Seth Arun, Kitching Richard, Landberg Goran, Xu Jing, Zubovits Judit, Burger Angelika M
Laboratory of Molecular Pathology, Department of Anatomic Pathology, Sunnybrook & Women's College Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
Anticancer Res. 2003 May-Jun;23(3A):2043-51.
Comparative and functional genomics are powerful tools to advance the understanding of the molecular basis of cancer. It is believed that genes are epigenetically regulated and, thus, each tumor type and stage will be characterized by a gene expression fingerprint. In this study we identified genes that are differentially expressed in ductal carcinoma in situ and invasive ductal carcinoma of the breast. To isolate genes that are associated with progression of breast cancer we performed differential display and subtractive cloning procedures using matched RNA from normal and tumor tissue. cDNA microarray analysis generated gene expression profiles typical of the transition from in situ to invasive breast cancer when we used mRNA extracted from a case of low- to intermediate-grade DCIS and a case of high-grade DCIS/IDC. cDNAs from these samples were the probes in a cDNA microarray hybridization to 9183 unique cDNAs representing 8507 genes. Signals from both transcriptomes were obtained for 8083 genes, and the balanced differential expression values between pure DCIS and DCIS/invasive tumors revealed 303 distinct cDNAs with a ratio of > 2. Interferon inducible genes were found to be expressed at the highest level in the pure DCIS sample. Genes most abundantly expressed in the invasive tumor were immunoglobulin heavy constant gamma 3 and calgranulin B. Further analysis of RNA and protein expression in breast tumor cell lines and patient tissue samples revealed that: IGFBP-rP1 is down-regulated in invasive tumors whereas cyclin I protein is regulated by ubiquitination and is associated with ER-negative breast cancers.
The known and novel genes discussed here represent targets for molecular characterization during breast cancer development as well as for designing novel strategies for diagnosis and treatment.
比较基因组学和功能基因组学是推进对癌症分子基础理解的有力工具。人们认为基因受到表观遗传调控，因此，每种肿瘤类型和阶段都将具有基因表达指纹特征。在本研究中，我们鉴定了在乳腺导管原位癌和浸润性导管癌中差异表达的基因。为了分离与乳腺癌进展相关的基因，我们使用来自正常和肿瘤组织的匹配RNA进行了差异显示和消减克隆程序。当我们使用从一例低至中级导管原位癌和一例高级导管原位癌/浸润性导管癌中提取的mRNA时，cDNA微阵列分析产生了从原位乳腺癌到浸润性乳腺癌转变的典型基因表达谱。这些样品的cDNA是与代表8507个基因的9183个独特cDNA进行cDNA微阵列杂交的探针。获得了8083个基因的两个转录组的信号，纯导管原位癌和导管原位癌/浸润性肿瘤之间的平衡差异表达值揭示了303个比率> 2的不同cDNA。发现干扰素诱导基因在纯导管原位癌样品中表达水平最高。在浸润性肿瘤中表达最丰富的基因是免疫球蛋白重链恒定γ3和钙粒蛋白B。对乳腺肿瘤细胞系和患者组织样品中RNA和蛋白质表达的进一步分析表明：IGFBP-rP1在浸润性肿瘤中下调，而细胞周期蛋白I蛋白受泛素化调节，并且与雌激素受体阴性乳腺癌相关。
本文讨论的已知和新基因代表了乳腺癌发展过程中分子特征的靶点，以及设计诊断和治疗新策略的靶点。
