A Prospective Study of Sentinel Node Biopsy Omission in Women Age ≥ 65 Years with ER+ Breast Cancer.

BACKGROUND: National guidelines recommend omitting SNB in older patients with favorable invasive breast cancer. However, there is a lack of prospective data specifically addressing this issue. This study evaluates recurrence and survival in estrogen receptor-positive/Her2- (ER+) breast cancer patients, aged ≥ 65 years who have breast-conserving surgery (BCS) without SNB. METHODS: This is a prospective, observational study at a single institution where 125 patients aged ≥ 65 years with clinical T1-2N0 ER+ invasive breast cancer undergoing BCS were enrolled. Patients were treated with BCS without SNB. Primary outcome measure was axillary recurrence. Secondary outcome measures include recurrence-free survival (RFS), disease-free survival (DFS), breast cancer-specific survival (BCSS), and overall survival (OS). RESULTS: From January 2016 to July 2022, 125 patients were enrolled with median follow-up of 36.7 months [95% confidence interval (CI) 35.0-38.0]. Median age was 77.0 years (range 65-93). Median tumor size was 1 cm (range 0.1-5.0). Most tumors were ductal (95/124, 77.0%), intermediate grade (60/116, 51.7%), and PR-positive (117/123, 91.7%). Radiation therapy was performed in 37 of 125 (29.6%). Only 60 of 125 (48.0%) who were recommended hormonal therapy were compliant at 2 years. Chemotherapy was administered to six of 125 (4.8%) patients. There were two of 125 (1.6%) axillary recurrences. Estimated 3-years rates of regional RFS, DFS, and OS were 98.2%, 91.2%, and 94.8%, respectively. Univariate Cox regression identified hormonal therapy noncompliance to be significantly associated with recurrence (p = 0.02). CONCLUSIONS: Axillary recurrence rates were extremely low in this cohort. These results provide prospective data to support omission of SNB in this patient population TRIAL REGISTRATION: ClinicalTrials.gov ID NCT02564848.

Reciprocal regulation of forkhead box C1 and L1 cell adhesion molecule contributes to triple-negative breast cancer progression.

PURPOSE: The potential of targeting forkhead box C1 (FOXC1) as a therapeutic approach for triple-negative breast cancer (TNBC) is promising. However, a comprehensive understanding of FOXC1 regulation, particularly upstream factors, remains elusive. Expression of the L1 cell adhesion molecule (L1CAM), a transmembrane glycoprotein associated with brain metastasis, was observed to be positively associated with FOXC1 transcripts. Thus, this study aims to investigate their relationship in TNBC progression. METHODS: Publicly available FOXC1 and L1CAM transcriptomic data were obtained, and their corresponding proteins were analyzed in four TNBC cell lines. In BT549 cells, FOXC1 and L1CAM were individually silenced, while L1CAM was overexpressed in BT549-shFOXC1, MDA-MB-231, and HCC1937 cells. CCK-8, transwell, and wound healing assays were performed in these cell lines, and immunohistochemical staining was conducted in tumor samples. RESULTS: A positive correlation between L1CAM and FOXC1 transcripts was observed in publicly available datasets. In BT549 cells, knockdown of FOXC1 led to reduced L1CAM expression at both the transcriptional and protein levels, and conversely, silencing of L1CAM decreased FOXC1 protein levels, but interestingly, FOXC1 transcripts remained largely unaffected. Overexpressing L1CAM resulted in increased FOXC1 protein expression without significant changes in FOXC1 mRNA levels. This trend was also observed in BT549-shFOXC1, MDA-MB-231-L1CAM, and HCC1937-L1CAM cells. Notably, alterations in FOXC1 or L1CAM levels corresponded to changes in cell proliferation, migration, and invasion capacities. Furthermore, a positive correlation between L1CAM and FOXC1 protein expression was detected in human TNBC tumors. CONCLUSION: FOXC1 and L1CAM exhibit co-regulation at the protein level, with FOXC1 regulating at the transcriptional level and L1CAM regulating at the post-transcriptional level, and together they positively influence cell proliferation, migration, and invasion in TNBC.

