Noncatalytic PTEN missense mutation predisposes to organ-selective cancer development in vivo.

Inactivation of phosphatase and tensin homology deleted on chromosome 10 (PTEN) is linked to increased PI3K-AKT signaling, enhanced organismal growth, and cancer development. Here we generated and analyzed Pten knock-in mice harboring a C2 domain missense mutation at phenylalanine 341 (Pten(FV)), found in human cancer. Despite having reduced levels of PTEN protein, homozygous Pten(FV/FV) embryos have intact AKT signaling, develop normally, and are carried to term. Heterozygous Pten(FV/+) mice develop carcinoma in the thymus, stomach, adrenal medulla, and mammary gland but not in other organs typically sensitive to Pten deficiency, including the thyroid, prostate, and uterus. Progression to carcinoma in sensitive organs ensues in the absence of overt AKT activation. Carcinoma in the uterus, a cancer-resistant organ, requires a second clonal event associated with the spontaneous activation of AKT and downstream signaling. In summary, this PTEN noncatalytic missense mutation exposes a core tumor suppressor function distinct from inhibition of canonical AKT signaling that predisposes to organ-selective cancer development in vivo.

Metastatic breast cancer patient perceptions of somatic tumor genomic testing.

BACKGROUND: To assess metastatic breast cancer (MBC) patient psychological factors, perceptions, and comprehension of tumor genomic testing. METHODS: In a prospective, single institution, single-arm trial, patients with MBC underwent next-generation sequencing at study entry with sequencing results released at progression. Patients who completed surveys before undergoing sequencing were included in the present secondary analysis (n = 58). We administered four validated psychosocial measures: Center for Epidemiologic Studies Depression Scale, Beck Anxiety Inventory, Trust in Physician Scale, and Communication and Attitudinal Self-Efficacy scale for Cancer. Genetic comprehension was assessed using 7-question objective and 6-question subjective measures. Longitudinal data were assessed (n = 40) using paired Wilcoxon signed rank and McNemar's test of agreement. RESULTS: There were no significant differences between the beginning and end of study in depression, anxiety, physician trust, or self-efficacy (median time on study: 7.6 months). Depression and anxiety were positively associated with each other and both negatively associated with self-efficacy. Self-efficacy decreased from pre- to post-genomic testing (p = 0.05). Objective genetics comprehension did not significantly change from pre- to post-genomic testing, but patients expressed increased confidence in their ability to teach others about genetics (p = 0.04). Objective comprehension was significantly lower in non-white patients (p = 0.02) and patients with lower income (p = 0.04). CONCLUSIONS: This is the only study, to our knowledge, to longitudinally evaluate multiple psychological metrics in MBC as patients undergo tumor genomic testing. Overall, psychological dimensions remained stable over the duration of tumor genomic testing. Among patients with MBC, depression and anxiety metrics were negatively correlated with patient self-efficacy. Patients undergoing somatic genomic testing had limited genomic knowledge, which varied by demographic groups and may warrant additional educational intervention. CLINICAL TRIAL INFORMATION: NCT01987726, registered November 13, 2013.

Circulating myeloid-derived suppressor cells increase in patients undergoing neo-adjuvant chemotherapy for breast cancer.

This study sought to evaluate whether myeloid-derived suppressor cells (MDSC) could be affected by chemotherapy and correlate with pathologic complete response (pCR) in breast cancer patients receiving neo-adjuvant chemotherapy. Peripheral blood levels of granulocytic (G-MDSC) and monocytic (M-MDSC) MDSC were measured by flow cytometry prior to cycle 1 and 2 of doxorubicin and cyclophosphamide and 1st and last administration of paclitaxel or paclitaxel/anti-HER2 therapy. Of 24 patients, 11, 6 and 7 patients were triple negative, HER2+ and hormone receptor+, respectively. 45.8% had pCR. Mean M-MDSC% were <1. Mean G-MDSC% and 95% confidence intervals were 0.88 (0.23-1.54), 5.07 (2.45-7.69), 9.32 (4.02-14.61) and 1.97 (0.53-3.41) at draws 1-4. The increase in G-MDSC by draw 3 was significant (p < 0.0001) in all breast cancer types. G-MDSC levels at the last draw were numerically lower in patients with pCR (1.15; 95% CI 0.14-2.16) versus patients with no pCR (2.71; 95% CI 0-5.47). There was no significant rise in G-MDSC from draw 1 to 3 in African American patients, and at draw 3 G-MDSC levels were significantly lower in African Americans versus Caucasians (p < 0.05). It was concluded that G-MDSC% increased during doxorubicin and cyclophosphamide therapy, but did not significantly differ between patients based on pathologic complete response.

