Targeting HER2 heterogeneity in breast cancer

Breaking barriers: CAR-NK cell therapy breakthroughs in female-related cancers

Cancer stands as a leading cause of mortality globally. The main female-related malignancies are breast cancer, with 2.3 million new cases annually, and ovarian cancer, with 300,000 new cases per year worldwide. The current treatments like surgery, chemotherapy, and radiation therapy have presumably had deficiencies in sustaining long-term anti-tumor responses. Cellular immunotherapy, also referred to as adoptive cell therapy, has shown encouraging advances by employing genetically modified immune cells in fighting cancer by engineering chimeric antigen receptors (CARs) mainly on T cells and natural killer (NK) cells. Studies in NK cell therapies involve unmodified NK cells and CAR-NK cell therapies, targeting cancer cells while limiting the destruction of normal cells. CAR-NK cells represent the next generation of therapeutic immune cells that have been shown to eliminate malignancies through CAR-dependent and CAR-independent mechanisms. They also represent possible candidates for "off-the-shelf" therapies due to their advantages, including the ability to target cancer cells independently of the major histocompatibility complex, reduced risk of alloreactivity, and fewer severe toxicities compared to CAR-T cells. To date, there have been no comprehensive review studies examining the therapeutic potential of CAR-NK cell therapy specifically for female-related malignancies, such as breast and ovarian cancers. This review offers a thorough exploration of CAR-NK cell therapy in relation to these cancers and their responses to treatment.

Neratinib and metformin: A novel therapeutic approach against HER2-Positive Breast Cancer

BACKGROUND

HER2-positive breast cancer (BC) is highly aggressive with a poor prognosis. It is driven by HER2 oncoprotein activation/crosstalk with other receptors like EGFR/(HER1), HER3, and HER4, in addition to IGF-1R, making these receptors ideal therapeutic targets as they are expressed/overexpressed in this subtype. We postulated that targeting HER2 and IGF-1R together is a promising therapy for HER2-positive BC. Thus, we explored the outcome of a novel combination treatment using neratinib, a pan-HER inhibitor, and metformin, an IGF-1R inhibitor, on HER2-positive BC cells.

METHODS

In this investigation, we used cellular and molecular biology techniques in addition to an angiogenesis model and tissue microarray analysis.

RESULTS

Our data revealed that this combination therapy significantly reduced cell viability compared to individual treatments and exhibited a synergistic effect in HER2-positive BC cells. Moreover, the combination disrupted cell cycle progression and inhibited colony formation, and invasion of HER2-positive BC cells; this is accompanied by the deregulation of HER1-3 and IGF-1R expression patterns, in addition to Caspase-3, BCL2, Fascin, and Vimentin. Moreover, key regulator molecular pathways, including, ERK1/2, AKT, p38 MAPK, and mTOR, were significantly downregulated upon treatment with neratinib and metformin combination. Additionally, our data pointed out that neratinib and metformin combination inhibited angiogenesis, in-ovo, an important biological event in cancer progression. Finally, using a cohort of 55 HER2-positive BC samples, we revealed that HER2 and IGF-1R are co-expressed in most of the cases.

CONCLUSIONS

These findings suggest that neratinib and metformin combination can present a promising strategy for targeting multiple pathways in HER2-positive BC.

MRI-based habitat analysis for Intratumoral heterogeneity quantification combined with deep learning for HER2 status prediction in breast cancer

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is a crucial determinant of breast cancer prognosis and treatment options. The study aimed to establish an MRI-based habitat model to quantify intratumoral heterogeneity (ITH) and evaluate its potential in predicting HER2 expression status.

METHODS

Data from 340 patients with pathologically confirmed invasive breast cancer were retrospectively analyzed. Two tasks were designed for this study: Task 1 distinguished between HER2-positive and HER2-negative breast cancer. Task 2 distinguished between HER2-low and HER2-zero breast cancer. We developed the ITH, deep learning (DL), and radiomics signatures based on the features extracted from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Clinical independent predictors were determined by multivariable logistic regression. Finally, a combined model was constructed by integrating the clinical independent predictors, ITH signature, and DL signature. The area under the receiver operating characteristic curve (AUC) served as the standard for assessing the performance of models.

RESULTS

In task 1, the ITH signature performed well in the training set (AUC = 0.855) and the validation set (AUC = 0.842). In task 2, the AUCs of the ITH signature were 0.844 and 0.840, respectively, which still showed good prediction performance. In the validation sets of both tasks, the combined model exhibited the best prediction performance, with AUCs of 0.912 and 0.917 respectively, making it the optimal model.

CONCLUSION

A combined model integrating clinical independent predictors, ITH signature, and DL signature can predict HER2 expression status preoperatively and noninvasively.

Redefining Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer in the Era of Novel Antibody-Drug Conjugates

The advent of next-generation antibody-drug conjugates (ADCs), particularly trastuzumab deruxtecan (T-DXd), has transformed our understanding of human epidermal growth factor receptor 2 (HER2) targetability for breast cancer (BC) treatment. Historically categorized as HER2-positive or HER2-negative on the basis of trastuzumab eligibility, this classification has evolved significantly over the past 5 years. The DESTINY-Breast04 trial marked the entry of anti-HER2 therapies for patients with HER2-low BC, while DESTINY-Breast06 demonstrated the potential for earlier and broader use of T-DXd. The latter trial revealed that even minimal HER2 expression in tumors previously classified as HER2-0 might be clinically relevant and targetable with T-DXd. This has led to further refinement of HER2 classification, introducing the concepts of HER2-ultralow (HER2-0 with staining) and HER2-null BC (HER2-0 without staining). With these findings, most patients with metastatic BC are currently considered eligible for T-DXd. Accurately identifying candidates for these therapies has highlighted the limitations of current HER2 diagnostic practices, on the basis of immunohistochemistry (IHC)/in situ hybridization assessment. IHC assay, optimized to detect high levels of HER2 protein, faces limitations in discriminating finer variations at the lower end of the HER2 expression spectrum. This is further complicated by the heterogeneity of HER2 expression. To overcome these barriers, new approaches may be required. Quantitative methods for HER2 membrane assessment, genomic and transcriptomic evaluations of HER2, and the integration of artificial intelligence into tissue analysis hold promise and are currently under investigation. Additionally, noninvasive strategies, such as analysis of circulating tumor DNA or circulating tumor cells, may enable real-time HER2 status assessment and better patient selection for ADC. However, these techniques require rigorous validation to ensure their clinical utility. This evolving landscape underscores the need for improvement of diagnostic approaches to support the expanding role of ADCs in BC treatment.

Exploring Novel Therapeutic Targets in Breast Cancer via Comprehensive Omics Profiling and Experimental Verification

BACKGROUND

Breast cancer is the leading cause of cancer-related deaths among women worldwide. Deciphering the molecular mechanisms of breast cancer is crucial for developing targeted therapeutic approaches.

METHODS

This study analyzed gene expression profiles from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) in breast cancer. Mendelian randomization (MR) analysis was then employed using publicly available eQTL databases to evaluate potential causal relationships between these DEGs and breast cancer. Enrichment analyses were further conducted to explore their functional significance. Furthermore, external validation of co-expressed genes was conducted using The Cancer Genome Atlas (TCGA) database. In vitro functional assays and drug sensitivity analyses were performed on selected target genes to validate their roles in breast cancer pathogenesis and treatment.

RESULTS

A total of 1052 upregulated and 1380 downregulated genes were identified in breast cancer. Additionally, MR analysis revealed 12 significant co-expressed genes potentially contributing to breast cancer pathogenesis. These genes were primarily enriched in lipid metabolism and immune responses via regulating microRNA functions and AMPK signaling. Validation through the TCGA database confirmed differential expression of these genes in breast cancer tissues. Strikingly, functional assays of the less-reported genes DNASE2 and ATOH8 demonstrated their involvement in breast cancer pathogenesis through modulating proliferation, migration, and invasion of cancer cells. Notably, several commonly used clinical drugs for breast cancer management, such as 5-Fluorouracil, exhibited dramatically increased sensitivity to DNASE2 and ATOH8 expression.

CONCLUSIONS

Our study provides novel insights into the molecular basis of breast cancer pathogenesis and identifies promising therapeutic strategies for this condition.

Structural optimization and characterization of highly potent and selective STAT3 inhibitors for the treatment of triple negative breast cancer

Effective targeted treatments for triple-negative breast cancer (TNBC), which has the worst prognosis among various types of breast cancer, are lacking owing to its clinical heterogeneity and malignant nature. STAT3, a key transcription factor, regulates multiple physiological functions. Aberrant activation of STAT3 plays a pivotal role in the initiation and progression of TNBC and is closely associated with a poor prognosis. Therefore, targeting STAT3 is a promising potential therapeutic approach for TNBC. In this study, we further optimized the core structure of 6f, which our research group previously identified as a STAT3 inhibitor and treatment for osteosarcoma, to identify additional potential STAT3 inhibitors for TNBC treatment. We identified WR-S-462 as a high-binding affinity inhibitor of STAT3 that effectively suppresses its phosphorylation and biological functions in vitro. Notably, WR-S-462 significantly inhibits TNBC growth and metastasis in a dose-dependent manner, providing robust evidence for its potential as a clinical intervention for TNBC.

Digitally quantified area of residual tumor after neoadjuvant chemotherapy in HER2-positive breast cancer

BACKGROUND

The area of residual tumor (ART) is a quantitative method for assessing tumors after neoadjuvant chemotherapy (NAC). This study evaluated whether ART can identify a favorable prognosis group in patients with HER2-positive surgically resected breast cancer and residual tumors post-NAC.

