Viscum album neutralizes tumor-induced immunosuppression in a human in vitro cell model

A randomized placebo-controlled double-blinded study comparing oral and subcutaneous administration of mistletoe extract for the treatment of equine sarcoid disease

BACKGROUND

Equine sarcoids (ES) are the most common cutaneous tumors in equids. Systemic treatment options are sparse. Subcutaneous (SC) injections of Viscum album extract (VAE) demonstrate efficacy as a systemic treatment directed against ES.

OBJECTIVES/AIM

To critically assess the therapeutic efficacy of orally administered VAE.

ANIMALS

Forty-five ES-affected, privately owned, 3-12 year-old horses.

METHODS

A 3-armed randomized placebo-controlled, double-blinded study was conducted in a double-dummy design. Horses were subjected to oral administration and SC injections of either VAE or placebo (VAE oral/placebo SC, VAE SC/placebo oral, placebo oral/placebo SC) over a 7-month treatment period. Primary endpoint was the change of baseline of a composite index of ES number and ES area after 14 months. Second endpoint was the clinical response.

RESULTS

No statistically significant difference in the composite endpoint between the 3 study arms was found. The primary endpoint showed 4 (27%) horses in the VAE oral group with complete ES regression, 3 (21%) in the VAE SC injection group, and 2 (13%) in the placebo group. The clinical response revealed complete or partial regression in 6 horses of the oral VAE group (40%), 4 of the SC injection group (29%), and 4 of the placebo group (25%). Direct comparison of oral VAE and placebo showed an odds ratio, stratified for prognosis of 2.16 (95%-CI: 0.45-10.42) and a P-value of 0.336.

CONCLUSION AND CLINICAL IMPORTANCE

Oral administration of VAE is well tolerated. No statistically significant difference in the effectiveness of systemic VAE versus placebo against ES was found.

Viscum album (mistletoe) extract for dogs with cancer?

Compared with the options available to human patients with cancer, treatment choices for dogs are often more limited. Chemotherapy is frequently the first-line treatment for many cancers. However, its efficacy can be limited, and its side effects can affect the quality of the remaining life. This paper briefly summarizes the experience with Viscum album L. (mistletoe) extract in human patients as a stipulation to consider treatment with mistletoe extract for canines with cancer. The mistletoe extract contains -among others - lectins and viscotoxins that have documented anti-proliferative effect on cancer cells as well as immune-stimulatory function. Importantly, it also improves the well-being of patients with cancer due to its lectin ML-1 content, which can trigger the release of endorphins. Being cross-reactive with canine cells and having a relatively low side effect profile, it raises the question of whether mistletoe preparations might be considered as part of the treatment approach for dogs with cancer.

Traditional Uses, Phytochemical Constituents and Ethnopharmacological Properties of Mistletoe from Phoradendron and Viscum Species

Plants from the genus Phoradendron and Viscum, also known as American and European mistletoe, are a group of hemiparasitic plants traditionally used to treat many diseases. Mistletoes have a rich content of natural compounds like terpenes, alkaloids, proteins, and phenolic compounds associated with their potential medicinal properties. In this sense, mistletoes have shown antiproliferative, antioxidant, anti-inflammatory, and antimicrobial activity, which has been attributed to their phytochemical constituents. The mechanisms in which mistletoe plants act vary and depend on their phytochemical content and distribution, which in part will depend on the mistletoe species. In this sense, recent literature research is needed to visualize state of the art in the ethnopharmacological potential of mistletoe. Thus, this literature review aims to systematically report recent studies (2010-2023) on the phytochemical characterization and bioactive studies of mistletoe plants, mainly the Viscum and Phoradendron genera. We gather recent information of 140 references selected in our research. Here we report that although there are several bioactivity studies of mistletoe species, bioavailability studies are still scarce, and the precise mechanisms of action are not fully known. We encourage that further studies include a systematic strategy to cover these areas of opportunity.

Mistletoe Extracts during the Oncological Perioperative Period: A Systematic Review and Meta-Analysis of Human Randomized Controlled Trials

BACKGROUND

We aim to evaluate the safety and efficacy of mistletoe extract (ME) use during the oncological perioperative period.

METHODS

Details registered a priori on PROSPERO (CRD42018086168).

