Chromatin conformational changes at human satellite II contribute to the senescence phenotype in the tumor microenvironment.

Cellular senescence and senescence-associated secretory phenotype (SASP) in stromal cells within the tumor microenvironment promote cancer progression. Although cellular senescence has been shown to induce changes in the higher-order chromatin structure and abnormal transcription of repetitive elements in the genome, the functional significance of these changes is unclear. In this study, we examined the human satellite II (hSATII) loci in the pericentromere to understand these changes and their functional significance. Our results indicated that the hSATII loci decompact during senescence induction, resulting in new DNA-DNA interactions in distinct genomic regions, which we refer to as DRISR (Distinctive Regions Interacted with Satellite II in Replicative senescent Fibroblasts). Interestingly, decompaction occurs before the expression of hSATII RNA. The DRISR with altered chromatin accessibility was enriched for motifs associated with cellular senescence and inflammatory SASP genes. Moreover, DNA-fluorescence in situ hybridization analysis of the breast cancer tissues revealed hSATII decompaction in cancer and stromal cells. Furthermore, we reanalyzed the single-cell assay for transposase-accessible chromatin with sequencing data and found increased SASP-related gene expression in fibroblasts exhibiting hSATII decompaction in breast cancer tissues. These findings suggest that changes in the higher-order chromatin structure of the pericentromeric repetitive sequences during cellular senescence might directly contribute to the cellular senescence phenotype and cancer progression via inflammatory gene expression.

Risk-reducing decisions regarding germline BRCA pathogenic variant: focusing on the timing of genetic testing and RRSO.

BACKGROUND: In Japan, the public insurance policy was revised in 2020 to cover hereditary breast and ovarian cancer (HBOC), including genetic testing and surveillance, for patients with breast cancer (BC). Consequently, the demand for risk-reducing salpingo-oophorectomy (RRSO) has increased. This study aimed to clarify the changes in the demand and timing of genetic testing and RRSO associated with public insurance coverage for HBOC in Japan. METHODS: This retrospective analysis included 350 women with germline BRCA (gBRCA) pathogenic variants (PVs) who had visited gynaecologists; they received gBRCA genetic testing at 45.1±10.6 (20-74) years. The use of medical testing and preventive treatment was compared between the preinsurance and postinsurance groups using Mann-Whitney U and Fisher's exact tests. RESULTS: The findings indicate that RRSO rates doubled from 31.4% to 62.6% among patients with gBRCA-PV. The implementation rate was 32.4% among unaffected carriers and 70.3% among BC-affected patients. Younger patients received genetic testing with significantly shorter intervals between BC diagnosis and genetic testing and between genetic testing and RRSO. CONCLUSION: Overall, the insurance coverage for HBOC patients with BC has increased the frequency of RRSO in Japan. However, a comparison between the number of probands and family members indicated that the diagnosis among family members is inadequate. The inequality in the use of genetic services by socioeconomic groups is an issue of further concern.

Genomic and transcriptomic profiling of pre- and postneoadjuvant chemotherapy triple negative breast cancer tumors.

Our understanding of neoadjuvant treatment with microtubule inhibitors (MTIs) for triple negative breast cancer (TNBC) remains limited. To advance our understanding of the role of breast cancer driver genes' mutational status with pathological complete response (pCR; ypT0/isypN0) prediction and to identify distinct gene sets for MTIs like eribulin and paclitaxel, we carried out targeted genomic (n = 50) and whole transcriptomic profiling (n = 64) of TNBC tumor samples from the Japan Breast Cancer Research Group 22 (JBCRG-22) clinical trial. Lower PIK3CA, PTEN, and HRAS mutations were found in homologous recombination deficiency (HRD)-high (HRD score ≥ 42) tumors with higher pCR rates. When HRD-high tumors were stratified by tumor BRCA mutation status, the pCR rates in BRCA2-mutated tumors were higher (83% vs. 36%). Transcriptomic profiling of TP53-positive tumors identified downregulation of FGFR2 (false discovery rate p value = 2.07e-7), which was also the only common gene between HRD-high and -low tumors with pCR/quasi-pCR treated with paclitaxel and eribulin combined with carboplatin, respectively. Differential enrichment analysis of the HRD-high group posttreatment tumors revealed significant correlation (p = 0.006) of the glycan degradation pathway. FGFR2 expression and the differentially enriched pathways play a role in the response and resistance to MTIs containing carboplatin treatment in TNBC patients.

