Circulating tumor DNA: from discovery to clinical application in breast cancer.

Breast cancer (BC) stands out as the cancer with the highest incidence of morbidity and mortality among women worldwide, and its incidence rate is currently trending upwards. Improving the efficiency of breast cancer diagnosis and treatment is crucial, as it can effectively reduce the disease burden. Circulating tumor DNA (ctDNA) originates from the release of tumor cells and plays a pivotal role in the occurrence, development, and metastasis of breast cancer. In recent years, the widespread application of high-throughput analytical technology has made ctDNA a promising biomarker for early cancer detection, monitoring minimal residual disease, early recurrence monitoring, and predicting treatment outcomes. ctDNA-based approaches can effectively compensate for the shortcomings of traditional screening and monitoring methods, which fail to provide real-time information and prospective guidance for breast cancer diagnosis and treatment. This review summarizes the applications of ctDNA in various aspects of breast cancer, including screening, diagnosis, prognosis, treatment, and follow-up. It highlights the current research status in this field and emphasizes the potential for future large-scale clinical applications of ctDNA-based approaches.

Immune characteristics and clinical significance of peripheral blood lymphocytes in breast cancer.

BACKGROUND: In the context of breast cancer (BC), the correlation between lymphocytes and clinical outcomes, along with treatment response, has garnered attention. Despite this, few investigations have delved into the interplay among distinct peripheral blood lymphocyte (PBL) types, immune attributes, and their clinical implications within the BC landscape. METHODS: The primary objective of this study was to scrutinize the baseline status of PBL subsets in patients with primary BC, track their dynamic changes throughout treatment, and ascertain their interrelation with prognosis. Flow cytometry was employed to analyse PBLs from a cohort of 74 BC patients. RESULTS: Our analysis revealed that baseline levels of Treg and PD-L1 + T cells were lower in BC patients compared to the reference values. Notably, a disparity in baseline PD-L1 + T cell levels surfaced between patients who underwent adjuvant therapy and those subjected to neoadjuvant therapy (NAT). Furthermore, a meticulous evaluation of PBL subsets before and after treatment underscored discernible alterations in 324 + T cells and CD19 + CD32 + B cells over the course of therapy. Strikingly, heightened CD4 + T cell levels at baseline were linked to enhanced event-free survival (EFS) (p = 0.02) and a robust response to chemotherapy. CONCLUSIONS: These results indicate that PBLs may serve as a significant marker to assess the immune status of BC patients, and therapy has the potential to modify patient immune profiles. In addition, peripheral blood CD4 + T cell levels may serve as promising biomarkers for diagnosis and prognosis in future studies of BC.

Multi-omics analysis reveals the involvement of origin recognition complex subunit 6 in tumor immune regulation and malignant progression.

Background: Origin recognition complex 6 (ORC6) is one of the six highly conserved subunit proteins required for DNA replication and is essential for maintaining genome stability during cell division. Recent research shows that ORC6 regulates the advancement of multiple cancers; however, it remains unclear what regulatory impact it has on the tumor immune microenvironment. Methods: Unpaired Wilcoxon rank sum and signed rank tests were used to analyze the differences in the expression of ORC6 in normal tissues and corresponding tumor tissues. Multiple online databases have evaluated the genetic alterations, protein expression and localization, and clinical relevance of ORC6. To evaluate the potential prognostic impact and diagnostic significance of ORC6 expression, we carried out log-rank, univariate Cox regression, and receiver operating characteristic curve analysis. The ICGC-LIRI-JP cohort, CGGA-301 cohort, CGGA-325 cohort, CGGA-693 cohort, and GSE13041 cohort were used for external validation of the study findings. The associations between ORC6 expression and immune cell infiltration, immune checkpoint expression, and immunotherapy cohorts was further analyzed. To explore the functional and signaling pathways related to ORC6 expression, gene set enrichment analysis was performed. To clarify the expression and function of ORC6 in hepatocellular carcinoma (LIHC) and glioma, we conducted in vitro experiments. Results: Expression of ORC6 is upregulated in the majority of cancer types and is associated with poor patient prognosis, notably in cases of LIHC and gliomas. In addition, ORC6 may be involved in multiple signaling pathways related to cancer progression and immune regulation. High expression of ORC6 correlates with an immunosuppressive state in the tumor microenvironment. The results of further immunotherapy cohort analysis suggested that patients in the ORC6 high-expression group benefited from immunotherapy. Inhibiting ORC6 expression suppressed the proliferative and migratory abilities of LIHC and glioma cells. Conclusion: High expression of ORC6 may be used as a biomarker to predict the poor prognosis of most tumor patients. The high expression of ORC6 may be involved in the regulation of the tumor immunosuppressive environment, and it is expected to become a molecular target for inhibiting tumor progression.