RESULTS

Seven RCTs (comprising 663 participants in nine reports) and three nonrandomized studies were included. In five RCTs, ME was evaluated as adjunctive care and the control group had no additional intervention, whereas in two RCTs, ME was compared head-to-head against common cancer treatments (i.e., etoposide or bacillus Calmette-Guérin) with the intervention groups not receiving standard care. Meta-analyses found no evidence for a difference between ME and no added therapy for mortality and recurrence (RR, 95% CI: 1.00, 0.79-1.27; and 1.03, 0.79-1.33, respectively). Two RCTs reported beneficial effects of ME on immune cells, specifically natural killer cells, in colorectal cancer, and one RCT reported quality of life improvement. Two RCTs reported ME discontinuations due to adverse events and grade 3/4 toxicities. Nevertheless, no safety signals were detected from these 10 studies. Quality appraisal revealed a substantial risk of bias.

CONCLUSIONS

Preliminary data are encouraging for mistletoe extracts, particularly in the context of colorectal cancer. However, the evidence is limited by the number of studies, an evaluation of different outcomes, and methodological limitations. Further high-quality research is warranted.

Mistletoe extracts for cancer treatment

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effects of mistletoe extracts (Viscum album , European mistletoe) as antitumour treatment and for supportive/palliative care in adults with cancer. We will assess whether mistletoe extracts administered alone or in combination with tumour‐specific therapies prolong progression free‐intervals (PFI) and/or overall survival (OS); enhance tumour response; alleviate treatment‐related adverse effects from conventional cancer treatment e.g. chemo‐ or radiotherapy; improve patient‐reported outcomes including health‐related QOL; and whether mistletoe extracts produce adverse effects.

In-Vitro Growth Kinetics of Mesenchymal Stem Cells in Cytotoxicity Tests Using Low-Diluted Viscum Album

INTRODUCTION

 The use of mesenchymal stem cells (MSC) in cytotoxicity tests is an in-vitro alternative model for predicting initial doses. Homeopathic medicines may stimulate the immune system to combat a pathology effectively and have been used for over two centuries. Viscum album (VA) extracts are widely used in the treatment of cancer, due to their immunomodulatory, cytotoxic and pro-apoptotic properties.

OBJECTIVE

 This study aimed to evaluate the in-vitro growth kinetics of canine MSC in relation to cytotoxicity, cell differentiation and expression of pluripotentiality markers, using a VA preparation at the D1D2 (1×10^-1, 1×10^-2 potency (VAD1D2).

METHODS

 MSC were obtained from adipose tissue sampled from a healthy dog that was undergoing an elective veterinary procedure and with its owner's permission. The experiments were performed in three groups: MSC treated with VAD1D2 or diluent or untreated (control). The cytotoxicity was evaluated by MTT assay. The differentiation was induced in three lineages, and apoptotic cell labeling was performed by an Annexin-V test.

RESULTS

 At the concentration of 10 μL/mL of VA, the number of cells after in-vitro culture was maintained when compared with the control (untreated) group. A significant and gradual decrease in cell viability was recorded as VA concentrations increased. The apoptosis analysis showed that VA at 20 μL/mL presented absolute percentages of initial apoptosis twice as high as at 10 μL/mL, which was similar to the control (untreated group).

CONCLUSION

 The results suggest that the use of efficient methods to assess the in-vitro cytotoxicity of VA-based homeopathic medicines using MSC lineages may predict the potential action at different concentrations. These findings demonstrated that VAD1D2 interferes with canine MSC growth kinetics.

Phytotherapy in Integrative Oncology-An Update of Promising Treatment Options

Modern phytotherapy is part of today's conventional evidence-based medicine and the use of phytopharmaceuticals in integrative oncology is becoming increasingly popular. Approximately 40% of users of such phytopharmaceuticals are tumour patients. The present review provides an overview of the most important plants and nature-based compounds used in integrative oncology and illustrates their pharmacological potential in preclinical and clinical settings. A selection of promising anti-tumour plants and ingredients was made on the basis of scientific evidence and therapeutic practical relevance and included Boswellia, gingko, ginseng, ginger, and curcumin. In addition to these nominees, there is a large number of other interesting plants and plant ingredients that can be considered for the treatment of cancer diseases or for the treatment of tumour or tumour therapy-associated symptoms. Side effects and interactions are included in the discussion. However, with the regular and intended use of phytopharmaceuticals, the occurrence of adverse side effects is rather rare. Overall, the use of defined phytopharmaceuticals is recommended in the context of a rational integrative oncology approach.

