Tumour necrosis is associated with poor prognosis in cancer^1,2 and is thought to occur passively when tumour growth outpaces nutrient supply. Here we report, however, that neutrophils actively induce tumour necrosis. In multiple cancer mouse models, we found a tumour-elicited Ly6G^HighLy6C^Low neutrophil population that was unable to extravasate in response to inflammatory challenges but formed neutrophil extracellular traps (NETs) more efficiently than classical Ly6G^HighLy6C^High neutrophils. The presence of these ‘vascular-restricted’ neutrophils correlated with the appearance of a ‘pleomorphic’ necrotic architecture in mice. In tumours with pleomorphic necrosis, we found intravascular aggregates of neutrophils and NETs that caused occlusion of the tumour vasculature, driving hypoxia and necrosis of downstream vascular beds. Furthermore, we found that cancer cells adjacent to these necrotic regions (that is, in ‘perinecrotic’ areas) underwent epithelial-to-mesenchymal transition, explaining the paradoxical metastasis-enhancing effect of tumour necrosis. Blocking NET formation genetically or pharmacologically reduced the extent of tumour necrosis and lung metastasis. Thus, by showing that NETs drive vascular occlusion, pleomorphic necrosis and metastasis, we demonstrate that tumour necrosis is not necessarily a passive byproduct of tumour growth and that it can be blocked to reduce metastatic spread.

Purpose: Antibody–drug conjugates (ADC) have transformed the treatment of breast cancer. FDA-approved ADC such as trastuzumab deruxtecan (T-DXd), sacituzumab govitecan (SG), and datopotamab deruxtecan (Dato-DXd) have demonstrated clinical benefit; however, drug resistance will almost inevitably emerge in the metastatic setting, and there is no established strategy for selecting subsequent ADC after disease progression following the first exposure to the ADC. This study aimed to define mechanisms of acquired resistance and evaluate rational sequencing approaches. Experimental Design: We generated breast cancer cell lines resistant to T-DXd (TDXd-R) and SG (SG-R). We assessed antigen expression, internalization, and resistance pathways, including efflux transporter activity. To identify therapeutic strategies, we tested the efficacy of ADC carrying non–topoisomerase I (Topo1) payloads in in vitro and in vivo models. Results: Resistance in both TDXd-R and SG-R models was primarily mediated by payload-specific factors, notably upregulation of efflux transporters, rather than loss of antigen expression. Switching to ADC with mechanistically different payloads, including microtubule inhibitors, restored antitumor activity in vitro and in vivo. Conclusions: Cross-resistance to sequential ADC is primarily driven by shared payload mechanisms rather than loss of the target. Our data also suggest that the clinical benefit of sequential Topo1-based ADC may be reduced following disease progression on a Topo1-based ADC, likely due to these shared resistance pathways. Importantly, switching to ADC with non–cross-resistant payload classes may offer a more effective approach to guide ADC sequencing in patients with metastatic breast cancer, supporting payload diversification as a clinically actionable strategy.

Ovarian cancer (OV) has the highest mortality rate among gynecological cancers. As OV progresses, tumor cells spread outside the ovaries to the peritoneal and abdominal cavities, forming cell clusters that float in the ascitic fluid caused by peritonitis carcinomatosa, leading to further dissemination and metastasis. These cell clusters are enriched with cancer stem cells (CSCs) which are responsible for treatment resistance, recurrence, and metastasis. Therefore, targeting CSCs is a potentially effective approach for treating OV. However, understanding how CSCs acquire treatment resistance and identifying targets against CSCs remains challenging. In this study, we demonstrate that 3D-spheroids of OV cell lines exhibit higher stemness than conventional adherent cells. Metabolomics profiling studies have revealed that 3D-spheroids maintain a high-energy state through increased glucose utilization in the citric acid cycle (TCA), efficient nucleotide phosphorylation, and elevated phosphocreatine as an energy buffer. We also found that nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme for NAD⁺ production, is highly expressed in OV. Furthermore, the approach based on NAMPT dependence rather than histology found NAMPT to be a potential therapeutic target against CSCs, while also serving as a prognostic indicator in OV. Moreover, we identified a previously unrecognized anti-tumor mechanism whereby disulfiram, an aldehyde dehydrogenase (ALDH) inhibitor, synergistically inhibited mitochondrial function when combined with NAMPT inhibitors - leading to cell cycle arrest in G2/M. Finally, the combination of a NAMPT inhibitor and disulfiram showed significant anti-tumor effects and extended survival in an animal model. Our findings demonstrate the potential of spheroids as a preclinical model for targeting OV CSCs and also indicate that the combination of NAMPT inhibitors and disulfiram is a promising therapeutic strategy to overcome recurrent OV.

