[Comparative immunohistochemistry study of different antibodies clones for detection of breast cancer markers (estrogen receptor, progesterone receptor, HER2/neu, Ki-67)]. / Sravnitel'noe issledovanie antitel razlichnykh klonov dlya vyyavleniya markerov raka molochnoi zhelezy (retseptorov estrogenov, progesterona, HER2/neu, Ki-67) immunogistokhimicheskim metodom.

OBJECTIVE: A comparative study of detection of breast cancer markers (estrogen receptors, progesterone receptors, HER2/neu, Ki-67) by immunohistochemical method with antibodies produced by PrimeBioMed (Russia) and antibodies produced by Roche Ventana (USA). MATERIAL AND METHODS: Surgical specimens and biopsies from 37 patients with invasive breast cancer were used. Sections were stained with antibodies of clones ER SP1 and GM030, PR 1E2 and PBM-5B8, HER2/neu 4B5 and PBM-46A6, Ki-67 30-9 and GM010. RESULTS: There was a high positive and significant correlation between the immunohistochemistry results and antibodies of the clones ER-SP1 and GM030, PR1E2 and PBM-5B8, HER2/neu4B5 and PBM-46A6, Ki-67 30-9 and GM010. CONCLUSION: The study showed the possibility of using antibodies of clones GM030, HER2/neu 4B5, PBM-46A6, GM010 (PrimeBioMed) on the Ventana Bench Marck Ultra automatic immunostainer using the detection system UltraView Universal DAB Detection Kit.

Comparative Preclinical Evaluation of HYNIC-Modified Designed Ankyrin Repeat Proteins G3 for the 99mTc-Based Imaging of HER2-Expressing Malignant Tumors.

HER2 status determination is a necessary step for the proper choice of therapy and selection of patients for the targeted treatment of cancer. Targeted radiotracers such as radiolabeled DARPins provide a noninvasive and effective way for the molecular imaging of HER2 expression. This study aimed to evaluate tumor-targeting properties of three 99mTc-labeled DARPin G3 variants containing Gly-Gly-Gly-Cys (G3C), (Gly-Gly-Gly-Ser)3-Cys ((G3S)3C), or Glu-Glu-Glu-Cys (E3C) amino acid linkers at the C-terminus and conjugated to the HYNIC chelating agent, as well as to compare them with the clinically evaluated DARPin G3 labeled with 99mTc(CO)3 using the (HE)3-tag at the N-terminus. The labeling of DARPin G3-HYNIC variants provided radiochemical yields in the range of 50-80%. Labeled variants bound specifically to human HER2-expressing cancer cell lines with affinities in the range of 0.5-3 nM. There was no substantial influence of the linker and HYNIC chelator on the binding of 99mTc-labeled DARPin G3 variants to HER2 in vitro; however, [99mTc]Tc-G3-(G3S)3C-HYNIC had the highest affinity. Comparative biodistribution of [99mTc]Tc-G3-G3C-HYNIC, [99mTc]Tc-G3-(G3S)3C-HYNIC, [99mTc]Tc-G3-E3C-HYNIC, and [99mTc]Tc-(HE)3-G3 in healthy CD1 mice showed that there was a strong influence of the linkers on uptake in normal tissues. [99mTc]Tc-G3-E3C-HYNIC had an increased retention of activity in the liver and the majority of other organs compared to the other conjugates. The tumor uptake of [99mTc]Tc-G3-(G3S)3C-HYNIC and [99mTc]Tc-(HE)3-G3 in Nu/j mice bearing SKOV-3 xenografts was similar. The specificity of tumor targeting in vivo was demonstrated for both tracers. [99mTc]Tc-G3-(G3S)3C-HYNIC provided comparable, although slightly lower tumor-to-lung, tumor-to spleen and tumor-to-liver ratios than [99mTc]Tc-(HE)3-G3. Radiolabeling of DARPin G3-HYNIC conjugates with 99mTc provided the advantage of a single-step radiolabeling procedure; however, the studied HYNIC conjugates did not improve imaging contrast compared to the 99mTc-tricarbonyl-labeled DARPin G3. At this stage, [99mTc]Tc-(HE)3-G3 remains the most promising candidate for the clinical imaging of HER2-overexpressing cancers.

Adjuvant Chemotherapy in Premenopausal Patients With Hormone-Positive Breast Cancer With a Recurrence Score of 16-25: A Retrospective Analysis Using the National Cancer Database.

