Systemic therapy options in BRCA mutation-associated breast cancer

A Phase II Study of Neoadjuvant PLD/Cyclophosphamide and Sequential nab-Paclitaxel Plus Dual HER2 Blockade in HER2-Positive Breast Cancer

BACKGROUND

Neoadjuvant trastuzumab/pertuzumab (HP) plus chemotherapy for HER2-positive breast cancer (BC) achieved promising efficacy. The additional cardiotoxicity still existed. Brecan study evaluated the efficacy and safety of neoadjuvant pegylated liposomal doxorubicin (PLD)/cyclophosphamide and sequential nab-paclitaxel based on HP (PLD/C/HP-nabP/HP).

PATIENTS AND METHODS

Brecan was a single-arm phase II study. Eligible patients with stages IIA-IIIC HER2-positive BC received 4 cycles of PLD, cyclophosphamide, and HP, followed by 4 cycles of nab-paclitaxel and HP. Definitive surgery was scheduled after 21 days for patients completing treatment or experiencing intolerable toxicity. The primary endpoint was the pathological complete response (pCR).

RESULTS

Between January 2020 and December 2021, 96 patients were enrolled. Ninety-five (99.0%) patients received 8 cycles of neoadjuvant therapy and all underwent surgery with 45 (46.9%) breast-conserving surgery and 51 (53.1%) mastectomy. The pCR was 80.2% (95%CI, 71.2%-87.0%). Four (4.2%) experienced left ventricular insufficiency with an absolute decline in LVEF (43%-49%). No congestive heart failure and ≥grade 3 cardiac toxicity occurred. The objective response rate was 85.4% (95%CI, 77.0%-91.1%), including 57 (59.4%) complete responses and 25 (26.0%) partial responses. The disease control rate was 99.0% (95%CI, 94.3%-99.8%). For overall safety, ≥grade 3 AEs occurred in 30 (31.3%) and mainly included neutropenia (30.2%) and asthenia (8.3%). No treatment-related deaths occurred. Notably, age of >30 (P = .01; OR = 5.086; 95%CI, 1.44-17.965) and HER2 IHC 3+ (P = .02; OR = 4.398; 95%CI, 1.286-15.002) were independent predictors for superior pCR (ClinicalTrials.gov Identifier NCT05346107).

CONCLUSION

Brecan study demonstrated the encouraging safety and efficacy of neoadjuvant PLD/C/HP-nabP/HP, suggesting a potential therapeutic option in HER2-positive BC.

Pregnancy after breast cancer in BRCA1/2 mutation carriers

Background

Often young women affected with BRCA1/2 positive breast cancer have not finished or even not started their childbearing before the onset of the disease. The aim of our mini-review is to summarize state of art knowledge on pregnancy after breast cancer in BRCA1/2 carriers.

Methods

A broad review of the literature was conducted using MEDLINE (via PubMed) for relevant articles published.

Main body of the abstract

This review summarizes the impact of different cytotoxic agents on a fertility, fertility preservation, maternal and fetal prognosis after pregnancy in breast cancer survivors with BRCA1/2.

Conclusion

According to the existing literature evidence pregnancy after therapy for breast cancer in BRCA carriers is safe for the mother and offspring, but patients’ needs, oncofertility counseling and fertility-sparing strategy should be carefully planned before starting the cytotoxic treatment.

AKT Isoforms Interplay in High-Grade Serous Ovarian Cancer Prognosis and Characterization

Simple Summary

New therapeutical strategies are needed to improve survival in high-grade serous ovarian cancer (HGSOC) patients. AKT inhibitors are promising agents able to act in synergy with PARP inhibitors and platinum-based therapies, but the subset of patients who could benefit from this approach is still unclear. We analyzed AKT isoforms expression in a retrospective cohort and we identified four AKT expression groups related to patients’ survival, tumor morphology and the BRCA status that could help in stratifying patients for future clinical trials.

Abstract

High-grade serous ovarian cancer (HGSOC) is among the deadliest gynecological malignancies. The acquired resistance to platinum-based therapies and the intrinsic heterogeneity of the disease contribute to the low survival rate. To improve patients’ outcomes, new combinatorial approaches able to target different tumor vulnerabilities and enhance the efficacy of the current therapies are required. AKT inhibitors are promising antineoplastic agents able to act in synergy with PARP inhibitors, but the spectrum of patients who can benefit from this combination is unclear, since the role of the three different isoforms of AKT is still unknown. Here, we study the expression of AKT isoforms on a retrospective cohort of archive tissue by RT-droplet digital PCR (ddPCR) analyzing their association with the clinicopathological features of patients. Based on AKT1/AKT2 and AKT1/AKT3 ratios, we define four AKT classes which were related to patients’ survival, tumor morphology and BRCA1 expression. Moreover, our results show that high AKT3 expression levels were frequently associated with tumors having classic features, a low number of mitoses and the presence of psammoma bodies. Overall, our study obtains new insights on AKT isoforms and their associations with the clinicopathological features of HGSOC patients. These evidences could help to better define the subsets of patients who can benefit from AKT and PARP inhibitors therapy in future clinical trials.

How Protective are Nipple-Sparing Prophylactic Mastectomies in BRCA1 and BRCA2 Mutation Carriers?

BACKGROUND

Nipple-sparing mastectomy (NSM) is now routinely offered to BRCA mutation carriers for risk reduction. We assessed the rates of ipsilateral cancer events after prophylactic and therapeutic NSM in BRCA1 and BRCA2 mutation carriers.

