BACKGROUND: Trastuzumab improved the prognosis of patients with human epidermal growth factor receptor 2 (HER2)+ breast cancer (BC). Here, we present a patient who developed acute vision loss due to optic atrophy in both eyes after trastuzumab.
METHODS: A 60-year-old female patient was diagnosed with locally advanced HER2+ BC in January 2021. After four cycles of neoadjuvant anthracycline-based chemotherapy followed by four cycles of docetaxel, trastuzumab, and pertuzumab combined treatment, the patient underwent a right modified radical mastectomy. Three days after the end of the second cycle of adjuvant trastuzumab, she presented with acute vision loss. The patient\'s visual acuity was 90% in the right eye and 60% in the left eye. The left eye had optic nerve edema and spindle hemorrhages. First, on suspicion of optic neuritis, the patient was given a 1 gram/day pulse steroid for three days. However, optic neuritis was not considered during the follow-up. Metastasis was considered at the exit of the left optic nerve. Trastuzumab was started by making a mutual decision with the patient. Six days after the sixth dose of adjuvant trastuzumab, she presented with almost complete vision loss.
METHODS: The patient was diagnosed with optic neuritis, and a pulse steroid was administered. Trastuzumab was permanently discontinued. However, the patient\'s visual acuity in both eyes remained at 5-10%.
CONCLUSIONS: Vision loss due to optic neuritis is a devastating side effect. Understanding that trastuzumab-induced optic neuritis may develop will help clinicians detect side effects early and manage them more effectively.

UNASSIGNED: Cardiotoxicity (CTX) induced by adjuvant chemotherapy is a significant factor that impacts the prognosis and quality of life in breast cancer (BC) patients. In this study, we aimed to investigate the changes in epicardial adipose tissue (EAT) before and after treatment in BC patients who received anthracyclines adjuvant chemotherapy protocol (AC-T) and anthracyclines combined with trastuzumabadjuvant chemotherapy protocol (AC-TH). Additionally, we assessed whether there were any differences in the changes in EAT between the two groups of patients. Our objective was to examine the effects of anthracyclines and trastuzumab on EAT and determine the potential role of EAT changes on CTX.
UNASSIGNED: We reviewed female BC patients who were treated with adjuvant chemotherapy protocols of AC-T and AC-TH, all of whom underwent baseline (T0) and follow-up (T1) chest computed tomography (CT) and echocardiography. A cohort of healthy women, matched in age, underwent two chest CTs. EAT was quantified on chest CT using semi-automated software. CTX was defined as a > 10% reduction in left ventricular ejection fraction (LVEF) from baseline, with an absolute value of < 53%.
UNASSIGNED: A total of 41 BC patients were included in the study, with 23 patients in the AC-T group and 18 patients in the AC-TH group. Additionally, 22 healthy females were included as the normal group. None of the BC patients developed CTX after chemotherapy. The age did not differ significantly between the normal group and the AC-T group (p = 0.341) or the AC-TH group (p = 0.853). Similarly, the body mass index (BMI) of the normal group was comparable to that of the AC-T group (p = 0.377, 0.346) and the AC-TH group (p = 0.148, 0.119) before and after chemotherapy. The EAT volume index (mL/kg/ m 2 ) was significantly higher in both the AC-T group (5.11 ± 1.85 vs. 4.34 ± 1.55, p < 0.001) and the AC-TH group (4.53 ± 1.61 vs. 3.48 ± 1.62, p < 0.001) at T1 compared with T0. In addition, both the AC-T group (-72.95 ± 5.01 vs. -71.22 ± 3.91, p = 0.005) and the AC-TH group (-72.55 ± 5.27 vs. -68.20 ± 5.98, p < 0.001) exhibited a significant decrease in EAT radiodensity (HU) at T1 compared to T0. However, there was no significant difference observed in the normal group. At T0, no difference was seen in EAT volume index (4.34 ± 1.55 vs. 3.48 ± 1.62, p = 0.090) and radiodensity (-71.22 ± 3.91 vs. -68.20 ± 5.98, p = 0.059) between the AC-T and AC-TH groups. Similarly, at T1, there was still no significant difference observed in the EAT volume index (-5.11 ± 1.85 vs. 4.53 ± 1.61, p = 0.308) and radiodensity (-72.95 ± 5.00 vs. -72.54 ± 5.27, p = 0.802) between the two groups.
UNASSIGNED: BC patients who underwent AC-T and AC-TH adjuvant chemotherapy protocols demonstrated a significant rise in the volume index of EAT, along with a substantial reduction in its radiodensity post-chemotherapy. These findings indicate that alterations in EAT could potentially aid in identifying cardiac complications caused by chemotherapeutic agents and remind clinicians to focus on changes in EAT after adjuvant chemotherapy in BC patients to prevent the practical occurrence of CTX.