PURPOSE: Results from the TAILORx trial revealed that the use of adjuvant chemotherapy along with endocrine therapy had no survival advantage in patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2-negative (HER2-), node-negative (N0) breast cancer (BC) with an intermediate (11-25) 21-gene recurrence score (RS) in the overall population. However, in patients under age 50 years, adjuvant chemotherapy demonstrated a progression-free survival benefit when the RS ranged from 16-25. We studied this cohort with the population-based national database. METHODS: The 2010-2018 National Cancer Database was used to include patients with BC age 18-50 years, N0, M0, RS 16-25, ER+/progesterone receptor±, and HER2-. Patients were divided into two groups on the basis of adjuvant chemotherapy use, and the survival between them was compared. RESULTS: Adjuvant chemotherapy use was noted in 4,808/15,792 (30.45%) patients. Median RS was 18 and 21 in patients without and with adjuvant chemotherapy, respectively. Factors associated with adjuvant chemotherapy use were higher T stage, poor and moderately differentiated tumors, age <40 years, care at an academic center, Caucasian race, patients undergoing mastectomy, regional lymph node surgery, and radiation therapy. Kaplan-Meier survival at 10 years was better with adjuvant chemotherapy (96.2% v 91.6%). Patients without adjuvant chemotherapy had more adverse outcomes (hazard ratio [HR], 1.683 [95% CI, 1.392 to 2.036]; P < .0001). Subgroup analysis showed that the benefit was significant in patients with RS scores 21-25 (HR, 1.953 [95% CI, 1.295 to 2.945]), ductal histology (HR, 1.521 [95% CI, 1.092 to 2.118]), Caucasian race (HR, 1.655 [95% CI, 1.180 to 2.322]), and 41-50 years age group (HR, 1.732 [95% CI, 1.244 to 2.411]). CONCLUSION: Our study showed an overall survival benefit for adjuvant chemotherapy use in patients with ER-positive, N0 premenopausal BC patients, age less than 50 years, with an intermediate RS score, particularly 21-25.

Exploring the effectiveness of molecular subtypes, biomarkers, and genetic variations as first-line treatment predictors in Asian breast cancer patients: a systematic review and meta-analysis.

BACKGROUND: Breast cancer incidence has been on the rise significantly in the Asian population, occurring at an earlier age and a later stage. The potential predictive value of molecular subtypes, biomarkers, and genetic variations has not been deeply explored in the Asian population. This study evaluated the effect of molecular subtype classification and the presence or absence of biomarkers and genetic variations on pathological complete response (pCR) after neoadjuvant treatment in Asian breast cancer patients. METHODS: A systematic search was conducted in MEDLINE (PubMed), Science Direct, Scopus, and Cochrane Library databases. Studies were selected if they included Asian breast cancer patients treated with neoadjuvant chemotherapy and contained data for qualitative or quantitative analyses. The quality of the included studies was assessed using the Newcastle Ottawa Scale. Following the random effects model, pooled odds ratios or hazard ratios with 95% confidence intervals for pCR were analysed using Review Manager Software. Heterogeneity between studies was assessed using Cochran's Q-test and I2 test statistics. RESULTS: In total, 19,708 Asian breast cancer patients were pooled from 101 studies. In the neoadjuvant setting, taxane-anthracycline (TA) chemotherapy showed better pCR outcomes in triple-negative breast cancer (TNBC) (p<0.0001) and human epidermal growth factor receptor 2 enriched (HER2E) (p<0.0001) than luminal breast cancer patients. Similarly, taxane-platinum (TP) chemotherapy also showed better pCR outcomes in TNBC (p<0.0001) and HER2E (p<0.0001). Oestrogen receptor (ER)-negative, progesterone receptor (PR)-negative, HER2-positive and high Ki-67 were significantly associated with better pCR outcomes when treated with either TA or TP. Asian breast cancer patients harbouring wildtype PIK3CA were significantly associated with better pCR outcomes when treated with TA in the neoadjuvant setting (p=0.001). CONCLUSIONS: In the neoadjuvant setting, molecular subtypes (HER2E and TNBC), biomarkers (ER, PR, HER2, HR, Ki-67, nm23-H1, CK5/6, and Tau), and gene (PIK3CA) are associated with increased pCR rates in Asian breast cancer patients. Hence, they could be further explored for their possible role in first-line treatment response, which can be utilised to treat breast cancer more efficiently in the Asian population. However, it needs to be further validated with additional powered studies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021246295.

Telangiectasias induced by combination tucatinib and ado-trastuzumab emtansine in a patient with metastatic breast cancer.

