Background: In the present study, we aimed to investigate whether early cardiac biomarker alterations and echocardiographic parameters, including left atrial (LA) strain, can predict anthracycline-induced cardiotoxicity (AIC) and thus develop a predictive risk score.Methods and Results: The AIC registry is a prospective, observational cohort study designed to gather serial echocardiographic and biomarker data before and after anthracycline chemotherapy. Cardiotoxicity was defined as a reduction in left ventricular ejection fraction (LVEF) ≥10 percentage points from baseline and <55%. In total, 383 patients (93% women; median age, 57 [46–66] years) completed the 2-year follow-up; 42 (11.0%) patients developed cardiotoxicity (median time to onset, 292 [175–440] days). Increases in cardiac troponin T (TnT) and B-type natriuretic peptide (BNP) and relative reductions in the left ventricular global longitudinal strain (LV GLS) and LA reservoir strain [LASr] at 3 months after anthracycline administration were independently associated with subsequent cardiotoxicity. A risk score containing 2 clinical variables (smoking and prior cardiovascular disease), 2 cardiac biomarkers at 3 months (TnT ≥0.019 ng/mL and BNP ≥31.1 pg/mL), 2 echocardiographic variables at 3 months (relative declines in LV GLS [≥6.5%], and LASr [≥7.5%]) was generated.Conclusions: Early decline in LASr was independently associated with subsequent cardiotoxicity. The AIC risk score may provide useful prognostication in patients receiving anthracyclines.

Neoantigens have attracted attention as biomarkers or therapeutic targets. However, accurate prediction of neoantigens is still challenging, especially in terms of its accuracy and cost. Variant detection using RNA sequencing (RNA‐seq) data has been reported to be a low‐accuracy but cost‐effective tool, but the feasibility of RNA‐seq data for neoantigen prediction has not been fully examined. In the present study, we used whole‐exome sequencing (WES) and RNA‐seq data of tumor and matched normal samples from six breast cancer patients to evaluate the utility of RNA‐seq data instead of WES data in variant calling to detect neoantigen candidates. Somatic variants were called in three protocols using: (i) tumor and normal WES data (DNA method, Dm); (ii) tumor and normal RNA‐seq data (RNA method, Rm); and (iii) combination of tumor RNA‐seq and normal WES data (Combination method, Cm). We found that the Rm had both high false‐positive and high false‐negative rates because this method depended greatly on the expression status of normal transcripts. When we compared the results of Dm with those of Cm, only 14% of the neoantigen candidates detected in Dm were identified in Cm, but the majority of the missed candidates lacked coverage or variant allele reads in the tumor RNA. In contrast, about 70% of the neoepitope candidates with higher expression and rich mutant transcripts could be detected in Cm. Our results showed that Cm could be an efficient and a cost‐effective approach to predict highly expressed neoantigens in tumor samples.

Metastasis remains the leading cause of cancer-related mortality, driven by complex interactions within the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) play a pivotal role in metastatic progression, yet their molecular diversity and upstream regulators remain poorly defined. Glycoprotein nonmetastatic melanoma protein B (GPNMB), overexpressed in subsets of tumors including triple-negative breast cancer (TNBC), is implicated in epithelial–mesenchymal transition (EMT) and cancer stemness. Recent single-cell RNA sequencing (scRNA-seq) identified GPNMB as a marker of immunosuppressive TAMs associated with poor prognosis, but its mechanistic role in TNBC has remained unclear. Coculturing monocytic cells with three-dimensional TNBC spheres induced GPNMB ⁺ TAMs expressing sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9). Tumor-expressed GPNMB promotes monocyte-to-TAM polarization by inducing secondary GPNMB expression in monocytes, establishing a feed-forward amplification loop. GPNMB knockdown in TNBC cells inhibited immunosuppressive TAM subsets, including Siglec-9 ⁺ and EMT-associated populations, as determined by deconvolution of bulk RNA-seq data using a custom TAM signature matrix derived from publicly available TNBC scRNA-seq datasets. TNBC-derived GPNMB carried α2,3-sialylation, whereas macrophage-derived GPNMB carried α2,6-sialylation, enabling differential Siglec-9 recognition. Elevated GPNMB and Siglec-9 correlated with poor prognosis in TNBCcohorts. Importantly, dual inhibition of Siglec-E (murine Siglec-9 ortholog) and PD-1 reduced tumor stemness, suppressed IL-6-dependent EMT, and limited lung metastasis in vivo. The GPNMB–Siglec-9 axis thus represents a critical glyco-immunological checkpoint driving TAM-mediated metastasis, providing a promising therapeutic target in TNBC.

Hyperthermia (HT) treatment is a noninvasive cancer therapy, often used with radiation therapy and chemotherapy. Compared with 37 °C, 42 °C is mild heat stress for cells and produces reactive oxygen species (ROS) from mitochondria. To involve subsequent intracellular accumulation of DOX, we have previously reported that the expression of ATP-binding cassette sub-family G member 2 (ABCG2), an exporter of doxorubicin (DOX), was suppressed by a larger amount of intracellular mitochondrial ROS. We then hypothesized that the additive effect of HT and chemotherapy would be induced by the downregulation of ABCG2 expression via intracellular ROS increase. We used human breast cancer cell lines, MCF-7 and MDA-MB-453, incubated at 37 °C or 42 °C for 1 h to clarify this hypothesis. Intracellular ROS production after HT was detected via electron spin resonance (ESR), and DOX cytotoxicity was calculated. Additionally, ABCG2 expression in whole cells was analyzed using Western blotting. We confirmed that the ESR signal peak with HT became higher than that without HT, indicating that the intracellular ROS level was increased by HT. ABCG2 expression was downregulated by HT, and cells were injured after DOX treatment. DOX cytotoxicity enhancement with HT was considered a result of ABCG2 expression downregulation via the increase of ROS production. HT increased intracellular ROS production and downregulated ABCG2 protein expression, leading to cell damage enhancement via DOX.

Purpose: The randomized phase 2 Neo-peaks study examined usefulness of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1 + P) following docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) as compared with the standard TCbHP regimen. We previously reported that pCR rate after neoadjuvant therapy tended to be higher with TCbHP followed by T-DM1 + P. We conducted an exploratory analysis of prognosis 5 years after surgery. Methods: Neoadjuvant treatment with TCbHP (6 cycles; group A), TCbHP (4 cycles) followed by T-DM1 + P (4 cycles; group B), and T-DM1 + P (4 cycles; group C, + 2 cycles in responders) were compared. Group C non-responders after 4 cycles were switched to an anthracycline-based regimen. We evaluated 5-year disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS). Results: Data from 203 patients (50, 52, and 101 in groups A–C, respectively) were analyzed. No significant intergroup differences were found for DFS, DDFS, or OS. The 5-year DFS rates (95% CI) were 91.8% (79.6–96.8%), 92.3% (80.8–97.0%), and 88.0% (79.9–93.0%) in groups A–C, respectively. TCbHP followed by T-DM1 + P and T-DM1 + P with response-guided addition of anthracycline therapy resulted in similar long-term prognosis to that of TCbHP. Conclusions: In patients who achieved pCR after neoadjuvant therapy with T-DM1 + P, omission of adjuvant anthracycline may be considered, whereas treatment should be adjusted for non-pCR patients with residual disease. T-DM1 + P with response-guided treatment adjustment may be useful for minimizing toxicity. Trial registration number and date of registration: UMIN-CTR, UMIN000014649, prospectively registered July 25, 2014. Some of the study results were presented as a Mini Oral session at the ESMO Breast Cancer 2023 (Berlin, Germany, 11–13 May 2023).