Prognosis comparison between intraoperative radiotherapy and whole-breast external beam radiotherapy for T1-2 stage breast cancer without lymph node metastasis treated with breast-conserving surgery: A case-control study after propensity score matching.

Background: External beam radiotherapy (EBRT), an adjuvant to breast-conserving surgery (BCS), requires a long treatment period, is costly, and is associated with numerous complications. Large sample studies with long follow-up periods are lacking regarding whether intraoperative radiotherapy (IORT), an emerging radiotherapy modality, can replace EBRT for patients with T1-2 early stage breast cancer without lymph node metastasis treated with BCS. Methods: We identified 270,842 patients with T1-2N0M0 breast cancer from 2000 to 2018 in the Surveillance, Epidemiology, and End Results (SEER) database. A total of 10,992 patients were matched by propensity score matching (PSM). According to the radiotherapy method, the patients were divided into the IORT and EBRT groups. Overall survival (OS) and breast cancer-specific survival (BCSS) rates were analyzed and compared between the IORT and EBRT groups by Kaplan-Meier analysis. Bilateral P < 0.05 was considered to indicate significance. Results: After PSM, the survival analysis showed no significant differences in OS or BCSS rates between the IORT and EBRT groups. In the subgroup analysis, the IORT population diagnosed from 2010 to 2013 (HRs = 0.675, 95% CI 0.467-0.976, P = 0.037) or with T2 stage (HRs = 0.449, 95% CI 0.261-0.772, P = 0.004) had better OS rates, but in the overall population, the OS and BCSS rates were better in patients with T1 stage than in patients with T2 stage (P < 0.0001), and the proportion of chemotherapy was significantly higher in T2 stage than in T1 stage. Patients who had EBRT with unknown estrogen receptor had better OS rates (HRs = 3.392, 95% CI 1.368-8.407, P = 0.008). In addition, the IORT group had better BCSS rates for married (HRs = 0.403, 95% CI 0.184-0.881, P = 0.023), grade III (HRs = 0.405, 95% CI 0.173-0.952, P = 0.038), and chemotherapy-receiving (HRs = 0.327, 95% CI 0.116-0.917, P = 0.034) patients with breast cancer compared to the EBRT group. Conclusion: Intraoperative radiotherapy results of non-inferior OS and BCSS rates, compared to those of EBRT, in patients with early stage breast cancer without lymph node metastasis treated with BCS, and IORT may provide substantial benefits to patients as an effective alternative to standard treatment. This finding provides new insights into radiotherapy strategies for early stage breast cancer.

LncRNA CASC9 activated by STAT3 promotes the invasion of breast cancer and the formation of lymphatic vessels by enhancing H3K27ac-activated SOX4.

Numerous long noncoding RNAs (lncRNAs) are abnormally expressed in breast cancer (BC), but the underlying mechanisms remain large unknown. Here, we aimed to investigate the functions and mechanisms of lncRNA cancer susceptibility candidate 9 (CASC9) in BC. Western blotting and quantitative real-time PCR (qRT-PCR) were performed to assess gene and protein expression, respectively. The proliferative and metastatic abilities of BC cells were tested by cell counting kit-8 and transwell assays, respectively. The formation of lymphatic vessels was detected by tube formation assay. Chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays were performed to verify molecular interactions. CASC9 was found to be highly expressed in BC tissues and cell lines, and ectopic overexpression was positively associated with tumor volume, TNM stage, and lymph node metastasis. In addition, CASC9 silencing significantly inhibited the proliferation and invasion of BC cells, as well as BC-associated invasion and formation of lymphatic vessels of human dermal lymphatic endothelial cells. Mechanical studies demonstrated that CASC9 could be transcriptionally activated by STAT3 and elevate SOX4 expression by enhancing the acetylation of its promoter region. Our results illustrated that STAT3-activated CASC9 served as a tumor-promoting gene involved in promoting BC invasion and BC-associated formation of lymphatic vessels by upregulating SOX4 through altering H3K27ac level. This finding elucidated a new underlying network of CASC9 in the metastasis of BC.