Insights Into the Impacts of BRCA Mutations on Clinicopathology and Management of Early-Onset Triple-Negative Breast Cancer

TROPION-Breast02: Datopotamab deruxtecan for locally recurrent inoperable or metastatic triple-negative breast cancer

Despite recent treatment advances, the prognosis for patients with locally recurrent inoperable or metastatic triple-negative breast cancer (TNBC) remains poor. The antibody-drug conjugate datopotamab deruxtecan (Dato-DXd) is composed of a humanized anti-TROP2 IgG1 monoclonal antibody linked to a topoisomerase I inhibitor payload via a stable, cleavable linker. The phase III TROPION-Breast02 trial in patients previously untreated for locally recurrent inoperable or metastatic TNBC, who are not candidates for PD-1/PD-L1 inhibitors is evaluating efficacy and safety of Dato-DXd versus investigator's choice of chemotherapy (ICC). Approximately 600 patients will be randomized 1:1 to Dato-DXd 6 mg/kg iv. every 3 weeks or ICC (paclitaxel, nab-paclitaxel, carboplatin, capecitabine or eribulin mesylate). Dual primary end points are progression-free survival by blinded independent central review and overall survival.

Survival Outcomes and Efficacy of Platinum in Early Breast Cancer Patients with Germline BRCA1 or BRCA2 Mutation: A Multicenter Retrospective Cohort Study

Purpose

The study aimed to compare the survival outcomes and efficacy of platinum in early breast cancer patients with BRCA1 and BRCA2 mutations.

Methods

Patients diagnosed with stage I-III breast cancer and carrying germline pathogenic/likely pathogenic BRCA mutations in three medical institutions in China from April 2016 to January 2021 were retrospectively analyzed. Data on clinical and pathological characteristics, treatment information, pathogenic variants of BRCA, and survival outcomes were collected for all eligible patients.

Outcomes

One hundred and sixty-nine patients with BRCA mutations were enrolled, including BRCA1 mutation (53.3%, n = 90) and BRCA2 mutation (46.7%, n = 79). The median age was 39 years, and most patients (68.1%, n = 115) were stage I-II. Patients with BRCA1 mutations were characterized by histological grade III (55.6%) and higher Ki-67 index (Ki-67 ≥ 30%, 78.9%) compared with patients with BRCA2 mutations (27.8%, 58.2%). BRCA1 mutation patients accounted for a significantly higher proportion of triple negative breast cancer than BRCA2 mutation patients (71.1% vs 19.0%, P < 0.0001). A total of 142 (84.0%) patients received neo/adjuvant chemotherapy, including anthracycline and/or taxane-based regimens (55.6%) or platinum-based regimens (27.2%). Median follow-up was 33.2 months. Three-year DFS (disease-free survival) and DRFS (distant recurrence-free survival) had no significant differences between patients with BRCA1 and BRCA2 mutations (82.0% vs 85.4%, P = 0.35; 94.3% vs 94.6%, P = 0.39). The 3-year DFS rate in BRCA1 mutation cohort of patients received platinum regimen was significantly higher than patients received non-platinum regimen (96.0% vs 75.2%, P = 0.01). No differences between DFS and DRFS were observed in patients with BRCA2 mutation received platinum regimen and non-platinum regimen.

Conclusion

Similar survival outcomes were observed in early breast cancer patients with BRCA1 and BRCA2 mutation, though they had different biological characteristics. Patients with BRCA1 mutations are more benefit from platinum-regimen. The value of platinum-regimen for early breast cancer patients with BRCA1 and BRCA2 needs to be verified further.

A phase 1 evaluation of the safety and tolerability of niraparib in combination with everolimus in advanced ovarian and breast cancers

OBJECTIVES

Phase 1 trial to determine the safety and tolerability of everolimus and niraparib in patients with advanced ovarian and breast malignancies.

RESULTS

Fourteen heavily pretreated patients were enrolled (12 high-grade serous ovarian cancer, 1 clear cell ovarian cancer, and 1 triple negative breast cancer). All patients were PARP naïve and received comprehensive genomic profiling prior to enrollment. Two DLTs were experienced in cohort 2 (niraparib 200 mg daily and everolimus 5 mg 3 days per week) with one patient experiencing prolonged thrombocytopenia and the other experiencing severe hypertension. Four additional patients were enrolled after dose de-escalation with one patient again experiencing severe hypertension leading to conclusion of the study. The most frequent grade 3 or greater adverse events were thrombocytopenia, hypertension, anemia, fatigue, neutropenia, and elevated alkaline phosphatase. Two patients had a PR and five patients had SD. ORR was 18% and the CBR was 45% in 11 evaluable patients. Median PFS was 6 months, and median OS is approximately 18 months with three patients still alive at the data cutoff.

CONCLUSIONS

The combination of everolimus and niraparib demonstrated significant toxicity at lower doses and is not feasible due to rapid onset and severe hypertension. This limitation possibly blunted the efficacy of the combination as PFS was modest, but OS was surprisingly robust due to three patients with ovarian cancer remaining alive with platinum refractory disease. Further investigation of multiagent blockade of the PI3K pathway combined with PARP is warranted.