Neoadjuvant dual HER2-targeted therapy with lapatinib and trastuzumab improves pathologic complete response in patients with early stage HER2-positive breast cancer: a meta-analysis of randomized prospective clinical trials.

BACKGROUND: Randomized clinical trials (RCT) that evaluated the addition of lapatinib to trastuzumab plus neoadjuvant chemotherapy (NAC) in patients with HER2-positive, operable breast cancer revealed a questionable improvement in pathologic complete response (pCR) rate. We performed a meta-analysis of prospective RCTs that examined the effect of adding lapatinib to trastuzumab and NAC on pCR rate. METHODS: PubMed databases and abstracts from the proceedings of the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium were searched for RCTs that compared lapatinib plus trastuzumab and NAC with trastuzumab in combination with NAC and that included pCR as the primary outcome. Our main objective was to estimate the effect of adding lapatinib to trastuzumab plus NAC on pCR rate, defined as no residual invasive cancer in breast and axillary lymph nodes. RESULTS: In total, 1,017 patients with early stage breast cancer from 5 trials were included. Four trials examined the addition of lapatinib to trastuzumab plus NAC; this resulted in statistically significant improvement in pCR, defined as no residual carcinoma in breast and lymph nodes. The pCR rate was 55.76% and 38.36% in the lapatinib plus trastuzumab and the trastuzumab plus NAC arms, respectively (odds ratio [OR]: 1.94; 95% confidence interval [CI]: 1.44-2.60). In three trials, the rates of pCR, defined as no residual invasive carcinoma in breast only, for the lapatinib plus trastuzumab and trastuzumab-alone groups were 55.01% and 40.70%, respectively, also resulting in significant improvement (OR: 1.78; 95% CI: 1.27-2.50). CONCLUSION: The addition of lapatinib to trastuzumab in combination with neoadjuvant chemotherapy significantly improves pCR rates in patients with HER2-positive breast cancer.

Heterogeneous atypical cell populations are present in blood of metastatic breast cancer patients.

INTRODUCTION: Circulating tumor cells (CTCs) are commonly isolated from the blood by targeting the epithelial cell adhesion molecule (EpCAM) through positive selection. However, EpCAM can be downregulated during metastatic progression, or it can be initially not present. We designed the present prospective trial to characterize CTCs as well as other circulating cell populations in blood samples from women with metastatic breast cancer without EpCAM-dependent enrichment and/or isolation technology. METHODS: A total of 32 patients with metastatic breast cancer were enrolled, and blood samples were processed using a previously described negative depletion immunomagnetic methodology. Samples from healthy volunteers were run as controls (n = 5). Multistep sequential labeling was performed to label and fix cell-surface markers followed by permeabilization for cytokeratins (CK) 8, 18 and 19. Multiparametric flow cytometry (FCM) analysis was conducted using a BD LSR II flow cytometer or a BD FACSAria II or FACSAria III cell sorter. Immunocytochemical staining on postenrichment specimens for DAPI, EpCAM, CD45, CK, epidermal growth factor receptor and vimentin was performed. Expression of these markers was visualized using confocal microscopy (CM). RESULTS: CD45-negative/CK-positive (CD45- CK+) populations with EpCAM + and EpCAM - expression were identified with both FCM and CM from the negatively enriched patient samples. In addition, EpCAM + and EpCAM - populations that were CK + and coexpressing the pan-hematopoietic marker CD45 were also noted. There were more CK + EpCAM - events/ml than CK + EpCAM + events/ml in both the CD45- and CD45+ fractions (both statistically significant at P ≤ 0.0005). The number of CK + CD45- and CK + CD45+ events per milliliter in blood samples (regardless of EpCAM status) was higher in patient samples than in normal control samples (P ≤ 0.0005 and P ≤ 0.026, respectively). Further, a significant fraction of the CK + CD45+ events also expressed CD68, a marker associated with tumor-associated macrophages. Higher levels of CD45-CK + EpCAM - were associated with worse overall survival (P = 0.0292). CONCLUSIONS: Metastatic breast cancer patients have atypical cells that are CK + EpCAM - circulating in their blood. Because a substantial number of these patients do not have EpCAM + CTCs, additional studies are needed to evaluate the role of EpCAM - circulating cells as a prognostic and predictive marker.