METHODS

BRCA1 and BRCA2 mutation carriers undergoing NSM from October 2007 to June 2019 were identified in a single-institution prospective database, with variants of unknown significance being excluded. Patient, tumor, and outcomes data were collected. Follow-up analysis was by cumulative breast-years (total years of follow-up of each breast) and woman-years (total years of follow-up of each woman).

RESULTS

Overall, 307 BRCA1 and BRCA2 mutation carriers (160 BRCA1, mean age 41.4 years [range 21-65]; and 147 BRCA2, mean age 43.8 years [range 23-65]) underwent 607 NSMs, with a median follow-up of 42 months (range 1-143). 388 bilateral prophylactic NSMs had 744 cumulative woman-years of follow-up, with no new cancers seen (< 0.0013 new cancers per woman-years); 251 BRCA1 prophylactic NSMs had 1034 cumulative breast-years of follow-up, with no new ipsilateral cancers seen (< 0.0010 per breast-year); 66 BRCA1 therapeutic NSMs had 328 cumulative breast-years of follow-up, with one ipsilateral cancer recurrence not directly involving the nipple or areola (0.0030 per breast-year); 237 BRCA2 prophylactic NSMs had 926 cumulative breast-years of follow-up, with no new ipsilateral cancers seen (< 0.0011 per breast-year); and 53 BRCA2 therapeutic NSMs had 239 cumulative breast-years of follow-up, with two ipsilateral recurrent cancers, neither of which directly involved the nipple or areola (0.0084 per breast-year).

CONCLUSIONS

The risk of new ipsilateral breast cancers is extremely low after NSM in BRCA1 and BRCA2 mutation carriers. NSM is an effective risk-reducing strategy for BRCA gene mutations.

Breast Cancer Predisposition Genes and Synthetic Lethality

BRCA1 and BRCA2 are tumor suppressor genes with pivotal roles in the development of breast and ovarian cancers. These genes are essential for DNA double-strand break repair via homologous recombination (HR), which is a virtually error-free DNA repair mechanism. Following BRCA1 or BRCA2 mutations, HR is compromised, forcing cells to adopt alternative error-prone repair pathways that often result in tumorigenesis. Synthetic lethality refers to cell death caused by simultaneous perturbations of two genes while change of any one of them alone is nonlethal. Therefore, synthetic lethality can be instrumental in identifying new therapeutic targets for BRCA1/2 mutations. PARP is an established synthetic lethal partner of the BRCA genes. Its role is imperative in the single-strand break DNA repair system. Recently, Olaparib (a PARP inhibitor) was approved for treatment of BRCA1/2 breast and ovarian cancer as the first successful synthetic lethality-based therapy, showing considerable success in the development of effective targeted cancer therapeutics. Nevertheless, the possibility of drug resistance to targeted cancer therapy based on synthetic lethality necessitates the development of additional therapeutic options. This literature review addresses cancer predisposition genes, including BRCA1, BRCA2, and PALB2, synthetic lethality in the context of DNA repair machinery, as well as available treatment options.

Small-molecule inhibitors of breast cancer-related targets: Potential therapeutic agents for breast cancer

Despite dramatic advances in cancer research and therapy, breast cancer remains a tricky health problem and represents a top biomedical research priority. Nowadays, breast cancer is still the leading cause of malignancy-related deaths in women, and incidence and mortality rates of it are expected to increase significantly the next years. Currently more and more researchers are interested in the study of breast cancer by its arising in young women. The common treatment options of breast cancer are chemotherapy, immunotherapy, hormone therapy, surgery, and radiotherapy. Most of them require chemical agents, such as PARP inhibitors, CDK4/6 inhibitors, and HER2 inhibitors. Recent studies suggest that some targets or pathways, including BRD4, PLK1, PD-L1, HDAC, and PI3K/AKT/mTOR, are tightly related to the occurrence and development of breast cancer. This article reviews the interplay between these targets and breast cancer and summarizes the progress of current research on small molecule inhibitors of these anti-breast cancer targets. The review aims to provide structural and theoretical basis for designing novel anti-breast cancer agents.

BRCA1 and BRCA2 associated breast cancer and the roles of current modelling systems in drug discovery

For a drug candidate to be fully developed takes years and investment of hundreds of millions of dollars. There is no doubt that drug development is difficult and risky, but vital to protecting against devastating disease. This difficulty is clearly evident in BRCA1 and BRCA2 related breast cancer, with current treatment options largely confined to invasive surgical procedures, as well as chemotherapy and radiotherapy regimes which damage healthy tissue and can leave remnant disease. Consequently, patient survival and relapse rates are far from ideal, and new candidate treatments are needed. The preclinical stages of drug discovery are crucial to get right for translation to hospital beds. Disease models must take advantage of current technologies and be accurate for rapid and translatable treatments. Careful selection of cell lines must be coupled with high throughput techniques, with promising results trialled further in highly accurate humanised patient derived xenograft models. Traditional adherent drug screening should transition to 3D culture systems amenable to high throughput techniques if the gap between in vitro and in vivo studies is to be partially bridged. The possibility of organoid, induced pluripotent stem cell, and conditionally reprogrammed in vitro models is tantalising, however protocols are yet to be fully established. This review of BRCA1 and BRCA2 cancer biology and current modelling systems will hopefully guide the design of future drug discovery endeavours and highlight areas requiring improvement.

Possible roles of genetic variations in chemotherapy related cardiotoxicity in pediatric acute lymphoblastic leukemia and osteosarcoma

Background

The treatment of acute lymphoblastic leukemia (ALL) and osteosarcoma (OSC) is very effective: the vast majority of patients recover and survive for decades. However, they still need to face serious adverse effects of chemotherapy. One of these is cardiotoxicity which may lead to progressive heart failure in the long term. Cardiotoxicity is contributed mainly to the use of anthracyclines and might have genetic risk factors. Our goal was to test the association between left ventricular function and genetic variations of candidate genes.