BACKGROUND: Tucatinib is a tyrosine kinase inhibitor currently used in salvage therapy for human epidermal growth factor receptor 2 (HER2)-positive breast and colorectal cancer. The use of tucatinib alone or in combination with ado-trastuzumab emtansine (T-DM1) in the treatment of advanced HER2-positive cancers is rapidly expanding. OBJECTIVE/METHODS: We report the case of a 66-year-old female who presented to the dermatology clinic with a one-year history of widespread telangiectasias that began after initiation of combination chemotherapy with tucatinib and T-DM1 for metastatic HER2-positive invasive ductal carcinoma. RESULTS: The patient's lesions regressed upon cessation of combination therapy and reappeared in the setting of tucatinib re-initiation, with gradual improvement over the following four months following electrocautery to the affected regions. CONCLUSIONS: We postulate that telangiectasias may be a previously unreported dermatologic side effect of combination treatment with tucatinib and T-DM1. Electrocautery is a safe and effective procedure to reduce the appearance of telangiectasias and improve patient satisfaction during chemotherapy.

Clinicopathological and prognostic significance of VEGF, PDGF-B, and HER2/neu expression in gallbladder cancer.

AIM: Gallbladder cancer (GBC) is usually diagnosed in advanced stages with poor survival. The molecular mechanisms of GBC still remain unexplored. Several angiogenesis factors play a pivotal role in tumor progression. We aimed to study the expression of VEGF, PDGF-B, and human epidermal growth factor receptor 2 (HER2/neu) and its association with clinicopathological features and survival in GBC. MATERIALS AND METHODS: VEGF, PDGF-B, and HER2/neu expression was studied by immunohistochemistry (IHC) after histological evaluation in 91 GBC cases. The relationship between these markers and clinicopathological features and survival was explained through the Cox regression model and Kaplan-Meier method. RESULTS: VEGF, PDGF-B, and HER2/neu overexpressed in 45, 79, and 68% GBC cases, respectively. VEGF was significantly overexpressed in GBC without gall stones (GS) (p = 0.007) and with moderately and poorly differentiated tumors (p = 0.012). HER2/neu was significantly overexpressed in GBC with GS (p = 0.022). Median overall survival (OS) was 39 months (95% CI: 23-55). In univariate analysis, histological type (adenocarcinoma and papillary) vs. others (signet ring/mucinous/adenosquamous) (p = 0.004), depth of tumor infiltration (p = 0.017), distant metastasis (p = 0.012), and adjuvant therapies (chemotherapy/radiotherapy) (p = 0.083) were associated with poor prognosis. Multivariate survival analysis showed histological type (p = 0.004) and distant metastasis (p = 0.032) to be independent prognostic factors for OS. Histological type (p = 0.002), distant metastasis (p = 0.003), and depth of tumor infiltration (T3-T4) (p = 0.012) showed poor median survival. Poor survival was seen in VEGF and HER2/neu positive cases. CONCLUSION: Overexpression of VEGF, PDGF-B, and HER2/neu might be possible prognostic biomarkers in GBC. Poor survival of VEGF and HER2/neu positive cases indicates the possibilities of using their blockers as therapeutic agents.

A Representative Clinical Course of Progression, with Molecular Insights, of Hormone Receptor-Positive, HER2-Negative Bone Metastatic Breast Cancer.

Despite treatment advances, breast cancer remains a leading cause of death of women in the United States, mostly due to metastatic disease. Bone is a preferential site for breast cancer metastasis, and most metastatic breast cancer patients experience bone involvement at the time of death. The majority of patients with bone metastatic breast cancer are first diagnosed with and treated for early-stage disease, and from development of early-stage breast cancer to the recurrence of cancer in the bones, up to 30 years may elapse. Throughout this timeframe, a typical patient undergoes many treatments that have effects on the bone microenvironment. Therefore, this review explores the clinical course of a representative patient with hormone receptor-positive bone metastatic breast cancer, examining key treatment options at each stage and their effects on preventing and treating bone metastases.

Trastuzumab deruxtecan in patients with metastatic non-small-cell lung cancer (DESTINY-Lung01): primary results of the HER2-overexpressing cohorts from a single-arm, phase 2 trial.