Mistletoe-Extract Drugs Stimulate Anti-Cancer Vγ9Vδ2 T Cells

Human phosphoantigen-reactive Vγ9Vδ2 T cells possess several characteristics, including MHC-independent recognition of tumor cells and potent killing potential, that make them attractive candidates for cancer immunotherapeutic approaches. Injectable preparations from the hemi-parasite plant Viscum album L. (European mistletoe) are commonly prescribed as complementary cancer therapy in European countries such as Germany, but their mechanism of action remains poorly understood. Here, we investigated in-depth the in vitro response of human T cells towards mistletoe-extract drugs by analyzing their functional and T-cell-receptor (TCR) response using flow cytometry and high-throughput sequencing respectively. Non-fermented mistletoe-extract drugs (AbnobaViscum), but not their fermented counterparts (Iscador), induced specific expansion of Vγ9Vδ2 T cells among T cells. Furthermore, AbnobaViscum rapidly induced the release of cytotoxic granules and the production of the cytokines IFNγ and TNFα in Vγ9Vδ2 T cells. This stimulation of anti-cancer Vγ9Vδ2 T cells was mediated by the butyrophilin BTN3A, did not depend on the accumulation of endogenous phosphoantigens and involved the same Vγ9Vδ2 TCR repertoire as those of phosphoantigen-reactive Vγ9Vδ2 T cells. These insights highlight Vγ9Vδ2 T cells as a potential target for mistletoe-extract drugs and their role in cancer patients receiving these herbal drugs needs to be investigated.

Biological activity of mistletoe: in vitro and in vivo studies and mechanisms of action

Mistletoe has been used as treatment of many diseases in traditional and folk medicine. To date, anticancer, immunomodulatory, cardiac, antidiabetic, hepatoprotective, neuropharmacological, antibacterial and antifungal properties of mistletoe extracts have been studied the most. In this review, we summarized in vitro and in vivo studies on the pharmacological activity of Viscum species. Furthermore, we proposed the possible mechanisms of action of this herb, which might include many signalling pathways. Mistletoe could regulate either similar or different targets in various pathways that act on membrane receptors, enzymes, ion channels, transporter proteins and transcriptional targets. Still, pharmacological activities of mistletoe have been investigated mainly for crude extracts. It is a new field for scientists to determined which chemical compounds are responsible for the individual biological activities of mistletoe and how these activities are achieved. As a result, mistletoe might become a source of new complementary therapies supporting the treatment of many diseases.

Identification of a four immune-related genes signature based on an immunogenomic landscape analysis of clear cell renal cell carcinoma

Renal clear cell carcinoma (ccRCC) is the most common type of renal cell carcinoma, which has strong immunogenicity. A comprehensive study of the role of immune-related genes (IRGs) in ccRCC is of great significance in finding ccRCC treatment targets and improving patient prognosis. In this study, we comprehensively analyzed the expression of IRGs in ccRCC based on The Cancer Genome Atlas datasets. The mechanism of differentially expressed IRGs in ccRCC was analyzed by bioinformatics. In addition, Cox regression analysis was used to screen prognostic related IRGs from differentially expressed IRGs. We also identified a four IRGs signature consisting of four IRGs (CXCL2, SEMA3G, PDGFD, and UCN) through lasso regression and multivariate Cox regression analysis. Further analysis results showed that the four IRGs signature could effectively predict the prognosis of patients with ccRCC, and its predictive power is independent of other clinical factors. In addition, the correlation analysis of immune cell infiltration showed that this four IRGs signature could effectively reflect the level of immune cell infiltration of ccRCC. We also found that the expression of immune checkpoint genes CTLA-4, LAG3, and PD-1 in the high-risk group was higher than that in the low-risk group. Our research revealed the role of IRGs in ccRCC, and developed a four IRGs signature that could be used to evaluate the prognosis of patients with ccRCC, which will help to develop personalized treatment strategies for patients with ccRCC and improve their prognosis. In addition, these four IRGs may be effective therapeutic targets for ccRCC.

