Indoleamine 2,3-dioxygenase expression and overall survival in patients diagnosed with breast cancer in Pakistan

Metabolomics as a tool for understanding and treating triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive and heterogeneous variant of breast cancer distinguished by a lack of targeted therapies, posing significant challenges in diagnosis and treatment. Metabolomics, the comprehensive study of small compounds in biological systems, has been identified as an instrument for revealing the metabolic underpinnings of TNBC. This review highlights recent advancements in metabolomic approaches, such as mass spectrometry and nuclear magnetic resonance, which have identified metabolic vulnerabilities, resistance mechanisms, and potential therapeutic targets. Key findings include alterations in fatty acid, amino acid, and glutathione metabolism, along with hypoxia-driven metabolic reprogramming that contributes to disease progression. The combination of metabolomics with multi-omics techniques, supported by advanced computational methods such as machine learning, offers a pathway to overcome challenges in data standardization and biological complexity. Emerging strategies, including the use of artificial intelligence and multidimensional omics approaches, are paving the way for personalized medicine by enabling the discovery of novel biomarkers and targeted therapies. Despite these advances, significant hurdles remain, including the need for robust data standardization, validation of findings in diverse patient cohorts, and seamless integration with clinical workflows. By addressing these challenges, metabolomics has the potential to revolutionize TNBC management, offering tools for early detection, precision therapy, and improved patient outcomes. This review underscores the importance of interdisciplinary collaboration to translate metabolomic insights into actionable clinical applications.

Cell Progression and Survival Functions of Enzymes Secreted in Extracellular Vesicles Associated with Breast and Prostate Cancers

Extracellular vesicles (EVs) are membrane-bound cargoes secreted by normal and pathological cells. Through their protein, nucleic acid, and lipid cargoes, EVs mediate several cellular processes, such as cell-cell communication, cell development, immune response, and tissue repair. Most importantly, through their enzyme cargo, EVs mediate pathophysiological processes, including the pathogenesis of cancer. In this review, we enumerate several enzymes secreted in EVs (EV enzyme cargo) from cells and patient clinical samples of breast and prostate cancers and detail their contributions to the progression and survival of both cancers. Findings in this review reveal that the EV enzyme cargo could exert cell progression functions via adhesion, proliferation, migration, invasion, and metastasis. The EV enzyme cargo might also influence cell survival functions of chemoresistance, radioresistance, angiogenesis, cell death inhibition, cell colony formation, and immune evasion. While the current literature provides evidence of the possible contributions of the EV enzyme cargo to the progression and survival mechanisms of breast and prostate cancers, future studies are required to validate that these effects are modified by EVs and provide insights into the clinical applications of the EV enzyme cargo in breast and prostate cancer.

Evaluation of Indoleamine 2,3-Dioxygenase (IDO) Expression in Osteosarcoma: Insights From a 10-Year Retrospective Cohort

Introduction

Osteosarcoma, a prevalent bone malignancy in children and adolescents, is currently treated through surgical resection and chemotherapy. Advancements in cancer research are targeting immune checkpoint molecules, such as indoleamine 2,3-dioxygenase, to advance the development of immunotherapy. However, the scarcity of research on IDO in osteosarcoma results in an absence of comprehensive data, highlighting the conflicting findings surrounding IDO's role in various cancers. Our study aims to explore IDO expression in primary tumors and metastatic lesions among osteosarcoma patients, investigating its association with clinicopathological characteristics and assessing its impact on survival outcomes.

Methods

150 patients diagnosed with osteosarcoma were selected between 2009 and 2019 from the Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan. FFPE tissue samples of primary tumors and metastatic lesions were retrieved to conduct immunohistochemical analysis. Moreover, the clinicopathological data of these patients were gathered from the hospital information system.

Results

Out of 150 patients, primary tumors were accessible for 134 individuals, while metastatic lesions were available for 49 patients. IDO expression was identified in 9 (6.71%) primary tumors and 2 (4.08%) metastatic lesions among osteosarcoma patients. Furthermore, 3 patients exhibited high expression (27.3%), while 8 displayed low IDO expression (72.7%).

Conclusion

Our comprehensive study findings indicate that most osteosarcoma patients do not exhibit expression of IDO. This absence of expression aligns with the characteristic "cold" tumor microenvironment observed in osteosarcoma. Further investigations are imperative to provide deeper insights into the intricacies of this immunomodulatory factor in the context of osteosarcoma.