Treatment-related mortality with everolimus in cancer patients.

INTRODUCTION: The overall incidence and odds of fatal adverse events (FAEs) after exposure to everolimus are not well defined. We performed a comprehensive meta-analysis of published randomized controlled trials (RCTs) to determine the role of everolimus in treatment-related mortality in patients with cancer. METHODS: PubMed databases and abstracts from the proceedings of the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium were searched for RCTs of everolimus either alone or in combination with another agent compared with the control arm without everolimus and that reported deaths from an adverse event from January 1966 to July 2013. The primary objective was to determine the difference of FAEs between everolimus-treated patients and control group patients. RESULTS: In total, 2,997 patients with multiple solid tumors from nine RCTs were included. The overall incidence of FAEs in cancer patients treated with everolimus was 0.7% (95% CI 0.3%-1.1%) compared with 0.4% (95% CI 0.0%-0.7%) in cancer patients who did not receive everolimus. The odds ratio of FAEs was greater in everolimus-treated patients (Peto odds ratio = 3.80, 95% CI 1.59-9.07, p = .003). In subgroup analyses, no significant difference was found in the incidence or odds of FAEs by everolimus administration (alone or in combination) or tumor type (breast cancer vs. nonbreast cancer; p = .63). CONCLUSION: In patients with cancer, everolimus is associated with a small but significant increase in the odds of a treatment-related fatal events.

A Phase II study of bevacizumab in combination with trastuzumab and docetaxel in HER2 positive metastatic breast cancer.

BACKGROUND: Preclinical and early clinical data support the use of Vascular Epithelial Growth Factor (VEGF)-targeted therapy with trastuzumab in Human Epidermal Receptor 2 (HER2) positive breast cancer. Adding bevacizumab to a taxane (docetaxel or paclitaxel) improves progression free survival (PFS) of metastatic breast cancer (MBC) patients. OBJECTIVES: We evaluated the efficacy and feasibility of combining bevacizumab with trastuzumab and docetaxel in patients with HER2- positive MBC who received 0-1 prior chemotherapy regimens for metastatic disease. The primary end point was PFS. MATERIALS AND METHODS: Eligible patients received bevacizumab (15 mg/kg), trastuzumab (8 mg/kg loading dose followed by 6 mg/kg), and docetaxel (100 mg/m2 initially, later amended to 75 mg/m2) every three weeks for six cycles and then were allowed to receive bevacizumab and trastuzumab alone. Results Thirteen (50%) of 26 patients enrolled completed all 6 cycles of bevacizumab, trastuzumab and docetaxel and went on to receive bevacizumab and trastuzumab alone (median: 11 cycles). The most common grade 3 or 4 toxicities include: neutropenia (8%), septic death (4%), infection not associated with neutropenia (15%), fatigue (27%), mylagia and/or arthraligia (20%), and hand-foot syndrome (8%). One patient (4%) and six patients (23%) developed grade 3 and grade 2 hypertension, respectively. Two (8%) patients had transient grade 2 drop in Left Ventricular Ejection Fraction (LVEF) with full recovery later. The median progression free survival (PFS) was 14.3 months (95% CI: 9.3-35 months), the objective response rate (ORR), defined as the best response of complete response (CR) or partial response (PR) was (12/26) 46%. The clinical benefit rate (CBR), defined as the best response of CR or PR or stable disease (SD) for at least 24 weeks, was (18/26) 69% (95% CI: 48-86%). CONCLUSION: The combination of bevacizumab, trastuzumab and docetaxel is well tolerated and is clinically active in patients with HER2-positive MBC, with response rate and PFS comparable to previous reports utilizing higher dose of docetaxel (100 mg/m2). Recent randomized trials did not demonstrate additional overall survival (OS) benefit of adding bevacizumab to trastuzumab and docetaxel despite an improvement in PFS. Identification of predictive biomarkers and careful patient selection should be incorporated in further investigation of anti-VEGF in breast cancer.