BACKGROUND: Trastuzumab has improved breast cancer (BC) prognosis and reduced anthracycline use. However, the characteristic changes of anthracycline-related cardiomyopathy (ARCM) in patients with BC remain unclear. We aimed to update our understanding of ARCM in the trastuzumab era.
METHODS: This retrospective observational cohort study included 2959 patients with BC treated with anthracyclines at three regional cancer centers in Niigata City between 1990 and 2020. Seventy-five patients (2.5%) developed ARCM and were categorized into two groups: pre- 2007 (early phase) and post-2007 (late phase), corresponding to before and during the trastuzumab era in Japan.
RESULTS: ARCM incidence peaked at 6% in the 1990s, then decreased and stabilized at 2% until the 2010s. Survivors of anthracycline-treated BC increased more rapidly in the late phase, with four times as many patients with ARCM compared to the end of the early phase (26 and six, respectively). Although the rate of change in accumulation from the early phase to the late phase was slight in the anthracycline-treated BC group, it was more pronounced in the ARCM group (P < 0.001). Mean anthracycline use in the late phase was significantly lower than in the early phase (307 vs. 525 mg/m2, P < 0.001). Five-year survival rates in the late phase tended to be higher than early phase (45% and 28%, respectively. P = 0.058). Human epidermal growth factor receptor type 2 (HER2) positivity with trastuzumab therapy in the late phase was an independent predictor for mortality within 10 years (hazard ratio = 0.24, 95% confidence interval: 0.10-0.56; P = 0.001).
CONCLUSIONS: HER2-positive patients with ARCM receiving trastuzumab therapy had a better prognosis than HER2-positive and HER2-negative patients with ARCM not receiving trastuzumab therapy, and this trend has been increasing in the trastuzumab era. These findings highlight the importance of HER2-targeted treatments in improving prognosis for BC patients with ARCM.

Cancer-specific monoclonal antibodies (CasMabs) that recognize cancer-specific antigens with in vivo antitumor efficacy are innovative therapeutic strategies for minimizing adverse effects. We previously established a cancer-specific anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibody (mAb), H2Mab-250/H2CasMab-2. In flow cytometry and immunohistochemistry, H2Mab-250 reacted with HER2-positive breast cancer cells but did not show reactivity to normal epithelial cells. In contrast, a clinically approved anti-HER2 mAb, trastuzumab, strongly recognizes both breast cancer and normal epithelial cells in flow cytometry. The human IgG1 version of H2Mab-250 (H2Mab-250-hG1) possesses compatible in vivo antitumor effects against breast cancer xenografts to trastuzumab despite the lower affinity and effector activation than trastuzumab in vitro. This study compared the antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cellular cytotoxicity (CDC) between H2Mab-250-hG1 and trastuzumab. Both H2Mab-250-hG1 and trastuzumab showed ADCC activity against HER2-overexpressed Chinese hamster ovary -K1 and breast cancer cell lines (BT-474 and SK-BR-3) in the presence of human natural killer cells. Some tendency was observed where trastuzumab showed a more significant ADCC effect compared to H2Mab-250-hG1. Importantly, H2Mab-250-hG1 exhibited superior CDC activity in these cells compared to trastuzumab. Similar results were obtained in the mouse IgG2a types of both H2Mab-250 and trastuzumab. These results suggest the different contributions of ADCC and CDC activities to the antitumor effects of H2Mab-250-hG1 and trastuzumab, and indicate a future direction for the clinical development of H2Mab-250-hG1 against HER2-positive tumors.