A Practical Approach for Targeting Structural Variants Genome-wide in Plasma Cell-free DNA.

Plasma cell-free DNA (cfDNA) is a promising source of gene mutations for cancer detection by liquid biopsy. However, no current tests interrogate chromosomal structural variants (SVs) genome-wide. Here, we report a simple molecular and sequencing workflow called Genome-wide Analysis of Palindrome Formation (GAPF-seq) to probe DNA palindromes, a type of SV that often demarcates gene amplification. With low-throughput next-generation sequencing and automated machine learning, tumor DNA showed skewed chromosomal distributions of high-coverage 1-kb bins (HCBs), which differentiated 39 breast tumors from matched normal DNA with an average Area Under the Curve (AUC) of 0.9819. A proof-of-concept liquid biopsy study using cfDNA from prostate cancer patients and healthy individuals yielded an average AUC of 0.965. HCBs on the X chromosome emerged as a determinant feature and were associated with androgen receptor gene amplification. As a novel agnostic liquid biopsy approach, GAPF-seq could fill the technological gap offering unique cancer-specific SV profiles.

Protein-encapsulated doxorubicin reduces cardiotoxicity in hiPSC-cardiomyocytes and cardiac spheroids while maintaining anticancer efficacy.

The chemotherapeutic doxorubicin (DOX) detrimentally impacts the heart during cancer treatment. This necessitates development of non-cardiotoxic delivery systems that retain DOX anticancer efficacy. We used human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), endothelial cells (hiPSC-ECs), cardiac fibroblasts (hiPSC-CFs), multi-lineage cardiac spheroids (hiPSC-CSs), patient-specific hiPSCs, and multiple human cancer cell lines to compare the anticancer efficacy and reduced cardiotoxicity of single protein encapsulated DOX (SPEDOX-6), to standard unformulated (UF) DOX. Cell viability assays and immunostaining in human cancer cells, hiPSC-ECs, and hiPSC-CFs revealed robust uptake of SPEDOX-6 and efficacy in killing these proliferative cell types. In contrast, hiPSC-CMs and hiPSC-CSs exhibited substantially lower cytotoxicity during SPEDOX-6 treatment compared with UF DOX. SPEDOX-6-treated hiPSC-CMs and hiPSC-CSs maintained their functionality, as indicated by sarcomere contractility assessment, calcium imaging, multielectrode arrays, and RNA sequencing. This study demonstrates the potential of SPEDOX-6 to alleviate cardiotoxic side effects associated with UF DOX, while maintaining its anticancer potency.

Human Breast Organoid Models for Lactation Research.

The human mammary gland is the major organ involved in lactation. In the mammary gland, alveoli secrete milk and myoepithelial cells contract to propel the milk through branched structures called ducts and eventually to the nipple. It is through this process of lactation that infants receive milk, which is essential for proper infant growth and development. The lactation process is comprised of sophisticated interactive networks at the cellular level that are not well understood. Whereas the majority of published mammary gland lactation studies have relied on mouse mammary glands, recent advancements in techniques to study mammary glands enable in vitro reproduction of lactation using human-representative frameworks. Currently, the 3D breast organoid is the state-of-the-art model in human mammary gland research, utilizing induced pluripotent stem cells (iPSCs) or processed patient-derived breast tissues embedded in a special matrix that are then able to grow into complex structures that recapitulate aspects of native human breast tissue. Gaining comprehensive biological insight into the process of lactation through these breast tissue-mimetic 3D models is essential for further studies on lactation-associated human mammary gland diseases, human milk composition, and potential solutions to challenges in maternal milk accessibility. In this short review, the benefits and potential utility of 3D breast organoids in understanding the underlying science of lactation and advancing further human mammary gland studies are discussed.

De-Implementation of Low-Value Care for Women 70 Years of Age or Older with Low-Risk Breast Cancer During the COVID-19 Pandemic.