Time-series blood cytokine profiles correlate with treatment responses in triple-negative breast cancer patients.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most heterogeneous breast cancer subtype. Partly due to its heterogeneity, it is currently challenging to stratify TNBC patients and predict treatment outcomes. METHODS: In this study, we examined blood cytokine profiles of TNBC patients throughout treatments (pre-treatment, during chemotherapy, pre-surgery, and 1 year after the surgery in a total of 294 samples). We analyzed the obtained cytokine datasets using weighted correlation network analyses, protein-protein interaction analyses, and logistic regression analyses. RESULTS: We identified five cytokines that correlate with good clinical outcomes: interleukin (IL)-1α, TNF-related apoptosis-inducing ligand (TRAIL), Stem Cell Factor (SCF), Chemokine ligand 5 (CCL5 also known as RANTES), and IL-16. The expression of these cytokines was decreased during chemotherapy and then restored after the treatment. Importantly, patients with good clinical outcomes had constitutively high expression of these cytokines during treatments. Protein-protein interaction analyses implicated that these five cytokines promote an immune response. Logistic regression analyses revealed that IL-1α and TRAIL expression levels at pre-treatment could predict treatment outcomes in our cohort. CONCLUSION: We concluded that time-series cytokine profiles in breast cancer patients may be useful for understanding immune cell activity during treatment and for predicting treatment outcomes, supporting precision medicine. TRIAL REGISTRATION: The study has been registered with the University Hospital Medical Information Network Clinical Trials Registry ( http://www.umin.ac.jp/ctr/index-j.htm ) with the unique trial number UMIN000023162. The association Japan Breast Cancer Research Group trial number is JBCRG-22. The clinical outcome of the JBCRG-22 study was published in Breast Cancer Research and Treatment on 25 March 2021. https://doi.org/10.1007/s10549-021-06184-w .

Absolute lymphocyte count predicts efficacy of palbociclib in patients with metastatic luminal breast cancer.

BACKGROUND: Absolute lymphocyte count (ALC) is a predictive and prognostic factor for various tumor types, including breast cancer. Palbociclib is a CDK4/6 inhibitor widely used for the treatment of metastatic estrogen receptor (ER)-positive, HER2-negative breast cancer. However, predictive biomarkers of the efficacy of palbociclib remain unelucidated. We conducted a retrospective study to examine the predictive value of the baseline ALC in patients treated with palbociclib. METHODS: The medical records of patients with ER-positive, HER2-negative breast cancer treated with palbociclib plus hormonal therapy between December 2017 and December 2021 were analyzed retrospectively. The cutoff value of ALC was set at 1800 cells/µL at the initiation of palbociclib treatment. The clinical benefit rate (CBR) was defined as the rate of complete or partial response or stable disease for at least 6 months. Progression-free survival (PFS) rates were estimated using the Kaplan-Meier method and compared using the log-rank test. Univariate and multivariate analyses were performed using Cox proportional hazards regression. RESULTS: All of the 202 patients were women, with a median age of 59 years and a performance status (PS) of ≤ 2. The median numbers of lines of chemotherapy and endocrine therapy before palbociclib treatment were 0 (range, 0-9) and 1 (range, 0-7), respectively. Fifty-one patients had liver metastases. Forty-six patients tested negative for progesterone receptor (PgR) expression. The median follow-up time was 9.1 months. The CBR was significantly higher in the ALC-high group than in the ALC-low group (79% vs. 60%; P = 0.018). The median PFS was significantly longer in the ALC-high group than in the ALC-low group (26.8 months vs. 8.4 moths, respectively; P = 0.000013). ALC, age, PS, PgR status, prior chemotherapy, prior endocrine therapy, and liver metastasis were entered into the multivariate analysis. ALC was identified as an independent factor for PFS (P = 0.00085), along with liver metastasis (P = 0.0020), PS (P = 0.026), and prior endocrine therapy (P = 0.019). CONCLUSION: ALC can serve as a predictor of palbociclib efficacy in patients with metastatic ER-positive, HER2-negative breast cancer.

Outcomes in Nonmetastatic Hormone Receptor-Positive HER2-Negative Pure Mucinous Breast Cancer: A Multicenter Cohort Study.