METHODS

We retrospectively reviewed patients with HER2-positive who underwent surgery after NAC, including trastuzumab, from 2005 to 2022 at our institution. ART was assessed at the maximum cut surface of the residual primary tumor using digital pathology images. Receiver operating characteristic curve analysis determined ART-Low and ART-High cutoffs, excluding ART-0 (0 mm2) patients.

RESULTS

Of the 219 patients, 82 had ART greater than 0 mm2. The median follow-up was 90.2 months. The number of patients in the ART-0, ART-Low (0 < ART ≤ 4.0 mm2), and ART-High (> 4.0 mm2) groups were 137, 39, and 43, respectively. The ART-Low group showed significantly shorter event-free survival compared to the ART-0 group (HR 3.50, 95% CI 1.52-8.06), and the ART-High group also tended toward poorer prognosis (HR 2.31, 95% CI 0.89-5.97). However, there was no significant difference in prognosis between the ART-Low and ART-High groups.

CONCLUSIONS

The current study suggests that even minimal residual tumor cells in the primary site can significantly impact on prognosis in HER2-positive early breast cancer.

Comprehensive analysis of HER2 Low Breast Cancer Response to Neoadjuvant Chemotherapy, a Retrospective Cohort Study

BACKGROUND

This study aimed to identify the response and survival outcomes of HER2-low patients following neoadjuvant chemotherapy (NAC).

METHOD

A retrospective cohort of patients who received NAC in the Department of Breast Surgery at Peking Union Medical College Hospital (PUMCH) from September 27, 2016, to January 23, 2024, was reviewed. Multivariate logistic regression and Cox proportional hazards models were used to identify factors associated with pathological complete response (pCR) and survival outcomes. The Kaplan-Meier method was applied to compare survival outcomes between HER2-zero and HER2-low patients.

RESULT

Four hundred and twenty-one patients meeting the inclusion criteria. The pCR rate of HER2-zero patients was significantly higher than that of HER2-low patients after adjusting for confounders (OR = 2.83, 95% CI: 1.44-5.65, adjusted P = .003). HER2-low patients demonstrated the most stable status after NAC within the hormone receptor (HR)-positive subset (80.82%) and the most unstable status within the HR-negative subset (57.69%). HER2-zero status was associated with worse disease-free survival (DFS) (HR = 1.94, 95% CI: 1.13-3.32, adjusted P = .02), but not with overall survival (OS) (HR = 1.18, 95% CI: 0.59-2.37, P = .65). HER2-zero patients had significantly worse DFS than HER2-low patients in the entire cohort (P = .014) and the HR-positive subset (P < .001). pCR could serve as a surrogate endpoint of favorable survival outcomes for HER2-zero patients, but not for HER2-low patients.

CONCLUSION

HER2-low patients might exhibit distinct characteristics compared with HER2-zero patients following NAC. Further multicenter, prospective studies are warranted to validate the conclusions of this exploratory research and assess whether HER2-low expression could serve as a new clinical subtype for evaluating NAC treatment outcomes.

Distinguishing Low Expression Levels of Human Epidermal Growth Factor Receptor 2 in Breast Cancer: Insights from Qualitative and Quantitative Magnetic Resonance Imaging Analysis

BACKGROUND

The discovery of novel antibody-drug conjugates for low-expression human epidermal growth factor receptor 2 (HER2-low) breast cancer highlights the inadequacy of the conventional binary classification of HER2 status as either negative or positive. Identification of HER2-low breast cancer is crucial for selecting patients who may benefit from targeted therapies. This study aims to determine whether qualitative and quantitative magnetic resonance imaging (MRI) features can effectively reflect low-HER2-expression breast cancer.

METHODS

Pre-treatment breast MRI images from 232 patients with pathologically confirmed breast cancer were retrospectively analyzed. Both clinicopathologic and MRI features were recorded. Qualitative MRI features included Breast Imaging Reporting and Data System (BI-RADS) descriptors from dynamic contrast-enhanced MRI (DCE-MRI), as well as intratumoral T2 hyperintensity and peritumoral edema observed in T2-weighted imaging (T2WI). Quantitative features were derived from diffusion kurtosis imaging (DKI) using multiple b-values and included statistics such as mean, median, 5th and 95th percentiles, skewness, kurtosis, and entropy from apparent diffusion coefficient (ADC), Dapp, and Kapp histograms. Differences in clinicopathologic, qualitative, and quantitative MRI features were compared across groups, with multivariable logistic regression used to identify significant independent predictors of HER2-low breast cancer. The discriminative power of MRI features was assessed using receiver operating characteristic (ROC) curves.

RESULTS

HER2 status was categorized as HER2-zero (n = 60), HER2-low (n = 91), and HER2-overexpressed (n = 81). Clinically, estrogen receptor (ER), progesterone receptor (PR), hormone receptor (HR), and Ki-67 levels significantly differed between the HER2-low group and others (all p < 0.001). In MRI analyses, intratumoral T2 hyperintensity was more prevalent in HER2-low cases (p = 0.009, p = 0.008). Mass lesions were more common in the HER2-zero group than in the HER2-low group (p = 0.038), and mass shape (p < 0.001) and margin (p < 0.001) significantly varied between the HER2 groups, with mass shape emerging as an independent predictive factor (HER2-low vs. HER2-zero: p = 0.010, HER2-low vs. HER2-over: p = 0.012). Qualitative MRI features demonstrated an area under the curve (AUC) of 0.763 (95% confidence interval [CI]: 0.667-0.859) for distinguishing HER2-low from HER2-zero status. Quantitative features showed distinct differences between HER2-low and HER2-overexpression groups, particularly in non-mass enhancement (NME) lesions. Combined variables achieved the highest predictive accuracy for HER2-low status, with an AUC of 0.802 (95% CI: 0.701-0.903).

CONCLUSIONS

Qualitative and quantitative MRI features offer valuable insights into low-HER2-expression breast cancer. While qualitative features are more effective for mass lesions, quantitative features are more suitable for NME lesions. These findings provide a more accessible and cost-effective approach to noninvasively identifying patients who may benefit from targeted therapy.

A comprehensive exploration of adverse reactions to lapatinib: a disproportionate analysis based on the FAERS database

BACKGROUND

Lapatinib, an FDA-approved tyrosine kinase inhibitor, treats HER2+ advanced/metastatic breast cancer. This study comprehensively analyzed its adverse reaction profile using FDA Adverse Event Reporting System (FAERS) to guide clinical use.

RESEARCH DESIGN AND METHODS

Adverse event (AE) reports for lapatinib from the second quarter of 2007 to the second quarter of 2024 in FAERS were analyzed using Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Multi-item Gamma Poisson Shrinkage (MGPS) and Bayesian Confidence Propagation Neural Network (BCPNN) to identify AE signals.

RESULTS

Among 8300 AE reports, females (91.47%) and ages 40-59.9 (33.71%) were predominant. 20 system organ classifications (SOCs) were affected, with gastrointestinal disorders (ROR = 3.46) and skin disorders (ROR = 2.47) most significant. Based on the PT level, a total of 111 PTs were analyzed that met the four algorithms, including typical AEs such as diarrhea (n = 3410), vomiting (n = 856), and rash (n = 856), as well as some rare AEs that were not prompted by the drug inserts, such as neutropenia (n = 252), pericardial effusion (n = 43), lymphedema (n = 20). The majority of lapatinib-associated AEs had onset within 30 days (51%).

CONCLUSIONS

Lapatinib has a generally favorable safety profile, but gastrointestinal toxicity and dermatotoxicity require close monitoring to prevent serious AEs.

The Breast Cancer Classifier refines molecular breast cancer classification to delineate the HER2-low subtype

Current breast cancer classification methods, particularly immunohistochemistry and PAM50, face challenges in accurately characterizing the HER2-low subtype, a therapeutically relevant entity with distinct biological features. This notable gap can lead to misclassification, resulting in inappropriate treatment decisions and suboptimal patient outcomes. Leveraging RNA-seq and machine-learning algorithms, we developed the Breast Cancer Classifier (BCC), a unique transcriptomic classifier for more precise breast cancer subtyping, specifically by delineating and incorporating HER2-low as a distinct subtype. BCC also redefined the PAM50 Normal subtype into other subtypes, disputing its classification as a unique molecular group. Our statistical analysis not only confirmed the reproducibility and accuracy of BCC, but also revealed similarities in prognostic characteristics between the HER2-low and Basal subtypes. Addressing this gap in breast cancer classification is clinically significant because it not only improves treatment stratification, but also uncovers novel molecular and immunohistochemical features associated with the HER2-low and HER2-high subtypes, thereby advancing our understanding of breast cancer heterogeneity and providing guidance in precision oncology.

Advances in Ultrasound-Targeted Microbubble Destruction (UTMD) for Breast Cancer Therapy

Breast cancer is one of the most common types of cancer in women worldwide and is a leading cause of cancer deaths among women. As a result, various treatments have been developed to combat this disease. Breast cancer treatment varies based on its stage and type of pathology. Among the therapeutic options, ultrasound has been employed to assist in the treatment of breast cancer, including radiation therapy, chemotherapy, targeted immunotherapy, hormonal therapy, and, more recently, radiofrequency ablation for early-stage and inoperable patients. One notable advancement is ultrasound-targeted microbubble destruction (UTMD), which is gradually becoming a highly effective and non-invasive anti-tumor modality. This technique can enhance chemical, genetic, immune, and anti-vascular therapies through its physical and biological effects. Specifically, UTMD improves drug transfer efficiency and destroys tumor neovascularization while reducing toxic side effects on the body during tumor treatment. Given these developments, the application of ultrasound-assisted therapy to breast cancer has gained significant attention from research scholars. In this review, we will discuss the development of various therapeutic modalities for breast cancer and, importantly, highlight the application of ultrasound microbubble-targeted disruption techniques in breast cancer treatment.

