Transcriptome analysis reveals differences in cell cycle, growth and migration related genes that distinguish fibroblasts derived from pre-invasive and invasive breast cancer.

As the most common form of pre-invasive breast cancer, ductal carcinoma in situ (DCIS) affects over 50,000 women in the US annually. Despite standardized treatment involving lumpectomy and radiation therapy, up to 25 % of patients with DCIS experience disease recurrence often with invasive ductal carcinoma (IDC), indicating that a subset of patients may be under-treated. As most DCIS cases will not progress to invasion, many patients may experience over-treatment. By understanding the underlying processes associated with DCIS to IDC progression, we can identify new biomarkers to determine which DCIS cases may become invasive and improve treatment for patients. Accumulation of fibroblasts in IDC is associated with disease progression and reduced survival. While fibroblasts have been detected in DCIS, little is understood about their role in DCIS progression.We sought to determine whether DCIS fibroblasts were similar or distinct from normal and IDC fibroblasts at the transcriptome level, fibroblasts underwent transcriptome profilingthrough bulk RNA seq and pathway analysis. DCIS fibroblasts are phenotypically distinct from normal breast and IDC fibroblasts, and play an important role in breast cancer growth, invasion, and recruitment of myeloid cells. These studies provide novel insight into the role of DCIS fibroblasts in breast cancer progression and identify some key biomarkers associated with DCIS progression to IDC, with important clinical implications. Overall design: Fibroblasts were isolated from normal breast, DCIS and IDC tissues and were subject to bulk RNA seq. Differential gene expression analysis was conducted on DCIS fibroblast vs. normal fibroblast, DCIS fibroblast vs. IDC fibroblast and IDC fibroblast vs. normal fibroblast. Genes were validated by RT-PCR. Data were subject to pathway enrichment analysis and network analysis.

作为最常见的浸润前乳腺癌类型，导管原位癌（ductal carcinoma in situ, DCIS）每年在美国影响超过5万名女性。尽管目前采用肿块切除术联合放射治疗的标准化治疗方案，但仍有高达25%的DCIS患者出现疾病复发，且复发灶多为浸润性导管癌（invasive ductal carcinoma, IDC），这提示存在一部分患者治疗不足。同时，由于大多数DCIS病例不会进展为浸润性癌，许多患者可能面临过度治疗的风险。若能阐明DCIS向IDC进展的潜在分子机制，便可识别出新的生物标志物，以甄别哪些DCIS病例可能发展为浸润性癌，进而优化患者的治疗方案。浸润性导管癌组织中成纤维细胞的聚集与疾病进展及生存率降低密切相关。尽管已在DCIS组织中检测到成纤维细胞，但目前对其在DCIS进展中的作用仍知之甚少。本研究旨在从转录组层面探究DCIS成纤维细胞与正常乳腺成纤维细胞及IDC成纤维细胞是相似还是存在差异。研究团队通过批量RNA测序（bulk RNA-seq）对成纤维细胞进行转录组谱分析，并开展通路富集分析。结果显示，DCIS成纤维细胞在表型上与正常乳腺成纤维细胞及IDC成纤维细胞存在显著差异，并在乳腺癌生长、侵袭及髓系细胞招募过程中发挥重要作用。本研究为DCIS成纤维细胞在乳腺癌进展中的作用提供了全新的见解，并鉴定出若干与DCIS向IDC进展相关的关键生物标志物，具有重要的临床意义。实验设计概况：研究人员从正常乳腺组织、DCIS组织及IDC组织中分离得到成纤维细胞，随后对其开展批量RNA测序。针对以下三组对比开展差异基因表达分析：DCIS成纤维细胞与正常成纤维细胞、DCIS成纤维细胞与IDC成纤维细胞，以及IDC成纤维细胞与正常成纤维细胞。通过逆转录聚合酶链式反应（RT-PCR）对差异基因进行验证，并对测序数据开展通路富集分析与网络分析。