Purpose: We evaluated healthcare providers’ current knowledge, practices, and perspectives on a novel clinical decision tool (beta-version) to facilitate individualized exercise prescriptions and discussions in clinical settings. Methods: We recruited healthcare providers who had treated or provided care to breast cancer survivors aged ≥ 35-years in the past 12 months. The participants were presented with a tool to provide individualized exercise recommendations considering women’s individual, clinical, and contextual characteristics. Validated and reliable pre-existing instruments were used to survey providers’ current knowledge, practices regarding exercise discussions, and perspectives on the beta-version (paper-draft) of the novel tool. Results: The sample consisted of complete survey responses from 177 healthcare providers including breast oncologists (27.7%), primary care physicians (10.7%), exercise specialists (19.8%), occupational/physical therapists (18.1%), advanced care providers, nurses, navigators, and social workers (23.7%). Median years of experience was 8-years (range: 5–13). Overall, 62.1% (n = 110) reported that they were knowledgeable about counseling survivors based on exercise guidelines. Among breast oncologists and primary care physicians (n = 68), only 39.7% reported that they were knowledgeable about identifying patients for exercise referals. The majority agreed that they would find the tool offering individualized information useful (n = 148, 83.6%), and would use it regularly to inform practice (82.5%). ‘Exercise Readiness’, ‘Exercise Resources at Home’, and ‘Quality-of-Life’ were the highest rated items for inclusion in the tool for exercise prescriptions. Provider perspectives were incorporated into the beta-version of the tool. Conclusion: A clinical decision tool considering individual, clinical, and contextual characteristics may support exercise prescriptions and discussions in clinical settings. Implications for cancer survivors: An evidence-based tool for exercise prescriptions may increase healthcare provider confidence to discuss, educate, encourage, and provide exercise referrals for breast cancer survivors.

Background: Pathological complete response has been used as a primary endpoint in neoadjuvant trials in early stage triple-negative breast cancer, and the Food and Drug Administration accepted pathological complete response as a surrogate endpoint for long-term survival outcomes in high-risk early stage breast cancer for new drug approval. However, there is insufficient trial-level data to robustly support pathological complete response as a surrogate for long-term survival in triple-negative breast cancer. Methods: A systematic literature review was performed to identify randomized clinical trials of neoadjuvant systemic therapy for patients with clinical stage I-III triple-negative breast cancer. Data of odds ratios (ORs) for pathological complete response and hazard ratios (HRs) for event-free survival and overall survival were extracted. Disease-free survival was used as an alternative when event-free survival data were unavailable. A linear regression model on a logarithmic scale, coefficient of difference, and 95% confidential interval (CI) were calculated to assess the trial-level association between odds ratio for pathological complete response and hazard ratio for overall survival and event-free survival. Results: Eight trials with 2342 patients were included. Three trials tested immune checkpoint inhibitors. Coefficient of difference (R2) was 0.2 for hazard ratio of event-free survival (95% CI = 0.17 to 0.22, P = .27), and R2 for hazard ratio of overall survival was 0.19 (95% CI = 0.17 to 0.22, P = .33). Conclusions: There is no strong evidence to support using pathological complete response as a surrogate marker for event-free survival or overall survival in early stage triple-negative breast cancer at the trial level. Because of the necessity of minimizing drug approval delay with reliable long-term outcome, further studies of surrogate markers in early stage triple-negative breast cancer are warranted.