Physical Activity and Depression in Breast Cancer Patients: Mechanisms and Therapeutic Potential

Breast cancer is a significant traumatic experience that often leads to chronic stress and mental health challenges. Research has consistently shown that physical activity-especially exercise-can alleviate depressive symptoms; however, the specific biological mechanisms underlying these antidepressant effects remain unclear. In this review, we comprehensively summarize the biological mechanisms of depression and the antidepressant mechanisms of physical activity and explore the biological processes through which exercise exerts its antidepressant effects in breast cancer patients. We focus on the impact of physical activity on inflammation, the endocrine system, glutamate, and other aspects, all of which play crucial roles in the pathophysiology of depression. Moreover, we discuss the heterogeneity of depression in breast cancer patients and the complex interactions between its underlying mechanisms. Additionally, we propose that a deeper understanding of these mechanisms in the breast cancer population can guide the design and implementation of exercise-based interventions that maximize the antidepressant benefits of physical activity. Finally, we summarize the current research and propose future research directions.

Patterns of immune evasion in triple-negative breast cancer and new potential therapeutic targets: a review

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer characterized by the absence of progesterone and estrogen receptors and low (or absent) HER2 expression. TNBC accounts for 15-20% of all breast cancers. It is associated with younger age, a higher mutational burden, and an increased risk of recurrence and mortality. Standard treatment for TNBC primarily relies on cytotoxic agents, such as taxanes, anthracyclines, and platinum compounds for both early and advanced stages of the disease. Several targeted therapies, including bevacizumab and sunitinib, have failed to demonstrate significant clinical benefit in TNBC. The emergence of immune checkpoint inhibitors (ICI) has revolutionized cancer treatment. By stimulating the immune system, ICIs induce a durable anti-tumor response across various solid tumors. TNBC is a particularly promising target for treatment with ICIs due to the higher levels of tumor-infiltrating lymphocytes (TIL), increased PD-L1 expression, and higher mutational burden, which generates tumor-specific neoantigens that activate immune cells. ICIs administered as monotherapy in advanced TNBC yields only a modest response; however, response rates significantly improve when ICIs are combined with cytotoxic agents, particularly in tumors expressing PD-L1. Pembrolizumab is approved for use in both early and advanced TNBC in combination with standard chemotherapy. However, more research is needed to identify more potent biomarkers, and to better elucidate the synergism of ICIs with other targeted agents. In this review, we explore the challenges of immunotherapy in TNBC, examining the mechanisms of tumor progression mediated by immune cells within the tumor microenvironment, and the signaling pathways involved in both primary and acquired resistance. Finally, we provide a comprehensive overview of ongoing clinical trials underway to investigate novel immune-targeted therapies for TNBC.

Secondary Transcriptomic Analysis of Triple-Negative Breast Cancer Reveals Reliable Universal and Subtype-Specific Mechanistic Markers

Background/Objectives: Breast cancer is diagnosed in 2.3 million women each year and kills 685,000 (~30% of patients) worldwide. The prognosis for many breast cancer subtypes has improved due to treatments targeting the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). In contrast, patients with triple-negative breast cancer (TNBC) tumors, which lack all three commonly targeted membrane markers, more frequently relapse and have lower survival rates due to a lack of tumor-selective TNBC treatments. We aim to investigate TNBC mechanistic markers that could be targeted for treatment. Methods: We performed a secondary TNBC analysis of 196 samples across 10 publicly available bulk RNA-sequencing studies to better understand the molecular mechanism(s) of disease and predict robust mechanistic markers that could be used to improve the mechanistic understanding of and diagnostic capabilities for TNBC. Results: Our analysis identified ~12,500 significant differentially expressed genes (FDR-adjusted p-value < 0.05), including KIF14 and ELMOD3, and two significantly modulated pathways. Additionally, our novel findings include highly accurate mechanistic markers identified using machine learning methods, including CIDEC (97.1% accuracy alone), CD300LG, ASPM, and RGS1 (98.9% combined accuracy), as well as TNBC subtype-differentiating mechanistic markers, including the targets PDE3B, CFD, IFNG, and ADM, which have associated therapeutics that can potentially be repurposed to improve treatment options. We then experimentally and computationally validated a subset of these findings. Conclusions: The results of our analyses can be used to better understand the mechanism(s) of disease and contribute to the development of improved diagnostics and/or treatments for TNBC.

Indoleamine-2,3 dioxygenase: a fate-changer of the tumor microenvironment

Indoleamine-2,3 dioxygenase is a rate-limiting enzyme in the tryptophan catabolism in kynurenine pathways that has an immunosuppressive effect and supports cancer cells to evade the immune system in different cancer types. Diverse cytokines and pathways upregulate the production of indoleamine-2,3 dioxygenase enzymes in the tumor microenvironment and cause more production and activity of this enzyme. Ultimately, this situation results in anti-tumor immune suppression which is in favor of tumor growth. Several inhibitors such as 1-methyl-tryptophan have been introduced for indoleamine-2,3 dioxygenase enzyme and some of them are widely utilized in pre-clinical and clinical trials. Importantly at the molecular level, indoleamine-2,3 dioxygenase is positioned in a series of intricate signaling and molecular networks. Here, the main objective is to provide a focused view of indoleamine-2,3 dioxygenase enhancer pathways and propose further studies to cover the gap in available information on the function of indoleamine-2,3 dioxygenase enzyme in the tumor microenvironment.