Challenges and Opportunities in Developing Targeted Therapies for Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is a heterogeneous group of breast cancers characterized by their lack of estrogen receptors, progesterone receptors, and the HER2 receptor. They are more aggressive than other breast cancer subtypes, with a higher mean tumor size, higher tumor grade, the worst five-year overall survival, and the highest rates of recurrence and metastasis. Developing targeted therapies for TNBC has been a major challenge due to its heterogeneity, and its treatment still largely relies on surgery, radiation therapy, and chemotherapy. In this review article, we review the efforts in developing targeted therapies for TNBC, discuss insights gained from these efforts, and highlight potential opportunities going forward. Accumulating evidence supports TNBCs as multi-driver cancers, in which multiple oncogenic drivers promote cell proliferation and survival. In such multi-driver cancers, targeted therapies would require drug combinations that simultaneously block multiple oncogenic drivers. A strategy designed to generate mechanism-based combination targeted therapies for TNBC is discussed.

Tumor-Derived Exosomes and Their Role in Breast Cancer Metastasis

Breast cancer has been the most common cancer in women worldwide, and metastasis is the leading cause of death from breast cancer. Even though the study of breast cancer metastasis has been extensively carried out, the molecular mechanism is still not fully understood, and diagnosis and prognosis need to be improved. Breast cancer metastasis is a complicated process involving multiple physiological changes, and lung, brain, bone and liver are the main metastatic targets. Exosomes are membrane-bound extracellular vesicles that contain secreted cellular constitutes. The biogenesis and functions of exosomes in cancer have been intensively studied, and mounting studies have indicated that exosomes play a crucial role in cancer metastasis. In this review, we summarize recent findings on the role of breast cancer-derived exosomes in metastasis organotropism and discuss the potential promising clinical applications of targeting exosomes as novel strategies for breast cancer diagnosis and therapy.

Overview on population screening for carriers with germline BRCA mutation in China

Carriers with BRCA1/2 germline pathogenic variants are associated with a high risk of breast and ovarian cancers (also pancreatic and prostate cancers). While the spectrum on germline BRCA mutations among the Chinese population shows ethnic specificity, the identification of carriers with germline BRCA mutation before cancer onset is the most effective approach to protect them. This review focused on the current status of BRCA1/2 screening, the surveillance and prevention measures, and discussed the issues and potential impact of BRCA1/2 population screening in China. We conducted literature research on databases PubMed and Google Scholar, as well as Chinese databases CNKI and Wangfang Med Online database (up to 31 March 2022). Latest publications on germline BRCA1/2 prevalence, spectrum, genetic screening as well as carrier counseling, surveillance and prevention were captured where available. While overall 15,256 records were retrieved, 72 publications using germline BRCA1/2 testing were finally retained for further analyses. Germline BRCA1/2 mutations are common in Chinese patients with hereditary breast, ovarian, prostate and pancreatic cancers. Within previous studies, a unique BRCA mutation spectrum in China was revealed. Next-generation sequencing panel was considered as the most common method for BRCA1/2 screening. Regular surveillance and preventive surgeries were tailored to carriers with mutated-BRCA1/2. We recommend that all Chinese diagnosed with breast, ovarian, pancreatic or prostate cancers and also healthy family members, shall undergo BRCA1/2 gene test to provide risk assessment. Subsequently, timely preventive measures for mutation carriers are recommended after authentic genetic counseling.

Determining prognostic factors and optimal surgical intervention for early-onset triple-negative breast cancer

Background

Few studies have focused specifically on prognostic factors and optimal surgical intervention for early-onset triple-negative breast cancer (eTNBC), which is characterized by high malignancy and poor prognosis.

Methods

We performed a cohort study with a median follow-up of 31 months using Surveillance, Epidemiology, and End Results (SEER) data of patients diagnosed with stages I–III eTNBC between 2010 and 2016. In addition, we collected cases between 2006 and 2016 from our center as an external validation set. Clinical features, pathologic characteristics and oncologic outcomes were analyzed. Prognostic factors for overall survival (OS) and breast cancer-specific survival (BCSS) were determined by Cox proportional hazards analyses and were incorporated into the prognostic nomogram. Subgroup analysis based on propensity score matching method was conducted to explore the subset of patients that would benefit from breast-conserving therapy (BCT).

Results

Based on SEER dataset, patients with eTNBC were more likely to undergo mastectomy than BCT. On multivariable analysis, patients with better survival outcomes were those not married, uninsured, had higher T and N stage, and had histological type of mixed invasive ductal and lobular carcinoma. The prognostic nomogram based on these variables successfully predicted the 3- and 5-year BCSS (C-index in training cohort, 0.774; in validation cohort from SEER, 0.768; in validation cohort from our center, 0.723). Subgroup analysis illustrated that patients with T1N0M0 or T2-4N+M0 tumors who underwent BCT achieved longer overall survival than those who underwent mastectomy (for T1N0M0, P = 0.022; for T2-4N+M0, P = 0.003); however, the type of surgery did not influence OS among patients with T1N+M0 or T2-4N0M0 tumors (for T1N+M0, P = 0.305; for T2-4N0M0, P = 0.317).

