Genetic interactions reveal distinct biological and therapeutic implications in breast cancer.

Co-occurrence and mutual exclusivity of genomic alterations may reflect the existence of genetic interactions, potentially shaping distinct biological phenotypes and impacting therapeutic response in breast cancer. However, our understanding of them remains limited. Herein, we investigate a large-scale multi-omics cohort (n = 873) and a real-world clinical sequencing cohort (n = 4,405) including several clinical trials with detailed treatment outcomes and perform functional validation in patient-derived organoids, tumor fragments, and in vivo models. Through this comprehensive approach, we construct a network comprising co-alterations and mutually exclusive events and characterize their therapeutic potential and underlying biological basis. Notably, we identify associations between TP53mut-AURKAamp and endocrine therapy resistance, germline BRCA1mut-MYCamp and improved sensitivity to PARP inhibitors, and TP53mut-MYBamp and immunotherapy resistance. Furthermore, we reveal that precision treatment strategies informed by co-alterations hold promise to improve patient outcomes. Our study highlights the significance of genetic interactions in guiding genome-informed treatment decisions beyond single driver alterations.

Clinical sequencing defines the somatic and germline mutation landscapes of Chinese HER2-Low Breast Cancer.

More than half of the breast cancer initially labeled as human epidermal growth factor receptor 2 (HER2)-negative actually exhibited low HER2 levels (IHC 1+ or IHC 2+/FISH-) and were classified as HER2-low breast cancer. Previous research emphasized the significant biological heterogeneity in HER2-low breast cancer, highlighting the importance of accurately characterizing HER2-low tumors to promote the precise management of antibody‒drug conjugates. In this study, we established a large-scale targeted sequencing cohort (N = 1907) representing Chinese HER2-low breast cancer patients with detailed clinical annotation. Our research findings revealed that HER2-low breast cancer demonstrated distinct clinical pathological characteristics and mutation landscapes compared to HER2-zero group. When compared to HER2-zero tumors, HER2-low tumors exhibited a higher proportion of Luminal B subtypes and better disease-free survival. In hormone receptor (HR)-positive breast cancer, HER2-low group showed a higher frequency of GATA3 somatic mutations, BRCA2 germline mutations, and mutations in the DNA damage repair pathway. In contrast, in HR-negative breast cancer, the HER2-low group displayed a higher frequency of PIK3CA mutations and PI3K pathway alterations. These findings offered valuable insights for the precise targeted treatment of HER2-low breast cancer in different HR statuses.

Integrated multiomic profiling of breast cancer in the Chinese population reveals patient stratification and therapeutic vulnerabilities.

Molecular profiling guides precision treatment of breast cancer; however, Asian patients are underrepresented in publicly available large-scale studies. We established a comprehensive multiomics cohort of 773 Chinese patients with breast cancer and systematically analyzed their genomic, transcriptomic, proteomic, metabolomic, radiomic and digital pathology characteristics. Here we show that compared to breast cancers in white individuals, Asian individuals had more targetable AKT1 mutations. Integrated analysis revealed a higher proportion of HER2-enriched subtype and correspondingly more frequent ERBB2 amplification and higher HER2 protein abundance in the Chinese HR+HER2+ cohort, stressing anti-HER2 therapy for these individuals. Furthermore, comprehensive metabolomic and proteomic analyses revealed ferroptosis as a potential therapeutic target for basal-like tumors. The integration of clinical, transcriptomic, metabolomic, radiomic and pathological features allowed for efficient stratification of patients into groups with varying recurrence risks. Our study provides a public resource and new insights into the biology and ancestry specificity of breast cancer in the Asian population, offering potential for further precision treatment approaches.

Comprehensive genomic profiling of breast cancers characterizes germline-somatic mutation interactions mediating therapeutic vulnerabilities.