Regulation of IDO2 by the Aryl Hydrocarbon Receptor (AhR) in Breast Cancer

Indoleamine 2,3-dioxygenase 2 (IDO2) is a tryptophan-catabolizing enzyme and a homolog of IDO1 with a distinct expression pattern compared with IDO1. In dendritic cells (DCs), IDO activity and the resulting changes in tryptophan level regulate T-cell differentiation and promote immune tolerance. Recent studies indicate that IDO2 exerts an additional, non-enzymatic function and pro-inflammatory activity, which may play an important role in diseases such as autoimmunity and cancer. Here, we investigated the impact of aryl hydrocarbon receptor (AhR) activation by endogenous compounds and environmental pollutants on the expression of IDO2. Treatment with AhR ligands induced IDO2 in MCF-7 wildtype cells but not in CRISPR-cas9 AhR-knockout MCF-7 cells. Promoter analysis with IDO2 reporter constructs revealed that the AhR-dependent induction of IDO2 involves a short-tandem repeat containing four core sequences of a xenobiotic response element (XRE) upstream of the start site of the human ido2 gene. The analysis of breast cancer datasets revealed that IDO2 expression increased in breast cancer compared with normal samples. Our findings suggest that the AhR-mediated expression of IDO2 in breast cancer could contribute to a pro-tumorigenic microenvironment in breast cancer.

The therapeutic potential of immunotherapy in the treatment of breast cancer: Rational strategies and recent progress

The second leading cause of cancer death in women worldwide is breast cancer (BC), and despite significant advances in BC therapies, a significant proportion of patients develop metastasis and disease recurrence. Currently used treatments, like radiotherapy, chemotherapy, and hormone replacement therapy, result in poor responses and high recurrence rates. Alternative therapies are therefore needed for this type of cancer. Cancer patients may benefit from immunotherapy, a novel treatment strategy in cancer treatment. Even though immunotherapy has been successful in many cases, some patients do not respond to the treatment or those who do respond relapse or progress. The purpose of this review is to discuss several different immunotherapy approaches approved for the treatment of BC, as well as different strategies for immunotherapy for the treatment of BC.

Indoleamine 2,3-Dioxygenase: A Novel Immunotherapeutic Target for Osteosarcoma

Introduction

Tumour-emitted molecules induce immunosuppression in the tumour microenvironment. An immunosuppressive enzyme, indoleamine 2,3-dioxygenase (IDO/IDO1), facilitates immune escape in several malignant tumours, including osteosarcoma. Upregulation of IDO establishes a tolerogenic environment in the tumour and the tumour-draining lymph nodes. IDO-induced downregulation of effector T-cells and upregulation of local regulatory T-cells creates immunosuppression and promotes metastasis.

Observations

Osteosarcoma is the most common bone tumour characterised by immature bone formation by the tumour cells. Almost 20% of osteosarcoma patients present with pulmonary metastasis at the time of diagnosis. The improvement in therapeutic modalities for osteosarcoma has been in a stagnant phase for two decades. Therefore, the development of novel immunotherapeutic targets for osteosarcoma is emergent. High IDO expression is associated with metastasis and poor prognosis in osteosarcoma patients.

Conclusion and Relevance

At present, only a few studies are available describing IDO's role in osteosarcoma. This review describes the prospects of IDO not only as a prognostic marker but also as an immunotherapeutic target for osteosarcoma.

Contracting triple-negative breast cancer with immunotherapeutic armamentarium: recent advances and clinical prospects

Triple negative breast cancer (TNBC) portraying deficient expression of estrogen receptor (ER), progesterone receptor (PR) and Human epidermal growth factor receptor 2 (HER2) is known to be the most aggressive subtype associated with poor prognosis and interventional strategies limited to chemotherapy and breast conserving surgery. Some TNBC incidences have also been reported with positive circ-HER2 expression thus rendering circ-HER2 a potential immunotherapy target to direct drug development. Resistance and recurrence reported with traditional approaches has led us towards the application of immunotherapeutic interventions owing to their anti-tumor efficacy. This review provides an elaborative insight on potential molecular biomarkers to be targeted by immunotherapy. Additionally, clinical trials proposing the application of immunotherapy in neoadjuvant, adjuvant and metastatic TNBC setting have also been included. The gathered evidence indicates a positive application of immunotherapy in TNBC with therapeutic limitation available only owing to the possibility of adverse events which can be dealt considering risk-to-benefit ratio. Furthermore, potential targets to aim for therapeutic vaccines along with evidence from clinical trials have also been mentioned.