Methods

Echocardiography data from medical records of 622 pediatric ALL and 39 OSC patients were collected from the period 1989–2015. Fractional shortening (FS) and ejection fraction (EF) were determined, 70 single nucleotide polymorphisms (SNPs) in 26 genes were genotyped. Multivariate logistic regression and multi-adjusted general linear model were performed to investigate the influence of genetic polymorphisms on the left ventricular parameters. Bayesian network based Bayesian multilevel analysis of relevance (BN-BMLA) method was applied to test for the potential interaction of the studied cofactors and SNPs.

Results

Our results indicate that variations in ABCC2, CYP3A5, NQO1, SLC22A6 and SLC28A3 genes might influence the left ventricular parameters. CYP3A5 rs4646450 TT was 17% among ALL cases with FS lower than 28, and 3% in ALL patients without pathological FS (p = 5.60E-03; OR = 6.94 (1.76–27.39)). SLC28A3 rs7853758 AA was 12% in ALL cases population, while only 1% among controls (p = 6.50E-03; OR = 11.56 (1.98–67.45)). Patients with ABCC2 rs3740066 GG genotype had lower FS during the acute phase of therapy and 5–10 years after treatment (p = 7.38E-03, p = 7.11E-04, respectively). NQO1 rs1043470 rare T allele was associated with lower left ventricular function in the acute phase and 5–10 years after the diagnosis (p = 4.28E-03 and 5.82E-03, respectively), and SLC22A6 gene rs6591722 AA genotype was associated with lower mean FS (p = 1.71E-03), 5–10 years after the diagnosis.

Conclusions

Genetic variants in transporters and metabolic enzymes might modulate the individual risk to cardiac toxicity after chemotherapy.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4629-6) contains supplementary material, which is available to authorized users.

Synthetic Lethality of PARP Inhibitors in Combination with MYC Blockade Is Independent of BRCA Status in Triple-Negative Breast Cancer

PARP inhibitors (PARPi) benefit only a fraction of breast cancer patients. Several of those patients exhibit intrinsic/acquired resistance mechanisms that limit efficacy of PARPi monotherapy. Here we show how the efficacy of PARPi in triple-negative breast cancers (TNBC) can be expanded by targeting MYC-induced oncogenic addiction. In BRCA-mutant/sporadic TNBC patients, amplification of the MYC gene is correlated with increased expression of the homologous DNA recombination enzyme RAD51 and tumors overexpressing both genes are associated with worse overall survival. Combining MYC blockade with PARPi yielded synthetic lethality in MYC-driven TNBC cells. Using the cyclin-dependent kinase inhibitor dinaciclib, which downregulates MYC expression, we found that combination with the PARPi niraparib increased DNA damage and downregulated homologous recombination, leading to subsequent downregulation of the epithelial-mesenchymal transition and cancer stem-like cell phenotypes. Notably, dinaciclib resensitized TBNC cells, which had acquired resistance to niraparib. We found that the synthetic lethal strategy employing dinaciclib and niraparib was also highly efficacious in ovarian, prostate, pancreatic, colon, and lung cancer cells. Taken together, our results show how blunting MYC oncogene addiction can leverage cancer cell sensitivity to PARPi, facilitating the clinical use of c-myc as a predictive biomarker for this treatment.Significance: Dual targeting of MYC-regulated homologous recombination and PARP-mediated DNA repair yields potent synthetic lethality in triple-negative breast tumors and other aggressive tumors characterized by MYC overexpression. Cancer Res; 78(3); 742-57. ©2017 AACR.

Therapy response testing of breast cancer in a 3D high-throughput perfused microfluidic platform

BACKGROUND

Breast cancer is the most common invasive cancer among women. Currently, there are only a few models used for therapy selection, and they are often poor predictors of therapeutic response or take months to set up and assay. In this report, we introduce a microfluidic OrganoPlate® platform for extracellular matrix (ECM) embedded tumor culture under perfusion as an initial study designed to investigate the feasibility of adapting this technology for therapy selection.

METHODS

The triple negative breast cancer cell lines MDA-MB-453, MDA-MB-231 and HCC1937 were selected based on their different BRCA1 and P53 status, and were seeded in the platform. We evaluate seeding densities, ECM composition (Matrigel®, BME2rgf, collagen I) and biomechanical (perfusion vs static) conditions. We then exposed the cells to a series of anti-cancer drugs (paclitaxel, olaparib, cisplatin) and compared their responses to those in 2D cultures. Finally, we generated cisplatin dose responses in 3D cultures of breast cancer cells derived from 2 PDX models.

RESULTS

The microfluidic platform allows the simultaneous culture of 96 perfused micro tissues, using limited amounts of material, enabling drug screening of patient-derived material. 3D cell culture viability is improved by constant perfusion of the medium. Furthermore, the drug response of these triple negative breast cancer cells was attenuated by culture in 3D and differed from that observed in 2D substrates.

CONCLUSIONS

We have investigated the use of a high-throughput organ-on-a-chip platform to select therapies. Our results have raised the possibility to use this technology in personalized medicine to support selection of appropriate drugs and to predict response to therapy in a real time fashion.

