To investigate the effects of age at diagnosis on metastatic breast cancer and patients’ prognosis, we collected patient data from the Surveillance, Epidemiology, and End Results (SEER) database. We finally identified 4932 eligible metastatic breast cancer patients diagnosed between 2010–2013, including 850 younger patients (69 years). The results revealed that in stage IV patients, elder patients were more likely to have lung metastasis (P < 0.001) and less likely to have only distant lymphatic spread (P = 0.004). Higher proportion of younger (34.9%) and middle-aged (36.2%) patients had multiple metastatic sites than elder patients (28.3%) (P < 0.001). In survival analysis, younger patients presented the best prognosis, while elder patients had the worst both in overall survival (χ² = 121.9, P < 0.001) and breast cancer-specific survival (χ² = 69.8, P < 0.001). Age at diagnosis was an independent prognostic factor for metastatic breast cancer patients. Moreover, patients with bone metastasis only had superior survival compared to other metastatic patients (P < 0.001). Brain metastasis only group and multiple sites metastasis group had the poorest prognosis (P < 0.05). We hope the results will provide insights into a better understanding of distant metastatic breast cancer.

Background: Brain malignancies encompass gliomas and brain metastases originating from extracranial tumours including lung cancer. Approximately 50% of patients with lung adenocarcinoma (LUAD) will eventually develop brain metastases. However, the specific characteristics of gliomas and lung‐to‐brain metastases (LC) are largely unknown.Methods: We applied single‐cell RNA sequencing to profile immune and nonimmune cells in 4 glioma and 10 LC samples.Results: Our analysis revealed that tumour microenvironment (TME) cells are present in heterogeneous subpopulations. LC reprogramed cells into immune suppressed state, including microglia, macrophages, endothelial cells, and CD8⁺ T cells, with unique cell proportions and gene signatures. Particularly, we identified that a subset of macrophages was associated with poor prognosis. ROS (reactive oxygen species)‐producing neutrophils was found to participant in angiogenesis. Furthermore, endothelial cells participated in active communication with fibroblasts. Metastatic epithelial cells exhibited high heterogeneity in chromosomal instability (CIN) and cell population.Conclusions: Our findings provide a comprehensive understanding of the heterogenicity of the tumor microenvironment and tumour cells and it will be crucial for successful immunotherapy development for brain metastasis of lung cancer.

Triple-negative breast cancer (TNBC) is a highly aggressive tumor subtype lacking effective prognostic indicators or therapeutic targets. Mitochondrial function is dysregulated frequently in cancer cells to allow for adaptation to a harsh tumor microenvironment. Targeting mitochondrial biogenesis and bioenergetics is, therefore, an attractive therapeutic strategy. In this study, we performed quantitative proteomic analyses in human parental and metastatic breast cancer cell lines to identify mitochondrial proteins involved in TNBC metastasis. We found that single-strand DNA-binding protein 1 (SSBP1) was downregulated in highly metastatic breast cancer cells. Moreover, SSBP1 downregulation promoted TNBC cell metastasis in vitro and in vivo. Mechanistically, SSBP1 loss decreased mitochondrial DNA copy number, thereby potentiating calcineurin-mediated mitochondrial retrograde signaling that induced c-Rel/p50 nuclear localization, activated TGFβ promoter activity, and TGFβ-driven epithelial-to-mesenchymal transition. Low SSBP1 expression correlated with tumor progression and poor prognosis in patients. Collectively, our findings identified SSBP1 as a novel metastasis suppressor and elucidated the mechanisms by which dysregulated mitochondrial signaling contributes to metastatic potential, providing potential new prognostic indicators for patients with TNBC. Cancer Res; 76(4); 952–64. ©2015 AACR.

Despite advances in basic and clinical research, metastasis remains the leading cause of death in breast cancer patients. Genetic abnormalities in mitochondria, including mutations affecting complex I and oxidative phosphorylation, are found in breast cancers and might facilitate metastasis. Genes encoding complex I components have significant breast cancer prognostic value. In this study, we used quantitative proteomic analyses to compare a highly metastatic cancer cell line and a parental breast cancer cell line; and observed that NDUFB9, an accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (complex I), was down-regulated in highly metastatic breast cancer cells. Furthermore, we demonstrated that loss of NDUFB9 promotes MDA-MB-231 cells proliferation, migration, and invasion because of elevated levels of mtROS, disturbance of the NAD⁺/NADH balance, and depletion of mtDNA. We also showed that, the Akt/mTOR/p70S6K signaling pathway and EMT might be involved in this mechanism. Thus, our findings contribute novel data to support the hypothesis that misregulation of mitochondrial complex I NADH dehydrogenase activity can profoundly enhance the aggressiveness of human breast cancer cells, suggesting that complex I deficiency is a potential and important biomarker for further basic research or clinical application.

Macrophage-capping protein (CAPG) has been shown to promote cancer cell metastasis, although the mechanism remains poorly understood.