Prognostic role of indoleamine 2,3-dioxygenase 1 expression in solid tumors: A systematic review and meta-analysis

Background

As an emerging immune checkpoint molecule, indoleamine 2,3-dioxygenase 1 (IDO1) is an immunosuppressive rate-limiting enzyme in metabolism of tryptophan to kynurenine. The expression of IDO1 affected the prognosis of patients in cancers by regulating the kynurenine pathway, inhibiting the proliferation of T cells. However, the association between IDO1 and solid tumor prognosis was controversial. To further investigate the role of IDO1 expression in solid tumors, we conducted the systematic review and meta-analysis.

Methods

We searched the Web of Science, PubMed, Embase, and Cochrane Library databases and China National Knowledge Infrastructure (CNKI) to identify studies evaluating the prognostic value of IDO1 in solid tumors. Overall survival (OS), progression-free survival (PFS), and disease-free survival (DFS) were extracted as the outcome. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated by using the fixed-effect/random-effect model, while heterogeneity, publication bias, and sensitivity between studies were also analyzed.

Results

Eighteen studies with 2,168 patients were included in this systematic review and meta-analysis. The results indicated that the high expression of IDO1 was associated with a shorter OS (n = 1926, HR = 1.60, 95% CI: 1.22–2.11, P = 0.001) and DFS (n = 327, HR = 2.65, 95% CI: 1.52–4.63, P = 0.001), while it was uncorrelated with PFS (n = 428, HR = 1.76, 95% CI: 0.99–3.14, P = 0.240). There was significant heterogeneity between studies on OS (I2 = 77.8%, P &lt; 0.001). Subgroup analysis showed that age, gender, tumor type, follow-up period, and study quality were possible reasons for high heterogeneity. The result of the trim-and-fill method indicated that publication bias for OS had no impact on our results. Egger’s test suggested no publication bias for PFS (P = 0.553) and DFS (P = 0.273). Furthermore, sensitivity analysis indicated the result was stable.

Conclusion

High expression of IDO1 was associated with poor clinical outcomes, indicating that it could be a potential prognostic marker in various cancer types.

COVID-19 in cancer patients with diabetes in Pakistan: Clinical features and management

Background

Diabetes and cancer are the leading causes of mortality all over the world. Infectious diseases are more common and/or life-threatening in patients with diabetes. Cancer patients with diabetes are individuals that are more susceptible to the current COVID-19 pandemic. We investigated the clinical features of survivor and non-survivor COVID-19-infected cancer patients with diabetes.

Patients and Methods

We did a retrospective study of 43 diabetic cancer patients with PCR-confirmed COVID-19 infection from Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan between March 03, 2020, and May 18, 2021. These patients either were discharged from the hospital or had died by Jun 16, 2021. Clinicopathological and radiological features were compared between survivors and non-survivors by fisher’s exact test and chi-square test.

Results

Forty-three diabetic cancer patients with SARS-CoV-2 infection were enrolled and the majority were males 26 (60.5%). The overall mean age was 61.67 ± 11.80. 39 (90.7%) had solid tumors and 3 (7.0%) had hematological malignancies. Fever (74.4%) and dyspnea (58.1%) were the most common symptoms. Complications were reported in 36 (83.7%) patients; during the course of the disease. Additionally, all the deceased patients (n=15) had acquired the complications. 11 (25.6%) patients were admitted to an intensive care unit (ICU). Furthermore, 29 (67.4%) out of 43 patients showed abnormal features in the radiological findings. We found significantly elevated levels of C-reactive protein (P=0.005), serum lactate (P=0.01), albumin (P=0.02), alkaline phosphate (P=0.03), and neutrophil count (P=0.04) in the non-survivors as compared to the survivors.

Conclusion

Cancer patients with diabetes are a vulnerable population in the current pandemic. Identifying how diabetes in cancer patients affects the severity of SARS-CoV-2 infection is crucial for the clinical management of these patients. Rigorous scrutiny of clinicopathological features of COVID-19 infected cancer patients with diabetes especially values of C-reactive protein, lactate, albumin, alkaline phosphate, neutrophils, and regular monitoring of blood glucose levels may play a critical role in the outcome of the disease.

