Plasma fractalkine contributes to systemic myeloid diversity and PD-L1/PD-1 blockade in lung cancer.

Recent studies highlight the importance of baseline functional immunity for immune checkpoint blockade therapies. High-dimensional systemic immune profiling is performed in a cohort of non-small-cell lung cancer patients undergoing PD-L1/PD-1 blockade immunotherapy. Responders show high baseline myeloid phenotypic diversity in peripheral blood. To quantify it, we define a diversity index as a potential biomarker of response. This parameter correlates with elevated activated monocytic cells and decreased granulocytic phenotypes. High-throughput profiling of soluble factors in plasma identifies fractalkine (FKN), a chemokine involved in immune chemotaxis and adhesion, as a biomarker of response to immunotherapy that also correlates with myeloid cell diversity in human patients and murine models. Secreted FKN inhibits lung adenocarcinoma growth in vivo through a prominent contribution of systemic effector NK cells and increased tumor immune infiltration. FKN sensitizes murine lung cancer models refractory to anti-PD-1 treatment to immune checkpoint blockade immunotherapy. Importantly, recombinant FKN and tumor-expressed FKN are efficacious in delaying tumor growth in vivo locally and systemically, indicating a potential therapeutic use of FKN in combination with immunotherapy.

Determination of essential biomarkers in lung cancer: a real-world data study in Spain with demographic, clinical, epidemiological and pathological characteristics.

BACKGROUND: The survival of patients with lung cancer has substantially increased in the last decade by about 15%. This increase is, basically, due to targeted therapies available for advanced stages and the emergence of immunotherapy itself. This work aims to study the situation of biomarker testing in Spain. PATIENTS AND METHODS: The Thoracic Tumours Registry (TTR) is an observational, prospective, registry-based study that included patients diagnosed with lung cancer and other thoracic tumours, from September 2016 to 2020. This TTR study was sponsored by the Spanish Lung Cancer Group (GECP) Foundation, an independent, scientific, multidisciplinary oncology society that coordinates more than 550 experts and 182 hospitals across the Spanish territory. RESULTS: Nine thousand two hundred thirty-nine patients diagnosed with stage IV non-small cell lung cancer (NSCLC) between 2106 and 2020 were analysed. 7,467 (80.8%) were non-squamous and 1,772 (19.2%) were squamous. Tumour marker testing was performed in 85.0% of patients with non-squamous tumours vs 56.3% in those with squamous tumours (p-value < 0.001). The global testing of EGFR, ALK, and ROS1 was 78.9, 64.7, 35.6% respectively, in non-squamous histology. PDL1 was determined globally in the same period (46.9%), although if we focus on the last 3 years it exceeds 85%. There has been a significant increase in the last few years of all determinations and there are even close to 10% of molecular determinations that do not yet have targeted drug approval but will have it in the near future. 4,115 cases had a positive result (44.5%) for either EGFR, ALK, KRAS, BRAF, ROS1, or high PDL1. CONCLUSIONS: Despite the lack of a national project and standard protocol in Spain that regulates the determination of biomarkers, the situation is similar to other European countries. Given the growing number of different determinations and their high positivity, national strategies are urgently needed to implement next-generation sequencing (NGS) in an integrated and cost-effective way in lung cancer.

Hyperprogressive Disease: Main Features and Key Controversies.

Along with the positioning of immunotherapy as a preferential treatment for a wide variety of neoplasms, a new pattern of response consisting in a sudden acceleration of tumor growth has been described. This phenomenon has received the name of "hyperprogressive disease", and several definitions have been proposed for its identification, most of them relying on radiological criteria. However, due to the fact that the cellular and molecular mechanisms have not been elucidated yet, there is still some debate regarding whether this fast progression is induced by immunotherapy or only reflects the natural course of some highly aggressive neoplasms. Moreover, contradictory results of trials including patients with different cancer types suggest that both the incidence, the associated factors and the implications regarding prognosis might differ depending on tumor histology. This article intends to review the main publications regarding this matter and critically approach the most controversial aspects.

PD-L1 Expression in Systemic Immune Cell Populations as a Potential Predictive Biomarker of Responses to PD-L1/PD-1 Blockade Therapy in Lung Cancer.