Evaluation of psychosocial aspects in participants of cancer genetic counseling

Background

The instrument called “Hospital Anxiety and Depression Scale” (HADS) is frequently used to evaluate anxious and depressive symptomatology in patients who receive Cancer Genetic Counseling (CGC). However, this instrument cannot identify all of the psychosocial factors, such as the antecedents of the patients’ emotional states or their concerns. The objective of the present research was to compare cases detected with psychosocial alterations by means of HADS and a Psychological Health Interview (PHI).

Methods

A transversal analytical design was used. One hundred ten participants were included (97.3% females and 2.7% males). The average age was 45 years ±10 years.

Results

The PHI identified twice the amount of participants with psychosocial alterations than did HADS, which only detected 43% of these participants.

Conclusions

The results of our study suggest that the PHI should be applied in addition to HADS to identify participants who would require psychological support due to recurrent concerns.

The role of BRCA status on prognosis in patients with triple-negative breast cancer

Studies have showed that dysfunction in the breast cancer susceptibility gene (BRCA) is associated with triple-negative breast cancer (TNBC); however, its effect on patient survival remains controversial. We investigated the distribution of BRCA1/2 mutations in unselected Chinese patients with TNBC and explored their roles in prognosis. Then a systematic review and meta-analysis were performed to evaluate the prognostic role of BRCA dysfunction, including BRCA1/2 germline/somatic mutations, BRCA1 promoter methylation, and low BRCA1 protein expression in TNBC patients. Pooled hazard ratios with 95% confidence intervals were estimated to determine the association between BRCA dysfunction and survival. Our results showed a high frequency of BRCA1/2 mutations, especially germline BRCA1 variants, were associated with bilateral breast cancer. Although no correlations were found between BRCA1/2 mutations and recurrence-free survival (RFS) or overall survival (OS). In the meta-analysis, patients with BRCA1 promoter methylation showed poor OS. However, there was a favorable impact on disease free survival (DFS) for TNBC patients with BRCA1 promoter methylation when received adjuvant-chemotherapy. In conclusion, BRCA1/2 mutations were associated with bilateral breast cancer and BRCA1 promoter methylation may have a prognostic effect on TNBC.

Systemic Treatment Strategies for Patients with Hereditary Breast Cancer Syndromes

Hereditary breast cancer syndromes are associated with an increased risk of breast cancer and constitute a unique patient population, making up approximately 5%-10% of breast cancer cases in the United States. By virtue of the germline mutations that define these syndromes, invasive breast cancers in these patients have unique mechanisms that can be rationally targeted for therapeutic opportunities distinct from standard of care treatments in nongermline mutation associated breast cancers. This review intends to describe existing data on several of the most common hereditary breast cancer syndromes, including BRCA-related breast cancer syndrome, Li-Fraumeni syndrome, Cowden syndrome, Peutz-Jeghers syndrome, and hereditary diffuse gastric cancer syndrome, specifically focusing on rational therapeutics utilized in these distinct patient subgroups and completed or ongoing clinical trials evaluating their efficacy. By exploiting the distinct biologic features associated with these syndromes, tailored treatment strategies have the potential for improved efficacy and lower toxicity. Knowledge of the emergence of these targeted cancer therapies is critical for appropriate management in these patients, extending beyond treatment to highlight the need for appropriate genetic screening to allow for early recognition of these patients and therefore appropriate treatment.

IMPLICATIONS FOR PRACTICE

Molecular testing allows for identification of germline mutations that place individuals at high risk for breast cancer and that are associated with distinct histopathology and molecular characteristics that define the invasive breast cancer cases that these patients develop. These unique characteristics may ultimately provide rational targets for systemic treatments with improvements in both morbidity and efficacy. Identification of patients with these germline mutations is important for not only appropriate screening and prophylaxis, but knowledge of therapies specifically targeting several of the most common hereditary breast cancer syndromes is essential to ensure appropriate treatment of invasive breast cancers in these patients.

Association of Distinct Mutational Signatures With Correlates of Increased Immune Activity in Pancreatic Ductal Adenocarcinoma

IMPORTANCE

Outcomes for patients with pancreatic ductal adenocarcinoma (PDAC) remain poor. Advances in next-generation sequencing provide a route to therapeutic approaches, and integrating DNA and RNA analysis with clinicopathologic data may be a crucial step toward personalized treatment strategies for this disease.

OBJECTIVE

To classify PDAC according to distinct mutational processes, and explore their clinical significance.

DESIGN, SETTING, AND PARTICIPANTS

We performed a retrospective cohort study of resected PDAC, using cases collected between 2008 and 2015 as part of the International Cancer Genome Consortium. The discovery cohort comprised 160 PDAC cases from 154 patients (148 primary; 12 metastases) that underwent tumor enrichment prior to whole-genome and RNA sequencing. The replication cohort comprised 95 primary PDAC cases that underwent whole-genome sequencing and expression microarray on bulk biospecimens.

MAIN OUTCOMES AND MEASURES

Somatic mutations accumulate from sequence-specific processes creating signatures detectable by DNA sequencing. Using nonnegative matrix factorization, we measured the contribution of each signature to carcinogenesis, and used hierarchical clustering to subtype each cohort. We examined expression of antitumor immunity genes across subtypes to uncover biomarkers predictive of response to systemic therapies.