BACKGROUND: Older women with early-stage estrogen receptor-positive (ER+) invasive breast cancer (IBC) are at risk for overtreatment. Guidelines allow for sentinel lymph node biopsy (SLNB) and radiotherapy omission after breast-conserving surgery (BCS) for women 70 years of age or older with T1, clinical node negativity (cN0), and ER+ IBC. The study objective was to evaluate radiotherapy and SLNB de-implementation in older women with low-risk IBC after the resource limitations of the COVID-19 pandemic. METHODS: An institutional database was analyzed to identify women 70 years of age or older who received BCS for IBC from 2012 to 2022. The patients were divided into two cohorts: (1) patients with low-risk IBC (pT1, cN0, and ER+/HER2-) who were eligible for radiotherapy and SLNB omission and (2) patients with high-risk IBC (pT2-T4, cN+, ER-, or HER2+) who were ineligible for therapy omission. Clinicopathologic variables in both cohorts were analyzed. RESULTS: The study enrolled 881 patients. For the patients with low-risk IBC, the annual rates of radiotherapy were stable from 2012 to 2019. However, radiotherapy utilization decreased significantly from 2020 to 2022 (58% in 2012 vs 36% in 2022; p = 0.04). In contrast, radiotherapy usage among the patients with high-risk IBC was stable from 2012 to 2022 (79% in 2012 vs 79% in 2022; p = 0.95). Among the patients with low-risk IBC, SLNB rates decreased from 86% in 2012 to 56% in 2022, but this trend predated those in 2020. The factors significantly associated with SLNB and receipt of radiotherapy among the patients with low-risk IBC were younger age, larger tumors, grade 3 disease, and involved nodal status (p < 0.01). CONCLUSION: This study demonstrated appropriate and sustained de-escalation of radiotherapy in older women with low-risk IBC after the COVID-19 pandemic.

Genome-Wide Analysis of Palindrome Formation with Next-Generation Sequencing (GAPF-Seq) and a Bioinformatics Pipeline for Assessing De Novo Palindromes in Cancer Genomes.

DNA palindromes are a type of chromosomal aberration that appears frequently during tumorigenesis. They are characterized by sequences of nucleotides that are identical to their reverse complements and often arise due to illegitimate repair of DNA double-strand breaks, fusion of telomeres, or stalled replication forks, all of which are common adverse early events in cancer. Here, we describe the protocol for enriching palindromes from genomic DNA sources with low-input DNA amounts and detail a bioinformatics tool for assessing the enrichment and location of de novo palindrome formation from low-coverage whole-genome sequencing data.

Local Recurrence After Breast-Conserving Therapy in Patients With Multiple Ipsilateral Breast Cancer: Results From ACOSOG Z11102 (Alliance).

PURPOSE: Breast-conserving therapy (BCT) is the preferred treatment for unifocal breast cancer (BC). The oncologic safety of BCT for multiple ipsilateral breast cancer (MIBC) has not been demonstrated in a prospective study. ACOSOG Z11102 (Alliance) is a phase II, single-arm, prospective trial designed to evaluate oncologic outcomes in patients undergoing BCT for MIBC. PATIENTS AND METHODS: Women age 40 years and older with two to three foci of biopsy-proven cN0-1 BC were eligible. Patients underwent lumpectomies with negative margins followed by whole breast radiation with boost to all lumpectomy beds. The primary end point was cumulative incidence of local recurrence (LR) at 5 years with an a priori rate of clinical acceptability of <8%. RESULTS: Among 270 women enrolled between November 2012 and August 2016, there were 204 eligible patients who underwent protocol-directed BCT. The median age was 61 years (range, 40-87 years). At a median follow-up of 66.4 months (range, 1.3-90.6 months), six patients developed LR for an estimated 5-year cumulative incidence of LR of 3.1% (95% CI, 1.3 to 6.4). Patient age, number of sites of preoperative biopsy-proven BC, estrogen receptor status and human epidermal growth factor receptor 2 status, and pathologic T and N categories were not associated with LR risk. Exploratory analysis showed that the 5-year LR rate in patients without preoperative magnetic resonance imaging (MRI; n = 15) was 22.6% compared with 1.7% in patients with a preoperative MRI (n = 189; P = .002). CONCLUSION: The Z11102 clinical trial demonstrates that breast-conserving surgery with adjuvant radiation that includes lumpectomy site boosts yields an acceptably low 5-year LR rate for MIBC. This evidence supports BCT as a reasonable surgical option for women with two to three ipsilateral foci, particularly among patients with disease evaluated with preoperative breast MRI.