PD-L1 tumor expression is a widely used biomarker for patient stratification in PD-L1/PD-1 blockade anticancer therapies, particularly for lung cancer. However, the reliability of this marker is still under debate. Moreover, PD-L1 is widely expressed by many immune cell types, and little is known on the relevance of systemic PD-L1⁺ cells for responses to immune checkpoint blockade. We present two clinical cases of patients with non-small cell lung cancer (NSCLC) and PD-L1-negative tumors treated with atezolizumab that showed either objective responses or progression. These patients showed major differences in the distribution of PD-L1 expression within systemic immune cells. Based on these results, an exploratory study was carried out with 32 cases of NSCLC patients undergoing PD-L1/PD-1 blockade therapies, to compare PD-L1 expression profiles and their relationships with clinical outcomes. Significant differences in the percentage of PD-L1⁺ CD11b⁺ myeloid cell populations were found between objective responders and non-responders. Patients with percentages of PD-L1⁺ CD11b⁺ cells above 30% before the start of immunotherapy showed response rates of 50%, and 70% when combined with memory CD4 T cell profiling. These findings indicate that quantification of systemic PD-L1⁺ myeloid cell subsets could provide a simple biomarker for patient stratification, even if biopsies are scored as PD-L1 null.

CAR-T Cells for the Treatment of Lung Cancer.

Adoptive cell therapy with genetically modified T lymphocytes that express chimeric antigen receptors (CAR-T) is one of the most promising advanced therapies for the treatment of cancer, with unprecedented outcomes in hematological malignancies. However, the efficacy of CAR-T cells in solid tumors is still very unsatisfactory, because of the strong immunosuppressive tumor microenvironment that hinders immune responses. The development of next-generation personalized CAR-T cells against solid tumors is a clinical necessity. The identification of therapeutic targets for new CAR-T therapies to increase the efficacy, survival, persistence, and safety in solid tumors remains a critical frontier in cancer immunotherapy. Here, we summarize basic, translational, and clinical results of CAR-T cell immunotherapies in lung cancer, from their molecular engineering and mechanistic studies to preclinical and clinical development.

Circulating Low Density Neutrophils Are Associated with Resistance to First Line Anti-PD1/PDL1 Immunotherapy in Non-Small Cell Lung Cancer.

Single-agent immunotherapy has been widely accepted as frontline treatment for advanced non-small cell lung cancer (NSCLC) with high tumor PD-L1 expression, but most patients do not respond and the mechanisms of resistance are not well known. Several works have highlighted the immunosuppressive activities of myeloid subpopulations, including low-density neutrophils (LDNs), although the context in which these cells play their role is not well defined. We prospectively monitored LDNs in peripheral blood from patients with NSCLC treated with anti-PD-1 immune checkpoint inhibitors (ICIs) as frontline therapy, in a cohort of patients treated with anti-PD1 immunotherapy combined with chemotherapy (CT+IT), and correlated values with outcomes. We explored the underlying mechanisms through ex vivo experiments. Elevated baseline LDNs predict primary resistance to ICI monotherapy in patients with NSCLC, and are not associated with response to CT+IT. Circulating LDNs mediate resistance in NSCLC receiving ICI as frontline therapy through humoral immunosuppression. A depletion of this population with CT+IT might overcome resistance, suggesting that patients with high PD-L1 tumor expression and high baseline LDNs might benefit from this combination. The activation of the HGF/c-MET pathway in patients with elevated LDNs revealed by quantitative proteomics supports potential drug combinations targeting this pathway.

Identification of a Dexamethasone Mediated Radioprotection Mechanism Reveals New Therapeutic Vulnerabilities in Glioblastoma.

