Li Jinong, Orlandi Rosaria, White C Nicole, Rosenzweig Jason, Zhao Jing, Seregni Ettore, Morelli Daniele, Yu Yinhua, Meng Xiao-Ying, Zhang Zhen, Davidson Nancy E, Fung Eric T, Chan Daniel W
Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
Clin Chem. 2005 Dec;51(12):2229-35. doi: 10.1373/clinchem.2005.052878. Epub 2005 Oct 13.
We previously selected a panel of 3 breast cancer biomarkers (BC1, BC2, and BC3) from serum samples collected at a single hospital based on their collective contribution to the optimal separation of breast cancer patients and noncancer controls by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The identities and general applicability of these markers, however, were unknown. In this study, we performed protein expression profiling on samples obtained from a second hospital, included a greater number of ductal carcinoma in situ (DCIS) cases, and performed purification and identification of the 2 confirmed markers.
Using a case-control study design, we performed protein expression profiling on serum samples from the National Cancer Institute (Milan, Italy). The validation sample cohort consisted of 61 women with locally invasive breast cancer, 32 with DCIS, 37 with various benign breast diseases (including 13 atypical), and 46 age-matched apparently healthy women (age range, 44-68 years). Validated biomarkers were purified and identified with serial chromatography, 1-dimensional gel electrophoresis, in-gel ASP-N digestion, peptide mass fingerprinting, and tandem mass peptide sequencing.
The BC3 and BC2 expression patterns in this sample set were consistent with the first study sample set. BC3 and BC2 were identified to be complement component C3a(desArg) and a C-terminal-truncated form of C3a(desArg), respectively.
Evaluation of biomarkers in independent sample sets can help determine the broader utility of candidate markers, and protein identification permits understanding of their molecular basis. C3a(desArg) appears to lack specificity among patients with benign diseases, limiting its utility as a stand-alone tumor marker, but it may still be useful in a multimarker panel for early detection of breast cancer.
我们之前从一家医院收集的血清样本中筛选出一组3种乳腺癌生物标志物（BC1、BC2和BC3），基于它们通过表面增强激光解吸/电离飞行时间质谱（SELDI-TOF MS）对乳腺癌患者和非癌症对照进行最佳区分的综合作用。然而，这些标志物的身份和普遍适用性尚不清楚。在本研究中，我们对从另一家医院获得的样本进行了蛋白质表达谱分析，纳入了更多的导管原位癌（DCIS）病例，并对2种已确认的标志物进行了纯化和鉴定。
采用病例对照研究设计，我们对来自意大利米兰国家癌症研究所的血清样本进行了蛋白质表达谱分析。验证样本队列包括61名局部浸润性乳腺癌女性、32名DCIS患者、37名患有各种良性乳腺疾病（包括13名非典型患者）的女性以及46名年龄匹配的表面健康女性（年龄范围44 - 68岁）。通过串联色谱、一维凝胶电泳、胶内ASP-N消化、肽质量指纹图谱和串联质谱肽测序对经过验证的生物标志物进行纯化和鉴定。
该样本集中BC3和BC2的表达模式与第一个研究样本集一致。BC3和BC2分别被鉴定为补体成分C3a（去精氨酸）和C3a（去精氨酸）的C末端截短形式。
在独立样本集中评估生物标志物有助于确定候选标志物更广泛的效用，蛋白质鉴定有助于了解其分子基础。C3a（去精氨酸）在良性疾病患者中似乎缺乏特异性，限制了其作为单一肿瘤标志物的效用，但在用于乳腺癌早期检测的多标志物组合中可能仍然有用。