Targeting PCSK9, through an innovative cVLP-based vaccine, enhanced the therapeutic activity of a cVLP-HER2 vaccine in a preclinical model of HER2-positive mammary carcinoma

BACKGROUND

HER2-targeted therapies have revolutionized the treatment of HER2-positive breast cancer patients, leading to significant improvements in tumor response rates and survival. However, resistance and incomplete response remain considerable challenges. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is a novel therapeutic strategy for the management of dyslipidemia by enhancing the clearance of low-density lipoprotein cholesterol receptors, however recent evidence also shows links between PCSK9 and cancer cells. We present an innovative immunization approach combining capsid virus-like particle (cVLP)-based vaccines against HER2 and PCSK9.

METHODS

The therapeutic activity of the combined vaccine was evaluated in female mice challenged with HER2-positive mammary carcinoma cells. Controls included untreated mice and mice treated with cVLP-PCSK9 and cVLP-HER2 as standalone therapies. Antibodies elicited by vaccinations were detected through ELISA immunoassay. The functional activity of the antibodies was tested in 3D-soft agar assay on human HER2 +  +  + trastuzumab sensitive and resistant cells.

RESULTS

Mice vaccinated with cVLP-HER2 + cVLP-PCSK9 displayed tumor regression from the 40th day after cell challenge in 100% of mice remaining tumor-free even 4 months later. In contrast, 83% of mice treated with cVLP-HER2 vaccine alone experienced an initial tumor regression, followed by tumor relapse in 60% of subjects. Untreated mice and mice treated with the cVLP-PCSK9 vaccine alone developed progressive tumors within 1-2 months after cell injection. The combined vaccine approach elicited strong anti-human HER2 antibody responses (reaching 1-2 mg/ml range) comprising multiple immunoglobulins isotypes. cVLP-PCSK9 vaccine elicited anti-PCSK9 antibody responses, resulting in a marked reduction in PCSK9 serum levels. Although the anti-PCSK9 response was reduced when co-administered with cVLP-HER2, it remained significant. Moreover, both cVLP-HER2 + cVLP-PCSK9 and cVLP-HER2 alone induced anti-HER2 antibodies able to inhibit the 3D growth of human HER2 +  +  + BT-474 and trastuzumab-resistant BT-474 C5 cells. Strikingly, antibodies elicited by the combined vaccination were more effective than those elicited by the cVLP-HER2 vaccine alone in the inhibition of trastuzumab-resistant C5 cells.

CONCLUSIONS

The results indicate that cVLP-PCSK9 vaccination shows adjuvant activity when combined with cVLP-HER2 vaccine, enhancing its therapeutic efficacy against HER2-positive breast cancer and holding promise in overcoming the challenges posed by resistance and incomplete responses to HER2-targeted therapy.

HER2-Positive Breast Cancer Treatment and Resistance

HER2-positive (+) breast cancer is an aggressive disease with poor prognosis, a narrative that changed drastically with the advent and approval of trastuzumab, the first humanized monoclonal antibody targeting HER2. In addition to another monoclonal antibody, more classes of HER2-targeted agents, including tyrosine kinase inhibitors, and antibody-drug conjugates were developed in the years that followed. While these potent therapies have substantially improved the outcome of patients with HER2+ breast cancer, resistance has prevailed as a clinical challenge ever since the arrival of targeted agents. Efforts to develop new treatment regimens to treat/overcome resistance is futile without a primary understanding of the mechanistic underpinnings of resistance. Resistance could be attributed to mechanisms that are either specific to the tumor epithelial cells or those that emerge through changes in the tumor microenvironment. Reactivation of the HER receptor layer due to incomplete blockade of the HER receptor layer or due to alterations in the HER receptors is one of the major mechanisms. In other instances, resistance may occur due to deregulations in key downstream signaling such as the PI3K/AKT or RAS/MEK/ERK pathways or due to the emergence of compensatory pathways such as ER, other RTKs, or metabolic pathways. Potent new targeted agents and approaches to target key actionable drivers of resistance have already been identified, many of which are in early clinical development or under preclinical evaluation. Ongoing and future translational research will continue to uncover additional therapeutic vulnerabilities, as well as new targeted agents and approaches to treat and/or overcome anti-HER2 treatment resistance.

siRNA-based therapy for overcoming drug resistance in human solid tumours; molecular and immunological approaches

RNA interference (RNAi) is a primordial biological process that protects against external intrusion. SiRNA has the potential to selectively silence disease-related genes in a sequence-specific way, thus offering a promising therapeutic approach. The efficacy of siRNA-based therapies in cancer treatment has gained significant recognition due to multiple studies demonstrating its ability to effectively suppress cancer cells' growth and multiplication. Moreover, siRNA-based medicines have shown considerable promise in enhancing the sensitivity of cancer cells to chemotherapy and other treatment methods by suppressing genes that play a role in the development of drug resistance. Exploring and identifying functional genes linked to cancer cell characteristics and drug resistance is crucial for developing effective siRNAs for cancer treatment and advancing targeted and personalized therapeutics. Targeting and silencing genes in charge of resistance mechanisms, such as those involved in drug efflux, cell survival, or DNA repair, is possible with siRNA therapy in the context of drug resistance, especially cancer. Through inhibiting these genes, siRNA therapy can prevent resistance and restore the efficacy of traditional medications. This review addresses the potential of siRNAs in addressing drug resistance in human tumours, opening up new possibilities in cancer therapy. This review article offers a non-systematic summary of how different siRNA types contribute to cancer cells' treatment resistance. Using pertinent keywords, sources were chosen from reliable databases, including PubMed, Scopus, and Google Scholar. The review covered essential papers in this area and those that mainly addressed the function of siRNA in drug resistance. The articles examined in connection with the title of this review were primarily published from 2020 onward and are based on in vitro studies. Furthermore, this article examines the potential barriers and prospective perspectives of siRNA therapies.

Antitumor Activity and Multi-Target Mechanism of Phenolic Schiff Bases Bearing Methanesulfonamide Fragments: Cell Cycle Analysis and a Molecular Modeling Study

Five phenolic Schiff bases (7-11) incorporating a fragment of methanesulfonamide were synthesized and evaluated for their efficacy as antitumor agents. Compounds 7 and 8 demonstrated the most potent antitumor action, with a positive cytotoxic effect (PCE) of 54/59 and 59/59 and a mean growth percentage (MG%) of 67.3% and 19.5%, respectively, compared with imatinib (PCE = 20/59 and MG% = 92.6%). The PCE values for derivatives 9-11 were 3/59, 4/59, and 4/59, respectively, indicating poor antitumor effect. Compound 8 exhibited the most significant efficacy, suppressing cell proliferation by an average of 50% at a dosage of 0.501 µM, in comparison with the reference drugs sorafenib (2.33 µM), gefitinib (2.10 µM), erlotinib (7.68 µM), and celecoxib (17.5 µM). Compounds 7 and 8 had substantial inhibitory effects on the human epidermal growth factor receptor 2 (HER2), with IC50 values of 0.183 μM and 0.464 μM, respectively. Furthermore, they exhibited significant inhibition of the epidermal growth factor receptor (EGFR), with IC50 values of 0.752 μM and 0.166 μM, respectively. Compound 8 exhibited the highest COX-2 inhibition (IC50 = 12.76 μM). We performed molecular docking dynamic experiments to examine the precise interaction and structural prerequisites for the anticancer activity of derivatives 7 and 8 by targeting EGFR and HER2.

Evaluating the Anticancer Properties of Novel Piscidinol A Derivatives: Insights from DFT, Molecular Docking, and Molecular Dynamics Studies

Cancer is characterized by uncontrolled cell growth and spreading throughout the body. This study employed computational approaches to investigate 18 naturally derived anticancer piscidinol A derivatives (1-18) as potential therapeutics. By examining their interactions with 15 essential target proteins (HIF-1α, RanGAP, FOXM1, PARP2, HER2, ERα, NGF, FAS, GRP78, PRDX2, SCF complex, EGFR, Bcl-xL, ERG, and HSP70) and comparing them with established drugs such as camptothecin, docetaxel, etoposide, irinotecan, paclitaxel, and teniposide, compound 10 emerged as noteworthy. In molecular dynamics simulations, the protein with the strongest binding to the crucial 1A52 protein exceeded druglikeness criteria and displayed extraordinary stability within the enzyme's pocket over varied temperatures (300-320 K). Additionally, density functional theory was used to calculate dipole moments and molecular orbital characteristics, as well as analyze the thermodynamic stability of the putative anticancer derivatives. This finding reveals a well-defined, potentially therapeutic relationship supported by theoretical analysis, which is in good agreement with subsequent assessments of their potential in vitro cytotoxic effects of piscidinol A derivatives (6-18) against various cancer cell lines. Future in vivo and clinical studies are required to validate these findings further. Compound 10 thus emerges as an intriguing contender in the fight against cancer.

Comparing core needle biopsy and surgical excision in breast cancer diagnosis: implications for clinical practice from a retrospective cohort study

BACKGROUND

Preoperative ultrasound-guided core needle biopsy (CNB) is currently the standard procedure for managing breast illnesses. However, the differences in outcomes between CNB and surgical excision (SE) have not been thoroughly assessed. This study aimed to explore the disparities in pathological outcomes between these two procedures, using a large sample dataset.