BACKGROUND: DESTINY-Lung01 is a multicentre, open-label, phase 2 study evaluating the antitumour activity and safety of trastuzumab deruxtecan, a HER2-directed antibody-drug conjugate, in patients with HER2-overexpressing or HER2 (ERBB2)-mutant unresectable or metastatic non-small-cell lung cancer (NSCLC). The results of the HER2-mutant cohort (cohort 2) have been reported elsewhere. Herein, we report the primary analysis of cohorts 1 and 1A, which aimed to evaluate the activity and safety of trastuzumab deruxtecan 5·4 mg/kg and 6·4 mg/kg in patients with HER2-overexpressing NSCLC. METHODS: Patients aged 18 years or older with unresectable or metastatic (or both unresectable and metastatic) non-squamous NSCLC who had relapsed following or were refractory to standard treatment or for whom no standard treatment was available, with an HER2 immunohistochemistry score of 3+ or 2+ (without known HER2 mutations) and an Eastern Cooperative Oncology Group performance status score of 0 or 1, were enrolled at 20 specialist hospitals in France, Japan, the Netherlands, Spain, and the USA. Patients were assigned to cohorts sequentially, first to cohort 1, to receive trastuzumab deruxtecan 6·4 mg/kg (cohort 1), then to cohort 1A, to receive trastuzumab deruxtecan 5·4 mg/kg, both administered intravenously once every 3 weeks. The primary endpoint was confirmed objective response rate by independent central review and was assessed in the full analysis set, which included all patients who signed an informed consent form and were enrolled in the study. Safety was assessed in all enrolled patients who received at least one dose of trastuzumab deruxtecan. This trial is registered with ClinicalTrials.gov, NCT03505710, and is ongoing (closed to recruitment). FINDINGS: Between Aug 27, 2018, and Jan 28, 2020, 49 patients were enrolled in cohort 1 (median age 63·0 years [IQR 58·0-68·0], 30 [61%] male, 19 [39%] female, and 31 [63%] White), and from June 16 to Dec 9, 2020, 41 patients were enrolled in cohort 1A (median age 62·0 years [IQR 56·0-66·0], 22 [54%] male, 19 [46%] female, and 31 [76%] White). As of data cutoff (Dec 3, 2021), the median treatment duration was 4·1 months (IQR 1·4-7·1) in cohort 1 and 5·5 months (1·4-8·7) in cohort 1A, and median follow-up was 12·0 months (5·4-22·4) in cohort 1 and 10·6 months (4·5-13·5) in cohort 1A. Confirmed objective response rate by independent central review was 26·5% (95% CI 15·0-41·1; 13 of 49, all partial responses) in cohort 1 and 34·1% (20·1-50·6; 14 of 41; two complete responses and 12 partial responses) in cohort 1A. The most common treatment-emergent adverse events of grade 3 or worse were neutropenia (12 [24%] of 49 in cohort 1, none in cohort 1A), pneumonia (six [12%] and two [5%], respectively), fatigue (six [12%] and three [7%], respectively), and disease progression (six [12%] and four [10%], respectively). Drug-related treatment-emergent adverse events of grade 3 or worse occurred in 26 (53%) of 41 patients in cohort 1 and nine (22%) of 49 patients in cohort 1A. Drug-related serious adverse events were reported in ten (20%) patients and three (7%) patients, respectively. Deaths due to treatment-emergent adverse events occurred in ten (20%) patients in cohort 1 (disease progression in six (12%) patients and bronchospasm, hydrocephalus, respiratory failure, and pneumonitis in one [2%] patient each), and in seven (17%) patients in cohort 1A (due to disease progression in four (10%) patients and dyspnoea, malignant neoplasm, and sepsis in one (2%) patient each). One death due to a treatment-emergent adverse event was determined to be due to study treatment by the investigator, which was in cohort 1 (pneumonitis). Independent adjudication of interstitial lung disease or pneumonitis found that drug-related interstitial lung disease or pneumonitis occurred in ten (20%) patients in cohort 1 (two [4%] grade 1, five [10%] grade 2, and three [6%] grade 5) and two (5%) patients in cohort 1A (one [2%] grade 2 and one [2%] grade 5). An additional patient in cohort 1A had grade 4 pneumonitis after the data cutoff, which was subsequently adjudicated as drug-related grade 5 interstitial lung disease or pneumonitis. INTERPRETATION: Given the low antitumour activity of existing treatment options in this patient population, trastuzumab deruxtecan might have the potential to fill a large unmet need in HER2-overexpressing NSCLC. Our findings support further investigation of trastuzumab deruxtecan in patients with HER2-overexpressing NSCLC. FUNDING: Daiichi Sankyo and AstraZeneca.

Discovery of Novel 5,6-Dihydro-4H-pyrido[2,3,4-de]quinazoline Irreversible Inhibitors Targeting Both Wild-Type and A775_G776insYVMA Mutated HER2 Kinases.

