Department of Chemistry, The University of Michigan, Ann Arbor, MI, USA.
Cancer Biomark. 2010;7(1):25-37. doi: 10.3233/CBM-2010-0145.
The immunogenic nature of cancer can be explored to distinguish pancreatic cancer from related non-cancer conditions. We describe a liquid-based microarray approach followed by statistical analysis and confirmation for discovery of auto-immune biomarkers for pancreatic cancer. Proteins from the Panc-1 pancreatic cancer cell line were fractionated using a 2-D liquid separation method into over 1052 fractions and spotted onto nitrocellulose coated glass slides. The slides were hybridized with 37 pancreatic cancer sera, 24 chronic pancreatitis sera and 23 normal sera to detect elevated levels of reactivity against the proteins in spotted fractions. The response data obtained from protein microarrays was first analyzed by Wilcoxon Rank-Sum Tests to generate two lists of fractions that positively responded to the cancer sera and showed p-values less than 0.02 in the pairwise comparison between cancer specimens and normal and chronic pancreatitis specimens. The top 3 fractions with the lowest correlations were combined in receiver operating characteristic analyses. The area-under-the-curve (AUC) values are 0.813 and 0.792 for cancer vs. normal and cancer vs. pancreatitis respectively. Outlier-Sum statistics were then applied to the microarray data to determine the existence of outliers exclusive in cancer sera. The selected fractions were identified by LC-MS/MS. We further confirmed the occurrence of outliers with three proteins among cancer samples in a confirmation experiment using a separate dataset of 165 serum samples containing 48 cancer sera and 117 non-cancer controls. Phosphoglycerate kinase 1 (PGK1) elicited greater reactivity in 20.9% (10 in 48) of the samples in the cancer group, while no outlier was present in the non-cancer groups.
癌症的免疫原性可用于区分胰腺癌与相关非癌性疾病。我们描述了一种基于液体的微阵列方法，随后进行了统计分析和确证，以发现胰腺癌的自身免疫生物标志物。使用二维液体分离方法将来自 Panc-1 胰腺癌细胞系的蛋白质分离成 1052 多个馏分，并点样到硝酸纤维素涂层的玻璃载玻片上。将载玻片与 37 份胰腺癌血清、24 份慢性胰腺炎血清和 23 份正常血清杂交，以检测斑点馏分中针对蛋白质的反应性升高。从蛋白质微阵列获得的反应数据首先通过 Wilcoxon 秩和检验进行分析，以生成两组分数，这些分数对癌症血清呈阳性反应，并且在癌症标本与正常和慢性胰腺炎标本之间的两两比较中 p 值小于 0.02。将相关性最低的前 3 个分数合并进行接受者操作特征分析。曲线下面积 (AUC) 值分别为 0.813 和 0.792，用于癌症与正常和癌症与胰腺炎的比较。然后对微阵列数据应用离群和总和统计，以确定仅在癌症血清中存在离群值。通过 LC-MS/MS 鉴定选定的分数。我们在使用包含 48 份癌症血清和 117 份非癌症对照的 165 份血清样本的独立数据集的确认实验中，进一步证实了三种蛋白质在癌症样本中离群值的发生。磷酸甘油酸激酶 1（PGK1）在癌症组的 20.9%（48 份样本中的 10 份）中引起更大的反应性，而在非癌症组中没有离群值。