(1) Background: Despite the indisputable effectiveness of dexamethasone (DEXA) to reduce inflammation in glioblastoma (GBM) patients, its influence on tumour progression and radiotherapy response remains controversial. (2) Methods: We analysed patient data and used expression and cell biological analyses to assess effects of DEXA on GBM cells. We tested the efficacy of tyrosine kinase inhibitors in vitro and in vivo. (3) Results: We confirm in our patient cohort that administration of DEXA correlates with worse overall survival and shorter time to relapse. In GBM cells and glioma stem-like cells (GSCs) DEXA down-regulates genes controlling G2/M and mitotic-spindle checkpoints, and it enables cells to override the spindle assembly checkpoint (SAC). Concurrently, DEXA up-regulates Platelet Derived Growth Factor Receptor (PDGFR) signalling, which stimulates expression of anti-apoptotic regulators BCL2L1 and MCL1, required for survival during extended mitosis. Importantly, the protective potential of DEXA is dependent on intact tyrosine kinase signalling and ponatinib, sunitinib and dasatinib, all effectively overcome the radio-protective and pro-proliferative activity of DEXA. Moreover, we discovered that DEXA-induced signalling creates a therapeutic vulnerability for sunitinib in GSCs and GBM cells in vitro and in vivo. (4) Conclusions: Our results reveal a novel DEXA-induced mechanism in GBM cells and provide a rationale for revisiting the use of tyrosine kinase inhibitors for the treatment of GBM.

Effects of a Multicomponent Exercise Program in Older Adults with Non-Small-Cell Lung Cancer during Adjuvant/Palliative Treatment: An Intervention Study.

Clinical intervention studies support the efficacy and safety of exercise programs as a treatment modality for non-small-cell lung cancer (NSCLC) during adjuvant/palliative treatment, but the effectiveness of real-world oncogeriatric services is yet to be established. We aimed to examine the effects of a 10-week structured and individualized multicomponent exercise program on physical/cognitive functioning and mental wellness in elderly patients with NSCLC under adjuvant therapy or palliative treatment. A non-randomized, opportunistic control, longitudinal-design trial was conducted on 26 patients with NSCLC stage I-IV. Of 34 eligible participants, 21 were allocated into two groups: (i) control group (n = 7) received usual medical care; and (ii) intervention group (n =19) received multicomponent program sessions, including endurance, strength, balance, coordination and stretching exercises. Tests included the Short Physical Performance Battery (SPPB), 5-m habitual Gait Velocity Test (GVT), Timed Up & Go Test (TUG), 6-Min Walk Test (6MWT), independence of activities in daily living (IADL), muscular performance, cognitive function, and quality of life, which were measured at baseline and after 10 weeks of the program. Results revealed a significant group×time interaction for SPPB (p = 0.004), 5-m GVT (p = 0.036), TUG (p = 0.007), and muscular performance (chest and leg power; p < 0.001). Similarly, significant changes were observed between groups for cognitive functioning (p = 0.021) and quality of life for EUROQoL 5D (p = 0.006). Our findings confirm that a multicomponent exercise program improves measures of physical/cognitive functioning and quality of life in the elderly with NSCLC under adjuvant therapy or palliative treatment. This is an interesting and important study that adds to our current body of knowledge on the safety of exercise interventions, especially in the elderly with solid tumors.

Early Detection of Hyperprogressive Disease in Non-Small Cell Lung Cancer by Monitoring of Systemic T Cell Dynamics.

Hyperprogressive disease (HPD) is an adverse outcome of immunotherapy consisting of an acceleration of tumor growth associated with prompt clinical deterioration. The definitions based on radiological evaluation present important technical limitations. No biomarkers have been identified yet. In this study, 70 metastatic NSCLC patients treated with anti-PD-1/PD-L1 immunotherapy after progression to platinum-based therapy were prospectively studied. Samples from peripheral blood were obtained before the first (baseline) and second cycles of treatment. Peripheral blood mononuclear cells (PBMCs) were isolated and differentiation stages of CD4 lymphocytes quantified by flow cytometry and correlated with HPD as identified with radiological criteria. A strong expansion of highly differentiated CD28- CD4 T lymphocytes (CD4 THD) between the first and second cycle of therapy was observed in HPD patients. After normalizing, the proportion of posttreatment/pretreatment CD4 THD was significantly higher in HPD when compared with the rest of patients (median 1.525 vs. 0.990; p = 0.0007), and also when stratifying by HPD, non-HPD progressors, and responders (1.525, 1.000 and 0.9700 respectively; p = 0.0025). A cut-off value of 1.3 identified HPD with 82% specificity and 70% sensitivity. An increase of CD28- CD4 T lymphocytes ≥ 1.3 (CD4 THD burst) was significantly associated with HPD (p = 0.008). The tumor growth ratio (TGR) was significantly higher in patients with expansion of CD4 THD burst compared to the rest of patients (median 2.67 vs. 0.86, p = 0.0049), and also when considering only progressors (median 2.67 vs. 1.03, p = 0.0126). A strong expansion of CD28- CD4 lymphocytes in peripheral blood within the first cycle of therapy is an early differential feature of HPD in NSCLC treated with immune-checkpoint inhibitors. The monitoring of T cell dynamics allows the early detection of this adverse outcome in clinical practice and complements radiological evaluation.