The molecular consequences of androgen activity in the human breast.

Estrogen and progesterone have been extensively studied in the mammary gland, but the molecular effects of androgen remain largely unexplored. Transgender men are recorded as female at birth but identify as male and may undergo gender-affirming androgen therapy to align their physical characteristics and gender identity. Here we perform single-cell-resolution transcriptome, chromatin, and spatial profiling of breast tissues from transgender men following androgen therapy. We find canonical androgen receptor gene targets are upregulated in cells expressing the androgen receptor and that paracrine signaling likely drives sex-relevant androgenic effects in other cell types. We also observe involution of the epithelium and a spatial reconfiguration of immune, fibroblast, and vascular cells, and identify a gene regulatory network associated with androgen-induced fat loss. This work elucidates the molecular consequences of androgen activity in the human breast at single-cell resolution.

Novel Prognostic Staging System for Patients With De Novo Metastatic Breast Cancer.

PURPOSE: Given the heterogeneity and improvement in outcomes for metastatic breast cancer (MBC), we developed a staging system that refines prognostic estimates for patients with metastatic cancer at the time of initial diagnosis, de novo MBC (dnMBC), on the basis of survival outcomes and disease-related variables. METHODS: Patients with dnMBC (2010-2016) were selected from the National Cancer Database (NCDB). Recursive partitioning analysis (RPA) was used to group patients with similar overall survival (OS) on the basis of clinical T category, grade, estrogen receptor (ER), progesterone receptor, human epidermal growth factor receptor 2, histology, organ system site of metastases (bone-only, brain-only, visceral), and number of organ systems involved. Three-year OS rates were used to assign a final stage: IVA: >70%, IVB: 50%-70%, IVC: 25 to <50%, and IVD: <25%. Bootstrapping was applied with 1,000 iterations, and final stage assignments were made based on the most commonly occurring assignment. Unadjusted OS was estimated. Validation analyses were conducted using SEER and NCDB. RESULTS: At a median follow-up of 52.9 months, the median OS of the original cohort (N = 42,467) was 35.4 months (95% CI, 34.8 to 35.9). RPA stratified patients into 53 groups with 3-year OS rates ranging from 73.5% to 5.7%; these groups were amalgamated into four stage groups: 3-year OS, A = 73.2%, B = 61.9%, C = 40.1%, and D = 17% (log-rank P < .001). After bootstrapping, the survival outcomes for the four stages remained significantly different (log-rank P < .001). This staging system was then validated using SEER data (N = 20,469) and a separate cohort from the NCDB (N = 7,645) (both log-rank P < .001). CONCLUSION: Our findings regarding the heterogeneity in outcomes for patients with dnMBC could guide future revisions of the current American Joint Committee on Cancer staging guidelines for patients with newly diagnosed stage IV disease. Our findings should be independently confirmed.

Invasive Lobular Carcinoma-Correlation Between Imaging and Final Pathology: Is MRI Better?

BACKGROUND: Invasive lobular carcinoma (ILC) is associated with high re-excision rates following breast-conserving surgery (BCS). The correlation between lesion size on different imaging modalities and final tumor size has not been well characterized. METHODS: A prospective database of patients with stage I-III breast cancer undergoing BCS between 2006 and 2016 was reviewed. Pearson correlation analysis was used to correlate tumor size on breast imaging to final pathology. RESULTS: Of these, 111 patients with ILC were identified. Mean lesion size was 1.93 cm for MMG, 1.61 cm for US, and 2.51 cm for MRI. Mean tumor size on surgical excision was 2.64 cm. The correlation coefficient between pathology and the different imaging modalities were as follows: MMG .17, US 0.37, and MRI .58. Actual tumor size was underestimated by 1 cm in 27.1% of MMGs, 50% of USs, and in 13.3% of MRIs. 38 patients (34.2%) underwent re-excision. No differences in re-excision rates were noted in patients with and without MRI, 30.3% vs 40.0%, respectively (P = .31). CONCLUSION: While MRI provides a better estimate of tumor size than MMG and US, the size of the tumor on imaging only weakly correlated with pathology. The use of MRI does not decrease re-excision rates.