Therapeutic Potential of Thymoquinone in Triple-Negative Breast Cancer Prevention and Progression through the Modulation of the Tumor Microenvironment

To date, the tumor microenvironment (TME) has gained considerable attention in various areas of cancer research due to its role in driving a loss of immune surveillance and enabling rapid advanced tumor development and progression. The TME plays an integral role in driving advanced aggressive breast cancers, including triple-negative breast cancer (TNBC), a pivotal mediator for tumor cells to communicate with the surrounding cells via lymphatic and circulatory systems. Furthermore, the TME plays a significant role in all steps and stages of carcinogenesis by promoting and stimulating uncontrolled cell proliferation and protecting tumor cells from the immune system. Various cellular components of the TME work together to drive cancer processes, some of which include tumor-associated adipocytes, fibroblasts, macrophages, and neutrophils which sustain perpetual amplification and release of pro-inflammatory molecules such as cytokines. Thymoquinone (TQ), a natural chemical component from black cumin seed, is widely used traditionally and now in clinical trials for the treatment/prevention of multiple types of cancer, showing a potential to mitigate components of TME at various stages by various pathways. In this review, we focus on the role of TME in TNBC cancer progression and the effect of TQ on the TME, emphasizing their anticipated role in the prevention and treatment of TNBC. It was concluded from this review that the multiple components of the TME serve as a critical part of TNBC tumor promotion and stimulation of uncontrolled cell proliferation. Meanwhile, TQ could be a crucial compound in the prevention and progression of TNBC therapy through the modulation of the TME.

Immunotherapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is characterized by extensive tumor heterogeneity at both the pathologic and molecular levels, particularly accelerated aggressiveness, and terrible metastasis. It is responsible for the increased mortality of breast cancer patients. Due to the negative expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2, the progress of targeted therapy has been hindered. Higher immune response in TNBCs than for other breast cancer types makes immunotherapy suitable for TNBC therapy. At present, promising treatments in immunotherapy of TNBC include immune checkpoints (ICs) blockade therapy, adoptive T-cell immunotherapy, and tumor vaccine immunotherapy. In addition, nanomedicines exhibit great potential in cancer therapy through the enhanced permeability and retention (EPR) effect. Immunotherapy-involved combination therapy may exert synergistic effects by combining with other treatments, such as traditional chemotherapy and new treatments, including photodynamic therapy (PTT), photodynamic therapy (PDT), and sonodynamic therapy (SDT). This review focuses on introducing the principles and latest development as well as progress in using nanocarriers as drug-delivery systems for the immunotherapy of TNBC.

The efficacy of indoximod upon stimulation with pro-inflammatory cytokines in triple-negative breast cancer cells

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO) inhibition has received much attention in cancer immunotherapy due to its role in immune escape in cancer cells. Additionally, changes in the pro-inflammatory cytokine levels can affect tumor growth and metastasis as well as the effectiveness of immunotherapy. The purpose of this study was for the first time to determine the effects of indoximod as an IDO inhibitor on triple-negative breast cancer (TNBC) and to assess the link between the efficacy of indoximod and IFN-γ or TNF-α stimulation.

METHODS

The cytotoxic and apoptotic effects of indoximod alone or IFN-γ or TNF-α induction to mimic an inflammatory environment were evaluated by WST-1, Annexin V, cell cycle analysis, and acridine orange (AO)/ethidium bromide (EtBr) staining. Furthermore, the expression levels of IDO1 and PD-L1 expression were analyzed by RT-PCR.

RESULTS

Our results demonstrated that indoximod significantly decreased the TNBC cell viability through apoptotic cell death (p < .05). The combination of indoximod and TNF-α was more effective than indoximod and IFN-γ stimulation or indoximod alone in TNBC cells. Additionally, PD-L1 expression level was significantly up-regulated after treatment with indoximod and TNF-α or IFN-γ combinations (p < .05).

CONCLUSIONS

Indoximod exhibited a therapeutic potential in TNBC cells and pro-inflammatory cytokines could affect the effectiveness of indoximod. However, further studies are required to identify the role of the IDO-associated signaling pathways, the molecular mechanisms of indoximod induced apoptotic cell death, and the relationship between IDO inhibition by IDO inhibitors and pro-inflammatory cytokine levels.

Perception of breast cancer risk factors: Dysregulation of TGF-β/miRNA axis in Pakistani females

Breast cancer poses a serious health risk for women throughout the world. Among the Asian population, Pakistani women have the highest risk of developing breast cancer. One out of nine women is diagnosed with breast cancer in Pakistan. The etiology and the risk factor leading to breast cancer are largely unknown. In the current study the risk factors that are most pertinent to the Pakistani population, the etiology, molecular mechanisms of tumor progression, and therapeutic targets of breast cancer are studied. A correlative, cross-sectional, descriptive, and questionnaire-based study was designed to predict the risk factors in breast cancer patients. Invasive Ductal Carcinoma (90%) and grade-II tumor (73.2%) formation are more common in our patient’s data set. Clinical parameters such as mean age of 47.5 years (SD ± 11.17), disturbed menstrual cycle (> 2), cousin marriages (repeated), and lactation period (< 0.5 Y) along with stress, dietary and environmental factors have an essential role in the development of breast cancer. In addition to this in silico analysis was performed to screen the miRNA regulating the TGF-beta pathway using TargetScanHuman, and correlation was depicted through Mindjet Manager. The information thus obtained was observed in breast cancer clinical samples both in peripheral blood mononuclear cells, and biopsy through quantitative real-time PCR. There was a significant dysregulation (**P>0.001) of the TGF-β1 signaling pathway and the miRNAs (miR-29a, miR-140, and miR-148a) in patients’ biopsy in grade and stage specifically, correlated with expression in blood samples. miRNAs (miR-29a and miR-140, miR-148a) can be an effective diagnostic and prognostic marker as they regulate SMAD4 and SMAD2 expression respectively in breast cancer blood and biopsy samples. Therefore, proactive therapeutic strategies can be devised considering negatively regulated cascade genes and amalgamated miRNAs to control breast cancer better.