Long-Term Follow-up of a Randomized Study of Oral Etoposide versus Viscum album Fermentatum Pini as Maintenance Therapy in Osteosarcoma Patients in Complete Surgical Remission after Second Relapse

BACKGROUND

In relapsed osteosarcoma, the 5-yr postrelapse disease-free survival (PRDFS) rate after the second relapse is <20%. In June 2007, a randomized study was started comparing oral etoposide vs Viscum album fermentatum Pini (an extract derived from the parasitic plant Viscum album L., European mistletoe) as maintenance therapy in patients with metastatic osteosarcoma in complete surgical remission after the second relapse. The primary endpoint was the PRDFS rate at 12 months (compared to the historical control rate). This is a long-term updated result. Patients and Methods. 10 patients received oral etoposide 50 mg/m2 daily for 21 days every 28 days for 6 months, and 9 patients received Viscum album fermentatum Pini 3 times/wk subcutaneously for 1 year. The study closed early in July 2011 due to insufficient recruitment. Lymphocyte subpopulations were analyzed at T0, T3, T6, T9, and T12 months.

RESULTS

On 30 June 2019, at a median follow-up ITT of 83 months (range 3-144 ms), a median PRDFS of 106 ms (2-144) was observed in the Viscum arm with 5/9 patients who never relapse vs a PRDFS of 7 months (3-134) in the etoposide arm (all patients in the Etoposide arm relapsed) (hazard ratio HR = 0.287, 95% CI: 0.076-0.884, p=0.03). Model forecast 10-yr overall survival rates as 64% in the Viscum arm and 33% in the etoposide arm. Lymphocyte subpopulation counts (CD3, CD4, and CD56) showed an increase in the Viscum arm while a decrease was observed in the etoposide arm during treatment.

CONCLUSIONS

After 12 years from the start of the trial, the patients in the Viscum arm continue to show a considerably longer PRDFS compared to oral etoposide, and a trend for an advantage in OS is evident even if the number of treated patients is too small to draw conclusions. Viscum as maintenance treatment after complete surgical remission in relapsed osteosarcoma should be further investigated and compared with other drugs.

First Steps in the Development of an Expertise-Based Anthroposophic Complex Intervention for Oncological Treatment in Primary Care: A Qualitative Study

Introduction:

The aim of this study was to develop a prototype of an anthroposophic complex intervention (CI) for oncological patients in primary care.

Methods:

Standardized methods for the development of CIs were used. Qualitative data were collected among professionals (n = 44) working in 3 Dutch anthroposophic primary care centers. The following topics were discussed in interviews and panel discussions (n = 12): treatment phases, treatment dimensions, treatment goals, and content of the indicated treatments and therapies. In a multidisciplinary focus group (n = 23) completeness and comprehensibility of the CI, and integration in daily practice were addressed. Subsequently, the developed CI was tested on face validity (n = 21) and compared with conventional guidelines.

Results:

Professionals reached consensus about 4 oncological treatment phases, 4 anthroposophic treatment dimensions, and twelve general treatment goals. The following anthroposophic therapies were found to be suited for oncological patients in primary care: medication (eg, mistletoe preparations); nursing (eg, external embrocation); physiotherapy (eg, rhythmic massage); eurythmy therapy; dietetics; art therapy; and counseling. The content of each therapy must be tailored to the individual. Comparison with existing guidelines demonstrated added value and the ability to fit with conventional care.

Discussion:

Strengths of the developed CI prototype are its focus on primary care, its practical applicability, the use of validated research methods, and the check on face validity in 2 other Dutch anthroposophic primary care centers. Limitations are that no systematic literature review was done and patient experiences were not collected.

Conclusions:

An applicable prototype of an anthroposophic CI for oncological patients in primary care was developed. To complete the development of this CI, a systematic review of the literature is needed, feasibility should be tested, patient experiences need to be collected, and implementation should be initiated and monitored. Finally, development of a patient decision aid (PtDA) and a decision-making tool (DMT) are recommended.