HER2 mutations were seen in 4% of non-small-cell lung cancer (NSCLC) patients. Most of these mutations (90%) occur as an insertion mutation within the exon 20 frame, leading to the downstream activation of the PI3K-AKT and RAS/MAPK pathways. However, no targeted therapies have yet been approved worldwide. Here a novel series of highly potent HER2 inhibitors with a pyrido[2,3,4-de]quinazoline core were designed and developed. The derivatives with the pyrido[2,3,4-de]quinazoline core displayed superior efficacy of antiproliferation in BaF3 cells harboring HER2insYVMA mutation compared with afatinib and neratinib. Rat studies showed that 8a and 9a with the newly developed core have good pharmacokinetic properties with an oral bioavailability of 41.7 and 42.0%, respectively. Oral administration of 4a and 10e (30 mg/kg, QD) displayed significant antitumor efficacy in an in vivo xenograft model. We proposed promising strategies for the development of HER2insYVMA mutant inhibitors in this study.

Breast Cancer Molecular Subtyping in Practice: A Real-World Study of the APIS Breast Cancer Subtyping Assay in a Consecutive Series of Breast Core Biopsies.

The APIS Breast Cancer Subtyping Kit is an mRNA-based assessment of the seven parameters including three biomarkers routinely assessed in all the newly diagnosed breast cancers (BC), oestrogen receptor (ER), progesterone receptor (PR) and HER-2 and an additional four genes that create a novel proliferation signature, MKI67, PCNA, CCNA2 and KIF23. Taken together, the data are used to produce a molecular subtype for every sample. The kit was evaluated against the current standard protocol of immunohistochemistry (IHC) and/or in situ hybridisation (ISH) in breast cancer patients. The data were presented at the weekly breast multidisciplinary team (MDT) meeting. A total of 98 consecutive cases of pre-operative breast cancer core biopsies and two core biopsies of nodal metastases yielding 100 cases were assessed. IHC and APIS results were available for 100 and 99 cases. ER was concordant in 97% cases, PR was concordant in 89% and HER-2 results were concordant with IHC/ISH in 100% of the cases. Ki-67 IHC was discordant in 3% of cases when compared with MK167 alone but discordant in 24% when compared with the four-gene proliferation signature. In conclusion, our study indicates that the APIS Breast Cancer Subtyping Kit is highly concordant when compared to the results produced for ER/PR/HER-2 by IHC and/or ISH. The assay could play a role in the routine assessment of newly diagnosed breast cancer (BC) specimens.

PIK3CA testing in hormone receptor-positive/HER2-negative metastatic breast cancer: real-world data from Italian molecular pathology laboratories.

Introduction: PIK3CA gene mutations occur in approximately 40% of hormone receptor-positive/HER2-negative (HR+/HER2-) metastatic breast cancers (MBCs), electing them to targeted therapy. Testing PIK3CA status is complex due to selection of biological specimen and testing method. Materials & methods: This work investigates real-life experience on PIK3CA testing in HR+/HER2- MBC. Clinical, technical and molecular data on PIK3CA testing were collected from two referral laboratories. Additionally, the results of a nationwide PIK3CA survey involving 116 institutions were assessed. Results: Overall, n = 35 MBCs were PIK3CA-mutated, with mutations mostly occurring in exons 9 (n = 19; 51.4%) and 20 (n = 15; 40.5%). The nationwide survey revealed significant variability across laboratories in terms of sampling methodology, technical assessment and clinical report signing healthcare figures for PIK3CA molecular testing in diagnostic routine practice. Conclusion: This study provides insights into the real-world routine of PIK3CA testing in HR+/HER2- MBC and highlights the need for standardization and networking in predictive pathology.

The application of HER2-ADC in future: More than expression.

We analyzed the potential of HER2-targeted antibody-drug conjugates (ADCs) in treating NSCLC with activating HER2 mutations. We identified specific mutations, notably G776delinsVC, that are associated with higher therapeutic response rates, suggesting a refined approach for precision treatment. Further validation and exploration are crucial for potential breakthroughs in ADC therapy.

The role of mir96 in predicting CTC status and prognostic evaluation in gastric cancer patients.