BACKGROUND: Although considered a favorable subtype, pure mucinous breast cancer (PMBC) can recur, and evidence for adjuvant therapy is limited. We aimed to compare outcomes of nonmetastatic PMBC with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) to address these uncertainties. METHODS: Individual patient-level data from 6 centers on stage I-III hormone receptor-positive and HER2-negative PMBC, IDC, and ILC were used to analyze recurrence-free interval (RFI), recurrence-free survival (RFS), and overall survival (OS), and to identify prognostic factors for PMBC. RESULTS: Data from 20,684 IDC cases, 1,475 ILC cases, and 943 PMBC cases were used. Median follow-up was 6.6 years. Five-year RFI, RFS, and OS for PMBC were 96.1%, 94.9%, and 98.1%, respectively. On multivariable Cox regression, PMBC demonstrated superior RFI (hazard ratio [HR], 0.59; 95% CI, 0.43-0.80), RFS (HR, 0.70; 95% CI, 0.56-0.89), and OS (HR, 0.71; 95% CI, 0.53-0.96) compared with IDC. ILC showed comparable outcomes to IDC. Fewer than half (48.7%) of recurrences in PMBC were distant, which was a lower rate than for IDC (67.3%) and ILC (80.6%). In contrast to RFI, RFS events were driven more by non-breast cancer deaths in older patients. Significant prognostic factors for RFI among PMBC included positive lymph node(s) (HR, 2.42; 95% CI, 1.08-5.40), radiotherapy (HR, 0.44; 95% CI, 0.23-0.85), and endocrine therapy (HR, 0.25; 95% CI, 0.09-0.70). No differential chemotherapy associations with outcomes were detected across PMBC subgroups by nodal stage, tumor size, and age. A separate SEER database analysis also did not find any association of improved survival with adjuvant chemotherapy in these subgroups. CONCLUSIONS: Compared with IDC, PMBC demonstrated superior RFI, RFS, and OS. Lymph node negativity, adjuvant radiotherapy, and endocrine therapy were associated with superior RFI. Adjuvant chemotherapy was not associated with better outcomes.

Socioeconomic status and incident depressive symptoms among older adults: A 3-year longitudinal study from the Japan Gerontological Evaluation Study.

OBJECTIVES: The association between socioeconomic status (SES) and the onset of depressive symptoms has attracted considerable attention. However, few studies have simultaneously examined the association of multiple SES indicators, including "assets," with the onset of depressive symptoms. Therefore, this study examined the association of four SES indicators in old age ('years of education' 'equivalent income,' 'equivalent assets,' and 'the longest-held job') with new-onset depressive symptoms in a large Japanese dataset. METHODS: This longitudinal study used panel data of cognitively and physically independent older adults from the Japan Gerontological Evaluation Study (JAGES) conducted in 2013 and 2016. Multivariate logistic regression analysis was conducted to examine the association of each SES indicator with new-onset depressive symptoms, and odds ratios and 95% confidence intervals (CIs) were calculated. RESULTS: We analyzed the data of 40,257 older adults, with a mean age (± standard deviation) of 72.9 (±5.5) years. In the follow-up survey, 4292 older adults had new-onset depression symptoms (10.7%). 39.3% had 10-12 years of education. 36.9% had an equivalent income of up to JPY 1.99 million. 24.4% had equivalent assets of JPY 4-17.99 million. Most had a clerical job for the long time. Furthermore, fewer years of education (males: OR = 1.42, 95% CI = 1.22-1.64, p-value <0.001/females: 1.26, [1.09-1.47], p = 0.002), lower income (males: 1.64, [1.34-2.01], p < 0.001/females: 1.82, [1.49-2.22], p < 0.001), and fewer assets (males: 1.40, [1.16-1.68], p < 0.001/females: 1.21, [1.02-1.42], p = 0.025) resulted in higher odds of having new-onset depressive symptoms, even when other SES indicators were entered simultaneously. CONCLUSIONS: All four SES indicators have an independent association with the development of new-onset depressive symptoms among older adults, reflecting different aspects of SES. The association between the "longest-held job" and new-onset depressive symptoms can be largely explained by other SES indicators. A multifaceted and lifetime approach is required to prevent the onset of depressive symptoms in old age.

Transcriptomic intratumor heterogeneity of breast cancer patient-derived organoids may reflect the unique biological features of the tumor of origin.

