Unknown,Transcriptomics,Genomics,Proteomics

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Tumor Intrinsic Subtype is Reflected in Cancer-Adjacent Benign Tissue

ABSTRACT: Introduction: Overall survival of early-stage breast cancer (BC) patients is similar for those who undergo breast conserving therapy (BCT) and mastectomy, however, 10-15% of women undergoing BCT suffer ipsilateral breast tumor recurrence. The risk of recurrence may vary with age or breast cancer subtype. Understanding the gene expression of the cancer-adjacent tissue and/or stromal response to specific tumor subtypes is important for developing clinical strategies to reduce recurrence risk. Methods: We studied gene expression data in cancer-adjacent tissue from 158 BC patients. Complementary in vitro cocultures were used to study cell-cell communication between fibroblasts and specific breast cancer subtypes. Results: Our results suggest that intrinsic tumor subtypes are reflected in histologically normal cancer-adjacent tissue. Gene expression of cancer-adjacent tissues shows that triple negative (Claudin-low or Basal-like tumors) exhibit increased expression of genes involved in inflammation and immune response. While such changes could reflect distinct immune populations present in the microenvironment of different breast cancer subtypes, altered immune response gene expression was also observed in cocultures in the absence of immune cell infiltrates, emphasizing that these inflammatory mediators are secreted by breast-specific cells. In addition, while triple negative BCs are associated with upregulated immune response genes, Luminal breast cancers are more commonly associated with estrogen-response in adjacent tissues. Conclusions: Specific characteristics of BCs are reflected in the surrounding benign tissue. This commonality between tumor and surrounding tissue may underlie second primaries and local recurrences. Biomarkers derived from cancer-adjacent tissue may be helpful in defining personalized surgical strategies or in predicting recurrence risk. reference x sample

ORGANISM(S): Homo sapiens

SUBMITTER: Melissa Troester

PROVIDER: E-GEOD-50939 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Introduction: Over the past several years, we have been interested in understanding the mechanisms by which hormone-dependent (HD) mammary carcinomas grow in the absence of the stimulatory hormone. We have hypothesized that the stromal compartment plays a pivotal role in the acquisition of the hormone-independent (HI) phenotype by providing stimulatory factors that replace the proliferative effects of the hormone. Methods: We used DNA microarrays to compare the gene expression profiles of tumors from the MPA mouse breast cancer model, one hormone-dependent (C4-HD) and one hormone-independent (C4-HI), using whole tumor samples or laser-captured purified stromal and epithelial cells obtained from the same tumors. The expression of selected genes was validated by immunohistochemistry and immunofluorescence assays. Results: We identified 413 genes that were expressed in tumor stroma but not in epithelial cells. Eighty-five percent of these genes were upregulated, whereas the remaining 15% were downregulated in C4-HI tumors relative to their expression in the C4-HD tumor stroma. Several matrix metallopeptidases, including Mmp13, Mmp3, Mmp10 and Mmp9, were overexpressed in the C4-HI tumor microenvironment. On the other hand, 1100 genes were specifically expressed in the tumor parenchyma. Among them, the 29% were upregulated, whereas the remaining 71% were downregulated, in C4-HI relative to C4-HD tumor epithelium. Steap, Pdgfc, Runx2, Cxcl9 and Sdf2 were among the genes with high expression in the C4-HI tumor parenchyma. Interestingly, we found that Fgf2 was one of the few genes upregulated by MPA in C4-HD tumors, confirming its pivotal role in regulating tumor growth in this model. Conclusions: We demonstrate a gene expression profile that distinguishes epithelial from stromal cells in mammary tumors with different hormone dependence. Our results support the hypothesis that the tumor-associated stroma may contribute to hormone-independent tumor growth. The fact that Fgf2 was one of these few stimulatory genes is worth investigating. reference X sample

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Tumor Intrinsic Subtype is Reflected in Cancer-Adjacent Benign Tissue

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