify novel molecular markers associated with clinical outcome in a cohort of Brazilian BC patients. We generated global gene expression profiles from 24 patients with invasive ductal BC followed for ≥ 5-years, including 15 samples from patients classified as presenting good prognosis based on traditional markers and clinical criteria and 9 patients that developed metastasis. We identified a set of 58 differentially expressed genes (p ≤0.01) between groups of patients with good and poor prognosis. Up-regulation of B3GNT7, PPM1D, TNKS2, PHB and GTSE1 in patients with poor prognosis was confirmed by quantitative RT-PCR in an independent sample set from patients with BC (47 with good prognosis and 8 that presented metastasis). Expression of BAD protein was investigated by immunohistochemistry in 1276 BC samples and confirmed the reduced expression levels in metastatic cases observed in the oligoarray data. These findings point to novel prognostic markers that can distinguish breast carcinoma samples according to clinical course and progression of the disease. Global expression profiles from 38 ductal breast tumor patient samples were used to search for molecular signatures correlated with current prognostic markers. A subset of 24 cases comprising 15 patients that remained free of disease after surgery and 9 patients that developed metastasis was used to identify candidate biomarkers associated with metastatic progression. Candidates were subsequently validated in additional independent samples by RT-qPCR or immunohistochemistry.

乳腺癌（Breast carcinoma, BC）是全球范围内女性致死率最高的癌症类型，占女性所有癌症病例的23%，每年全球新增病例达138万例，致死病例约46万例。尽管原发性乳腺癌的分子标志物筛选与多种治疗手段已取得显著进展，但目前对乳腺癌转移行为的预测能力仍较为有限。本研究旨在针对巴西乳腺癌患者队列，筛选与临床结局相关的新型分子标志物。本研究从24名随访时长≥5年的浸润性导管乳腺癌患者中获取了全局基因表达谱：其中15份样本来自基于传统标志物与临床标准判定为预后良好的患者，剩余9名患者则出现了肿瘤转移。本研究在预后良好与预后不良患者组之间筛选得到58个差异表达基因（p≤0.01）。通过实时定量逆转录PCR（quantitative RT-PCR）在独立乳腺癌患者样本集（含47名预后良好者与8名转移患者）中验证了B3GNT7、PPM1D、TNKS2、PHB及GTSE1在预后不良患者中的上调表达。本研究采用免疫组化（immunohistochemistry）方法对1276份乳腺癌样本中的BAD蛋白表达水平进行检测，验证了寡核苷酸芯片（oligoarray）数据中观察到的转移病例中BAD蛋白表达下调的现象。上述研究结果表明，本研究筛选得到的新型预后标志物可依据临床病程与疾病进展情况对乳腺癌样本进行有效区分。本研究利用38份导管乳腺肿瘤患者样本的全局表达谱，筛选与现有预后标志物相关的分子特征。研究选取其中24例样本作为子集（含15名术后未复发患者与9名出现转移的患者），用于筛选与肿瘤转移进展相关的候选生物标志物。后续通过RT-qPCR或免疫组化方法在额外的独立样本中对候选生物标志物进行了验证。