Germline-somatic mutation interactions are universal and associated with tumorigenesis, but their role in breast cancer, especially in non-Caucasians, remains poorly characterized. We performed large-scale prospective targeted sequencing of matched tumor-blood samples from 4079 Chinese females, coupled with detailed clinical annotation, to map interactions between germline and somatic alterations. We discovered 368 pathogenic germline variants and identified 5 breast cancer DNA repair-associated genes (BCDGs; BRCA1/BRCA2/CHEK2/PALB2/TP53). BCDG mutation carriers, especially those with two-hit inactivation, demonstrated younger onset, higher tumor mutation burden, and greater clinical benefits from platinum drugs, PARP inhibitors, and immune checkpoint inhibitors. Furthermore, we leveraged a multiomics cohort to reveal that clinical benefits derived from two-hit events are associated with increased genome instability and an immune-activated tumor microenvironment. We also established an ethnicity-specific tool to predict BCDG mutation and two-hit status for genetic evaluation and therapeutic decisions. Overall, this study leveraged the large sequencing cohort of Chinese breast cancers, optimizing genomics-guided selection of DNA damaging-targeted therapy and immunotherapy within a broader population.

Molecular classification of hormone receptor-positive HER2-negative breast cancer.

Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most prevalent type of breast cancer, in which endocrine therapy resistance and distant relapse remain unmet challenges. Accurate molecular classification is urgently required for guiding precision treatment. We established a large-scale multi-omics cohort of 579 patients with HR+/HER2- breast cancer and identified the following four molecular subtypes: canonical luminal, immunogenic, proliferative and receptor tyrosine kinase (RTK)-driven. Tumors of these four subtypes showed distinct biological and clinical features, suggesting subtype-specific therapeutic strategies. The RTK-driven subtype was characterized by the activation of the RTK pathways and associated with poor outcomes. The immunogenic subtype had enriched immune cells and could benefit from immune checkpoint therapy. In addition, we developed convolutional neural network models to discriminate these subtypes based on digital pathology for potential clinical translation. The molecular classification provides insights into molecular heterogeneity and highlights the potential for precision treatment of HR+/HER2- breast cancer.

Prediction of clinicopathological features, multi-omics events and prognosis based on digital pathology and deep learning in HR+/HER2- breast cancer.

Background: Breast cancer has the highest incidence and mortality rates among women worldwide. Hormone receptor (HR)+/human epidermal growth factor receptor 2 (HER2)- breast cancer is the most common molecular subtype, accounting for 50-79% of breast cancers. Deep learning has been widely used in cancer image analysis, especially for predicting targets related to precise treatment and patient prognosis. However, studies focusing on therapeutic target and prognosis predicting in HR+/HER2- breast cancer are lacking. Methods: This study retrospectively collected hematoxylin and eosin (H&E)-stained slides of HR+/HER2- breast cancer patients between January 2013 and December 2014 at Fudan University Shanghai Cancer Center (FUSCC) and scanned to generate whole-slide images (WSIs). Then, we built a deep-learning-based workflow to train and validate model to predict clinicopathological features, multi-omics molecular features and prognosis; the area under the curve (AUC) of the receiver operating characteristic (ROC) and the concordance index (C-index) of the test set were used to assess model effectiveness. Results: A total of 421 HR+/HER2- breast cancer patients were included in our study. Regarding clinicopathological features, grade III could be predicted with an AUC of 0.90 [95% confidence interval (CI): 0.84-0.97]. Regarding somatic mutations, TP53 and GATA3 mutation could be predicted with AUCs of 0.68 (95% CI: 0.56-0.81) and 0.68 (95% CI: 0.47-0.89), respectively. Regarding gene set enrichment analysis (GSEA) pathways, the G2-M checkpoint pathway was predicted with an AUC of 0.79 (95% CI: 0.69-0.90). Regarding markers of immunotherapy response, intratumoral tumor-infiltrating lymphocytes (iTILs), stromal tumor-infiltrating lymphocytes (sTILs), CD8A, and PDCD1 were predicted with AUCs of 0.78 (95% CI: 0.55-1.00), 0.76 (95% CI: 0.65-0.87), 0.71 (95% CI: 0.60-0.82), and 0.74 (95% CI: 0.63-0.85), respectively. In addition, we found that the integration of clinical prognostic variables and deep features of images can improve the stratification of patient prognosis. Conclusions: Using a deep-learning-based workflow, we developed models to predict the clinicopathological features, multi-omics features and prognosis of patients with HR+/HER2- breast cancer using pathological WSIs. This work may contribute to efficient patient stratification to promote the personalized management of HR+/HER2- breast cancer.