Single-cell profile of tumor and immune cells in primary breast cancer, sentinel lymph node, and metastatic lymph node.

PURPOSE: Little is known about the host-tumor interaction in the lymph-node basin at a single cell level. This study examines single cell sequences in breast cancer nodal metastases of a patient with triple-negative breast cancer. METHODS: The primary breast tumor, sentinel lymph node, an adjacent lymph node with metastatic involvement and a clinically normal-appearing lymph node were collected during surgery. Single-cell sequencing was performed on all four specimens. RESULTS: 14,016 cells were clustered into 6 cell subpopulations. Cancer cells demonstrated the molecular characteristics of TNBC basal B subtype and highly expressed genes in the MAPK signaling cascade. Tumor-associated macrophages regulated antigen processing and presentation and other immune-related pathways to promote tumor invasion. CD8 + and CD4 + T lymphocytes concentrated more in sentinel lymph node and mainly stratified into two transcriptional states. The immune-cell amount variation among primary tumor, sentinel and normal lymph nodes showed a similar tendency between the sc-RNA-seq profile of TNBC samples and a previous reported bulk RNA-seq profile of a breast cancer cohort, including all four breast cancer subtype samples. DISCUSSION: Single-cell sequencing analysis suggested that the sentinel lymph node was the initial meeting site of tumor infiltration and immune response, where partial T lymphocytes perform anti-tumor activity, while other T cells exhibit an exhausted state. We proposed a molecular explanation to the well-established clinical principle that the 5-year and 10-year survival outcomes were noninferior between SLND and ALND.

Breast cancer liver metastasis: Pathogenesis and clinical implications.

Breast cancer is the most common malignant disease in female patients worldwide and can spread to almost every place in the human body, most frequently metastasizing to lymph nodes, bones, lungs, liver and brain. The liver is a common metastatic location for solid cancers as a whole, and it is also the third most common metastatic site for breast cancer. Breast cancer liver metastasis (BCLM) is a complex process. Although the hepatic microenvironment and liver sinusoidal structure are crucial factors for the initial arrest of breast cancer and progression within the liver, the biological basis of BCLM remains to be elucidated. Importantly, further understanding of the interaction between breast cancer cells and hepatic microenvironment in the liver metastasis of breast cancer will suggest ways for the development of effective therapy and prevention strategies for BCLM. In this review, we provide an overview of the recent advances in the understanding of the molecular mechanisms of the hepatic microenvironment in BCLM formation and discuss current systemic therapies for treating patients with BCLM as well as potential therapeutic development based on the liver microenvironment-associated signaling proteins governing BCLM.

TOP1 inhibition induces bifurcated JNK/MYC signaling that dictates cancer cell sensitivity.