RESULTS

The discovery cohort was 53% male (n = 79) and had a median age of 67 (interquartile range, 58-74) years. The replication cohort was 50% male (n = 48) and had a median age of 68 (interquartile range, 60-75) years. Five predominant mutational subtypes were identified that clustered PDAC into 4 major subtypes: age related, double-strand break repair, mismatch repair, and 1 with unknown etiology (signature 8). These were replicated and validated. Signatures were faithfully propagated from primaries to matched metastases, implying their stability during carcinogenesis. Twelve of 27 (45%) double-strand break repair cases lacked germline or somatic events in canonical homologous recombination genes-BRCA1, BRCA2, or PALB2. Double-strand break repair and mismatch repair subtypes were associated with increased expression of antitumor immunity, including activation of CD8-positive T lymphocytes (GZMA and PRF1) and overexpression of regulatory molecules (cytotoxic T-lymphocyte antigen 4, programmed cell death 1, and indolamine 2,3-dioxygenase 1), corresponding to higher frequency of somatic mutations and tumor-specific neoantigens.

CONCLUSIONS AND RELEVANCE

Signature-based subtyping may guide personalized therapy of PDAC in the context of biomarker-driven prospective trials.

BRCA1 and BRCA2 mutations and treatment strategies for breast cancer

Breast cancer is a global burden with a woman's lifetime risk of developing breast cancer at 1 in 8. Although breast cancer is a disease that affects mostly women, the lifetime risk in men is about 1 in 1000. Most cases of breast cancer are associated with somatic mutations in breast cells that are acquired during a person's lifetime. In this scenario, the mutations are not inherited and they do not cluster in families. In hereditary breast cancer, the specific genetic factors involved will determine the inherited cancer risk. Inherited mutations in the BRCA1 or BRCA2 genes have been well-described, but mutations in ATM, CDH1, CHEK2, PALB2, PTEN, STK11, and TP53 also confer breast cancer risk. Understanding the functional significance of hereditary mutations has opened new paths for breast cancer prevention and is uncovering promising treatment strategies.

Molecular determination of the clonal relationships between multiple tumors in BRCA1/2-associated breast and/or ovarian cancer patients is clinically relevant

Female BRCA1/2 mutation carriers affected with breast and/or ovarian cancer may develop new tumor deposits over time. It is of utmost importance to know the clonal relationships between multiple tumor localizations, enabling differentiation between multiple primaries or metastatic disease with consequences for therapy and prognosis. We evaluated the value of targeted next generation sequencing in the diagnostic workup of BRCA1/2 mutation carriers with ≥2 tumor localizations and uncertain tumor origins. Forty-two female BRCA1/2 mutation carriers with ≥2 tumor localizations were selected. Patients with inconclusive tumor origin after histopathological revision were 'cases'; patients with certain tumor origin of ≥3 tumors served as 'controls'. Tumors of cases and controls were analyzed by targeted next generation sequencing using a panel including CDKN2A, PTEN and TP53, hotspot mutation sites for 27 different genes and 143 single nucleotide polymorphisms for detection of loss of heterozygosity. Based on prevalence of identical or different mutations and/or loss of heterozygosity patterns, tumors were classified as 'multiple primaries' or 'one entity'. Conventional histopathology yielded a conclusive result in 38/42 (90%) of patients. Four cases and 10 controls were analyzed by next generation sequencing. In 44 tumor samples, 48 mutations were found; 39 (81%) concerned TP53 mutations. In all 4 cases, the intra-patient clonal relationships between the tumor localizations could be unequivocally identified by molecular analysis. In all controls, molecular outcomes matched the conventional histopathological results. In most BRCA1/2 mutation carriers with multiple tumors routine pathology work-up is sufficient to determine tumor origins and relatedness. In case of inconclusive conventional pathology results, molecular analyses using next generation sequencing can reliably determine clonal relationships between tumors, enabling optimal treatment of individual patients.

Cytotoxic and targeted therapy for hereditary cancers

There is a number of drugs demonstrating specific activity towards hereditary cancers. For example, tumors in BRCA1/2 mutation carriers usually arise via somatic inactivation of the remaining BRCA allele, which makes them particularly sensitive to platinum-based drugs, PARP inhibitors (PARPi), mitomycin C, liposomal doxorubicin, etc. There are several molecular assays for BRCA-ness, which permit to reveal BRCA-like phenocopies among sporadic tumors and thus extend clinical indications for the use of BRCA-specific therapies. Retrospective data on high-dose chemotherapy deserve consideration given some unexpected instances of cure from metastatic disease among BRCA1/2-mutated patients. Hereditary non-polyposis colorectal cancer (HNPCC) is characterized by high-level microsatellite instability (MSI-H), increased antigenicity and elevated expression of immunosuppressive molecules. Recent clinical trial demonstrated tumor responses in HNPCC patients treated by the immune checkpoint inhibitor pembrolizumab. There are successful clinical trials on the use of novel targeted agents for the treatment or rare cancer syndromes, e.g. RET inhibitors for hereditary medullary thyroid cancer, mTOR inhibitors for tumors arising in patients with tuberous sclerosis (TSC), and SMO inhibitors for basal-cell nevus syndrome. Germ-line mutation tests will be increasingly used in the future for the choice of the optimal therapy, therefore turnaround time for these laboratory procedures needs to be significantly reduced to ensure proper treatment planning.