Review of 10 years of research on breast cancer patients: Focus on indoleamine 2,3-dioxygenase

Therapeutic manipulation of the immune system in cancer has been an extensive area of research in the field of oncoimmunology. Immunosuppression regulates antitumour immune responses. An immunosuppressive enzyme, indoleamine 2,3-dioxygenase (IDO) mediates tumour immune escape in various malignancies including breast cancer. IDO upregulation in breast cancer cells may lead to the recruitment of regulatory T (T-regs) cells into the tumour microenvironment, thus inhibiting local immune responses and promoting metastasis. Immunosuppression induced by myeloid derived suppressor cells activated in an IDO-dependent manner may enhance the possibility of immune evasion in breast cancer. IDO overexpression has independent prognostic significance in a subtype of breast cancer of emerging interest, basal-like breast carcinoma. IDO inhibitors as adjuvant therapeutic agents may have clinical implications in breast cancer. This review proposes future prospects of IDO not only as a therapeutic target but also as a valuable prognostic marker for breast cancer.

A New Paradigm in the Relationship between Melatonin and Breast Cancer: Gut Microbiota Identified as a Potential Regulatory Agent

In this review we summarize a possible connection between gut microbiota, melatonin production, and breast cancer. An imbalance in gut bacterial population composition (dysbiosis), or changes in the production of melatonin (circadian disruption) alters estrogen levels. On the one hand, this may be due to the bacterial composition of estrobolome, since bacteria with β-glucuronidase activity favour estrogens in a deconjugated state, which may ultimately lead to pathologies, including breast cancer. On the other hand, it has been shown that these changes in intestinal microbiota stimulate the kynurenine pathway, moving tryptophan away from the melatonergic pathway, thereby reducing circulating melatonin levels. Due to the fact that melatonin has antiestrogenic properties, it affects active and inactive estrogen levels. These changes increase the risk of developing breast cancer. Additionally, melatonin stimulates the differentiation of preadipocytes into adipocytes, which have low estrogen levels due to the fact that adipocytes do not express aromatase. Consequently, melatonin also reduces the risk of breast cancer. However, more studies are needed to determine the relationship between microbiota, melatonin, and breast cancer, in addition to clinical trials to confirm the sensitizing effects of melatonin to chemotherapy and radiotherapy, and its ability to ameliorate or prevent the side effects of these therapies.

Clinical Characteristics of COVID-19-Infected Cancer Patients in Pakistan: Differences Between Survivors and Non-Survivors

Background

Cancer patients are considered as highly vulnerable individuals in the current COVID-19 pandemic. We studied the clinical characteristics of survivor and non-survivor COVID-19-infected cancer patients in Pakistan.

Patients and Methods

We did a retrospective study of 70 cancer patients with PCR-confirmed COVID-19 infection from Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore and Peshawar, Pakistan between April 13 and July 09, 2020. These patients were discharged from the hospital or had died by July 09, 2020. Clinical, pathological and radiological characteristics were compared between survivors and non-survivors by fisher's exact test and chi-square test. Univariable and multivariable logistic regression models were performed to explore the risk factors of mortality.

Results

Seventy cancer patients with SARS-CoV-2 infection were enrolled and the majority were males 38 (54.3%). 57 (81.4%) had solid tumors and 13 (18.6%) had hematological malignancies. Dyspnea (44 cases) was the most common symptom (62.9%). Complications were reported in 51 (72.9%) patients during the course of disease. 19 (27.1%) patients were admitted to an intensive care unit (ICU). A significant increase in the C-reactive protein level and neutrophil count was observed in the deceased patients as compared to the surviving patients. D-dimer values of ≥0.2 mg/L were significantly associated with mortality (P=0.01). We identified two independent risk factors associated with death, ICU admission (P=0.007) and D-dimer (P=0.003).