Conclusions

The prognosis of patients with eTNBC is mainly affected by marital status, insurance status, T stage, N stage and histological type. The prognostic nomogram based on these factors is quite reliable. Subgroup analysis suggested that BCT may be a superior option for patients with eTNBC, especially those with T1N0M0 and T2-4N+M0 tumors.

A Systematic Review and Meta-Analysis on the Prognostic Value of BRCA Mutations, Homologous Recombination Gene Mutations, and Homologous Recombination Deficiencies in Cancer

Patients with BRCA1/2 mutations (BRCAm), loss-of-function mutations in other homologous recombination repair (HRRm) genes, or tumors that are homologous recombination deficiency positivity (HRD+) demonstrate a robust response to PARPi therapy. We conducted a systematic literature review and meta-analysis to evaluate the prognostic value of BRCAm, HRRm, and HRD+ on overall survival (OS) among those treated by chemotherapy or targeted therapy other than PARPi across tumor types. A total of 135 eligible studies were included. Breast cancer (BC) patients with BRCA1/2m had a similar overall survival (OS) to those with wild-type BRCA1/2 (BRCA1/2 wt) across 18 studies. Ovarian cancer (OC) patients with BRCA1/2m had a significantly longer OS than those with BRCA1/2 wt across 24 studies reporting BRCA1m and BRCA2m, with an HR of 0.7 (0.6–0.8). Less OS data were reported for other tumors: 6 studies for BRCA2m compared with BRCA2 wt in prostate cancer with an HR of 1.9 (1.1–3.2) and 2 studies for BRCA1/2m compared with BRCA1/2 wt in pancreatic cancer with an HR of 1.5 (0.8–3.1). Only 4 studies reported HRD+ by either BRCA m or genomic instability score (GIS) ≥ 42 and OS by HRD status. The HR was 0.67 (0.43–1.02) for OS with HRD+ vs. HRD−. A total of 15 studies reported the association between HRRm and OS of cancers in which one or more HRR genes were examined. The HR was 1.0 (0.7–1.4) comparing patients with HRRm to those with HRR wild-type across tumors. Our findings are useful in improving the precision and efficacy of treatment selection in clinical oncology.

Immune Checkpoint Inhibitors in Tumors Harboring Homologous Recombination Deficiency: Challenges in Attaining Efficacy

Cancer cells harbor genomic instability due to accumulated DNA damage, one of the cancer hallmarks. At least five major DNA Damage Repair (DDR) pathways are recognized to repair DNA damages during different stages of the cell cycle, comprehending base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR), and non-homologous end joining (NHEJ). The unprecedented benefits achieved with immunological checkpoint inhibitors (ICIs) in tumors with mismatch repair deficiency (dMMR) have prompted efforts to extend this efficacy to tumors with HR deficiency (HRD), which are greatly sensitive to chemotherapy or PARP inhibitors, and also considered highly immunogenic. However, an in-depth understanding of HRD's molecular underpinnings has pointed to essential singularities that might impact ICIs sensitivity. Here we address the main molecular aspects of HRD that underlie a differential profile of efficacy and resistance to the treatment with ICIs compared to other DDR deficiencies.

Favorable Response to Olaparib in a Patient with Cancer of Unknown Primary Carrying a Germline BRCA1 R71K Mutation

The treatment options for cancer of unknown primary (CUP) are challenging due to the lack of knowledge about the primary sites, often resulting in a poor prognosis. The emerging next-generation sequencing (NGS) technique has provided a reliable approach to facilitate tumor primary site prediction and targetable gene alteration identification for CUP patients. In this report, we described a 63-year-old female patient who experienced recurrent CUP. NGS-based genetic profiling results revealed a pathogenic germline BRCA1 R71K mutation. Accordingly, the patient received the poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitor olaparib treatment and demonstrated a favorable response to this treatment. Our case suggests that NGS holds great promise for providing improved diagnosis and treatment options to patients with CUP, warranting further clinical investigation.

Small Molecules Targeting Programmed Cell Death in Breast Cancer Cells

Targeted chemotherapy has become the forefront for cancer treatment in recent years. The selective and specific features allow more effective treatment with reduced side effects. Most targeted therapies, which include small molecules, act on specific molecular targets that are altered in tumour cells, mainly in cancers such as breast, lung, colorectal, lymphoma and leukaemia. With the recent exponential progress in drug development, programmed cell death, which includes apoptosis and autophagy, has become a promising therapeutic target. The research in identifying effective small molecules that target compensatory mechanisms in tumour cells alleviates the emergence of drug resistance. Due to the heterogenous nature of breast cancer, various attempts were made to overcome chemoresistance. Amongst breast cancers, triple negative breast cancer (TNBC) is of particular interest due to its heterogeneous nature in response to chemotherapy. TNBC represents approximately 15% of all breast tumours, however, and still has a poor prognosis. Unlike other breast tumours, signature targets lack for TNBCs, causing high morbidity and mortality. This review highlights several small molecules with promising preclinical data that target autophagy and apoptosis to induce cell death in TNBC cells.