BACKGROUND: The intratumor heterogeneity (ITH) of cancer cells plays an important role in breast cancer resistance and recurrence. To develop better therapeutic strategies, it is necessary to understand the molecular mechanisms underlying ITH and their functional significance. Patient-derived organoids (PDOs) have recently been utilized in cancer research. They can also be used to study ITH as cancer cell diversity is thought to be maintained within the organoid line. However, no reports investigated intratumor transcriptomic heterogeneity in organoids derived from patients with breast cancer. This study aimed to investigate transcriptomic ITH in breast cancer PDOs. METHODS: We established PDO lines from ten patients with breast cancer and performed single-cell transcriptomic analysis. First, we clustered cancer cells for each PDO using the Seurat package. Then, we defined and compared the cluster-specific gene signature (ClustGS) corresponding to each cell cluster in each PDO. RESULTS: Cancer cells were clustered into 3-6 cell populations with distinct cellular states in each PDO line. We identified 38 clusters with ClustGS in 10 PDO lines and used Jaccard similarity index to compare the similarity of these signatures. We found that 29 signatures could be categorized into 7 shared meta-ClustGSs, such as those related to the cell cycle or epithelial-mesenchymal transition, and 9 signatures were unique to single PDO lines. These unique cell populations appeared to represent the characteristics of the original tumors derived from patients. CONCLUSIONS: We confirmed the existence of transcriptomic ITH in breast cancer PDOs. Some cellular states were commonly observed in multiple PDOs, whereas others were specific to single PDO lines. The combination of these shared and unique cellular states formed the ITH of each PDO.

Prognostic impact of cancer genomic profile testing for advanced or metastatic solid tumors in clinical practice.

Cancer genomic profile (CGP) testing, which is covered by the national health insurance system in Japan, has been introduced as a routine clinical practice. However, the effects of CGP testing on prognoses remain unclear. Drug accessibility rates and prognoses after CGP testing were retrospectively investigated in 713 patients who underwent CGP testing examined by our molecular tumor board between November 2019 and October 2022,. Overall survival (OS) was examined using the log-rank test and the Kaplan-Meier method. The median age of patients (326 males and 387 females) was 58 years (12-85 years). CGP testing revealed one or more gene mutations in 681 cases (95.5%), among which actionable gene mutations were detected in 439 (61.6%). Although treatment options were recommended for 285 cases (40.0%) by the molecular tumor board, only 45 received treatment based on their gene mutations. During the median observation period of 8.6 months, 351 (49.2%) patients died of the exacerbation of existing diseases. No significant differences were observed in OS between patients treated with and without genomically matched therapy (p = 0.285). According to clinical responses to treatment based on gene mutations, median OS was significantly longer in patients who achieved partial response and stable disease (26.5 months; 95% CI 14.4-38.6) than in those with progressive disease and not evaluated (9.8 months; 95% CI 5.8-13.8, p = 0.013). Responses to treatment based on gene mutations may improve prognoses, and it is important to increase the drug accessibility rate after CGP testing.

Chromatin profile-based identification of a novel ER-positive breast cancer subgroup with reduced ER-responsive element accessibility.

BACKGROUND: Oestrogen receptor (ER) signalling-dependent cancer cell growth is one of the major features of ER-positive breast cancer (BC). Inhibition of ER function is a standard and effective treatment for ER-positive tumours; however, ~20% of patients with ER-positive BC experience early or late recurrence. In this study, we examined intertumour heterogeneity from an epigenetic perspective based on the hypothesis that the intrinsic difference in epigenetic states around ER signalling pathway underlies endocrine therapy resistance. METHODS: We performed transposase-accessible chromatin sequencing (ATAC-seq) analysis of 42 BC samples, including 35 ER-positive(+) human epidermal growth factor receptor 2 (HER2)-negative(-) and 7 triple-negative tumours. We also reanalysed ATAC-seq data of 45 ER + /HER2 - tumours in the Cancer Genome Atlas (TCGA) BC cohort to validate our observations. RESULTS: We conducted a comprehensive analysis of cis-regulatory elements (CREs) using ATAC-seq, identifying three subgroups based on chromatin accessibility profiles. We identified a subgroup of ER-positive BCs with a distinctive chromatin accessibility pattern including reduced accessibility to ER-responsive elements (EREs). The same subgroup was also observed in TCGA BC cohort. Despite the reduced accessibility to EREs, the expression of ER and potential ER target genes were not decreased in these tumours. CONCLUSION: Our findings highlight the existence of a subset of ER-positive BCs with unchanged ER expression but reduced EREs accessibility that cannot be distinguished by conventional immunostaining for ER. Future studies should determine whether these tumours are associated with resistance to endocrine therapy.

Prognostic impact of adjuvant endocrine therapy for estrogen receptor-positive and HER2-negative T1a/bN0M0 breast cancer.