Looking for a Better Characterization of Triple-Negative Breast Cancer by Means of Circulating Tumor Cells.

Traditionally, studies to address the characterization of mechanisms promoting tumor aggressiveness and progression have been focused only on primary tumor analyses, which could provide relevant information but have limitations to really characterize the more aggressive tumor population. To overcome these limitations, circulating tumor cells (CTCs) represent a noninvasive and valuable tool for real-time profiling of disseminated tumor cells. Therefore, the aim of the present study was to explore the value of CTC enumeration and characterization to identify markers associated with the outcome and the aggressiveness of triple-negative breast cancer (TNBC). For that aim, the CTC population from 32 patients diagnosed with TNBC was isolated and characterized. This population showed important cell plasticity in terms of expression of epithelia/mesenchymal and stemness markers, suggesting the relevance of epithelial to mesenchymal transition (EMT) intermediate phenotypes for efficient tumor dissemination. Importantly, the CTC signature demonstrated prognostic value to predict the patients' outcome and pointed to a relevant role of tissue inhibitor of metalloproteinases 1 (TIMP1) and androgen receptor (AR) for TNBC biology. Furthermore, we also analyzed the usefulness of the AR and TIMP1 blockade to target TNBC proliferation and dissemination using in vitro and in vivo zebra fish and mouse models. Overall, the molecular characterization of CTCs from advanced TNBC patients identifies highly specific biomarkers with potential applicability as noninvasive prognostic markers and reinforced the value of TIMP1 and AR as potential therapeutic targets to tackle the most aggressive breast cancer.

Systematic Review and Meta-Analysis of Randomized, Controlled Trials on Preoperative Physical Exercise Interventions in Patients with Non-Small-Cell Lung Cancer.

Preoperative physical exercise protocols prior to cancer surgery increased in popularity over recent years; however, the beneficial effect of such protocols is not well established, with conflicting results reported. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effects of different modalities or combinations of preoperative exercise interventions and/or prehabilitation multicomponent training in patients with non-small-cell lung cancer (NSCLC) after surgery on the outcomes related to functional capacity, mental wellness and medical care. We searched in OVID Embase, Pubmed, Cochrane Library, CINAHL, Scopus, and Web of Science. Characteristics of studies and program results and outcome data were extracted. Changes between the intervention and control groups, from baseline to follow-up (standardized mean difference (SMD) or relative risk (RR) with 95% confidence interval (CI) for each intervention was pooled using weighted random-effects models). A total of 676 participants from 10 RCTs were included in the final analysis (aerobic training + inspiratory muscle training, n = 5; aerobic training + strength training + inspiratory muscle training, n = 2; aerobic training + strength training, n = 1; multicomponent training, n = 1; aerobic training alone, n = 1). The results showed intervention-induced improvement in walking endurance (SMD = 0.27; 95% CI, 0.11 to 0.44; I2 = 0.0%), peak exercise capacity (SMD = 0.78; 95% CI, 0.35 to 1.21; I2 = 76.7%), dyspnoea (SMD = -0.30; 95% CI, -0.51 to -0.10; I2 = 0.0%), risk of hospitalization (SMD = -0.58; 95% CI, -0.97 to -0.20; I2 = 70.7%), and postoperative pulmonary complications (relative risk (RR) = 0.50; 95% CI, 0.39 to 0.66; I2 = 0.0%). For the functional capacity and medical care parameters, preoperative combined aerobic, resistance, and inspiratory muscle training was shown to be effective if comprising one to four weeks, performing 1-3 sessions per week, with moderate intensity (50% for endurance capacity). Further studies with larger samples and higher methodological quality are needed to clarify the potential benefits of preoperative exercise training for patients with NSCLC.