Conclusion

Pakistani cancer patients with COVID-19 infection reported poor prognosis. Intensive surveillance of clinicopathological characteristics of cancer patients infected with COVID-19 especially D-dimer values may play a pivotal role in the outcome of the disease.

Tackling Immune Targets for Breast Cancer: Beyond PD-1/PD-L1 Axis

The burden of breast cancer is imposing a huge global problem. Drug discovery research and novel approaches to treat breast cancer have been carried out extensively over the last decades. Although immune checkpoint inhibitors are showing promising preclinical and clinical results in treating breast cancer, they are facing multiple limitations. From an immunological perspective, a recent report highlighted breast cancer as an "inflamed tumor" with an immunosuppressive microenvironment. Consequently, researchers have been focusing on identifying novel immunological targets that can tune up the tumor immune microenvironment. In this context, several novel non-classical immune targets have been targeted to determine their ability to uncouple immunoregulatory pathways at play in the tumor microenvironment. This article will highlight strategies designed to increase the immunogenicity of the breast tumor microenvironment. It also addresses the latest studies on targets which can enhance immune responses to breast cancer and discusses examples of preclinical and clinical trial landscapes that utilize these targets.

Forkhead box P3 and indoleamine 2,3-dioxygenase co-expression in Pakistani triple negative breast cancer patients

BACKGROUND

Forkhead box P3 (FOXP3) is a specific marker for immunosuppressive regulatory T (T-reg) cells. T-regs and an immunosuppressive enzyme, indoleamine 2,3-dioxygenase (IDO), are associated with advanced disease in cancer.

AIM

To evaluate the co-expression of FOXP3 and IDO in triple negative breast cancer (TNBC) with respect to hormone-positive breast cancer patients from Pakistan.

METHODS

Immunohistochemistry was performed to analyze the expression of FOXP3, IDO, estrogen receptor, progesterone receptor, and human epidermal growth factor receptor on tissues of breast cancer patients (n = 100): Hormone-positive breast cancer (n = 51) and TNBC (n = 49). A total of 100 patients were characterized as FOXP3 negative vs positive and further categorized based on low, medium, and high IDO expression score. Univariate and multivariate logistic regression models were used.

RESULTS

Out of 100 breast tumors, 25% expressed FOXP3 positive T-regs. A significant co-expression of FOXP3 and IDO was observed among patients with TNBC (P = 0.01) compared to those with hormone-positive breast cancer. Two variables were identified as significant independent risk factors for FOXP3 positive: IDO expression high (adjusted odds ratio (AOR) 5.90; 95% confidence interval (CI): 1.22-28.64; P = 0.03) and TNBC (AOR 2.80; 95%CI: 0.96-7.95; P = 0.05).

CONCLUSION

Our data showed that FOXP3 positive cells might be associated with high expression of IDO in TNBC patients. FOXP3 and IDO co-expression may also suggest its involvement in disease, and evaluation of FOXP3 and IDO expression in TNBC patients may offer a new therapeutic option.

Association between Cyclooxygenase-2 and Indoleamine 2,3-Dioxygenase Expression in Breast Cancer Patients from Pakistan

Background:

Tumors use several immunosuppressive mechanisms to evade immune destruction. Cyclooxygenase-2 (COX-2) expression may be a driver of immunosuppression in breast cancer, but the mechanisms involved remain elusive. COX-2 expression induces the expression of indoleamine 2,3 dioxygenase (IDO) in tumor cells. IDO is an immunosuppressive enzyme which is involved in tumor immune escape mechanisms in breast cancer. Our aim was to evaluate the association between COX-2 and IDO expression to find evidence of immunosuppression in Pakistani breast cancer patients.

Methods:

Immunohistochemical analysis was performed to evaluate the expression of COX-2, IDO, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) on formalin-fixed paraffin-embedded breast cancer tissues of 100 patients. Univariable and multivariable logistic regression model was used to identify the independent risk factors of COX-2.

Results:

A total of 100 patients were included with a mean age and standard deviation of 48.28 ± 11.83. A significant association was observed among COX-2, IDO, ER, PR and tumor grade. In multivariable analysis, three variables were identified as significant independent risk factors for high COX-2: IDO expression high; [adjusted odds ratio (AOR) 6.51; 95% confidence interval (CI) (2.00-21.20), p=0.001], ER; [AOR 5.62; 95% CI (1.80-17.84), p=0.002] and age [AOR 1.04; 95% CI (1.00-1.10), p=0.05] respectively.

Conclusion:

Our data showed that high IDO expression is associated with high COX-2 expression in Pakistani breast cancer patients. The co-expression of both enzymes may suggest their role in disease pathogenesis. Hence the concurrent targeting of COX-2 and IDO may be a promising therapy for breast cancer.