In this study, 20 patients clinically diagnosed with advanced gastric cancer were selected as subjects. Circulating tumor cells (CTCs) in the peripheral blood of gastric cancer patients were detected and counted by collecting peripheral blood samples at Ningbo No. 2 Hospital and using the Cell Rich TM system combined with a negative enrichment strategy. In addition, routine pathological examination and immunohistochemical staining were performed on surgical specimens, including HER2, EBER, E-cadherin, and vimentin indicators. These indicators were correlated and analyzed with CTC counts and routine clinical tests. At the same time, miRNA groups were performed to explore the miRNAs with or without correlation with CTC and to try to construct a predictive model for CTC status. Tumor tissue from patients whose CTC counts did not match the results of the miRNA prediction model was subjected to second-generation gene sequencing to analyze indicators such as tumor heterogeneity and immune microenvironment. The results of the study showed that CTCs were detected in the peripheral blood of 50% (10/20) of gastric cancer patients using the Cell Rich TM system, serum fibrinogen was negatively correlated with CTC counts, whereas TNM staging elements, HER2 receptor and p53 were not correlated with CTC counts. miRNA assays showed that the expression levels of miR218, miR1207, miR96, miR409, miR149, miR148a, miR155, miR370 and miR223 were significantly different between the two groups of CTC≥2 and CTC<2. Among them, miR-96 showed good efficacy as an indicator for predicting CTC status and assisting in determining the prognosis of gastric cancer. In conclusion, the present study demonstrated that the Cell Rich TM system combined with the negative enrichment strategy can effectively detect CTCs in the peripheral blood of gastric cancer patients and that the expression of miR-96 can be used as an effective indicator to predict CTC status and assist in determining the prognosis of gastric cancer. These findings have important implications for the diagnosis and treatment of gastric cancer and provide new clues for the further study of the tumor immune microenvironment and tumor heterogeneity.

HER2 targeted therapy in colorectal Cancer: Current landscape and future directions.

Colorectal cancer (CRC) is one of the most common causes of tumor-related deaths globally. Despite recent improvements in the comprehensive therapy of malignancy, metastatic CRC continues to have a poor prognosis. Human epidermal growth factor receptor 2 (HER2) is an established oncogenic driver, which is successfully targeted for breast and gastric cancers. Approximately 5% of CRC patients carry somatic HER2 mutations or gene amplification. In 2019, the U.S. Food and Drug Administration have approved trastuzumab and pertuzumab in combination with chemotherapy for the treatment of HER2-positive metastatic CRC. This approval marked a significant milestone in the treatment of CRC, as HER2-positive patients now have access to targeted therapies that can improve their outcomes. Yet, assessment for HER2 overexpression/ amplification in CRC has not been standardized. The resistance mechanisms to anti-HER2 therapy have been not clearly investigated in CRC. Although many unknowns remain, an improved understanding of these anti-HER2 agents will be essential for advanced CRC. In this review, we provide an overview of the role of HER2 in CRC as an oncogenic driver, a prognostic and predictive biomarker, and a clinically actionable target, as well as the current progress and challenges in the field.

Trastuzumab plus pertuzumab for HER2-amplified advanced colorectal cancer: Results from the drug rediscovery protocol (DRUP).

BACKGROUND: In 2-5% of patients with colorectal cancer (CRC), human epidermal growth factor 2 (HER2) is amplified or overexpressed. Despite prior evidence that anti-HER2 therapy confers clinical benefit (CB) in one-third of these patients, it is not approved for this indication in Europe. In the Drug Rediscovery Protocol (DRUP), patients are treated with off-label drugs based on their molecular profile. Here, we present the results of the cohort 'trastuzumab/pertuzumab for treatment-refractory patients with RAS/BRAF-wild-type HER2amplified metastatic CRC (HER2+mCRC)'. METHODS: Patients with progressive treatment-refractory RAS/BRAF-wild-type HER2+mCRC with measurable disease were included for trastuzumab plus pertuzumab treatment. Primary endpoints of DRUP are CB (defined as confirmed objective response (OR) or stable disease (SD) ≥ 16 weeks) and safety. Patients were enrolled using a Simon-like 2-stage model, with 8 patients in stage 1 and 24 patients in stage 2 if at least 1/8 patients had CB. To identify biomarkers for response, whole genome sequencing (WGS) was performed on pre-treatment biopsies. RESULTS: CB was observed in 11/24 evaluable patients (46%) with HER2+mCRC, seven patients achieved an OR (29%). Median duration of response was 8.4 months. Patients had undergone a median of 3 prior treatment lines. Median progression-free survival and overall survival were 4.3 months (95% CI 1.9-10.3) and 8.2 months (95% CI 7.2-14.7), respectively. No unexpected toxicities were observed. WGS provided potential explanations for resistance in 3/10 patients without CB, for whom WGS was available. CONCLUSIONS: The results of this study confirm a clinically significant benefit of trastuzumab plus pertuzumab treatment in patients with HER2+mCRC.

