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Predicting the evolution of metastatic disease in breast cancer: results from 50 years of autopsies

ABSTRACT: This is a genomic analysis of breast cancer metastasis using array based CGH and is part of a large study investigating the patterns and evolution of metastases from breast cancer using autopsy material accumulated over the last 50 years from a single institution. The samples used in the genomic profiling comprise the primary breast tumour and multiple matched metastases from each patient. The data demonstrate both the clonal nature of metastatic progression and the role of clonal evolution during progression.

ORGANISM(S): Homo sapiens

PROVIDER: GSE46826 | GEO | 2013/11/11

SECONDARY ACCESSION(S): PRJNA202420

REPOSITORIES: GEO

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Project description:There remain no clear guidelines for the optimal management of patients with metastatic breast cancer. To better understand its natural history, we undertook a detailed examination of 197 autopsies performed on women who died of breast cancer. We reviewed clinical, treatment and pathological aspects of all cases and, additionally, pathological features and biomarker expression (ER, PgR, HER2, EGFR, p53, Ki67, c-Kit, CK AE1/AE3) were assessed in detail for the primary tumour and matched metastases for 55 of the cases. Genomes of the primary tumour and multiple metastases were analysed by array-based comparative genomic hybridization for six cases(##) . 945 metastatic deposits were identified, with a median of four/patient. The most common organs involved were lung/pleura (80%), bone (74%), liver (71%) and non-axillary lymph nodes (55%). Major findings included: (a) patients with CNS metastases were more likely to have bone metastases (p < 0.013); (b) younger age was associated with metastasis to the liver (≤ 49 years; p < 0.001) and to gynaecological organs (≤ 49 years; p = 0.001); (c) surgical excision of the primary tumour was associated with metastasis to the liver (p = 0.002); and (d) ER and PgR showed down-regulation during progression in a non-random manner, particularly in lung/pleura (ER; p < 0.001), liver and bone metastases. Genomic analysis revealed DNA copy number variation between the primary tumour and metastases (e.g. amplification of 2q11.2-q12.1 and 10q22.2-q22.3) but little variation between metastases from the same patient. In summary, the association of CNS and bone metastases, liver and gynaecological metastases in young women and the risk of liver metastases following surgery have important implications for the management of patients with breast cancer. Clonal heterogeneity of the primary tumour is important in developing metastatic propensity and the change in tumour phenotype during progression/colonization highlights the importance of sampling metastatic disease for optimal treatment strategies.

Project description:The goal of this dataset is to compare the gene expression patterns between primary and metastatic tumors Metastatic cancer patients typically have short survival times and their successful treatment represents one of most challenging aspects of patient care. This poor prognostic behavior is likely due to many factors, including increased clonal heterogeneity, multiple drug resistance mechanisms, and the role of the tumor microenvironment. The AURORA US Metastasis Project was established to collect and molecularly characterize specimens from 55 breast cancer (BC) patients representing 51 primary cancers and 102 metastases. The 153 unique tumors were assayed using RNAseq, tumor/germline DNA exomes and low pass whole genome sequencing, and global DNA methylation microarrays. We found intrinsic molecular subtype differences between primary tumors and their matched metastases to be rare in triple negative breast cancer (TNBC)/Basal-like subtype tumors. Conversely, tumor subtype changes were relatively frequent in estrogen receptor positive (ER+) cancers where ~30% of Luminal A cases switched to Luminal B or HER2-enriched (HER2E) subtype. Clonal evolution studies identified changes in expression subtype coincident with DNA clonality shifts, especially involving HER2 amplification and/or the HER2E expression subtype. Microenvironment differences varied according to tumor subtype where ER+/Luminal metastases had lower fibroblast and endothelial cell content, while TNBC/Basal-like metastases showed a dramatic decrease in adaptive immunity. In 17% of metastatic tumors, we identified DNA methylation and/or focal DNA deletions near HLA-A that were associated with its significantly reduced expression, and with lower immune cell infiltrates. We also identified low immune cell features in brain and liver metastases when compared to other metastatic sites, even within the same patient. These findings have direct implications for the treatment of metastatic breast cancer patients with immune- and HER2-targeting therapies and suggest potential novel therapeutic avenues for the improvement of outcomes for some MBC patients.

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Predicting the evolution of metastatic disease in breast cancer: results from 50 years of autopsies

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