Inflammation, immunosuppressive microenvironment and breast cancer: opportunities for cancer prevention and therapy

Breast cancer is the most commonly diagnosed malignancy and a leading cause of cancer-related death in women worldwide. It also exhibits pronounced racial disparities in terms of incidence and clinical outcomes. There has been a growing interest in research community to better understand the role of the microenvironment in cancer. Several lines of evidence have highlighted the significance of chronic inflammation at the local and/or systemic level in breast tumor pathobiology. Inflammation can influence breast cancer progression, metastasis and therapeutic outcome by establishing a tumor supportive immune microenvironment. These processes are mediated through a variety of cytokines and hormones that exert their biological actions either locally or distantly via systemic circulation. Targeting of immune and inflammatory pathways has met tremendous success in some cancers underscoring the importance of research to further our understanding of these systems in breast cancer. This knowledge can be helpful not only in the development of novel prevention and therapeutic strategies, but also help in better prediction of therapeutic responses in patients. This review summarizes some of the significant findings on the role of inflammation in breast cancer to gain collective molecular and mechanistic insights. We also discuss ongoing efforts and future outlook to exploit the existing knowledge for improved breast cancer management.

The Complex Interaction between the Tumor Micro-Environment and Immune Checkpoints in Breast Cancer

The progression of breast cancer and its association with clinical outcome and treatment remain largely unexplored. Accumulating data has highlighted the interaction between cells of the immune system and the tumor microenvironment in cancer progression, and although studies have identified multiple facets of cancer progression within the development of the tumor microenvironment (TME) and its constituents, there is lack of research into the associations between breast cancer subtype and staging. Current literature has provided insight into the cells and pathways associated with breast cancer progression through expression analysis. However, there is lack of co-expression studies between immune pathways and cells of the TME that form pro-tumorigenic relationships contributing to immune-evasion. We focus on the immune checkpoint and TME elements that influence cancer progression, particularly studies in molecular subtypes of breast cancer.

Breast cancer: Occluded role of mitochondria N-acetylserotonin/melatonin ratio in co-ordinating pathophysiology

A plethora of factors contribute to the biochemical underpinnings of breast cancer, in the absence of any clear, integrative framework. This article proposes that melatonergic pathway regulation within mitochondria provides an integrative framework for the wide array of data driving breast cancer pathophysiology. As melatonin is toxic to breast cancer cells, its production within mitochondria poses a significant challenge to breast cancer cell survival. Consequently, the diverse plasticity in breast cancer cells may arise from a requirement to decrease mitochondria melatonin synthesis. The aryl hydrocarbon receptor role in breast cancer pathophysiology may be mediated by an increase in cytochrome P450 (CYP)1b1 in mitochondria, leading to the backward conversion of melatonin to N-acetylserotonin (NAS). NAS has distinct effects to melatonin, including its activation of the tyrosine receptor kinase B (TrkB) receptor. TrkB activation significantly contributes to breast cancer cell survival and migration. However, the most important aspect of NAS induction by CYP1b1 in breast cancer cells is the prevention of melatonin effects in mitochondria. Many of the changes occurring in breast cancer cells arise from the need to regulate this pathway in mitochondria, allowing this to provide a framework that integrates a host of previously disparate data, including: microRNAs, estrogen, 14-3-3 proteins, sirtuins, glycolysis, oxidative phosphorylation, indoleamine 2,3-dioxygenase and the kynurenine pathways. It is also proposed that this framework provides a pathoetiological model incorporating the early developmental regulation of the gut microbiome that integrates breast cancer risk factors, including obesity. This has significant treatment, prevention and research implications.

Beyond PD-1/PD-L1 Inhibition: What the Future Holds for Breast Cancer Immunotherapy

Cancer immunotherapy has altered the management of human malignancies, improving outcomes in an expanding list of diseases. Breast cancer - presumably due to its perceived low immunogenicity - is a late addition to this list. Furthermore, most of the focus has been on the triple negative subtype because of its higher tumor mutational load and lymphocyte-enriched stroma, although emerging data show promise on the other breast cancer subtypes as well. To this point the clinical use of immunotherapy is limited to the inhibition of two immune checkpoints, Programmed Cell Death Protein 1 (PD-1) and Cytotoxic T-lymphocyte-associated Protein 4 (CTLA-4). Consistent with the complexity of the regulation of the tumor - host interactions and their lack of reliance on a single regulatory pathway, combinatory approaches have shown improved efficacy albeit at the cost of increased toxicity. Beyond those two checkpoints though, a large number of co-stimulatory or co-inhibitory molecules play major roles on tumor evasion from immunosurveillance. These molecules likely represent future targets of immunotherapy provided that the promise shown in early data is translated into improved patient survival in randomized trials. The biological role, prognostic and predictive implications regarding breast cancer and early clinical efforts on exploiting these immune-related therapeutic targets are herein reviewed.