METHODS

This retrospective study consecutively included patients who underwent CNB and SE at Shenzhen People's Hospital from May 2016 to June 2023. Immunohistochemistry (IHC) was utilized to determine the status of estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor-2 (HER2), and Ki-67. Patients presenting with HER2 IHC 2+ underwent additional fluorescence in situ hybridization (FISH) examination. The cutoff value for high Ki-67 expression was established at 14%. Molecular subtypes were classified into four groups (Luminal A, Luminal B, Triple-negative, and HER2-positive) and five groups [Luminal A, Luminal B+ (HER2-positive), Luminal B- (HER2-negative), Triple-negative, and HER2-positive], based on different criteria.

RESULTS

A total of 4,209 patients were included in this study. Post-surgical confirmation revealed 2,410 cases as benign and 1,799 as malignant. Among the malignant cases, 334 were excluded due to either not having undergone direct surgery or having incomplete IHC results. The remaining 1,465 cases underwent IHC testing. CNB demonstrated a 97% concordance rate (CR) in diagnosing benign cases. The CRs for diagnosing invasive breast cancer (IBC) and carcinoma in situ (CIS) were 92% and 54%, respectively. ER, PgR, HER2, and Ki-67 exhibited CRs of 94%, 91%, 98%, and 84%, respectively. In the four-group classification, the overall diagnostic CR was 82%, with CRs for Luminal A, Luminal B, HER2-positive, and triple-negative breast cancer (TNBC) being 84%, 82%, 78%, and 85%, respectively. Under the five-group classification, the overall diagnostic CR was also 82%, with CRs for Luminal A, Luminal B+, Luminal B-, HER2-positive, and TNBC being 86%, 85%, 94%, 88%, and 92%, respectively.

CONCLUSIONS

This study demonstrates that CNB is highly accurate in differentiating benign from malignant breast lesions, particularly showing significant consistency in the diagnosis of molecular subtypes, providing a reliable reference for clinical diagnosis.

HER-2 expression is correlated with multimodal imaging features in breast cancer: a pilot study

OBJECTIVE

A pilot study to evaluate the correlation between multimodal imaging features and the expression of the human epidermal growth factor receptor type 2 (HER-2) in breast cancer to provide a basis for clinical treatment and prognosis evaluation.

METHODS

We included a total of 62 patients with breast cancer admitted to the Affiliated Hospital of Hebei University between 2018 and 2022. All of them underwent the relevant investigations, including ultrasound, mammography, and enhanced magnetic resonance imaging (MRI), in the hospital within one month before surgery or biopsy. HER-2 expression level was divided into negative and positive by immunohistochemistry(IHC). Using SPSS 24.0 statistical software to analyze the differences in imaging features between the HER-2 positive and the HER-2 negative groups.

RESULTS

There was a statistically significant difference between the HER-2 positive and the HER-2 negative groups (p = 0.005) in the hyperechoic halo sign around the lesion detected by ultrasonography as well as in the apparent diffusion coefficient (ADC) on MRI (p = 0.047). The sensitivity and specificity of the hyperechoic halo sign in predicting HER-2 positivity was 48.3% and 84.8% respectively, and the area under the curve (AUC) for the ADC value to predict HER-2 expression was 0.533. When b was equal to 800 and the ADC value (cutoff value) was 0.000888 mm2/s, the sensitivity and specificity were 65.5% and 51.5%, respectively.

CONCLUSION

A combination of multimodal imaging features and HER-2 gene expression can provide more valuable information for clinical diagnosis and therapeutic schedule in breast cancer.

MRI-based vector radiomics for predicting breast cancer HER2 status and its changes after neoadjuvant therapy

PURPOSE

To develop a novel MRI-based vector radiomic approach to predict breast cancer (BC) human epidermal growth factor receptor 2 (HER2) status (zero, low, and positive; task 1) and its changes after neoadjuvant therapy (NAT) (positive-to-positive, positive-to-negative, and positive-to-pathologic complete response; task 2).

MATERIALS AND METHODS

Both dynamic contrast-enhanced (DCE) MRI data and multi-b-value (MBV) diffusion-weighted imaging (DWI) data were acquired in BC patients at two centers. Vector-radiomic and conventional-radiomic features were extracted from both DCE-MRI and MBV-DWI. After feature selection, the following models were built using the retained features and logistic regression: vector model, conventional model, and combined model that integrates the vector-radiomic and conventional-radiomic features. The models' performances were quantified by the area under the receiver-operating characteristic curve (AUC).

RESULTS

The training/external test set (center 1/2) included 483/361 women. For task 1, the vector model (AUCs=0.73∼0.86) was superior to (p<.05) the conventional model (AUCs=0.68∼0.81), and the addition of vector-radiomic features to conventional-radiomic features yielded an incremental predictive value (AUCs=0.80∼0.90, p<.05). For task 2, the combined MBV-DWI model (AUCs=0.85∼0.89) performed better than (p<.05) the conventional MBV-DWI model (AUCs=0.73∼0.82). In addition, for the combined DCE-MRI model and the combined MBV-DWI model, the former (AUCs=0.85∼0.90) outperformed (p<.05) the latter (AUCs=0.80∼0.85) in task 1, whereas the latter (AUCs=0.85∼0.89) outperformed (p<.05) the former (AUCs=0.76∼0.81) in task 2. The above results are true for the training and external test sets.

CONCLUSIONS

MRI-based vector radiomics may predict BC HER2 status and its changes after NAT and provide significant incremental prediction over and above conventional radiomics.

MRI-based machine learning radiomics for prediction of HER2 expression status in breast invasive ductal carcinoma

Background

Human epidermal growth factor receptor 2 (HER2) is a tumor biomarker with significant prognostic and therapeutic implications for invasive ductal breast carcinoma (IDC).

Objective

This study aimed to explore the effectiveness of a multisequence magnetic resonance imaging (MRI)-based machine learning radiomics model in classifying the expression status of HER2, including HER2-positive, HER2-low, and HER2 completely negative (HER2-zero), among patients with IDC.

Methods

A total of 402 female patients with IDC confirmed through surgical pathology were enrolled and subsequently divided into a training group (n = 250, center I) and a validation group (n = 152, center II). Radiomics features were extracted from the preoperative MRI. A simulated annealing algorithm was used for key feature selection. Two classification tasks were performed: task 1, the classification of HER2-positive vs. HER2-negative (HER2-low and HER2-zero), and task 2, the classification of HER2-low vs. HER2-zero. Logistic regression, random forest (RF), and support vector machine were conducted to establish radiomics models. The performance of the models was evaluated using the area under the curve (AUC) of the operating characteristics (ROC).

Results

In total, 4506 radiomics features were extracted from multisequence MRI. A radiomics model for prediction of expression state of HER2 was successfully developed. Among the three classification algorithms, RF achieved the highest performance in classifying HER2-positive from HER2-negative and HER2-low from HER2-zero, with AUC values of 0.777 and 0.731, respectively.

Conclusions

Machine learning-based MRI radiomics may aid in the non-invasive prediction of the different expression status of HER2 in IDC.

Targeting drug resistance in breast cancer: the potential of miRNA and nanotechnology-driven delivery systems

Breast cancer is the second leading cause of cancer-related deaths in females worldwide. Despite significant advancements in treatment, drug resistance remains a major challenge, limiting the effectiveness of therapies and leading to dismal outcomes. Approximately 50% of HER2+ breast cancer patients develop resistance to trastuzumab, and patients with triple-negative breast cancer often experience resistance to first-line therapies. The drug resistance mechanisms involve altered drug uptake, enhanced DNA repair, and dysregulated apoptosis pathways. MicroRNAs are essential in regulating cellular processes involved in both homeostasis and disease. Recent data suggest that microRNAs can overcome drug resistance by regulating the pathways that confer drug resistance. Combining different conventional anticancer agents with microRNA therapies holds promise for enhancing treatment effectiveness against drug resistant breast cancer. Advancements in nano-drug delivery systems have facilitated the effective delivery of microRNAs by improving their stability, targeting specific cells, and enhancing cellular uptake. This review elucidates the recent advancements in microRNA-based therapies, their effects on gene expression, and their clinical efficacy in overcoming drug resistance in breast cancer.

Differences in axillary response and treatment implications in HER2 positive node positive breast cancer during neoadjuvant HER2 targeted dual therapy

Explore whether the axillary outcomes differ among HER2 positive subgroups receiving standard dual-targeted therapy, aiming to identify subgroups exhibiting enhanced sensitivity to NAT among HER2-positive/node-positive breast cancer patients. HER2 positive female patients with biopsy-proven node-positive disease from April 2020 to May 2023 were included. All patients underwent standard Neoadjuvant HER2-targeted dual therapy and axillary lymph node dissection (ALND) at Breast Surgery Center of Sichuan Cancer Hospital. Univariate and multivariate analyses were used to identify factors associate with axillary pathological complete response (ApCR). Statistical analysis and graphing were performed using SPSS 24.0 and GraphPad Prism 9.0 software. This study enrolled 215 HER2 positive patients with a total ApCR rate of 76.7%, which included 49 HER2 2+/FISH + and 166 HER2 3 + cases with approximate ApCR rates of 63.3% and 80.7% (P = 0.011). Univariate and multivariate analysis indicated that HER2 3 + disease (OR = 2.43, 95% CI 1.21-4.88, P = 0.012), Ki-67 ≥ 20% disease (OR = 3.00, 95% CI 1.26-7.13, P = 0.013) and NAC regimen of TCb (OR = 2.71, 95% CI 1.39-5.38, P = 0.004) were more likely to achieve ApCR. Further subgroup analysis revealed that HER2 3 + patients receiving TCb regimen showed the highest ApCR rate of 88% compared to other subgroups. HER2 3 + breast cancer had a higher ApCR rate than HER2 2+/FISH + breast cancer during Neoadjuvant HER2-targeted dual therapy. HER2 positive patients could benefit from NAC regimen of TCb in axillary response.