Long-term survival of a patient with an inoperable thymic neuroendocrine tumor stage IIIa under sole treatment with Viscum album extract: A CARE compliant clinical case report

RATIONALE

Thymic neuroendocrine tumor (TNET) is very rare and characterized by a tendency to invade adjacent structures, frequent metastasis, resistance to therapy, and a poor prognosis. Viscum album extracts (VAE) have shown immunological, apoptogenic, and cytotoxic properties.

PATIENT CONCERNS

A 54-year-old Peruvian man was suffering from constant fatigue, cough, dyspnea, and fever for a couple of months.

DIAGNOSES

He was diagnosed with TNET (12.8 cm × 10 cm × 7 cm) stage IIIa, G1. Due to the size and extensive invasiveness (vena cava superior, also obstructing 85% of its lumen, pericardium, and pleura), the TNET was inoperable.

INTERVENTIONS

We report the case of this patient who declined chemotherapy and was treated instead with sole subcutaneous VAE 3 times per week for 85 months. No other tumor-specific intervention was applied.

OUTCOMES

Quality of life (QoL) improved substantially. The patient returned to work, and the tumor remained stable for 71 months. Thereafter, the tumor progressed, and the patient died 90 months after initial diagnosis. Besides self-limited local skin reactions around the application site, no side effects occurred.

LESSONS

This is an exceptionally good course of disease of an inoperable, large, obstructing, and invasive TNET with a reduced baseline condition (Karnofsky index: 50-60) due to pronounced symptoms. Given the considerable reduction of symptoms and improved QoL following the onset of VAE therapy and other reports describing long disease stability and improvement of the QoL using VAE in different cancer types, we presume that the VAE treatment was supportive in this case. As TNETs are rare and few trials are available, future treatments of TNETs using VAE should be carefully documented and published to help determine whether further investigation of the use of VAE in TNET treatment is worthwhile.

Influence of traditionally used Nepalese plants on wound healing and immunological properties using primary human cells in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

The improvement of wound healing has always been an important issue for both ethnopharmacological and modern medical research. In this study, we used state-of-the-art methods to investigate extracts of plants used traditionally in Nepal for more than 1000 years to treat inflammatory injuries.

AIM OF THE STUDY

We focused on the potential of the plant extracts to ameliorate wound healing and to influence immune modulatory properties.

MATERIALS AND METHODS

Nine Nepalese plant extracts in three different solvents (methanol, ethyl acetate, petroleum ether) were immunologically characterised. Water-soluble tetrazolium (WST-1) assays and scratch assays were performed to determine their impact on viability and wound healing capacity of human keratinocytes and fibroblasts. Effects on proliferation, viability and function of physiologically relevant anti-CD3 and anti-CD28 stimulated primary human T lymphocytes were assessed using carboxyfluorescein succinimidyl ester (CFSE), annexin V/propidium iodide staining assays and flow cytometry-based surface receptor characterisation. The secretion level of interleukin-2 (IL-2) was analysed with the ELISA technique. Dendritic cells were generated out of peripheral blood mononuclear cells (PBMC) by CD14⁺ magnetic bead selection. Flow cytometry-based surface receptor characterisation and ELISA-based technique were used to evaluate the DC activation state and the interleukin-8 (IL-8) secretion level.

RESULTS

We demonstrate that an ethyl acetate extract of Bassia longifolia and of Gmelina arborea have anti-inflammatory capacities, indicated by reduced proliferation, inhibition of IL-2 secretion and degranulation capacity of activated human T cells, when compared with adequate concentrations of synthetic positive drug controls. Furthermore, Gmelina arborea improved the wound healing of keratinocytes and fibroblasts and has tendency to increase the secretion of IL-8 by human primary dendritic cells.

CONCLUSION

With this preliminary screening, we offer a scientific basis for the immunomodulatory properties of the two Nepalese medicinal plants Bassia longifolia and Gmelina arborea. However, further detailed studies regarding the responsible compounds are necessary.