Calcifications in triple-negative breast cancer: Molecular features and treatment strategies.

Despite the high prevalence of mammographic calcifications, our understanding remains limited regarding the clinical and molecular features of calcifications within triple-negative breast cancer (TNBC). To investigate the clinical relevance and biological basis of TNBC with calcifications of high suspicion for malignancy, we established a study cohort (N = 312) by integrating mammographic records with clinical data and genomic, transcriptomic, and metabolomic profiling. Despite similar clinicopathological features, patients with highly suspicious calcifications exhibited a worse overall survival than those without. In addition, TNBC with highly suspicious calcifications was characterized by a higher frequency of PIK3CA mutation, lower infiltration of immune cells, and increased abnormality of lipid metabolism. Overall, our study systematically revealed clinical and molecular heterogeneity between TNBC with or without calcifications of high suspicion for malignancy. These data might help to understand the clinical relevance and biological basis of mammographic calcifications.

Identification of a novel signature with prognostic value in triple-negative breast cancer through clinico-transcriptomic analysis.

Background: Although perceived as a highly aggressive disease, triple-negative breast cancer (TNBC) constitutes heterogeneous features with various outcomes. In this study, we aimed to establish a prognostic signature for patients with TNBC to improve risk stratification. Methods: Gene expression data were obtained from The Cancer Genome Atlas (TCGA). Differentially expressed genes (DEGs) were detected pairwise between TNBC and other subtypes of samples. Then, TNBC-correlated modules were determined using coexpression network analysis. A gene signature was established based on the prognostic genes in the intersection between DEGs and selected gene modules using least absolute shrinkage and selection operator (LASSO) Cox regression. Finally, a clinico-transcriptomic signature was developed to predict overall survival (OS). Model performance was quantified, and the bootstrap resampling method was used for validation. Results: The gene signature included 6 messenger RNAs (mRNAs) and a clinical score indicating an increased likelihood of death when used as continuous or categorical predictors. A nomogram was built by integrating the pathological stage and gene signature to predict 2-, 3-, and 5-year OS. The addition of pathological stage increased the concordance index (C-index) compared with pathological stage alone and the gene signature alone. Bootstrap resampling revealed a stable performance of the nomogram. Conclusions: A 6-mRNA signature was established to inform prognosis for patients with TNBC. Its combination with pathological stage can contribute to improving performance and provide additional supporting evidence for clinical decision-making.

Omission of axillary surgery for ipsilateral breast tumor recurrence with negative nodes after previous breast-conserving surgery: is it oncologically safe?

PURPOSE: Salvage mastectomy is traditionally recommended for patients who developed ipsilateral breast tumor recurrence (IBTR) in light of previous breast irradiation. However, it remains controversial whether surgical axillary staging (SAS) is necessary for IBTR patients with negative nodes. This study aimed to evaluate the oncologic safety of omitting SAS for IBTR. METHODS: We retrospectively identified patients who developed invasive IBTR with negative nodes after undergoing breast-conserving surgery (BCS) from 2010 to 2018. Patterns of care in nodal staging were analyzed based on prior axillary staging status. Clinicopathologic characteristics and adjuvant treatment of the initial tumor, as well as the IBTR, were compared between the SAS and no SAS groups. Kaplan-Meier method and Cox regression model were utilized to compare the locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS), and overall survival (OS) rates after IBTR removal between the two groups. RESULTS: A total of 154 IBTR patients were eligible for final analysis. Compared to the no SAS group, SAS group was less likely to undergo ALND (15.1 vs 73.3%, p < 0.001) at initial BCS, had a longer recurrence interval (2.8 vs 2.1 years, p = 0.03), and were more likely to have discordant molecular subtype (35.8 vs 12.9%, p = 0.001) and different quadrant location (37.7 vs 19.8%, p = 0.02) with primary tumor. However, the extent of axillary staging did not affect systemic or radiation recommendations. In the subgroup of patients without previous ALND, the clinicopathologic characteristics were roughly comparable. No significant differences were observed in LRRFS, DMFS or OS between the two groups. CONCLUSION: For node-negative IBTR patients, we observed selection bias on the basis of prior ALND, shorter recurrence interval, and concordant molecular subtype favoring no SAS but comparable LRRFS, DMFS, and OS. These results support a wider consideration of sparing SAS in the management of IBTR, especially in patients without previous ALND.

