In mammary gland development, normal stem cell activity occurs in the embryonic stage and postnatally. Research supports that certain breast cancers contain a small sub-population of cells that mimic stem-like activity. It is believed stem cell activation in the mutated mature human mammary tissue is what drives quiescent epithelial cells to convert to mesenchymal states initiating migration, invasion, and metastasis in breast cancer. The goal of the work reported herein was to investigate early mammary development gene expression in the postnatal pig using fine needle biopsy methods in order to establish a reliable model for human breast cancer detection. Tissue samples were collected from pig mammary glands beginning at Day 11 of age through Day 39 in order to capture early postnatal-growth gene expression. Based on the initial clustering analysis, two distinct clusters of gene expression profiles occurred before and after Day 25 of mammary development. Gene set enrichment analysis (GSEA) ontology indicated the cellular processes that changed after Day 25, and many of these processes were implicated in epithelial-mesenchymal transition (EMT) signaling events. Gene expression in the postnatal pig was compared with the Epithelial-Mesenchymal Transition gene database (dbEMT) confirming the presence of EMT activity in this early developmental program. Information from this study will provide insight into early postnatal mammary gland development. In addition, mechanisms exploited by mutated mammary epithelial cells leading to cancer initiation and growth may be detected considering that mutated mammary epithelial cells can reactivate early developmental signals.

中文翻译：

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分析猪模型早期乳腺发育的基因表达模式的方法。

在乳腺发育中，正常的干细胞活性发生在胚胎期和出生后。研究支持某些乳腺癌包含一小部分模仿干细胞样活性的细胞。据信，突变的成熟人类乳腺组织中的干细胞活化是驱使静止的上皮细胞转化为间充质状态的状态，从而启动了乳腺癌的迁移，侵袭和转移。本文报道的工作目标是使用细针穿刺活检方法研究出生后猪的早期乳腺发育基因表达，以便建立用于人类乳腺癌检测的可靠模型。从年龄的第11天到第39天从猪的乳腺收集组织样本，以捕获出生后早期生长的基因表达。根据最初的聚类分析，在乳腺发育的第25天前后，基因表达谱出现了两个不同的簇。基因集富集分析（GSEA）本体论表明第25天后细胞过程发生了变化，其中许多过程都涉及上皮-间质转化（EMT）信号事件。将产后猪的基因表达与上皮-间质转化基因数据库（dbEMT）进行了比较，证实了该早期发育程序中存在EMT活性。这项研究的信息将提供有关出生后早期乳腺发育的见识。此外，