Preclinical studies suggest that simultaneous HER2/VEGF blockade may have cooperative effects in gastroesophageal adenocarcinomas. In a single-arm investigator initiated clinical trial for patients with untreated advanced HER2+ gastroesophageal adenocarcinoma, bevacizumab was added to standard of care capecitabine, oxaliplatin, and trastuzumab in 36 patients (NCT01191697). Primary endpoint was objective response rate and secondary endpoints included safety, duration of response, progression free survival, and overall survival. The study met its primary endpoint with an objective response rate of 81% (95% CI 65-92%). Median progression free and overall survival were 14.0 (95% CI, 11.3-36.4) and 23.2 months (95% CI, 16.6-36.4), respectively. The median duration of response was 14.9 months. The regimen was well tolerated without unexpected or severe toxicities. In post-hoc ctDNA analysis, baseline ctDNA features were prognostic: Higher tumor fraction and alternative MAPK drivers portended worse outcomes. ctDNA at resistance identified oncogenic mutations and these were detectable 2-8 cycles prior to radiographic progression. Capecitabine, oxaliplatin, trastuzumab and bevacizumab shows robust clinical activity in HER2+ gastroesophageal adenocarcinoma. Combination of VEGF inhibitors with chemoimmunotherapy and anti-PD1 regimens is warranted.

UNASSIGNED: Serous endometrial cancers (ECs) are an aggressive histotype of ECs which are disproportionately responsible for 40% of cancer-specific mortality rates despite constituting only 5-10% of all uterine cancers in incidence. In recent times, it has become increasingly evident that about 20-40% of uterine serous cancers (USCs) have molecular alterations in ERBB2 pathway with human epidermal growth factor receptor 2 (HER2/neu) amplification or overexpression. We summarise the evidence on genetic and molecular alterations in HER2/neu pathway in USC with a focus on testing criteria, targeting agents and resistance mechanisms.
UNASSIGNED: We conducted a database search of PubMed/Medline up to 28th February 2023 for articles published in the English language using pre-defined search terms. One hundred and seventy-one relevant articles were subsequently reviewed for eligibility and inclusion in the review.
UNASSIGNED: The Cancer Genome Atlas (TCGA) classification is a significant development in the molecular profiling of ECs with a positive impact on the treatment of these tumors including USCs. Testing criteria for HER2/neu in USC with immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) has evolved in more than a decade with progress made towards EC specific testing guidelines. The findings of a recent phase III study have led to the development of practice changing guidelines towards improving patient outcomes.
UNASSIGNED: Molecular aberration in the HER2/neu pathway contributes to the aggressive behaviour of USC. Considering the clinical benefit conferred by HER2/neu targeted therapy, HER2/neu testing is recommended for all cases of serous EC in advanced and recurrent settings. Trastuzumab in combination with platinum and taxanes based chemotherapy is the recommended treatment option for patients with advanced or recurrent serous cancers who test positive to HER2/neu. Clinical trials on targeted therapy are ongoing and future research should focus on selection of patients who will derive the most benefit from such therapy.

UNASSIGNED: Gastric cancer remains a challenging malignancy with a high global mortality rate. Recent advances in targeted therapy and immunotherapy have shown promise in improving patient outcomes. This paper reviews the impact of incorporating targeted agents such as trastuzumab and immunotherapeutic agents like pembrolizumab into standard chemotherapy regimens for gastric cancer treatment.
UNASSIGNED: A comprehensive analysis was conducted on pivotal clinical trials, including KEYNOTE-590, KEYNOTE-811, and ToGA, focusing on their methodologies, patient populations, treatment regimens, and outcome measures. The review also explored emerging research avenues in precision medicine, particularly genomic sequencing and biomarker identification.
UNASSIGNED: To assess the efficacy and survival benefits of adding trastuzumab and pembrolizumab to standard chemotherapy in the treatment of gastric cancer and to outline future directions in gastric cancer research.
UNASSIGNED: Including trastuzumab and pembrolizumab in treatment regimens for human epidermal growth factor receptor 2 (HER2)-positive and PD-L1-expressing gastric cancers significantly improved progression-free and overall survival rates compared to chemotherapy alone. These findings highlight the potential of personalized therapy in enhancing treatment outcomes. Furthermore, ongoing research into the gastric cancer microenvironment and the role of the microbiome suggests novel targets for future therapeutic interventions.
UNASSIGNED: The integration of targeted and immunotherapeutic agents with traditional chemotherapy represents a pivotal shift in gastric cancer treatment, moving towards more personalized and effective regimens.