Phase II Single-Arm Study to Assess Trastuzumab and Vinorelbine in Advanced Breast Cancer Patients With HER2-Negative Tumors and HER2-Positive Circulating Tumor Cells.

PURPOSE: Human epidermal growth factor receptor 2 (HER2)-directed treatments improve outcomes for patients with HER2-positive metastatic breast cancer (MBC). Current identification of patients with HER2-positive disease relies on tumor tissue testing, which can be inaccurate because of tumor heterogeneity or tumor evolution. Circulating tumor cells (CTCs) are often present in patients with cancer. We hypothesized that HER2 assessment of CTCs in patients with HER2-negative breast cancer could identify a subset of patients with HER2-positive CTCs who could benefit from HER2-directed treatments. METHODS: This was a single-arm, two-stage, phase II trial. Patients with HER2-negative progressive MBC with HER2-positive CTC (defined as HER2/CEP17 ratio ≥ 2.0 by fluorescence in situ hybridization), ≥ 1 prior chemotherapy regimen for MBC, and no prior vinorelbine received trastuzumab in combination with vinorelbine on days 1, 8, and 15 of a 21-day cycle. The primary end point was objective response rate. RESULTS: From January 2013 to June 2014, we prospectively screened CTCs from patients with HER2-negative MBC. CTCs were detected in 201 of 311 patients (65%). The median number of CTCs was 10 (interquartile range, 3-57). Sixty-nine of 311 patients (22%) had HER2+ CTCs, with a median of three HER2+ CTCs (range 1-21). Twenty patients with HER2+ CTCs were treated on study. At data cutoff (January 13, 2017), no patients remained on study therapy. The objective response rate was 5% (95% CI, 0.1 to 24.9), with one of 20 patients experiencing a partial response. The clinical benefit rate was 20.0% (1 partial response and 3 stable diseases > 24 weeks, 95% CI, 5.7% to 43.7%). The median progression-free survival was 2.7 months. CONCLUSION: CTC analysis of patients with HER2-negative MBC identifies a subset with HER2-amplified CTCs. However, clinical activity of an HER2-directed regimen in this population was low. The functional significance of HER2-positive CTCs remains uncertain.

Endocrine Treatment and Targeted Therapy for Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: ASCO Guideline Update.