Dissecting the roles of prosaposin as an emerging therapeutic target for tumors and its underlying mechanisms

As a dual-function protein, prosaposin (PSAP) is a lysosome-associated protein that participates in a variety of cellular processes. In the lysosome, PSAP is processed to activate enzymes that degrade lipids. In addition, PSAP proteins located extracellularly are involved in cancer progression, such as proliferation and tumor death suppression signaling. Moreover, under different situations, PSAP exhibits distinct metastasis potentials in tumors. However, comprehensive insight into PSAP in cancer progression has been lacking. Here, we provide a framework of the role of PSAP in cancer and its clinical application in cancer patients, providing a novel perspective on the clinical translation of PSAP.

Efficacy and safety of pyrotinib-based regimens in HER2 positive metastatic breast cancer: A retrospective real-world data study

OBJECTIVE

Pyrotinib is a novel irreversible tyrosine kinase inhibitor that has shown efficacy for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). This study explored the efficacy and safety of pyrotinib in the treatment of HER2-positive MBC patients in the real world.

METHODS

From September 2018 to February 2022, 137 female patients with HER2-positive MBC treated in this center were enrolled in this study. The follow-up period ended on January 12, 2023. The primary endpoint of this study was progression-free survival (PFS). Overall survival (OS), objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), central nervous system (CNS)-PFS, CNS-ORR, CNS-CBR, CNS-DCR, and adverse event (AE) were the secondary endpoints.

RESULTS

The ORR, DCR and CBR were 41.98 % (55/131), 87.79 % (115/131) and 44.27 % (58/131) in this cohort, respectively. The median PFS for this cohort was 10.37 months [95 % confidence interval (CI): 9.205-11.535] and the median OS was 37.53 months (not reached). Univariate and multivariate analyses showed that trastuzumab sensitivity was an independent predictor of improved PFS [hazard ratio (HR): 0.579 (0.371-0.904, p=0.016)] and improved OS [0.410 (0.213-0.790, p=0.008)]. Patients treated with a pyrotinib-based regimen as second-line and third-or-post-line therapy had poorer PFS [second-line: 3.315 (1.832-6.000, p<0.001); third-or-post-line: 3.304 (1.749-6.243, p<0.001)] and OS [second-line: 4.631 (1.033-20.771, p=0.045); third-or-post-line: 5.738 (1.212-27.174, p=0.028)]. There were 38 brain metastases (BM) patients in this study, the CNS-mPFS [14.37 months (7.815-20.925) vs. 7.83 months (7.047-8.613), p=0.375] and mOS [not reached vs. 36.40 months (18.551-54.249), p=0.034] were better in brain radiotherapy (BRT) group than NBRT group. 18.98 % (26/137) of patients experienced grade 3 or higher diarrhea. No AE-related death was reported.

CONCLUSION

This study confirms the promising antitumor activity and acceptable safety of real-world pyrotinib-based regimens for the treatment of HER2-positive MBC patients, particularly those who are trastuzumab-sensitive and who are receiving pyrotinib-based regimens as advanced first-line therapy. It has also been demonstrated that these regimens combined with BRT, provide better intracranial responses and long-term survival benefits for these patients with BM.

Overexpression of mir-489-3p inhibits proliferation and migration of non-small cell lung cancer cells by suppressing the HER2/PI3K/AKT/Snail signaling pathway

Background

Lung cancer is a highly prevalent malignancy with significant morbidity and mortality rates. MiR-489-3p, a microRNA, has been identified as a regulator of tumor cell proliferation and invasion. Its expression is downregulated in non-small cell lung cancer (NSCLC). Elucidating the molecular mechanisms underlying miR-489-3p's role in NSCLC pathogenesis is crucial for identifying potential diagnostic and therapeutic targets.

Methods

To investigate the molecular mechanism of miR-489-3p in NSCLC, this study utilized A549, a commonly used NSCLC cell line. MiR-489-3p mimics and inhibitors were transfected into A549 cells. Additionally, co-transfection experiments using wortmannin, an inhibitor of the PI3K/AKT pathway, were performed. Expression of miR-489-3p and related proteins was analyzed by Western blotting and quantitative real-time PCR (qRT-PCR). Cell migration and proliferation were assessed by wound healing and colony formation assays, respectively.

Results

Overexpression of miR-489-3p significantly inhibited the proliferation and migration of A549 cells. This inhibitory effect was further enhanced upon co-transfected with wortmannin. Analysis of human lung specimens showed increased expression of HER2, PI3K, and AKT in lung adenocarcinoma tissues compared to adjacent non-cancerous tissues.

Conclusions

These findings suggest that miR-489-3p overexpression may inhibit NSCLC cell proliferation and migration by suppressing the HER2/PI3K/AKT/Snail signaling pathway. This study elucidates miR-489-3p's molecular mechanisms in NSCLC and provides experimental basis for identifying early diagnostic markers and novel therapeutic targets.

Bimetallic Single-Atom Nanozyme-Based Electrochemical-Photothermal Dual-Function Portable Immunoassay with Smartphone Imaging

Rapid and accurate detection of human epidermal growth factor receptor 2 (HER2) is crucial for the early diagnosis and prognosis of breast cancer. In this study, we reported an iron-manganese ion N-doped carbon single-atom catalyst (FeMn-NCetch/SAC) bimetallic peroxidase mimetic enzyme with abundant active sites etched by H2O2 and further demonstrated unique advantages of single-atom bimetallic nanozymes in generating hydroxyl radicals by density functional theory (DFT) calculations. As a proof of concept, a portable device-dependent electrochemical-photothermal bifunctional immunoassay detection platform was designed to achieve reliable detection of HER2. In the enzyme-linked reaction, H2O2 was generated by substrate catalysis via secondary antibody-labeled glucose oxidase (GOx), while FeMn-NCetch/SAC nanozymes catalyzed the decomposition of H2O2 to form OH*, which catalyzed the conversion of 3,3',5,5'-tetramethylbenzidine (TMB) to ox-TMB. The ox-TMB generation was converted from the colorimetric signals to electrical and photothermal signals by applied potential and laser irradiation, which could be employed for the quantitative detection of HER2. With the help of this bifunctional detection technology, HER2 was accurately detected in two ways: photothermally, with a linear scope of 0.01 to 2.0 ng mL-1 and a limit of detection (LOD) of 7.5 pg mL-1, and electrochemically, with a linear scope of 0.01 to 10 ng mL-1 at an LOD of 3.9 pg mL-1. By successfully avoiding environmental impacts, the bifunctional-based immunosensing strategy offers strong support for accurate clinical detection.

What Proportion of BRCA-Associated Breast Cancer Is Human Epidermal Growth Factor 2-Low and Eligible for Additional Targeted Therapy?

INTRODUCTION

DESTINY B04 provided clinical meaning to a new classification of human epidermal growth factor 2 (HER2) expression in breast cancer: HER2-low. Patients with germline breast cancer type 1 gene pathogenic variants (gBRCA1) often develop triple negative breast cancer (TNBC), but the proportion who could be classified as HER2-low and qualify for an additional targeted therapy option is unknown. This study aims to characterize the proportion of gBRCA1 or germline breast cancer type 2 gene pathogenic variants patients for whom these novel targeted therapies may be an option.

METHODS

We performed a retrospective chart review of patients with gBRCA1/2 treated at our institution for invasive breast cancer from 2000 to 2021. Synchronous or metachronous contralateral breast cancers were recorded separately. HER2 status was determined by immunohistochemistry and fluorescence in situ hybridization. We excluded patients without complete HER2 data.

RESULTS

Among the 95 breast cancers identified in our cohort of 85 gBRCA1/2 patients, 41 (43%) were TNBC, 38 (40%) were hormone receptor positive (HR+)/HER2-negative, and 16 (17%) were HER2-positive based on standard conventions. We found that 82% of the HR+/HER2-cancers and 66% of TNBCs would be reclassified as HER2-low. After stratifying by BRCA gene status, 64% of cancers in patients with gBRCA1 and 58% of cancers in patients with germline breast cancer type 2 gene pathogenic variants were HER2-low.

CONCLUSIONS

A significant portion of gBRCA1/2 patients who were previously diagnosed with TNBC or HR+/HER2- breast cancer would now be classified as HER2-low and could be considered for the use of trastuzumab deruxtecan in the metastatic setting. Outcome differences from therapy changes in this cohort should now be assessed.

Dynamic changes in tumor profiling reveal intra- and inter-tumoral heterogeneity focused on an uncharacterized HER2 mutation: a case report of a young breast cancer patient

Despite multiple recent advances in systemic therapy for metastatic breast cancer, cases which display suboptimal response to guideline-driven treatment are frequently seen in the clinic. Effective options for such patients are limited, particularly in later line of therapy, and selection of optimal treatment options is essentially empirical and based largely on considerations of previous regimens received. Comprehensive cancer profiling includes detection of genetic alterations in tissue and circulating tumor DNA (ctDNA), immunohistochemistry (IHC) from re-biopsied metastatic disease, circulating tumor cells (CTCs), gene expression analysis and pharmacogenomics. The advent of this methodology and application to metastatic breast cancer, facilitates a more scientifically informed approach to identification of optimal systemic therapy approaches independent of the restrictions implied by clinical guidelines. Here we describe a case of metastatic breast cancer where consecutive comprehensive tumor profiling reveals ongoing tumor evolution, guiding the identification of novel effective therapeutic strategies.

