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癌的发生与发展过程涉及大量基因的异常表达。在目前基因表达谱分析中采用的标准化方法通常假设在疾病中差异表达的基因的比例很小并且差异上、下调的比例大致相等。这个被研究者所广泛采用的标准化的前提假设尚未被充分地论证过。通过分析胰腺癌的两套表达谱数据,我们发现在胰腺癌样本中基因表达的中值显著高于正常样本,提示传统的标准化假设并不适用于胰腺癌表达谱数据。采用标准化数据会导致错误地判断大量的差异下调的基因并失查许多差异上调的基因。采用原始数据分析发现在胰腺癌中的基因表达有广泛上调的特征,为深入研究胰腺癌的发生和发展机制提供了新线索。
The occurrence and development of cancer involves the abnormal expression of a large number of genes. The standardization methods used in current gene expression profiling generally assume that the proportion of genes differentially expressed in disease is small and the difference is roughly equal for down-regulation. This standardized assumptions prevalent by researchers has not yet been fully demonstrated. By analyzing two sets of expression data of pancreatic cancer, we found that the median of gene expression in pancreatic cancer samples was significantly higher than that of normal samples, suggesting that the traditional standardization hypothesis does not apply to pancreatic cancer expression profile data. The use of standardized data can lead to falsely judging a large number of differentially down-regulated genes and misdiagnosing many genes with differential up-regulation. Using the original data analysis found that gene expression in pancreatic cancer has a wide range of features, which provide new clues for further study of the pathogenesis and development of pancreatic cancer.