PURPOSE: Mammography screening has increased the detection of subcentimeter breast cancers. The prognosis for estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative T1a/bN0M0 breast cancers is excellent; however, the necessity of adjuvant endocrine therapy (ET) is uncertain. METHODS: We evaluated the effectiveness of adjuvant ET in patients with ER-positive and HER2-negative T1a/bN0M0 breast cancer who underwent surgery from 2008 to 2012. Standard ET was administrated after surgery. The primary endpoint was the cumulative incidence of distant metastasis. All statistical tests were 2-sided. RESULTS: Adjuvant ET was administered to 3991 (83%) of the 4758 eligible patients (1202 T1a [25.3%] and 3556 T1b [74.7%], diseases). The median follow-up period was 9.2 years. The 9-year cumulative incidence of distant metastasis was 1.5% with ET and 2.6% without ET (adjusted subdistribution hazard ratio [sHR], 0.54; 95% CI, 0.32-0.93). In multivariate analysis, the independent risk factors for distant metastasis were no history of ET, mastectomy, high-grade, and lymphatic invasion. The 9-year overall survival was 97.0% and 94.4% with and without ET, respectively (adjusted HR, 0.57; 95% CI, 0.39-0.83). In addition, adjuvant ET reduced the incidence of ipsilateral and contralateral breast cancer (9-year rates; 1.1% vs. 6.9%; sHR, 0.17, and 1.9% vs. 5.2%; sHR, 0.33). CONCLUSIONS: The prognosis was favorable in patients with ER-positive and HER2-negative T1a/bN0M0 breast cancer. Furthermore, adjuvant ET reduced the incidence of distant metastasis with minimal absolute risk difference. These findings support considering the omission of adjuvant ET, especially for patients with low-grade and no lymphatic invasion disease.

A risk-based subgroup analysis of the effect of adjuvant S-1 in estrogen receptor-positive, HER2-negative early breast cancer.

PURPOSE: The Phase III POTENT trial demonstrated the efficacy of adding S-1 to adjuvant endocrine therapy for estrogen receptor-positive, HER2-negative early breast cancer. We investigated the efficacy of S-1 across different recurrence risk subgroups. METHODS: This was a post-hoc exploratory analysis of the POTENT trial. Patients in the endocrine-therapy-only arm were divided into three groups based on composite risk values calculated from multiple prognostic factors. The effects of S-1 were estimated using the Cox model in each risk group. The treatment effects of S-1 in patients meeting the eligibility criteria of the monarchE trial were also estimated. RESULTS: A total of 1,897 patients were divided into three groups: group 1 (≤ lower quartile of the composite values) (N = 677), group 2 (interquartile range) (N = 767), and group 3 (> upper quartile) (N = 453). The addition of S-1 to endocrine therapy resulted in 49% (HR: 0.51, 95% CI: 0.33-0.78) and 29% (HR: 0.71, 95% CI 0.49-1.02) reductions in invasive disease-free survival (iDFS) events in groups 2 and 3, respectively. We could not identify any benefit from the addition of S-1 in group 1. The addition of S-1 showed an improvement in iDFS in patients with one to three positive nodes meeting the monarchE cohort 1 criteria (N = 290) (HR: 0.47, 95% CI: 0.29-0.74). CONCLUSIONS: The benefit of adding adjuvant S-1 was particularly marked in group 2. Further investigations are warranted to explore the optimal usage of adjuvant S-1.

Childbirth after perioperative systemic therapy in patients with breast cancer: a retrospective single institutional study in Japan.

BACKGROUND: The number of breast cancer patients of childbearing age has been increasing. Therefore, we investigated the characteristics and the childbearing status of the patients who received systemic therapy for breast cancer during their childbearing age to better understand the clinical impact of childbirth. METHODS: Female patients with breast cancer younger than 40 years old who underwent surgery and received perioperative systemic therapy from 2007 to 2014 were included in this study. We compared the characteristics of patients with and without childbirth after treatment. RESULT: Of 590 patients, 26 delivered a child, and 355 did not bear a child during the median observation period of 8.1 years, whilst 209 had unknown childbirth data. The childbirth group had a lower mean age at surgery (32.2 vs. 35.1, P < 0.001). The proportion of patients who desired childbirth and used assisted reproductive technology was significantly higher in the childbirth group (65.4 vs. 23.9% and 45.2 vs. 5.1%, respectively, P < 0.001). The patients in the childbirth group had significantly less advanced disease (P = 0.002). In the childbirth group, the age at childbirth was significantly older in patients who received combined endocrine therapy and chemotherapy (40.8 years) than in patients who received either alone (endocrine therapy: 36.9 years, chemotherapy: 36.7 years, P = 0.04). However, survival was not different between those with and without childbirth. CONCLUSION: It is critical to recognize the desire for childbirth in patients with breast cancer who are receiving systemic therapy and to provide them with necessary fertility information before treatment to support their decision-making.