Biomarkers for Antibody-Drug Conjugates in Solid Tumors

The clinical development and then the progressive entry in clinical practice of antibody-drug conjugates (ADC) have marked a transformative advancement in the overall cancer treatment. ADCs have been extensively tested for a large number of tumors, reporting heterogeneous clinical efficacy and safety results. In some diseases, the advent of ADCs has yielded significant changes in the prognostic trajectory, portending an improvement of the survival and/or quality of life. ADCs are targeted agents, capable of delivering highly cytotoxic payloads selectively to antigen-expressing cancer cells. As such, they have been intended as perfect "bullets" to enable the promise of precision medicine, toward high-efficacy and limited-toxicity treatment options. However, only some approved ADCs are intended for the use in biomarker-selected patient populations, restricting potentially the opportunity to be more precise. Yet, key characteristics of modern ADCs might allow the activity of ADCs in tumors with heterogeneous or low expression of cancer antigens, resulting in a clinical activity that could sublimate the classic paradigm of a drug-to-target perfect match. In our review, we portrayed the current landscape of approved ADCs, reporting data of activity as related to the expression of the cancer antigens, and elucidating possible determinants of the safety and efficacy, including when used in a therapeutic sequence.

HER2-low breast cancer and response to neoadjuvant chemotherapy: a population-based cohort study

About half of breast cancers (BC) without amplification of the human epidermal growth factor receptor 2 (HER2) have a low HER2 protein expression level (HER2-low). The clinical impact of HER2-low and the response to neoadjuvant chemotherapy (NAC) is unclear. This study aimed to assess the association between HER2-low BC and pathological response to NAC. Data from the Dutch Pathology Registry were collected for 11,988 BC patients treated with NAC between 2014 and 2022. HER2-low BC was defined as an immunohistochemical score of 1+ or 2+ and a negative molecular reflex test. We compared clinicopathological features of HER2-0 versus HER2-low BC and assessed the correlation between HER2 status and the pathological complete response (pCR) rate after NAC, including overall survival. Among hormone receptor (HR)-positive tumours, 67% (n=4,619) were HER2-low, compared to 47% (n=1,167) in the HR-negative group. Around 32% (n=207) of patients had a discordant HER2 status between the pre-NAC biopsy and the corresponding post-NAC resection, within which 87% (n=165) changed from HER2-0 to HER2-low or vice versa. The pCR rate was significantly lower in HER2-low BC compared to HER2-0 BC within the HR-positive group (4% versus 5%; p=0.022). However, the absolute difference was limited, so the clinical relevance is questionable. In HR-negative cases, the difference in pCR was not significant (32% versus 34%; p=0.266). No significant difference in overall survival was observed between HER2-low and HER2-0 tumours, regardless of hormone receptor status. The antibody-drug conjugate trastuzumab deruxtecan (T-DXd) has improved survival outcomes of patients with HER2-low metastatic BC. The finding that one-third of the patients in this study had a discordant HER2 status between the pre-NAC biopsy and the post-NAC resection specimen could impact clinical decision-making should T-DXd be used in early BC treatment.

LncRNAs in necroptosis: Deciphering their role in cancer pathogenesis and therapy

Necroptosis, a controlled type of cell death that is different from apoptosis, has become a key figure in the aetiology of cancer and offers a possible target for treatment. A growing number of biological activities, including necroptosis, have been linked to long noncoding RNAs (lncRNAs), a varied family of RNA molecules with limited capacity to code for proteins. The complex interactions between LncRNAs and important molecular effectors of necroptosis, including mixed lineage kinase domain-like pseudokinase (MLKL) and receptor-interacting protein kinase 3 (RIPK3), will be investigated. We will explore the many methods that LncRNAs use to affect necroptosis, including protein-protein interactions, transcriptional control, and post-transcriptional modification. Additionally, the deregulation of certain LncRNAs in different forms of cancer will be discussed, highlighting their dual function in influencing necroptotic processes as tumour suppressors and oncogenes. The goal of this study is to thoroughly examine the complex role that LncRNAs play in controlling necroptotic pathways and how that regulation affects the onset and spread of cancer. In the necroptosis for cancer treatment, this review will also provide insight into the possible therapeutic uses of targeting LncRNAs. Techniques utilising LncRNA-based medicines show promise in controlling necroptotic pathways to prevent cancer from spreading and improve the effectiveness of treatment.

Open questions, current challenges, and future perspectives in targeting human epidermal growth factor receptor 2-low breast cancer

Approximately 60% of traditionally defined human epidermal growth factor receptor 2 (HER2)-negative breast cancers express low levels of HER2 [HER2-low; defined as immunohistochemistry (IHC) 1+ or IHC 2+/in situ hybridization (ISH)-]. HER2-low breast cancers encompass a large percentage of both hormone receptor-positive (up to 85%) and triple-negative (up to 63%) breast cancers. The DESTINY-Breast04 trial established that HER2-low tumors are targetable, leading to the approval of trastuzumab deruxtecan (T-DXd) as the first HER2-directed therapy for the treatment of HER2-low breast cancer in the United States and Europe. This change in the clinical landscape results in a number of questions and challenges-including those related to HER2 assessment and patient identification-and highlights the need for careful assessment of HER2 expression to identify patients eligible for T-DXd. This review provides context for understanding how to identify patients with HER2-low breast cancer with respect to sample types, scoring and reporting HER2 status, and testing methods and assays. It also discusses management of important T-DXd-related adverse events. Available evidence supports the efficacy of T-DXd in patients with any history of IHC 1+ or IHC 2+/ISH- scores; however, future research may further refine the population who could benefit from T-DXd or other HER2-directed therapies and identify novel methods for patient identification. Because HER2 expression can change with disease progression or treatment, and variability exists in scoring and interpretation of HER2 status, careful re-evaluation in certain scenarios may help to identify more patients who may benefit from T-DXd.

HER2 Low Expression in Primary Male Breast Cancer

Purpose

The introduction of HER2-targeting antibody drug conjugates (ADCs) offers new treatment options for female breast cancer patients (FBC) expressing low levels of HER2 (HER2 low). No evidence was found that HER2 low describes a new FBC subtype. There is a lack of studies determining the impact of HER2 low in male breast cancer (MBC). In this study, we evaluate the prevalence of HER2 low in primary MBC and correlate the results with patient characteristics.

Patients and Methods

In this study, histological specimens were obtained from 120 male patients diagnosed and treated for primary invasive breast cancer from 1995 to 2022 at Breast Cancer Units in Bergisch Gladbach, Chemnitz, and Zwickau, Germany. HER2 immunostaining and in situ hybridization were performed by central pathology and evaluated based on the ASCO/CAP guidelines. The correlation of expression of HER2 low with tumor biological characteristics and patient outcomes was investigated.

Results

Out of all cases, four patients (3.3%) showed HER2 positivity (3+), 39 (32.5%) patients were classified as HER2 low, 7 (5.8%) were HER2 2+ (no amplification), 32 (26.7%) were HER2 1+, and 77 (64.2%) were classified as HER2 zero. Out of 77 HER2 zero cases, 47 tumors (61.0%) showed incomplete staining, with <10% of tumor cells classified as HER2 ultralow. No statistical correlation between HER2 low and tumor biological characteristics and patients' survival was found.

Conclusion

Our findings show a notable, albeit lower, prevalence of HER2 low expression in primary MBC. However, tumors expressing HER2 low do not show specific tumor biological features to define a new breast cancer subtype in MBC. Our results suggest that a significant number of MBC patients could benefit from ADCs, as shown in FBC. Further studies are required to better understand HER2 low breast cancer, both generally and in MBC.

HER2-low and tumor infiltrating lymphocytes in triple-negative breast cancer: Are they connected?

Most patients with triple-negative breast cancer (TNBC) are not candidates for targeted therapy, leaving chemotherapy as the primary treatment option. Recently, immunotherapy has demonstrated promising results in TNBC, due to its immunogenicity. In addition, a novel antibody-drug conjugate, namely, trastuzumab-deruxtecan, has shown effectiveness in TNBC patients with low-HER2 expression (HER2-low). These novel treatment options raise the question about the potential association between the density of stromal tumor-infiltrating lymphocytes (sTILs) and the level of HER2 expression. We aimed to evaluate the association between the level of HER2 expression (HER2-low versus HER2-0) and density of sTILs in TNBC patients, and how they impact the response to neoadjuvant chemotherapy (NAC). This was a retrospective multicenter study including all TNBC patients diagnosed between 2018 and 2022. Central pathology review included sTILs percentages and level of HER2 expression. Tumors were reclassified as either HER2-0 (HER2 IHC 0) or HER2-low (IHC 1 + or 2 + with negative reflex test). Various clinicopathologic characteristics, including sTILs density, and response to NAC were compared between HER2-0 and HER2-low cases. In total, 753 TNBC patients were included in this study, of which 292 patients received NAC. Interobserver agreement between the original pathology report and central review was moderate (77% had the same IHC status after reclassification in either HER2-0 or HER2-low; k = 0.45). HER2-low TNBC represented about one third (36%) of the tumors. No significant difference in sTILs density or complete pathologic response rate was found between HER2-0 and HER2-low cases (p = 0.476 and p = 0.339, respectively). The density of sTILs (≥ 10% sTILs vs. < 10%) was independently associated with achieving a pCR (p = 0.011). In conclusion, no significant association was found between HER2-low status and density of sTILs nor response to NAC. Nonetheless, sTILs could be an independent biomarker for predicting NAC response in TNBC patients.