OBJECTIVE: To evaluate the efficacy and safety of the combination of olaparib plus trastuzumab in patients with HER2-positive advanced breast cancer (ABC) and germinal BRCA mutations (gBRCAm).
METHODS: OPHELIA (NCT03931551) was a single-arm, open-label, phase 2 clinical trial. Patients aged ≥18 years diagnosed with HER2-positive ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease were enrolled. Patients received olaparib plus trastuzumab until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint was investigator-assessed clinical benefit rate for at least 24 weeks as per RECIST v.1.1. Key secondary endpoints included overall response rate (ORR) and safety profile.
RESULTS: A total of 68 pre-treated HER2-positive ABC patients were screened. Due to slow accrual the trial was stopped after enrolling 5 patients instead of the planned sample size of 20. Four patients achieved clinical benefit (80.0 %, 95 % CI; 28.4-99.5, p < 0.001) and the primary endpoint was met. The ORR was 60.0 % (95 % CI; 14.7-94.7), including one complete response. Four (80.0 %) patients experienced at least one treatment-related treatment-emergent adverse event (TEAE). Most TEAEs were grade 1 or 2. There were no treatment-related deaths and no new safety signals were identified.
CONCLUSIONS: This study suggests that the combination of olaparib plus trastuzumab may be effective and safe in pre-treated patients with HER2-positive gBRCAm ABC. This ABC patient population should be further studied and not be pre-emptively excluded from clinical trials of targeted therapy for BRCA1/2-driven cancers.

Trastuzumab deruxtecan (T-DXd) is a novel anti-HER2 antibody-drug conjugate formed by the combination of trastuzumab and deruxtecan. It is used in human epidermal growth factor 2 receptor (HER2) mutant breast, stomach and colorectal cancers as well as non-small cell lung cancer (NSCLC). The 58-year-old denovo metastatic NSCLC patient we will discuss here progressed with newly developing brain metastasis under first-line carboplatin/paclitaxel treatment. After next generation sequencing revealed a mutation in the ERBB2 gene located in exon 20, we administered T-DXd to our patient. While a significant improvement was observed in the clinical condition of the patient after one course of treatment, brain metastases were found to be in complete response in control screening after four courses of treatment. Systemic screening with PET/computed tomography showed nearly complete regression of the primary lesion, metastatic lymphadenopathies, and surrenal metastases. T-DXd may be successfully used in HER2 mutant metastatic NSCLC patients. In addition, it can also be successfully used in patients with central nervous system metastases with or without cranial radiotherapy.

About 20% of breast cancer patients are positive for HER2. The efficacy of current treatments is limited by primary and secondary resistance to trastuzumab. tRNA-derived fragments (tRFs) have shown crucial regulatory roles in various cancers. This study aimed to evaluate the role of tRF-27 in regulating the resistance of HER2-positive breast cancer against trastuzumab. tRF-27 was highly expressed in trastuzumab-resistant cells, and its expression level could predict the resistance to trastuzumab. High expression of tRF-27 promoted the growth and proliferation of trastuzumab-exposed cells. RNA-pulldown assay and mass spectrometry were performed to identify Ras GTPase-activating protein-binding proteins 1 and 2 (G3BPs) (two proteins targeted by tRF-27); RNA-immunoprecipitation (RIP) to confirm their bindings; co-immunoprecipitation (co-IP) and RNA-pulldown assay to determine the binding domains between G3BPs and tRF-27.tRF-27 bound to the nuclear transport factor 2 like domain(NTF2 domain) of G3BPs through a specific sequence. tRF-27 relied on G3BPs and NTF2 domain to increase trastuzumab tolerance. tRF-27 competed with lysosomal associated membrane protein 1(LAMP1) for NTF2 domain, thereby inhibiting lysosomal localization of G3BPs and tuberous sclerosis complex (TSC). Overexpression of tRF-27 inhibited phosphorylation of TSCs and promoted the activation of mechanistic target of rapamycin complex 1(MTORC1) to enhance cell proliferation and entice the resistance of HER2-positive breast cancer against trastuzumab.