Predictive imaging of chemotherapeutic response in a transgenic mouse model of pancreatic cancer

The underglycosylated mucin 1 tumor antigen (uMUC1) is a biomarker that forecasts the progression of adenocarcinomas. In this study, we evaluated the utility of a dual-modality molecular imaging approach based on targeting uMUC1 for monitoring chemotherapeutic response in a transgenic murine model of pancreatic cancer (KCM triple transgenic mice). An uMUC1-specific contrast agent (MN-EPPT) was synthesized for use with magnetic resonance imaging (MRI) and fluorescence optical imaging. It consisted of dextran-coated iron oxide nanoparticles conjugated to the near infrared fluorescent dye Cy5.5 and to a uMUC1-specific peptide (EPPT). KCM triple transgenic mice were given gemcitabine as chemotherapy while control animals received saline injections following the same schedule. Changes in uMUC1 levels following chemotherapy were monitored using T2-weighted MRI and optical imaging before and 24 hr after injection of the MN-EPPT. uMUC1 expression in tumors from both groups was evaluated by histology and qRT-PCR. We observed that the average delta-T2 in the gemcitabine-treated group was significantly reduced compared to the control group indicating lower accumulation of MN-EPPT, and correspondingly, a lower level of uMUC1 expression. In vivo optical imaging confirmed the MRI findings. Fluorescence microscopy of pancreatic tumor sections showed a lower level of uMUC1 expression in the gemcitabine-treated group compared to the control, which was confirmed by qRT-PCR. Our data proved that changes in uMUC1 expression after gemcitabine chemotherapy could be evaluated using MN-EPPT-enhanced in vivo MR and optical imaging. These results suggest that the uMUC1-targeted imaging approach could provide a useful tool for the predictive assessment of therapeutic response.

Thyroid Hormone Receptors Predict Prognosis in BRCA1 Associated Breast Cancer in Opposing Ways

Since BRCA1 associated breast cancers are frequently classified as hormone receptor negative or even triple negative, the application of endocrine therapies is rather limited in these patients. Like hormone receptors that bind to estrogen or progesterone, thyroid hormone receptors (TRs) are members of the nuclear hormone receptor superfamily. TRs might be interesting biomarkers - especially in the absence of classical hormone receptors. The current study aimed to investigate whether TRs may be specifically expressed in BRCA1 associated cancer cases and whether they are of prognostic significance in these patients as compared to sporadic breast cancer cases. This study analyzed TRα and TRβ immunopositivity in BRCA1 associated (n = 38) and sporadic breast cancer (n = 86). Further, TRs were studied in MCF7 (BRCA1 wildtype) and HCC3153 (BRCA1 mutated) cells. TRβ positivity rate was significantly higher in BRCA1 associated as compared to sporadic breast cancers (p = 0.001). The latter observation remained to be significant when cases that had been matched for clinicopathological criteria were compared (p = 0.037). Regarding BRCA1 associated breast cancer cases TRβ positivity turned out to be a positive prognostic factor for five-year (p = 0.007) and overall survival (p = 0.026) while TRα positivity predicted reduced five-year survival (p = 0.030). Activation of TRβ resulted in down-modulation of CTNNB1 while TRα inhibition reduced cell viability in HCC3153. However, only BRCA1 wildtype MCF7 cells were capable of rapidly degrading TRα1 in response to T3 stimulation. Significantly, this study identified TRβ to be up-regulated in BRCA1 associated breast cancer and revealed TRs to be associated with patients’ prognosis. TRs were also found to be expressed in triple negative BRCA1 associated breast cancer. Further studies need to be done in order to evaluate whether TRs may become interesting targets of endocrine therapeutic approaches, especially when tumors are triple-negative.

Sensitivity to systemic therapy for metastatic breast cancer in CHEK2 1100delC mutation carriers

PURPOSE

The role of CHEK2 in DNA repair by homologous recombination suggests that CHEK2-associated breast cancer (BC) patients might be more sensitive to chemotherapy inducing double-strand DNA breaks, but results hereon are lacking. We compared the sensitivity to first-line chemotherapy and endocrine therapy between CHEK2 1100delC and non-CHEK2 metastatic breast cancer (MBC) patients.

METHODS

Sixty-two CHEK2 1100delC MBC patients were selected from three cohorts genotyped for CHEK2 1100delC (one non-BRCA1/2 cohort and two sporadic cohorts). Controls were 62 non-CHEK2 MBC patients, matched for age at and year of primary BC diagnosis, and year of metastatic disease. Objective response rate (complete and partial response) to, and progression-free survival (PFS) and overall survival (OS) after start of first-line chemotherapy and endocrine therapy were compared between CHEK2 and non-CHEK2 patients.

RESULTS

Median age at BC diagnosis was 46 and 51 years at MBC diagnosis. First-line chemotherapy consisted of anthracycline-based chemotherapy (n = 73), taxanes (n = 16), CMF(-like) chemotherapy (n = 33) and taxane/anthracycline regimens (n = 2). CHEK2 and non-CHEK2 patients had a comparable objective response rate (44 vs. 52 %). Also, PFS and OS after start of chemotherapy were comparable between both patient groups (hazard ratio 0.91; 95 % confidence interval 0.63-1.30 and 1.03; 95 % CI 0.71-1.49, respectively). Thirty-six CHEK2 and 32 non-CHEK2 patients received first-line endocrine therapy (mainly tamoxifen) for MBC. No significant differences were observed in objective response rate to, and PFS and OS after start of endocrine therapy.

CONCLUSION

No differential efficacy of chemotherapy and endocrine therapy given for MBC was observed in CHEK2 versus non-CHEK2 patients.

Skin cancer risk in BRCA1/2 mutation carriers

Women with BRCA1/2 mutations have an elevated risk of breast and ovarian cancer. These patients and their clinicians are often concerned about their risk for other cancers, including skin cancer. Research evaluating the association between BRCA1/2 mutations and skin cancer is limited and has produced inconsistent results. Herein, we review the current literature on the risk of melanoma and nonmelanoma skin cancers in BRCA1/2 mutation carriers. No studies have shown a statistically significant risk of melanoma in BRCA1 families. BRCA2 mutations have been linked to melanoma in large breast and ovarian cancer families, though a statistically significant elevated risk was reported in only one study. Five additional studies have shown some association between BRCA2 mutations and melanoma, while four studies did not find any association. With respect to nonmelanoma skin cancers, studies have produced conflicting results. Given the current state of medical knowledge, there is insufficient evidence to warrant increased skin cancer surveillance of patients with a confirmed BRCA1/2 mutation or a family history of a BRCA1/2 mutation, in the absence of standard risk factors. Nonetheless, suspected BRCA1/2 mutation carriers should be counselled about skin cancer risks and may benefit from yearly full skin examinations.