Detection of HER2 expression using 99mTc-NM-02 nanobody in patients with breast cancer: a non-randomized, non-blinded clinical trial

BACKGROUND

99mTc radiolabeled nanobody NM-02 (99mTc-NM-02) is a novel single photon emission computed tomography (SPECT) probe with a high affinity and specificity for human epidermal growth factor receptor 2 (HER2). In this study, a clinical imaging trial was conducted to investigate the relationship between 99mTc-NM-02 uptake and HER2 expression in patients with breast cancer.

METHODS

Thirty patients with pathologically confirmed breast cancer were recruited and imaged with both 99mTc-NM-02 SPECT/computed tomography (CT) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT. According to the treatment conditions before recruitment, patients were divided into two groups, the newly diagnosed group (n = 24) and the treated group (n = 6). The maximal standard uptake value (SUVmax) of 18F-FDG and SUVmax and mean SUV (SUVmean) of 99mTc-NM-02 in the lesions were determined to analyze the relationship with HER2 expression.

RESULTS

No meaningful relationship was observed between 18F-FDG uptake and HER2 expression in 30 patients with breast cancer. 99mTc-NM-02 uptake was positively correlated with HER2 expression in the newly diagnosed group, but no correlation was observed in the treated group. 99mTc-NM-02 uptake in HER2-positive lesions was lower in those with effective HER2-targeted therapy compared with the newly diagnosed group. 99mTc-NM-02 SPECT/CT detected brain and bone metastases of breast cancer with a different imaging pattern from 18F-FDG PET/CT. 99mTc-NM-02 showed no non-specific uptake in inflamed tissues and revealed intra- and intertumoral HER2 heterogeneity by SPECT/CT imaging in 9 of the 30 patients with breast cancer.

CONCLUSIONS

99mTc-NM-02 SPECT/CT has the potential for visualizing whole-body HER2 overexpression in untreated patients, making it a promising method for HER2 assessment in patients with breast cancer.

TRIAL REGISTRATION

NCT04674722, Date of registration: December 19, 2020.

High HER2 Intratumoral Heterogeneity Is a Predictive Factor for Poor Prognosis in Early-Stage and Locally Advanced HER2-Positive Breast Cancer

PURPOSE

Breast cancer tumors frequently have intratumoral heterogeneity (ITH). Tumors with high ITH cause therapeutic resistance and have human epidermal growth factor receptor 2 (HER2) heterogeneity in response to HER2-targeted therapies. This study aimed to investigate whether high HER2 heterogeneity levels were clinically related to a poor prognosis for HER2-targeted adjuvant therapy resistance in primary breast cancers.

METHODS

This study included patients with primary breast cancer (n = 251) treated with adjuvant HER2-targeted therapies. HER2 heterogeneity was manifested by the shape of HER2 fluorescence in situ hybridization amplification (FISH) distributed histograms with the HER2 gene copy number within a tumor sample. Each tumor was classified into a biphasic grade graph (high heterogeneity [HH]) group or a monophasic grade graph (low heterogeneity [LH]) group based on heterogeneity. Both groups were evaluated for disease-free survival (DFS) and overall survival (OS) for a median of ten years of annual follow-up.

RESULTS

Of 251 patients with HER2-positive breast cancer, 46 (18.3%) and 205 (81.7%) were classified into the HH and LH groups, respectively. The HH group had more distant metastases and a poorer prognosis than the LH group (DFS: p < 0.001 (HH:63% vs. LH:91% at 10 years) and for the OS: p = 0.012 (HH:78% vs. LH:95% at 10 years).

CONCLUSIONS

High HER2 heterogeneity is a poor prognostic factor in patients with HER2-positive breast cancer. A novel approach to heterogeneity, which is manifested by the shape of HER2 FISH distributions, might be clinically useful in the prognosis prediction of patients after HER2 adjuvant therapy.

Targeting HER2 heterogeneity in breast and gastrointestinal cancers

About 20% of breast and gastric cancers and 3% of colorectal carcinomas overexpress the human epidermal growth factor receptor 2 (HER2) and are sensitive to HER2-directed agents. The expression of HER2 may differ within the same tumoral lesion (spatial intralesional heterogeneity), from different tumor locations (spatial interlesional heterogeneity), and throughout treatments (temporal heterogeneity). Spatial and temporal heterogeneity may impact on response and resistance to HER2-targeting agents and its prevalence and predictive role changes across HER2-overexpressing solid tumors. Therefore, the definition and the characterization of HER2 heterogeneity pose many challenges and its implementation as a reproducible predictive biomarker would help in guiding treatment modulation.

Phase II Trial Assessing the Repeatability and Tumor Uptake of [68Ga]Ga-HER2 Single-Domain Antibody PET/CT in Patients with Breast Carcinoma

Human epidermal growth factor receptor 2 (HER2) status is used for decision-making in breast carcinoma treatment. The status is obtained through immunohistochemistry or in situ hybridization. These two methods have the disadvantage of necessitating tissue sampling, which is prone to error due to tumor heterogeneity or interobserver variability. Whole-body imaging might be a solution to map HER2 expression throughout the body. Methods: Twenty patients with locally advanced or metastatic breast carcinoma (5 HER2-positive and 15 HER2-negative patients) were included in this phase II trial to assess the repeatability of uptake quantification and the extended safety of the [68Ga]Ga-NOTA-anti-HER2 single-domain antibody (sdAb). The tracer was injected, followed by a PET/CT scan at 90 min. Within 8 d, the procedure was repeated. Blood samples were taken for antidrug antibody (ADA) assessment and liquid biopsies. On available tissues, immunohistochemistry, in situ hybridization, and mass spectrometry were performed to determine the correlation of HER2 status with uptake values measured on PET. If relevant preexisting [18F]FDG PET/CT images were available (performed as standard of care), a comparison was made. Results: With a repeatability coefficient of 21.8%, this imaging technique was repeatable. No clear correlation between PET/CT uptake values and pathology could be established, as even patients with low levels of HER2 expression showed moderate to high uptake. Comparison with [18F]FDG PET/CT in 16 patients demonstrated that in 7 patients, [68Ga]Ga-NOTA-anti-HER2 shows interlesional heterogeneity within the same patient, and [18F]FDG uptake did not show the same heterogeneous uptake in all patients. In some patients, the extent of disease was clearer with the [68Ga]Ga-NOTA-anti-HER2-sdAb. Sixteen adverse events were reported but all without a clear relationship to the tracer. Three patients with preexisting ADAs did not show adverse reactions. No new ADAs developed. Conclusion: [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT imaging shows similar repeatability to [18F]FDG. It is safe for clinical use. There is tracer uptake in cancer lesions, even in patients previously determined to be HER2-low or -negative. The tracer shows potential in the assessment of interlesional heterogeneity of HER2 expression. In a subset of patients, [68Ga]Ga-NOTA-anti-HER2-sdAb uptake was seen in lesions with no or low [18F]FDG uptake. These findings support further clinical development of [68Ga]Ga-NOTA-anti-HER2-sdAb as a PET/CT tracer in breast cancer patients.

Edge-generated N-doped carbon-supported dual-metal active sites for enhancing electrochemical immunoassay

Development of high-precision human epidermal growth factor receptor 2 (HER2) assay is essential for the early diagnostic and prevention of breast cancer. In this work, an innovative Fe/Mn bimetallic nanozyme at the edge of N-doped carbon defects (FeMn-NCedge) with abundant active sites was prepared through the hydrothermal synthetic method. FeMn-NCedge nanozyme displayed excellent peroxidase-like activity relative to the H2O2-catalyzed 3,3',5,5'-tetramethylbenzidine (TMB) system for generation of the oxidized TMB (oxTMB). As a proof-of-concept application, we constructed an electrochemical immunoassay for the detection of HER2 based on the unique merits of FeMn-NCedge. Initially, a sandwiched immunoreaction was carried out in the microtiter plate coated with monoclonal anti-HER2 capture antibodies using glucose oxidase (GOx)-labeled anti-HER2 as detection antibody. The carried GOx could catalyze glucose to produce H2O2, thus resulting in the formation of oxTMB with the assistance of TMB and FeMn-NCedge nanozyme. The produced oxTMB could be determined on the electrode by the chronoamperometry at an applied potential of +10 mV. Experimental results revealed that the steady-state current increased with the increasing HER2 concentration in the sample, and gave a good linear relationship within the dynamic range of 0.01-10 ng/mL at a limit of detection of 5.4 pg/mL HER2. In addition, good reproducibility, high specificity and acceptable accuracy were acquired for the measurement of human serum samples. Importantly, this method can be extended for quantitative monitoring other disease-related proteins by changing the corresponding antibodies.

Real-time assessment of HER2 status in circulating tumor cells of breast cancer patients: Methods of detection and clinical implications

The human epidermal growth factor receptor 2 (HER2) plays a central role in breast cancer (BC). Therefore, it is critical to develop a method that can capture its spatial and temporal heterogeneity. Nowadays, therapeutic decisions for BC patients relies on evaluation of HER2 status from tissue biopsies using immunohistochemistry and in situ hybridization. Nevertheless, considering the technical and logistical challenges associated with tissue biopsies, there is an unmet need for a non-invasive and accurate approach to obtain real-time assessment of HER2 status. In this context, circulating biomarkers, particularly circulating tumor cells (CTCs), emerged as promising candidates. HER2 assessment on CTCs can be performed at genomic, transcriptomic, and protein levels on both bulk CTCs and at the single-cell resolution. However, the main limitation of the literature to date is the lack of a consistent definition of HER2-positive CTCs, which poses a major challenge for both, future research and clinical applications. Several studies revealed discordance in HER2 status between the primary tumor and corresponding CTCs. For instance, HER2-positive CTCs have been detected among patients with HER2-negative BC and vice versa. As a result, researchers have evaluated the prognostic and predictive value of HER2 status in CTCs, both in the early and metastatic settings, to increase the possibility of using anti-HER2 therapy also for these patients and to dissect mechanisms of treatment resistance. This review aims to provide an overview of the methods to determine HER2 status in CTCs and to summarize the evidence and future perspective on how CTCs-HER2 assessment can be integrated into the clinical management of BC patients.