Mistletoe and Immunomodulation: Insights and Implications for Anticancer Therapies

In early tumor development, cancer cells develop a plethora of strategies to escape surveillance from the adaptive and innate immune system. Cancer immunotherapies, in particular immune checkpoint inhibitors, are becoming a highly promising cancer therapeutic approach that has remarkable increased progress in combating various cancer types. Unfortunately, their mechanisms of action induce some complications, such as inflammatory reactions and immune-related adverse events. In the management of side effects during anticancer therapy, complementary and integrative therapy approaches are becoming of growing interest. Particularly, mistletoe, Viscum album L. (VA), has a long traditional history of about 100 years as an add-on therapy of cancer treatment in German-speaking countries. Besides antitumoral and quality of life-promoting activities, VA applications reduce side effects of modern conventional anticancer therapies and exert immunomodulatory characteristics. As these properties may provide a good basis for a combination with modern oncological therapies, the biological activities of VA applications and mechanisms involved have to be understood. In this review, the impact of VA compounds on different cellular pathways and immunological reactions in the fight against cancerous cells is discussed.

Chemoimmunotherapy in Advanced Renal Cell Carcinoma: A Case Report of a Long-Term Survivor Adjunctly Treated with Viscum album Extracts

INTRODUCTION

Metastatic renal cell carcinoma has a poor prognosis. Treatment approaches with immunotherapy show promising results in subpopulations. Viscum album extracts - used as an adjunct to cancer treatment - have cytotoxic, apoptogenic, and immune-stimulating properties and show synergistic effects with chemotherapy agents.

CASE REPORT

A 51-year-old man was diagnosed with metastatic renal cell carcinoma of clear cell histology which was classified as pT3a, N1, M1, G3. Nephrectomy was performed, and the patient received chemoimmunotherapy (interferon-α2a, interleukin-2, fluorouracil, isotretinoin). Additionally, he received V. album extracts as intravenous infusions and subcutaneous injections. One year after surgery, the patient was in complete remission, which is ongoing 18 years after the initial diagnosis.

DISCUSSION

This case shows an extraordinarily long survival of a metastasized renal cell carcinoma patient under chemoimmunotherapy and fever-inducing V. album extracts. This combined treatment might have synergistically contributed to tumor remission and control. With regard to clinical relevance, further investigations are needed.

Immunotherapy in ovarian cancer: fake news or the real deal?

Cancer immunotherapy has emerged as one of the most promising approaches in oncology, and comprises the activation of the immune system to induce tumor immune surveillance or to reverse the tumor immune escape. Different therapeutic strategies for ovarian carcinoma have evolved over the years. Already 30 years ago, the first clinical studies focused on modulating the tumor cytokine network with special attention to interferon-mediated immune responses. With the exploration of specific tumor antigens such as NY-ESO-1, which is expressed in ovarian carcinoma and other malignancies, the development of therapeutic cancer vaccines has been pursued initiating the era of personalized anti-cancer medicine. Almost at the same time, the adoptive transfer of genetically modified autologous tumor-reactive T-cells occurred, but response rates in ovarian carcinoma were disappointing. Today, probably the most promising therapeutic approach in this context is the blockade of immune checkpoints, such as programed cell death protein 1 (PD-1) and one of its ligands (PD-L1) or cytotoxic T-cell lymphocyte-associated antigen 4 (CTLA-4), which has demonstrated impressive response rates in malignant melanoma and non-small cell lung cancer. Despite increasing availability of treatment approaches that target tumor immune surveillance in ovarian carcinoma, selecting patient groups that particularly benefit from these treatment modalities is clinically challenging as predictive biomarkers are lacking. Here, we summarize different immunotherapy approaches in ovarian cancer and discuss why immunotherapy in ovarian cancer is still in its infancy.

Long-Term Tumor-Free Survival in a Patient with Stage IV Epithelial Ovarian Cancer Undergoing High-Dose Chemotherapy and Viscum album Extract Treatment: A Case Report

INTRODUCTION

Epithelial ovarian cancer (EOC) has a poor prognosis in advanced stages. High-dose chemotherapy (HDC) was pursued in the 1990s but was not found to improve survival of patients with EOC in larger studies. Many patients with cancer use Viscum album extracts (VAE). Also called European mistletoe, Viscum album can lead to improved quality of life and reduced chemotherapy side effects and may have synergistic cytotoxic and proliferation-inhibiting effects when used together with chemotherapy.