Breast cancers with a BRCA1-like DNA copy number profile recur less often than expected after high-dose alkylating chemotherapy

PURPOSE

Breast cancers in carriers of inactivating mutations of the BRCA1 gene carry a specific DNA copy-number signature ("BRCA1-like"). This signature is shared with cancers that inactivate BRCA1 through other mechanisms. Because BRCA1 is important in repair of DNA double-strand breaks through error-free homologous recombination, patients with a BRCA1-like tumor may benefit from high-dose alkylating (HD) chemotherapy, which induces DNA double-strand breaks.

EXPERIMENTAL DESIGN

We investigated a single institution cohort of high-risk patients that received tandem HD chemotherapy schedule comprising ifosfamide, epirubicin, and carboplatin or conventional chemotherapy. We classified copy-number profiles to be BRCA1-like or non-BRCA1-like and analyzed clinical associations and performed survival analysis with a treatment by biomarker interaction design.

RESULTS

BRCA1-like status associated with high-grade and triple-negative breast cancers. BRCA1-like cases benefitted from the HD compared with a conventional regimen on disease-free survival (DFS): [hazard ratio (HR), 0.05; 95% confidence interval (CI), 0.01-0.38; P = 0.003]; distant DFS (DDFS): (HR, 0.06; 95% CI, 0.01-0.43; P = 0.01); and overall survival (OS; HR, 0.15; 95% CI, 0.03-0.83; P = 0.03) after correction for prognostic factors. No such benefit was observed in the non-BRCA1-like cases on DFS (HR, 0.74; 95% CI, 0.38-1.46; P = 0.39), DDFS (HR, 0.79; 95% CI, 0.41-1.52; P = 0.47), and OS (HR, 0.93; 95% CI, 0.52-1.64; P = 0.79). The P values for interaction were 0.01 (DFS), 0.01 (DDFS), and 0.045 (OS).

CONCLUSIONS

BRCA1-like tumors recurred significantly less often after HD than conventional chemotherapy. BRCA1-like copy-number profile classification may be a predictive marker for HD alkylating chemotherapy.

A Peptide mimicking a region in proliferating cell nuclear antigen specific to key protein interactions is cytotoxic to breast cancer

Proliferating cell nuclear antigen (PCNA) is a highly conserved protein necessary for proper component loading during the DNA replication and repair process. Proteins make a connection within the interdomain connector loop of PCNA, and much of the regulation is a result of the inherent competition for this docking site. If this target region of PCNA is modified, the DNA replication and repair process in cancer cells is potentially altered. Exploitation of this cancer-associated region has implications for targeted breast cancer therapy. In the present communication, we characterize a novel peptide (caPeptide) that has been synthesized to mimic the sequence identified as critical to the cancer-associated isoform of PCNA. This peptide is delivered into cells using a nine-arginine linking mechanism, and the resulting peptide (R9-cc-caPeptide) exhibits cytotoxicity in a triple-negative breast cancer cell line, MDA-MB-436, while having less of an effect on the normal counterparts (MCF10A and primary breast epithelial cells). The novel peptide was then evaluated for cytotoxicity using various in vivo techniques, including ATP activity assays, flow cytometry, and clonogenetic assays. This cytotoxicity has been observed in other breast cancer cell lines (MCF7 and HCC1937) and other forms of cancer (pancreatic and lymphoma). R9-cc-caPeptide has also been shown to block the association of PCNA with chromatin. Alanine scanning of the peptide sequence, combined with preliminary in silico modeling, gives insight to the disruptive ability and the molecular mechanism of action of the therapeutic peptide in vivo.

Novel treatment strategies in triple-negative breast cancer: specific role of poly(adenosine diphosphate-ribose) polymerase inhibition

Inhibitors of the poly(adenosine triphosphate-ribose) polymerase (PARP)-1 enzyme induce synthetic lethality in cancers with ineffective DNA (DNA) repair or homologous repair deficiency, and have shown promising clinical activity in cancers deficient in DNA repair due to germ-line mutation in BRCA1 and BRCA2. The majority of breast cancers arising in carriers of BRCA1 germ-line mutations, as well as half of those in BRCA2 carriers, are classified as triple-negative breast cancer (TNBC). TNBC is a biologically heterogeneous group of breast cancers characterized by the lack of immunohistochemical expression of the ER, PR, or HER2 proteins, and for which the current standard of care in systemic therapy is cytotoxic chemotherapy. Many "sporadic" cases of TNBC appear to have indicators of DNA repair dysfunction similar to those in BRCA-mutation carriers, suggesting the possible utility of PARP inhibitors in a subset of TNBC. Significant genetic heterogeneity has been observed within the TNBC cohort, creating challenges for interpretation of prior clinical trial data, and for the design of future clinical trials. Several PARP inhibitors are currently in clinical development in BRCA-mutated breast cancer. The use of PARP inhibitors in TNBC without BRCA mutation will require biomarkers that identify cancers with homologous repair deficiency in order to select patients likely to respond. Beyond mutations in the BRCA genes, dysfunction in other genes that interact with the homologous repair pathway may offer opportunities to induce synthetic lethality when combined with PARP inhibition.