The ELEANOR noncoding RNA expression contributes to cancer dormancy and predicts late recurrence of estrogen receptor-positive breast cancer.

The recurrence risk of estrogen receptor (ER)-positive breast cancer remains high for a long period of time, unlike other types of cancer. Late recurrence reflects the ability of cancer cells to remain dormant through various events, including cancer stemness acquisition, but the detailed mechanism is unknown. ESR1 locus enhancing and activating noncoding RNAs (ELEANORS) are a cluster of nuclear noncoding RNAs originally identified in a recurrent breast cancer cell model. Although their functions as chromatin regulators in vitro are well characterized, their roles in vivo remain elusive. In this study, we evaluated the clinicopathologic features of ELEANORS, using primary and corresponding metastatic breast cancer tissues. The ELEANOR expression was restricted to ER-positive cases and well-correlated with the ER and progesterone receptor expression levels, especially at the metastatic sites. ELEANORS were detected in both primary and metastatic tumors (32% and 29%, respectively), and frequently in postmenopausal cases. Interestingly, after surgery, patients with ELEANOR-positive primary tumors showed increased relapse rates after, but not within, 5 years. Multivariate analysis showed that ELEANORS are an independent recurrence risk factor. Consistently, analyses with cell lines, mouse xenografts, and patient tissues revealed that ELEANORS upregulate a breast cancer stemness gene, CD44, and maintain the cancer stem cell population, which could facilitate tumor dormancy. Our findings highlight a new role of nuclear long noncoding RNAs and their clinical potential as predictive biomarkers and therapeutic targets for late recurrence of ER-positive breast cancer.

Pertuzumab retreatment for HER2-positive advanced breast cancer: A randomized, open-label phase III study (PRECIOUS).

No standard options existed for human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer that progresses after second-line trastuzumab emtansine therapy before 2020. The purpose of this study was to examine the efficacy of pertuzumab retreatment after disease progression following pertuzumab-containing therapy for HER2-positive locally advanced or metastatic breast cancer for the first time. This randomized, open-label, multicenter phase III trial was undertaken in 93 sites in Japan. Eligible patients with HER2-positive breast cancer who had received pertuzumab, trastuzumab, and chemotherapy as first- and/or second-line therapy were randomly assigned (1:1) to: (i) pertuzumab, trastuzumab, and physician's choice chemotherapy (PTC), or (ii) trastuzumab and physician's choice chemotherapy (TC). The primary end-point was investigator-assessed progression-free survival (PFS). Between August 1, 2015 and December 31, 2018, 219 patients were randomized to PTC (n = 110) or TC (n = 109). Median follow-up was 14.2 months (interquartile range, 9.0-22.2), and median PFS was 5.3 months (95% confidence interval [CI], 4.0-6.6) with PTC and 4.2 months (95% CI, 3.2-4.8) with TC (stratified hazard ratio 0.76 [95% CI upper limit 0.967]; p = 0.022). Progression-free survival was improved by adding pertuzumab in all prespecified subgroups. The PTC arm showed a trend towards better overall survival and duration of response, but similar objective response and health-related quality of life. The incidence of treatment-related adverse events was similar between groups except for diarrhea. Pertuzumab retreatment contributes to disease control for HER2-positive locally advanced or metastatic breast cancer previously treated with pertuzumab-containing regimens.

Serial circulating tumor DNA monitoring of CDK4/6 inhibitors response in metastatic breast cancer.

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) significantly improve progression-free survival and have become the standard therapy for estrogen receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer patients. Treatment surveillance by radiological imaging has some limitations in detection and repeated biopsy genomic profiling is not clinically feasible. Serial circulating tumor DNA (ctDNA) analysis may provide insights into treatment response. Here we performed serial ctDNA analysis (n = 178) on 33 patients. Serial ctDNA analysis identified disease progression with sensitivity of 75% and specificity of 92%. In eight of 12 patients (61%) responding to CDK4/6i who eventually developed progressive disease, serial sampling every 3 or 6 months captured the initial rise of ctDNA with an average lead time of 3 months. In three of eight patients that did not respond to CDK4/6i (progressive disease at first radiological assessment, 3 months), biweekly sequencing within the first cycle of CDK4/6i treatment (1 month) detected sustained ctDNA levels (≥0.2% variant allele frequency), with lead time of 2 months. Serial ctDNA analysis tracked RECIST response, including clinically challenging scenarios (bone metastases or small-sized target lesions), as well as detecting acquired genetic alterations linked to CDK4/6i resistance in the G1 to S transition phase. Circulating tumor DNA analysis was more sensitive than carcinoembryonic antigen or cancer antigen 15-3 serum tumor markers at monitoring tumor response to CDK4/6i treatment. Our findings indicated the possible clinical utility of serial ctDNA analysis for earlier progressive disease detection and real-time monitoring of CDK4/6i response.