Real-world efficacy and safety of eribulin in advanced and pretreated HER2-negative breast cancer in a Spanish comprehensive cancer center.

BACKGROUND: Eribulin improves survival in pre-treated HER2-negative advanced breast cancer (ABC). However, limited data exist on co-morbidities and central nervous system (CNS) efficacy. The purpose of this study was to review eribulin's efficacy and safety in everyday clinical practice with special focus on age, body mass index (BMI) and central nervous system (CNS) activity. METHODS: An observational study was conducted in a series of HER2-negative ABC patients treated from January'14-December'17 outside a clinical trial. Objective Response Rate (ORR), Progression Free Survival (PFS), Overall Survival (OS), and association of clinical and pathological variables with outcome were evaluated. RESULTS: Ninety-five women were treated with at least one cycle of eribulin. Median age was 57 (33-83), and 18% were obese. Median number of prior chemotherapies for ABC was 3 (2-5) and 76% of patients had visceral metastases, including 21% with CNS involvement. Most tumors were estrogen receptor-positive (79%). ORR and stable disease (SD) at 6 months were 26.2 and 37.5%, respectively. Remarkably, relevant CNS efficacy was observed with eribulin: 20% of patients obtained partial response and 25% SD. Treatment was generally well tolerated and manageable, with 29% grade 3 and 10.9% grade 4 toxicities. Median PFS and OS were 4.1 months (CI95% 3.2-4.9) and 11.1 months (CI95% 9.5-14.7), respectively. Triple-negative disease, > 2organs involved and being younger than 70 years old were independent prognosis factors for worse OS in multivariate analysis. Most patients (75%) progressed in pre-existing metastases sites. CONCLUSION: In everyday clinical practice, eribulin's efficacy seems similar to pivotal trials. CNS-efficacy was observed. TNBC, > 2 organs involved and being younger than 70 years old were independent prognosis factors for worse OS. Remarkably, less incidence of grade 4-toxicity compared to previous studies was found.

Functional systemic CD4 immunity is required for clinical responses to PD-L1/PD-1 blockade therapy.

The majority of lung cancer patients progressing from conventional therapies are refractory to PD-L1/PD-1 blockade monotherapy. Here, we show that baseline systemic CD4 immunity is a differential factor for clinical responses. Patients with functional systemic CD4 T cells included all objective responders and could be identified before the start of therapy by having a high proportion of memory CD4 T cells. In these patients, CD4 T cells possessed significant proliferative capacities, low co-expression of PD-1/LAG-3 and were responsive to PD-1 blockade ex vivo and in vivo. In contrast, patients with dysfunctional systemic CD4 immunity did not respond even though they had lung cancer-specific T cells. Although proficient in cytokine production, CD4 T cells in these patients proliferated very poorly, strongly co-upregulated PD-1/LAG-3, and were largely refractory to PD-1 monoblockade. CD8 immunity only recovered in patients with functional CD4 immunity. T-cell proliferative dysfunctionality could be reverted by PD-1/LAG-3 co-blockade. Patients with functional CD4 immunity and PD-L1 tumor positivity exhibited response rates of 70%, highlighting the contribution of CD4 immunity for efficacious PD-L1/PD-1 blockade therapy.

PAM50 Subtypes in Baseline and Residual Tumors Following Neoadjuvant Trastuzumab-Based Chemotherapy in HER2-Positive Breast Cancer: A Consecutive-Series From a Single Institution.