CASE PRESENTATION

A high-grade serous epithelial ovarian carcinoma with peritoneal, adrenal, and hepatic metastases (FIGO Stage IV) was diagnosed in a 50-year-old premenopausal woman. Tumor and metastases were surgically removed in cytoreductive surgery, and the patient received adjuvant chemotherapy, without experiencing side effects from treatment. After a second-look surgery revealed lymph node metastases, HDC and autologous hematopoietic stem cell transplantation were performed. Additionally, the patient opted for treatment with VAE, which she continuously received. The patient remained tumor-free in follow-up examinations and has enjoyed good health for 20 years after initial diagnosis.

DISCUSSION

Treatment with VAE in this case might have contributed to the reduction of side effects from HDC and may have acted synergistically with HDC in tumor control. Cases of VAE in EOC should be carefully documented and reported to further illustrate the influence of VAE on this cancer presentation.

Clinical Safety of Combined Targeted and Viscum album L. Therapy in Oncological Patients

Background: Despite improvement of tumor response rates, targeted therapy may induce toxicities in cancer patients. Recent studies indicate amelioration of adverse events (AEs) by add-on mistletoe (Viscum album L., VA) in standard oncological treatment. The primary objective of this multicenter observational study was to determine the safety profile of targeted and add-on VA therapy compared to targeted therapy alone. Methods: Demographic and medical data were retrieved from the Network Oncology registry. Allocation to either control (targeted therapy) or combinational group (targeted/add-on VA) was performed. Safety-associated variables were evaluated by adjusted multivariable analyses. Results: The median age of the study population (n = 310) at first diagnosis was 59 years; 67.4% were female. In total, 126 patients (40.6%) were in the control and 184 patients (59.4%) in the combination group. Significant differences were observed between both groups with respect to overall AE frequency (χ² = 4.1, p = 0.04) and to discontinuation of standard oncological treatment (χ² = 4.8, p = 0.03) with lower rates in the combinational group (20.1%, 35% respectively) compared to control (30.2%, 60.5%, respectively). Addition of VA to targeted therapy significantly reduced the probability of oncological treatment discontinuation by 70% (Odds ratio (OR) 0.30, p = 0.02). Conclusions: Our results indicate a highly significant reduction of AE-induced treatment discontinuation in all-stage cancer patients when treated with VA in addition to targeted therapy.

Adjuvant Therapy Using Mistletoe Containing Drugs Boosts the T-Cell-Mediated Killing of Glioma Cells and Prolongs the Survival of Glioma Bearing Mice

Viscum album L. extracts (VE) are applied as complementary cancer therapeutics for more than one century. Extracts contain several compounds like mistletoe lectins (ML) 1-3 and viscotoxins, but also several minor ingredients. Since ML-1 has been described as one of the main active components harboring antitumor activity, purified native or recombinant ML-1 has been also used in clinical trials in the last years. The present study examined and compared the immunoboosting effects of three ML-1 containing drugs (the extract ISCADOR Qu, the recombinant ML-1 Aviscumine, and purified native ML-1) in the context of the T-cell mediated killing of glioma cells. Additionally we examined the possible underlying T-cell stimulating mechanisms. Using cocultures of immune and glioma cells, a PCR-based microarray, quantitative RT-PCR, and an antibody-based array to measure cytokines in blood serum, immunosupporting effects were determined. A highly aggressive, orthotopic, immunocompetent syngeneic mouse glioma model was used to determine the survival of mice treated with ISCADOR Qu alone or in combination with tumor irradiation and temozolomide (TMZ). Treatment of glioblastoma (GBM) cells with ISCADOR Qu that contains a high ML concentration, but also viscotoxins and other compounds, as well as with Aviscumine or native ML-1, enhanced the expansion of cancer cell-specific T-cells as well as T-cell-mediated tumor cell lysis, but to a different degree. In GBM cells all three ML-1-containing preparations modulated the expression of immune response associated genes. In vivo, subcutaneous ISCADOR Qu injections at increasing concentration induced cytokine release in immunocompetent VM/Dk-mice. Finally, ISCADOR Qu, if applied in combination with tumor irradiation and TMZ, further prolonged the survival of glioma mice. Our findings indicate that ML-1 containing drugs enhance anti-GBM immune responses and work in synergy with radiochemotherapy. Therefore, adjuvant mistletoe therapy should be considered as an auspicious treatment option for glioma patients.

Correction: Viscum album neutralizes tumor-induced immunosuppression in a human in vitro cell model

[This corrects the article DOI: 10.1371/journal.pone.0181553.].