Clinical significance of the neutrophil-to-lymphocyte ratio in oligometastatic breast cancer.

PURPOSE: This study investigated the clinical impact of pretreatment neutrophil-to-lymphocyte ratio (NLR) on survival in patients with oligometastatic breast cancer. PATIENTS AND METHODS: We collected data from 397 patients who underwent primary breast surgery from 2004 to 2015 and developed recurrence during the follow-up. We reviewed the images and clinical information and defined OMD according to the European Society for Medical Oncology advanced breast cancer guidelines. The NLR was calculated using pretreatment data of primary breast cancer. The cutoff value of the NLR was determined by receiver operating characteristic curve with Youden Index. RESULTS: Among 397 patients, 131 had OMD at recurrence. The low-NLR group included patients of significantly older age at primary cancer than those in the high-NLR group. A low NLR indicated a better overall survival (p = 0.023) after adjusting for relevant factors, including estrogen receptor status, surgical resection of metastatic disease, metastatic organ number, disease-free interval, and liver metastasis than did the high-NLR group. We developed prognostic models for OMD using six independent prognostic factors, including the NLR. The number of factors was associated with overall survival; patients with all six favorable factors showed a good overall survival of 90.9% at 8 years and those with four or more factors showed 70.4%. CONCLUSIONS: The NLR was an independent prognostic factor for overall survival in OMD. The number of favorable prognostic factors was associated with overall survival. A prognostic model, including the NLR, will help identify patients with a favorable prognosis.

Immune microenvironment, homologous recombination deficiency, and therapeutic response to neoadjuvant chemotherapy in triple-negative breast cancer: Japan Breast Cancer Research Group (JBCRG)22 TR.

BACKGROUND: Triple-negative breast cancer (TNBC) is a biologically diverse disease, with characteristics such as homologous recombination deficiency (HRD), gene mutation, and immune reactions. Japan Breast Cancer Research Group 22 is a multicenter trial examining TNBC's response to neoadjuvant chemotherapy (NAC) according to the HRD status. This translational research investigated the clinical significance of the immune microenvironment of TNBC in association with HRD, tumor BRCA1/2 (tBRCA1/2) mutation, and response to NAC. METHODS: Patients aged below 65 years with high HRD or germline BRCA1/2 (gBRCA1/2) mutation randomly received paclitaxel + carboplatin (group A1) or eribulin + carboplatin (A2), followed by anthracycline. Patients aged below 65 years with low HRD or those aged 65 years or older without gBRCA1/2 mutation randomly received eribulin + cyclophosphamide (B1) or eribulin + capecitabine (B2); nonresponders to the first four cycles of the therapy received anthracycline. A pathological complete response (pCR) was defined as the absence of residual cancer cells in the tissues. Pretreatment biopsy specimens were stained by multiplexed fluorescent immunohistochemistry using antibodies against CD3, CD4, CD8, Foxp3, CD204, and pan-cytokeratin. Immune cells with specific phenotypes were counted per mm2 in cancer cell nests (intratumor) and stromal regions. The immune cell densities were compared with clinicopathological and genetic factors including tumor response. RESULTS: This study analyzed 66 samples. T1 tumors had a significantly higher density of intratumoral CD8+ T cells than T2 or larger tumors. The tBRCA1/2 mutation or HRD status was not associated with the density of any immune cell. The density of intratumoral and stromal CD4+ T cells was higher in patients showing pCR than in those without pCR. In a multivariate analysis, intratumoral and stromal CD4+ T cell density significantly predicted pCR independent of age, chemotherapy dose, HRD status, and treatment groups (P = 0.009 and 0.0057, respectively). In a subgroup analysis, the predictive value of intratumoral and stromal CD4+ T cell density persisted in the platinum-containing chemotherapy group (A1+A2) but not in the non-platinum-containing group (B1+B2). CONCLUSIONS: Intratumoral and stromal CD4+ T cell density was an independent predictor of pCR in patients with TNBC. A larger study is warranted to confirm the results. TRIAL REGISTRATION: UMIN000023162.