PURPOSE: To update recommendations of the ASCO systemic therapy for hormone receptor (HR)-positive metastatic breast cancer (MBC) guideline. METHODS: An Expert Panel conducted a systematic review to identify new, potentially practice-changing data. RESULTS: Fifty-one articles met eligibility criteria and form the evidentiary basis for the recommendations. RECOMMENDATIONS: Alpelisib in combination with endocrine therapy (ET) should be offered to postmenopausal patients, and to male patients, with HR-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, ABC, or MBC following prior endocrine therapy with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor. Clinicians should use next-generation sequencing in tumor tissue or cell-free DNA in plasma to detect PIK3CA mutations. If no mutation is found in cell-free DNA, testing in tumor tissue, if available, should be used as this will detect a small number of additional patients with PIK3CA mutations. There are insufficient data at present to recommend routine testing for ESR1 mutations to guide therapy for HR-positive, HER2-negative MBC. For BRCA1 or BRCA2 mutation carriers with metastatic HER2-negative breast cancer, olaparib or talazoparib should be offered in the 1st-line through 3rd-line setting. A nonsteroidal aromatase inhibitor (AI) and a CDK4/6 inhibitor should be offered to postmenopausal women with treatment-naïve HR-positive MBC. Fulvestrant and a CDK4/6 inhibitor should be offered to patients with progressive disease during treatment with AIs (or who develop a recurrence within 1 year of adjuvant AI therapy) with or without one line of prior chemotherapy for metastatic disease, or as first-line therapy. Treatment should be limited to those without prior exposure to CDK4/6 inhibitors in the metastatic setting.Additional information can be found at www.asco.org/breast-cancer-guidelines.

Dabrafenib and Trametinib in Patients With Tumors With BRAFV600E Mutations: Results of the NCI-MATCH Trial Subprotocol H.

PURPOSE: BRAFV600 mutations are commonly found in melanoma and thyroid cancers and to a lesser degree in other tumor types. Subprotocol H (EAY131-H) of the NCI-MATCH platform trial sought to investigate the selective BRAF inhibitor dabrafenib and the MEK1/2 inhibitor trametinib in patients with solid tumors, lymphomas, or multiple myeloma whose tumors harbored a BRAFV600 mutation. PATIENTS AND METHODS: EAY131-H is an open-label, single-arm study. Patients with melanoma, thyroid, or colorectal cancer were excluded; patients with non-small-cell lung cancer were later excluded in an amendment. Patients received dabrafenib 150 mg twice per day and trametinib 2 mg per day continuously until disease progression or intolerable toxicity. The primary end point was centrally assessed objective response rate (ORR); secondary end points included progression-free survival (PFS), 6-month PFS, and overall survival. RESULTS: Thirty-five patients were enrolled, and 29 were included in the primary efficacy analysis as prespecified in the protocol. Median age was 59 years, and 45% of the patients had received ≥ 3 lines of therapy. The confirmed ORR was 38% (90% CI, 22.9% to 54.9%) with P < .0001 against a null rate of 5%, and PFS was 11.4 months (90% CI, 8.4 to 16.3 months); responses were seen in 7 distinct tumor types. Seven patients had a duration of response of > 12 months, including 4 patients with a duration of response of > 24 months. An additional 8 patients had a PFS > 6 months. The median overall survival was 28.6 months. Reported adverse events were comparable to those noted in previously reported profiles of dabrafenib and trametinib. CONCLUSION: This study met its primary end point, with an ORR of 38% (P < .0001) in this mixed histology, pretreated cohort. This promising activity warrants additional investigations in BRAFV600-mutated tumors outside of currently approved indications.

Prospective Decision Analysis Study of Clinical Genomic Testing in Metastatic Breast Cancer: Impact on Outcomes and Patient Perceptions.

PURPOSE: To evaluate the impact of targeted DNA sequencing on selection of cancer therapy for patients with metastatic breast cancer (MBC). PATIENTS AND METHODS: In this prospective, single-center, single-arm trial, patients with MBC were enrolled within 10 weeks of starting a new therapy. At enrollment, tumor samples underwent next-generation sequencing for any of 315 cancer-related genes to high depth (> 500×) using FoundationOne CDx. Sequencing results were released to providers at the time of disease progression, and physician treatment recommendations were assessed via questionnaire. We evaluated three prespecified questions to assess patients' perceptions of genomic testing. RESULTS: In all, 100 patients underwent genomic testing, with a median of five mutations (range, 0 to 13 mutations) detected per patient. Genomic testing revealed one or more potential therapies in 98% of patients (98 of 100), and 60% of patients (60 of 100) had one or more recommended treatments with level I/II evidence for actionability. Among the 94 genomic text reports that were released, there was physician questionnaire data for 87 patients (response rate, 92.6%) and 31.0% of patients (27 of 87) had treatment change recommended by their physician. Of these, 37.0% (10 of 27) received the treatment supported by genomic testing. We did not detect a statistically significant difference in time-to-treatment failure (log-rank P = .87) or overall survival (P = .71) among patients who had treatment change supported by genomic testing versus those who had no treatment change. For patients who completed surveys before and after genomic testing, there was a significant decrease in confidence of treatment success, specifically among patients who did not have treatment change supported by genomic testing (McNemar's test of agreement P = .001). CONCLUSION: In this prospective study, genomic profiling of tumors in patients with MBC frequently identified potential treatments and resulted in treatment change in a minority of patients. Patients whose therapy was not changed on the basis of genomic testing seemed to have a decrease in confidence of treatment success.