Efficacy and safety of trastuzumab deruxtecan in treating human epidermal growth factor receptor 2-low/positive advanced breast cancer:A meta-analysis of randomized controlled trials.

BACKGROUND: A novel antibody-drug conjugate, trastuzumab deruxtecan is a combination of a human epidermal growth factor receptor 2 (HER2)-targeting antibody and DNA topoisomerase I inhibitor used to treat HER2-low/positive advanced breast cancer. To determine its safety and efficacy in treating HER2-low/positive advanced breast cancer, we performed a meta-analysis of several randomized clinical trials (RCTs) including DESTINY-Breast02 (NCT03523585), DESTINY-Breast03 (NCT03529110), and DESTINY-Breast04 (NCT03734029). METHODS: We searched PubMed, Embase, and the Cochrane Library for RCTs on the efficacy and safety of trastuzumab deruxtecan that were published before May 2023. The efficacy endpoints included median progressive-free survival (PFS), overall survival (OS), duration of response (DOR), overall response rate (ORR), and clinical benefit rate (CBR). The safety endpoints included treatment-related adverse events. Statistical analyses were performed using RevMan 5.4 software. To ensure transparency, this study was registered on the International Prospective Register of Systematic Reviews website (CRD42023414170). RESULTS: Three RCTs involving 1689 patients were included. Compared with physician-recommended and conventional treatments, trastuzumab deruxtecan exhibited statistically significant improvements in PFS, ORR, and CBR. The median OS and DOR failed to be combined; however, the analyzed studies showed that they were longer. The incidence of adverse events was generally higher with trastuzumab deruxtecan than with physician-recommended or conventional treatments. CONCLUSION: The results of this study suggest that trastuzumab deruxtecan is more effective in treating HER2-low/positive advanced breast cancer than physician-recommended or conventional treatments. However, trastuzumab deruxtecan-related adverse drug reactions should be closely monitored because of its higher incidence of adverse events.

Cdc42-driven endosomal cholesterol transport promotes collateral resistance in HER2-positive gastric cancer.

Resistance to trastuzumab and the poor efficacy of subsequent chemotherapy have become major challenges for HER2-positive gastric cancer (GC). As resistance evolves, tumor cells may acquire a new drug susceptibility profile, profoundly impacting the subsequent treatment selection and patient survival. However, the interplay between trastuzumab and other types of drugs in HER2-positive GC remains elusive. In our study, we utilized resistant cell lines and tissue specimens to map the drug susceptibility profile of trastuzumab-resistant GC, discovering that resistance to trastuzumab induces collateral resistance to commonly used chemotherapeutic agents. Additionally, patients with collateral resistance distinguished by a 13-gene scoring model in HER2-positive GC cohorts are predicted to have a poor prognosis and may be sensitive to cholesterol-lowering drugs. Mechanistically, endosomal cholesterol transport is further confirmed to enrich cholesterol in the plasma membrane, contributing to collateral resistance through the Hedgehog-ABCB1 axis. As a driver for cholesterol, Cdc42 is activated by the formation of the NPC1-TßRI-Cdc42 complex to facilitate endosomal cholesterol transport. We demonstrated that inhibiting Cdc42 activation with ZCL278 reduces cholesterol levels in the plasma membrane and reverses collateral resistance between trastuzumab and chemotherapy in vitro and in vivo. Collectively, our findings verify the phenomena and mechanism of collateral resistance between trastuzumab and chemotherapy, and propose a potential therapeutic target and strategy in the second-line treatment for trastuzumab-resistant HER2-positive GC.

A deep learning based holistic diagnosis system for immunohistochemistry interpretation and molecular subtyping.

BACKGROUND: Breast cancer in different molecular subtypes, which is determined by the overexpression rates of human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER), progesterone receptor (PR), and Ki67, exhibit distinct symptom characteristics and sensitivity to different treatment. The immunohistochemical method, one of the most common detecting tools for tumour markers, is heavily relied on artificial judgment and in clinical practice, with an inherent limitation in interpreting stability and operating efficiency. Here, a holistic intelligent breast tumour diagnosis system has been developed for tumour-markeromic analysis, combining the automatic interpretation and clinical suggestion. METHODS: The holistic intelligent breast tumour diagnosis system included two main modules. The interpreting modules were constructed based on convolutional neural network, for comprehensively extracting and analyzing the multi-features of immunostaining. Referring to the clinical classification criteria, the interpreting results were encoded in a low-dimensional feature representation in the subtyping module, to efficiently output a holistic detecting result of the critical tumour-markeromic with diagnosis suggestions on molecular subtypes. RESULTS: The overexpression rates of HER2, ER, PR, and Ki67, as well as an effective determination of molecular subtypes were successfully obtained by this diagnosis system, with an average sensitivity of 97.6 % and an average specificity of 96.1 %, among those, the sensitivity and specificity for interpreting HER2 were up to 99.8 % and 96.9 %. CONCLUSION: The holistic intelligent breast tumour diagnosis system shows improved performance in the interpretation of immunohistochemical images over pathologist-level, which can be expected to overcome the limitations of conventional manual interpretation in efficiency, precision, and repeatability.