Clinicopathologic Features and Prognosis of Female Early Breast Cancer With HER2 Low Expression: A Propensity Score Matched Analysis

Background

Metastatic breast cancer (MBC) patients with low expression of human epidermal growth factor 2 (HER2) have been proven to benefit from HER2 targeted therapy. We aimed to determine how HER2-low status affected survival and metastatic risk as well as how it affected pathological complete response (pCR) in neoadjuvant chemotherapy (NAC) patients.

Methods

According to the results of immunohistochemistry (IHC) and in situ hybridization (ISH) testing, 321 female patients were sorted into HER2-low (IHC 1+/2+ with ISH negative) and HER2-zero (IHC 0) groups using propensity score matching (PSM). Overall survival (OS), disease-free survival (DFS), and distant disease-free survival (DDFS) were compared for both groups, while pCR was only analyzed for NAC patients.

Results

In total, 97 patients in each group after PSM were included. We discovered that pCR was not associated with HER2 expression status in 45 patients who underwent NAC. Five-year OS in the HER2-low group was significantly higher (98.99%) than in the HER2-zero group (95.87%, P = .044); however, this difference was not reflected in the 5-year DFS (90.61 vs 90.52%, P = .868) and 5-year DDFS (93.67 vs 91.53%, P = .757). Meanwhile, multivariate analysis revealed that HER2-low expression could indicate better OS (P = .047, hazard ratios [HRs] = 16.121, 95% confidence interval [CI] = 1.035-251.046), but it had no prognostic value for DFS or DDFS.

Conclusion

When compared with HER2-zero expression, HER2-low expression was not connected to pCR and could not modify metastasis risk in female patients with early-stage breast cancer (BC), but it may prolong patient survival.

Cbl induced ubiquitination of HER2 mediate immune escape from HER2-targeted CAR-T

Breast cancer (BC) with high HER2 expression has higher recurrence rate and worse prognosis, and its immunotherapy is promising. Based on the high expression of HER2, develop Chimeric Antigen Receptor T-cell (CAR-T) and PDL-1 immunotherapy, and study the molecular pathways of related immune cells and recurrence. HER2-CAR-T cells were constructed using retroviruses, and their specific recognition and immune effects on HER2+ BC cells were verified by in vivo and in vitro experiments. PDL-1 was used as adjuvant immunotherapy, knocking down PDL-1 in tumor cells or dendritic cells, or depleted macrophages to study immune pathways. The negative regulation of HER2 by cbl was determined by IP, ubiquitination experiments, and segmented plasmids, elucidating the molecular mechanism of HER2+ BC recurrence after immunotherapy. HER2-CAR-T specifically recognizes HER2-positive tumor cells and inhibits tumor growth in vivo and in vitro, and anti-PDL1 treatment enhances the therapeutic effect of HER2-CAR-T on tumors. HER2-CART therapy eradicated solid tumors after PDL1 knockdown in dendritic cells. Immunotherapy of relapsed tumors lost HER2 expression by upregulating cbl. HER2-CAR-T shows specific recognition of HER2+ cells and can mediate immune response therapy with the cooperation of PDL-1.

Survivin expression as a prognostic marker for breast cancer

OBJECTIVE

Due to the speed of development observed in breast cancer, several studies aimed at discovering new biomarkers have been carried out in order to arrive at an early diagnosis. As survivin plays a fundamental role in the evasion of apoptosis in tumor cells, the aim of this study was to verify the expression profile of the survivin gene in paraffin-embedded breast tumor samples and associate it with the clinical characteristics of the patients.

METHODS

This is a cross-sectional study, for which 100 tumor samples were obtained from cancer patients treated throughout the year 2019 at Instituto de Mama do Cariri (Juazeiro do Norte, in the state of Ceará). This study included women over 30 years old who had confirmed breast cancer through anatomopathological examination but excluded those with non-neoplastic breast comorbidities, other neoplasms, or chronic diseases. Survivin gene expression was assessed by quantitative polymerase chain reaction.

RESULTS

The expression of survivin is associated with the lack of expression of estrogen (p=0.027) and progesterone (p>0.0005) receptors. It means that survivin expression is higher in patients in which labeling was absent for estrogen receptor and progesterone receptor.

CONCLUSION

Our data reinforce that survivin expression is higher in estrogen receptor-patients, thus representing an additional prognostic tool.

Investigation of Tumor Heterogeneity Using Integrated Single-Cell RNA Sequence Analysis to Focus on Genes Related to Breast Cancer-, EMT-, CSC-, and Metastasis-Related Markers in Patients with HER2-Positive Breast Cancer

Human epidermal growth factor receptor 2 (HER2) protein, which is characterized by the amplification of ERBB2, is a molecular target for HER2-overexpressing breast cancer. Many targeted HER2 strategies have been well developed thus far. Furthermore, intratumoral heterogeneity in HER2 cases has been observed with immunohistochemical staining and has been considered one of the reasons for drug resistance. Therefore, we conducted an integrated analysis of the breast cancer single-cell gene expression data for HER2-positive breast cancer cases from both scRNA-seq data from public datasets and data from our cohort and compared them with those for luminal breast cancer datasets. In our results, heterogeneous distribution of the expression of breast cancer-related genes (ESR1, PGR, ERBB2, and MKI67) was observed. Various gene expression levels differed at the single-cell level between the ERBB2-high group and ERBB2-low group. Moreover, molecular functions and ERBB2 expression levels differed between estrogen receptor (ER)-positive and ER-negative HER2 cases. Additionally, the gene expression levels of typical breast cancer-, CSC-, EMT-, and metastasis-related markers were also different across each patient. These results suggest that diversity in gene expression could occur not only in the presence of ERBB2 expression and ER status but also in the molecular characteristics of each patient.

Increased Expression of miR-223-3p and miR-375-3p and Anti-Inflammatory Activity in HDL of Newly Diagnosed Women in Advanced Stages of Breast Cancer

The expression of inflammation-related miRs bound to high-density lipoproteins (HDLs), the anti-inflammatory activity of HDLs isolated from individuals with breast cancer, and controls were determined. Forty newly diagnosed women with breast cancer naïve of treatment and 10 control participants were included. Cholesterol-loaded bone-marrow-derived macrophages were incubated with HDL from both groups and challenged with lipopolysaccharide (LPS). Interleukin 6 (IL6) and tumor necrosis factor (TNF) in the medium were quantified. The miRs in HDLs were determined by RT-qPCR. Age, body mass index, menopausal status, plasma lipids, and HDL composition were similar between groups. The ability of HDL to inhibit IL6 and TNF production was higher in breast cancer compared to controls, especially in advanced stages of the disease. The miR-223-3p and 375-3p were higher in the HDLs of breast cancer independent of the histological type of the tumor and had a high discriminatory power between breast cancer and controls. The miR-375-3p was greater in the advanced stages of the disease and was inversely correlated with the secretion of inflammatory cytokines. Inflammation-related miRs and the anti-inflammatory role of HDLs may have a significant impact on breast cancer pathophysiology.

Low and Ultra-Low HER2 in Human Breast Cancer: An Effort to Define New Neoplastic Subtypes

HER2-low and ultra-low breast cancer (BC) have been recently proposed as new subcategories of HER2 BC, supporting a re-consideration of immunohistochemical negative scores of 0, 1+ and the 2+/in situ hybridization (ISH) negative phenotype. In the present review, we outline the criteria needed to exactly distinguish HER2-low and ultra-low BC. Recent clinical trials have demonstrated significant clinical benefits of novel HER2 directing antibody-drug conjugates (ADCs) in treating these groups of tumors. In particular, trastuzumab-deruxtecan (T-Dxd), a HER2-directing ADC, has been recently approved by the US Food and Drug Administration as the first targeted therapy to treat HER2-low BC. Furthermore, ongoing trials, such as the DESTINY-Breast06 trial, are currently evaluating ADCs in patients with HER2-ultra low BC. Finally, we hope that new guidelines may help to codify HER2-low and ultra-low BC, increasing our knowledge of tumor biology and improving a targetable new therapeutical treatment.

Omics Technologies Improving Breast Cancer Research and Diagnostics

Breast cancer (BC) has yielded approximately 2.26 million new cases and has caused nearly 685,000 deaths worldwide in the last two years, making it the most common diagnosed cancer type in the world. BC is an intricate ecosystem formed by both the tumor microenvironment and malignant cells, and its heterogeneity impacts the response to treatment. Biomedical research has entered the era of massive omics data thanks to the high-throughput sequencing revolution, quick progress and widespread adoption. These technologies-liquid biopsy, transcriptomics, epigenomics, proteomics, metabolomics, pharmaco-omics and artificial intelligence imaging-could help researchers and clinicians to better understand the formation and evolution of BC. This review focuses on the findings of recent multi-omics-based research that has been applied to BC research, with an introduction to every omics technique and their applications for the different BC phenotypes, biomarkers, target therapies, diagnosis, treatment and prognosis, to provide a comprehensive overview of the possibilities of BC research.