HER2 expression, copy number variation and survival outcomes in HER2-low non-metastatic breast cancer: an international multicentre cohort study and TCGA-METABRIC analysis.

BACKGROUND: HER2-low breast cancer (BC) is currently an area of active interest. This study evaluated the impact of low expression of HER2 on survival outcomes in HER2-negative non-metastatic breast cancer (BC). METHODS: Patients with HER2-negative non-metastatic BC from 6 centres within the Asian Breast Cancer Cooperative Group (ABCCG) (n = 28,280) were analysed. HER2-low was defined as immunohistochemistry (IHC) 1+ or 2+ and in situ hybridization non-amplified (ISH-) and HER2-zero as IHC 0. Relapse-free survival (RFS) and overall survival (OS) by hormone receptor status and HER2 IHC 0, 1+ and 2+ ISH- status were the main outcomes. A combined TCGA-BRCA and METABRIC cohort (n = 1967) was also analysed to explore the association between HER2 expression, ERBB2 copy number variation (CNV) status and RFS. RESULTS: ABCCG cohort median follow-up was 6.6 years; there were 12,260 (43.4%) HER2-low BC and 16,020 (56.6%) HER2-zero BC. The outcomes were better in HER2-low BC than in HER2-zero BC (RFS: centre-adjusted hazard ratio (HR) 0.88, 95% CI 0.82-0.93, P < 0.001; OS: centre-adjusted HR 0.82, 95% CI 0.76-0.89, P < 0.001). On multivariable analysis, HER2-low status was prognostic (RFS: HR 0.90, 95% CI 0.85-0.96, P = 0.002; OS: HR 0.86, 95% CI 0.79-0.93, P < 0.001). These differences remained significant in hormone receptor-positive tumours and for OS in hormone receptor-negative tumours. Superior outcomes were observed for HER2 IHC1+ BC versus HER2-zero BC (RFS: HR 0.89, 95% CI 0.83-0.96, P = 0.001; OS: HR 0.85, 95% CI 0.78-0.93, P = 0.001). No significant differences were seen between HER2 IHC2+ ISH- and HER2-zero BCs. In the TCGA-BRCA and METABRIC cohorts, ERBB2 CNV status was an independent RFS prognostic factor (neutral versus non-neutral HR 0.71, 95% CI 0.59-0.86, P < 0.001); no differences in RFS by ERBB2 mRNA expression levels were found. CONCLUSIONS: HER2-low BC had a superior prognosis compared to HER2-zero BC in the non-metastatic setting, though absolute differences were modest and driven by HER2 IHC 1+ BC. ERBB2 CNV merits further investigation in HER2-negative BC.

Trastuzumab and fulvestrant combination therapy for women with advanced breast cancer positive for hormone receptor and human epidermal growth factor receptor 2: a retrospective single-center study.

BACKGROUND: Trastuzumab and fulvestrant combination therapy is one of the treatment options for patients with hormone receptor- and human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer; however, there are limited studies evaluating the efficacy of this combination therapy. METHODS: We retrospectively reviewed the data of women with hormone receptor- and HER2-positive metastatic breast cancer who received trastuzumab and fulvestrant combination therapy between August 1997 and August 2020 at the Cancer Institute Hospital. The primary endpoint of this study was progression-free survival, and the secondary endpoints were response rate, overall survival and safety. RESULTS: We reviewed the data of 1612 patients with recurrent or metastatic breast cancer, of which 118 patients were diagnosed with hormone receptor- and HER2-positive breast cancer. Of these, 28 patients who received trastuzumab and fulvestrant combination therapy were eligible for this study. The median treatment line for advanced breast cancer was 6 (range, 1-14), the median progression-free survival was 6.4 months (95% confidence interval [CI], 3.46-8.17), and the median overall survival was 35.3 months (95% CI, 20.0-46.7). Of the 28 patients, partial response was observed in 1 (4%), stable disease in 17 (61%), and progressive disease in 10 (36%) patients. The disease control rate was 64%. Adverse events of grade ≥ 3 were not observed. CONCLUSIONS: Trastuzumab and fulvestrant combination therapy showed moderate clinical efficacy and no severe toxicity after standard anti-HER2 treatment, which is a reasonable treatment option for patients with hormone receptor- and HER2-positive metastatic breast cancer. These data contribute to understanding the efficacy of trastuzumab and fulvestrant combination therapy as control data for further development of anti-HER2 agents plus hormone therapy.