Clinical application of the HM-1000 image processing for HER2 fluorescence in situ hybridization signal quantification in breast cancer.

BACKGROUND: Accurate quantification of human epidermal growth factor receptor 2 (HER2) gene amplification is important for predicting treatment response and prognosis in patients with breast cancer. Fluorescence in situ hybridization (FISH) is the gold standard for the diagnosis of HER2 status, particularly in cases with equivocal status on immunohistochemistry (IHC) staining, but has some limitations of non-classical amplifications and such cases are diagnosed basing on additional IHC and FISH. This study investigated the clinical utility of a novel super-resolution fluorescence microscopy technique for the better FISH signal visualization and HER2 FISH classification. METHODS: Fourteen breast cancer tissue samples were retrospectively collected between September 2018 and February 2022, and FISH HER2 signal quantification was evaluated by determining the HER2/chromosome 17 centromere (CEP17) ratio and the number of HER2 signals per nucleus in super- versus conventional-resolution images. RESULTS: Super-resolution images maintained the same overall HER2 diagnosis from routine, but HER2 FISH amplification changed negative to monosomy in two cases. Two Letrozole non-response relapses coincided to monosomy samples. The median number of HER2 signals per nucleus was 7.5 in super-resolution images and 4.0 in conventional-resolution images in HER2-positive samples and 2.8 and 2.1 signals per nucleus, respectively, in HER2-negative samples. CONCLUSIONS: Super-resolution images improved signal visualization, including a significant difference in the number of countable HER2 and CEP17 signals in a single nucleus compared with conventional-resolution images. Increased accuracy of signal quantification by super-resolution microscopy may provide clinicians with more detailed information regarding HER2 FISH status that allows to better FISH classification such as HER2-low samples.

Somatic mutations in a multigene panel and impact on prognosis based on TP53 status in Chinese HER2-positive patients undergoing neoadjuvant therapy: A single-institution retrospective cohort.

BACKGROUND: Gene mutations play a crucial role in the occurrence and development of tumors, particularly in breast cancer (BC). Neoadjuvant therapy (NAT) has shown greater clinical benefit in HER2-positive breast cancer. However, further clinical investigation is needed to fully understand the correlation between genetic mutations and NAT efficacy and the long-term prognosis in HER2-positive BC. METHODS: This was a retrospective cohort study of 222 patients receiving NAT between 2017 and 2021 in the Department of Breast Surgery of Fudan University Shanghai Cancer Center. Tumor samples from these patients were subjected to Next Generation Sequencing (NGS) to analyze mutations in 513 cancer-related genes. This study aimed to investigate the association between these genetic mutations and postoperative pathological complete response (pCR), as well as their impact on disease-free survival (DFS). RESULTS: In total, 48.65% patients reached pCR, ER-negative status (p < 0.001), PR-negative status (p < 0.001), Ki67 ≥ 20 (p = 0.011), and dual-targeted therapy (p < 0.001) were all associated with enhanced pCR rates. The frequency of somatic alterations in TP53 (60%), PIK3CA (15%), and ERBB2 (11%) was highest. In the HER2+/HR- cohort, patients who achieved pCR had a significant benefit in prognosis (HR = 3.049, p = 0.0498). KMT2C (p = 0.036) and TP53 (p = 0.037) mutations were significantly increased in patients with DFS events. Moreover, TP53 mutations had prognostic significance in HER2-positive BC patients with HR-negative (HR = 3.712, p = 0.027) and pCR (HR = 6.253, p = 0.027) status and who received herceptin-only targeted therapy (HR = 4.145, p = 0.011). CONCLUSIONS: The genetic mutation profiles of Chinese HER2+ patients who received NAT were discrepant with respect to HR status or DFS events. TP53 mutations have significant prognostic value in patients with NAT for HER2-positive BC and patients benefit differently depending on HR status, the neoadjuvant regimen and response, which highlights the significance of genetic factors in treatment customization based on individual genetic and clinical characteristics.