Introduction: HER2-enriched subtype has been associated with higher response to neoadjuvant anti-HER2-based therapy across various clinical trials. However, limited data exist in real-world practice and regarding residual disease. Here, we evaluate the association of HER2-enriched with pathological response (pCR) and gene expression changes in pre- and post-treatment paired samples in HER2-positive breast cancer patients treated outside of a clinical trial. Methods: We evaluated clinical-pathological data from a consecutive series of 150 patients with stage II-IIIC HER2-positive breast cancer treated from August 2004 to December 2012 with trastuzumab-based neoadjuvant chemotherapy. Expression of 105 breast cancer-related genes, including the PAM50 genes, was determined in available pre-and post-treatment formalin-fixed paraffin-embedded tumor samples using the nCounter platform. Intrinsic molecular subtypes were determined using the research-based PAM50 predictor. Association of genomic variables with total pCR was performed. Results: The pCR rate was 53.3%, with higher pCR among hormonal receptor (HR)-negative tumors (70 vs. 39%; P < 0.001). A total of 89 baseline and 28 residual tumors were profiled, including pre- and post-treatment paired samples from 26 patients not achieving a pCR. HER2-enriched was the predominant baseline subtype not only in the overall and HR-negative cohorts (64 and 75%, respectively), but also in the HR-positive cohort (55%). HER2-enriched was associated with higher pCR rates compared to non-HER2-enriched subtypes (65 vs. 31%; OR = 4.07, 95% CI 1.65-10.61, P < 0.002) and this association was independent of HR status. In pre- and post-treatment paired samples from patients not achieving a pCR, a lower proportion of HER2-enriched and twice the number of luminal tumors were observed at baseline, and luminal A was the most frequent subtype in residual tumors. Interestingly, most (81.8%) HER2-enriched tumors changed to non-HER2-enriched, whereas most luminal A samples maintained the same subtype in residual tumors. Conclusions: Outside of a clinical trial, PAM50 HER2-enriched subtype predicts pCR beyond HR status following trastuzumab-based chemotherapy in HER2-positive disease. The clinical value of intrinsic molecular subtype in residual disease warrants further investigation.

Corrigendum: PAM50 Subtypes in Baseline and Residual Tumors Following Neoadjuvant Trastuzumab-Based Chemotherapy in HER2-Positive Breast Cancer: A Consecutive-Series From a Single Institution.

[This corrects the article DOI: 10.3389/fonc.2019.00707.].

The C Allele of ATM rs11212617 Associates With Higher Pathological Complete Remission Rate in Breast Cancer Patients Treated With Neoadjuvant Metformin.

Background: The minor allele (C) of the single-nucleotide polymorphism (SNP) rs11212617, located near the ataxia telangiectasia mutated (ATM) gene, has been associated with an increased likelihood of treatment success with metformin in type 2 diabetes. We herein investigated whether the same SNP would predict clinical response to neoadjuvant metformin in women with early breast cancer (BC). Methods: DNA was collected from 79 patients included in the intention-to-treat population of the METTEN study, a phase 2 clinical trial of HER2-positive BC patients randomized to receive either metformin combined with anthracycline/taxane-based chemotherapy and trastuzumab or equivalent regimen without metformin, before surgery. SNP rs11212617 genotyping was assessed using allelic discrimination by quantitative polymerase chain reaction. Results: Logistic regression analyses revealed a significant relationship between the rs11212617 genotype and the ability of treatment arms to achieve a pathological complete response (pCR) in patients (odds ratio [OR]genotype×arm = 10.33, 95% confidence interval [CI]: 1.29-82.89, p = 0.028). In the metformin-containing arm, patients bearing the rs11212617 C allele had a significantly higher probability of pCR (OR A/C,C/C = 7.94, 95%CI: 1.60-39.42, p = 0.011). Conversely, no association was found between rs11212617 and clinical response in the reference arm (OR A/C,C/C = 0.77, 95%CI: 0.20-2.92, p = 0.700). After controlling for tumor size and hormone receptor status, the rs11212617 C allele remained a significant predictor of pCR solely in the metformin-containing arm. Conclusions: If reproducible, the rs11212617 C allele might warrant consideration as a predictive clinical biomarker to inform the personalized use of metformin in BC patients. Trial Registration: EU Clinical Trials Register, EudraCT number 2011-000490-30. Registered 28 February 2011, https://www.clinicaltrialsregister.eu/ctr-search/trial/2011-000490-30/ES.

Metformin induces a fasting- and antifolate-mimicking modification of systemic host metabolism in breast cancer patients.