Evolution of pre-existing versus acquired resistance to platinum drugs and PARP inhibitors in BRCA-associated cancers

Platinum drugs and PARP inhibitors (“PARPis”) are considered to be effective in BRCA-associated cancers with impaired DNA repair. These agents cause stalled and collapsed replication forks and create double-strand breaks effectively in the absence of repair mechanisms, resulting in arrest of the cell cycle and induction of cell death. However, recent studies have shown failure of these chemotherapeutic agents due to emerging drug resistance. In this study, we developed a stochastic model of BRCA-associated cancer progression in which there are four cancer populations: those with (i) functional BRCA, (ii) dysfunctional BRCA, (iii) functional BRCA and a growth advantage, and (iv) dysfunctional BRCA and a growth advantage. These four cancer populations expand from one cancer cell with normal repair function until the total cell number reaches a detectable amount. We derived formulas for the probability and expected numbers of each population at the time of detection. Furthermore, we extended the model to consider the tumor dynamics during treatment. Results from the model were validated and showed good agreement with clinical and experimental evidence in BRCA-associated cancers. Based on the model, we investigated conditions in which drug resistance during the treatment course originated from either a pre-existing drug-resistant population or a de novo population, due to secondary mutations. Finally, we found that platinum drugs and PARPis were effective if (i) BRCA inactivation is present, (ii) the cancer was diagnosed early, and (iii) tumor growth is rapid. Our results indicate that different types of cancers have a preferential way of acquiring resistance to platinum drugs and PARPis according to their growth and mutational characteristics.

Survival and contralateral breast cancer in CHEK2 1100delC breast cancer patients: impact of adjuvant chemotherapy

Background:

We assessed the sensitivity to adjuvant chemotherapy in cell cycle checkpoint kinase 2 (CHEK2) vs non-CHEK2 breast cancer patients by comparing the contralateral breast cancer incidence and distant disease-free and breast cancer-specific survival between both groups, stratified for adjuvant chemotherapy.

Methods:

One Dutch hereditary non-BRCA1/2 breast cancer patient cohort (n=1220) and two Dutch cohorts unselected for family history (n=1014 and n=2488, respectively) were genotyped for CHEK2 1100delC. Hazard ratios for contralateral breast cancer, distant disease-free and breast cancer-specific death for mutation carriers vs noncarriers were calculated using the Cox proportional hazard method, stratified for adjuvant chemotherapy.

Results:

The CHEK2 mutation carriers (n=193) had an increased incidence of contralateral breast cancer (multivariate hazard ratio 3.97, 95% confidence interval 2.59–6.07). Distant disease-free and breast cancer-specific survival were similar in the first 6 years in mutation carriers compared with noncarriers, but diverted as of 6 years after breast cancer diagnosis (multivariate hazard ratios and 95% confidence intervals 2.65 (1.79–3.93) and 2.05 (1.41–2.99), respectively). No significant interaction between CHEK2 and adjuvant chemotherapy was observed.

Conclusions:

The CHEK2 1100delC-associated breast cancer is associated with a higher contralateral breast cancer rate as well as worse survival measures beyond 6 years after diagnosis. No differential sensitivity to adjuvant chemotherapy was observed in CHEK2 patients.

The degree of segmental aneuploidy measured by total copy number abnormalities predicts survival and recurrence in superficial gastroesophageal adenocarcinoma

Background

Prognostic biomarkers are needed for superficial gastroesophageal adenocarcinoma (EAC) to predict clinical outcomes and select therapy. Although recurrent mutations have been characterized in EAC, little is known about their clinical and prognostic significance. Aneuploidy is predictive of clinical outcome in many malignancies but has not been evaluated in superficial EAC.

Methods

We quantified copy number changes in 41 superficial EAC using Affymetrix SNP 6.0 arrays. We identified recurrent chromosomal gains and losses and calculated the total copy number abnormality (CNA) count for each tumor as a measure of aneuploidy. We correlated CNA count with overall survival and time to first recurrence in univariate and multivariate analyses.

Results

Recurrent segmental gains and losses involved multiple genes, including: HER2, EGFR, MET, CDK6, KRAS (recurrent gains); and FHIT, WWOX, CDKN2A/B, SMAD4, RUNX1 (recurrent losses). There was a 40-fold variation in CNA count across all cases. Tumors with the lowest and highest quartile CNA count had significantly better overall survival (p = 0.032) and time to first recurrence (p = 0.010) compared to those with intermediate CNA counts. These associations persisted when controlling for other prognostic variables.

Significance

SNP arrays facilitate the assessment of recurrent chromosomal gain and loss and allow high resolution, quantitative assessment of segmental aneuploidy (total CNA count). The non-monotonic association of segmental aneuploidy with survival has been described in other tumors. The degree of aneuploidy is a promising prognostic biomarker in a potentially curable form of EAC.

Breast cancer biomarkers: proteomic discovery and translation to clinically relevant assays

Although the molecular classification and prognostic assessment of breast tumors based on gene expression profiling is well established, a number of proteomic studies that propose potential breast cancer biomarkers has not yet led to any new diagnostic, prognostic or predictive test in wide clinical use. This review examines the current status of breast cancer biomarkers, discusses sample types (including plasma, tumor tissue, nipple aspirate and ductal lavage, as well as cell culture models) and different electrophoretic and mass spectrometry methods that have been widely used for the discovery of proteomic biomarkers in breast cancer, and also considers several approaches to biomarker validation. The pathway leading from the initial proteomic discovery and validation process to translation into a clinically useful test is also discussed.