Discovery of Stromal Regulatory Networks that Suppress Ras-Sensitized Epithelial Cell Proliferation.

Mesodermal cells signal to neighboring epithelial cells to modulate their proliferation in both normal and disease states. We adapted a Caenorhabditis elegans organogenesis model to enable a genome-wide mesodermal-specific RNAi screen and discovered 39 factors in mesodermal cells that suppress the proliferation of adjacent Ras pathway-sensitized epithelial cells. These candidates encode components of protein complexes and signaling pathways that converge on the control of chromatin dynamics, cytoplasmic polyadenylation, and translation. Stromal fibroblast-specific deletion of mouse orthologs of several candidates resulted in the hyper-proliferation of mammary gland epithelium. Furthermore, a 33-gene signature of human orthologs was selectively enriched in the tumor stroma of breast cancer patients, and depletion of these factors from normal human breast fibroblasts increased proliferation of co-cultured breast cancer cells. This cross-species approach identified unanticipated regulatory networks in mesodermal cells with growth-suppressive function, exposing the conserved and selective nature of mesodermal-epithelial communication in development and cancer.

Pertuzumab in Combination with Trastuzumab and Chemotherapy in the Treatment of HER2-Positive Metastatic Breast Cancer: Safety, Efficacy, and Progression Free Survival.

UNLABELLED: Tyrosine kinase inhibitors have revolutionized the oncology community and were pioneered by the use in HER2-targeted therapies. Improved outcomes were seen with the advent of trastuzumab, leading investigators to develop newer agents to target the HER2 pathway such as the novel monoclonal antibody pertuzumab. In this paper, we describe the attributes of pertuzumab including: mechanism of action, pharmacokinetics and metabolism, safety/cardiotoxicity, drug interactions, efficacy, and role in HER2-positive breast cancer management. Newly reviewed here versus previously published reviews on pertuzumab oriented therapy are data of pertuzumab monotherapy as it is used in combination with other anti-HER2 agents derived from preclinical research and ongoing clinical trials. MATERIALS AND METHODS: A computer based literature search was carried out using PubMed data reported at international meetings (ASCO) up to September 2013 were included.

Role of trastuzumab emtansine in the treatment of HER2-positive breast cancer.

Trastuzumab is a monoclonal antibody that is used in the treatment of breast cancer. Trastuzumab targets the human epidermal growth factor receptor 2 (HER2) receptor on breast cancer cells that express this tyrosine kinase receptor. These cancers are referred to as HER2-positive breast cancer. The original studies of trastuzumab showed improved survival in metastatic breast cancer; however, resistance often develops. In the adjuvant setting, women often progress despite therapy that includes trastuzumab. Antibody-drug conjugates are a new class of powerful drugs designed to target high-dose chemotherapy directly to the cancer cells. Trastuzumab emtansine is one of these antibody-drug conjugates and was the first Food and Drug Administration approved drug for a solid tumor. Emtansine is a potent antimicrotubule agent. Trastuzumab is used to target this potent chemotherapy agent directly to the HER2-expressing cancer cells. This review article will summarize the evidence from the preclinical studies, summarize evidence from the clinical trials, discuss current clinical trials, discuss current approval of trastuzumab emtansine, and discuss future directions of research.