Certain dietary interventions might improve the therapeutic index of cancer treatments. An alternative to the "drug plus diet" approach is the pharmacological reproduction of the metabolic traits of such diets. Here we explored the impact of adding metformin to an established therapeutic regimen on the systemic host metabolism of cancer patients. A panel of 11 serum metabolites including markers of mitochondrial function and intermediates/products of folate-dependent one-carbon metabolism were measured in paired baseline and post-treatment sera obtained from HER2-positive breast cancer patients randomized to receive either metformin combined with neoadjuvant chemotherapy and trastuzumab or an equivalent regimen without metformin. Metabolite profiles revealed a significant increase of the ketone body ß-hydroxybutyrate and of the TCA intermediate α-ketoglutarate in the metformin-containing arm. A significant relationship was found between the follow-up levels of homocysteine and the ability of treatment arms to achieve a pathological complete response (pCR). In the metformin-containing arm, patients with significant elevations of homocysteine tended to have a higher probability of pCR. The addition of metformin to an established anti-cancer therapeutic regimen causes a fasting-mimicking modification of systemic host metabolism. Circulating homocysteine could be explored as a clinical pharmacodynamic biomarker linking the antifolate-like activity of metformin and biological tumor response.

Neoadjuvant Metformin Added to Systemic Therapy Decreases the Proliferative Capacity of Residual Breast Cancer.

The proliferative capacity of residual breast cancer (BC) disease indicates the existence of partial treatment resistance and higher probability of tumor recurrence. We explored the therapeutic potential of adding neoadjuvant metformin as an innovative strategy to decrease the proliferative potential of residual BC cells in patients failing to achieve pathological complete response (pCR) after pre-operative therapy. We performed a prospective analysis involving the intention-to-treat population of the (Metformin and Trastuzumab in Neoadjuvancy) METTEN study, a randomized multicenter phase II trial of women with primary, non-metastatic (human epidermal growth factor receptor 2) HER2-positive BC evaluating the efficacy, tolerability, and safety of oral metformin (850 mg twice-daily) for 24 weeks combined with anthracycline/taxane-based chemotherapy and trastuzumab (arm A) or equivalent regimen without metformin (arm B), before surgery. We centrally evaluated the proliferation marker Ki67 on sequential core biopsies using visual assessment (VA) and an (Food and Drug Administration) FDA-cleared automated digital image analysis (ADIA) algorithm. ADIA-based pre-operative values of high Ki67 (≥20%), but not those from VA, significantly predicted the occurrence of pCR in both arms irrespective of the hormone receptor status (p = 0.024 and 0.120, respectively). Changes in Ki67 in residual tumors of non-pCR patients were significantly higher in the metformin-containing arm (p = 0.025), with half of all patients exhibiting high Ki67 at baseline moving into the low-Ki67 (<20%) category after neoadjuvant treatment. By contrast, no statistically significant changes in Ki67 occurred in residual tumors of the control treatment arm (p = 0.293). There is an urgent need for innovative therapeutic strategies aiming to provide the protective effects of decreasing Ki67 after neoadjuvant treatment even if pCR is not achieved. Metformin would be evaluated as a safe candidate to decrease the aggressiveness of residual disease after neoadjuvant (pre-operative) systemic therapy of BC patients.

Tumor xenograft modeling identifies an association between TCF4 loss and breast cancer chemoresistance.

Understanding the mechanisms of cancer therapeutic resistance is fundamental to improving cancer care. There is clear benefit from chemotherapy in different breast cancer settings; however, knowledge of the mutations and genes that mediate resistance is incomplete. In this study, by modeling chemoresistance in patient-derived xenografts (PDXs), we show that adaptation to therapy is genetically complex and identify that loss of transcription factor 4 (TCF4; also known as ITF2) is associated with this process. A triple-negative BRCA1-mutated PDX was used to study the genetics of chemoresistance. The PDX was treated in parallel with four chemotherapies for five iterative cycles. Exome sequencing identified few genes with de novo or enriched mutations in common among the different therapies, whereas many common depleted mutations/genes were observed. Analysis of somatic mutations from The Cancer Genome Atlas (TCGA) supported the prognostic relevance of the identified genes. A mutation in TCF4 was found de novo in all treatments, and analysis of drug sensitivity profiles across cancer cell lines supported the link to chemoresistance. Loss of TCF4 conferred chemoresistance in breast cancer cell models, possibly by altering cell cycle regulation. Targeted sequencing in chemoresistant tumors identified an intronic variant of TCF4 that may represent an expression quantitative trait locus associated with relapse outcome in TCGA. Immunohistochemical studies suggest a common loss of nuclear TCF4 expression post-chemotherapy. Together, these results from tumor xenograft modeling depict a link between altered TCF4 expression and breast cancer chemoresistance.