Spatiotemporal Patterns of Loco-Regional Recurrence After Breast-Conserving Surgery.

BACKGROUND: Loco-regional recurrences (LRR) following breast-conserving surgery (BCS) remain a heterogeneous class of disease that has significant variation in its biological behavior and prognosis. METHODS: To delineate the spatiotemporal patterns of LRR after BCS, we analyzed the data of 4325 patients treated with BCS from 2006 to 2016. Clinico-pathological and treatment specific factors were analyzed using the Cox proportional hazards model to identify factors predictive for LRR events. Recurrence patterns were scrutinized based on recurrence type and recurrence-free interval (RFI). Annual recurrence rates (ARR) were compared according to recurrence type and molecular subtype. RESULTS: With a median follow-up of 66 months, 120 (2.8%) LRRs were recorded as the first site of failure. Age, pathologic stage, and molecular subtype were identified as predictors of LRR. The major recurrence type was ipsilateral breast tumor recurrence, which mainly (83.6%) occurred ≤5y post surgery. In the overall population, ARR curves showed that relapse peaked in the first 2.5 years. Patients with regional nodal recurrence, shorter RFI, and synchronous distant metastasis were associated with a poorer prognosis. HER2-positive disease had a higher rate of LRR events, more likely to have in-breast recurrence, and had an earlier relapse peak in the first 2 years after surgery. CONCLUSIONS: LRR risk following BCS is generally low in Chinese ethnicity. Different recurrence patterns after BCS were related to distinct clinical outcomes. Management of LRR should be largely individualized and tailored to the extent of disease, the molecular profile of the recurrence, and to baseline clinical variables.

Chemolipiodolization with or without embolization in transcatheter arterial chemoembolization combined with radiofrequency ablation for hepatocellular carcinoma-propensity score matching analysis.

To retrospectively compare the outcome of chemolipiodolization with or without embolization in transcatheter arterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) in Patients with hepatocellular carcinoma (HCC) within the Milan criteria. From August 2002 to December 2014, 112 patients (median age, 56.7 years; age range, 22-80 years; 97 men, 15 women) underwent TACE with gelatin sponge particle embolization, and 125 patients (median age, 56.6 years; age range, 23-82 years; 109 men, 16 women) underwent TACE without embolization. RFA was performed within 2 weeks after the TACE. Cumulative overall survival (OS) and disease-free survival (DFS) rates were compared before and after propensity score matching. Before matching, the 1-, 3-, and 5-year OS rate were 96%, 80%, and 62% for embolization group and 94%, 76%, and 59% for non-embolization group . The 1-, 3-, and 5-year DFS rate were 77%, 38%, and 30% for embolization group and 75%, 35%, and 26% for non-embolization group. After matching, the 1-, 3-, and 5-year OS rate were 97%, 82%, and 62% for embolization group and 92%, 74%, and 56% for non-embolization group. The 1-, 3-, and 5-year DFS rate were 79%, 36%, and 30% for embolization group and 74%, 33%, and 26% for non-embolization group. There were no significant difference in OS and DFS rates between the two groups before matching (P =0.999 and P =0.654) and after matching (P =0.951 and P =0.670). In conclusion, embolization in TACE combined with RFA could not improve the survival for patients with HCC within the Milan criteria.