Rationale: Triple-negative breast cancer (TNBC) does not respond to anti-estrogen and anti-HER2 therapies and is commonly treated by chemotherapy. TNBC has a high recurrence rate, particularly within the first 3 years. Thus, there is an urgent clinical need to develop more effective therapies for TNBC. Topoisomerase I (TOP1) inhibitors cause DNA damage, making these drugs desirable for TNBC treatment since DNA repair machinery is defective in this subtype of breast cancer. Among the main molecular subtypes of breast cancer, the TNBC cell lines exhibited the highest TOP1 inhibition sensitivity. However, clinically used TOP1 inhibitors, such as topotecan and irinotecan, have shown limited clinical applications and the reasons remain unclear. Understanding the mechanism of differential responses to TOP1 blockade and identifying the predictive markers for cancer cell sensitivity will help further TOP1-targeted therapy for TNBC treatment and improve the clinical use of TOP1 inhibitors. Methods: Viability assays were used to evaluate breast cancer cell sensitivity to topotecan and other TOP1 inhibitors as well as TOP2 inhibitors. An in vitro-derived topotecan-resistant TNBC cell model and TNBC xenograft models were employed to confirm cancer cell response to TOP1 blockade. RNA-seq was used to identify potential predictive markers for TNBC cell response to TOP1 blockade. Western blotting and qRT-PCR were performed to measure the protein levels and RNA expression. ATAC-seq and luciferase reporter assays were used to examine MYC transcriptional regulations. The effects of MYC and JNK in cancer cell response to TOP1 inhibition were validated via loss-of-function and gain-of-function experiments. Results: We observed two distinct and diverging cancer cell responses - sensitive versus resistant to TOP1 inhibition, which was confirmed by TNBC xenograft mouse models treated by topotecan. TNBC cells exhibited bifurcated temporal patterns of ATR pathway activation upon TOP1 inhibitor treatment. The sensitive TNBC cells showed an "up then down" dynamic pattern of ATR/Chk1 signaling, while the resistant TNBC cells exhibited a "persistently up" profile. On the contrary, opposite temporal patterns of induced expression of MYC, a key regulator and effector of DNA damage, were found in TNBC cells treated by TOP1 inhibitors. Mechanistically, we showed that TOP1-induced JNK signaling upregulated MYC expression. Furthermore, pharmacological inhibition of ATR reversed TNBC cell resistance to topotecan, whereas MYC knockdown and JNK inhibition reduced cancer cell sensitivity. Conclusions: Dynamic temporal profiles of induced ATR/Chk1 and JNK activation as well as MYC expression, may predict cancer cell response to TOP1 inhibitors. JNK activation-mediated constitutive elevation of MYC expression may represent a novel mechanism governing cancer cell sensitivity to TOP1-targeting therapy. Our results may provide implications for identifying TNBC patients who might benefit from the treatment with TOP1 inhibitors.

Expanding the Staging Criteria for T1-2N0 Hormone-Receptor Positive Breast Cancer Patients Enrolled in TAILORx.

BACKGROUND: The American Joint Committee on Cancer (AJCC) 8th edition pathologic prognostic staging (PPS) incorporates anatomic and biologic factors. The OncotypeDX Breast Recurrence Score (RS) was included based on the initial report of the TAILORx trial, with T1-2N0 hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer patients who had a RS < 11 staged as PPS 1A. This study examined whether the RS criteria for PPS 1A can be further expanded using patients enrolled in the TAILORx trial. METHODS: The TAILORx trial enrolled 10,273 HR+HER2- T1-2N0 patients. Those with incomplete HR-status/grade and T3 disease were excluded for analysis. The recurrence-free interval (RFI) was compared between the patients who did and those who did not fall into the current PPS 1A category using the Kaplan-Meier method. RESULTS: The study enrolled 9535 patients for analysis. The RS was < 11 in 16.1%, 11-17 in 35.9%, 18-25 in 32.4%, and > 25 in 15.6% of the patients. The majority (91.2%) of the patients (including all the T1N0 patients regardless of RS) were PPS 1A, and 8.8% were not-PPS 1A. The median follow-up time was 95 months. The PPS 1A patients had an 8-year RFI of 94.2%, which was similar to that of the patients with a RS of 11-17 who were not-PPS 1A (91.7%; p = 0.07) and better than that of the patients with a RS ≥ 18 who were not-PPS 1A (85.4% for a RS of 18-25, 76.0% for a RS > 25; both p < 0.01). Similar RFI trends were seen in patients who received endocrine therapy or chemotherapy followed by endocrine therapy. CONCLUSIONS: Patients with T1-2N0 HR+HER2- breast cancer and a RS < 18 have an RFI similar to that of patients staged as PPS 1A by the current AJCC staging system, regardless of treatment, suggesting that the criteria for PPS 1A can be expanded to include a RS < 18.