Regression in cancer following fever and acute infection

Hypothesis: hematogenous metastatic cancer cells of solid tumors may disguise themselves as memory macrophages for metastasis

German pathologist Otto Aichel suggested, a century ago, that the cancer cell acquired its metastatic property from a leukocyte via cell-cell fusion. Since then, several revised versions of this theory have been proposed. Most of the proposals attribute the generation of the metastatic cancer cell to the fusion between a primary cancer cell and a macrophage. However, these theories have not addressed several issues, such as dormancy and stem cell-like self-renewal, of the metastatic cancer cell. On the other hand, recent studies have found that, like T- and B-/plasma cells, macrophages can also be categorized into naïve, effector, and memory/trained macrophages. As a memory/trained macrophage can enter dormancy/quiescence, be awakened from the dormancy/quiescence by acquainted primers, and re-populate via stem cell-like self-renewal, we, therefore, further specify that the macrophage fusing with the cancer cell and contributing to metastasis, belongs with the memory/trained macrophage, not other subtypes of macrophages. The current theory can explain many puzzling clinical features of cancer, including the paradoxal effects (recurrence vs. regression) of microbes on tumors, "spontaneous" and Coley's toxin-induced tumor regression, anticancer activities of β-blockers and anti-inflammatory/anti-immune/antibiotic drugs, oncotaxis, surgery- and trauma-promoted metastasis, and impact of microbiota on tumors. Potential therapeutic strategies, such as Coley's toxin-like preparations, are proposed. This is the last article of our trilogy on carcinogenesis theories.

Causal associations of COVID-19 on neurosurgical diseases risk: a Mendelian randomization study

Many researchers have explored the potential association between one neurosurgical disease and coronavirus disease 2019 (COVID-19), but few systematically analyzed the association and causality between COVID-19 and various neurosurgical diseases. A Mendelian randomization analysis was conducted to evaluate the causal association between COVID-19 (including critically ill COVID-19, hospitalized COVID-19, and respiratory syndrome coronavirus 2 (SARS-CoV-2) infection) and 30 neurosurgical diseases within European populations. The consequences of inverse variance weighted models suggest that genetic susceptibility of critically ill COVID-19 may increase the risk of cerebral infarction (odds ratio [OR] = 1.02; p-value = 0.006), genetic susceptibility of SARS-CoV-2 infection may increase the risk of stroke (OR = 1.02; p-value = 0.047), and conversely, genetic susceptibility of hospitalized COVID-19 may reduce the risk of pituitary adenoma and craniopharyngioma (OR = 0.90; p-value = 0.032). In addition, evidences revealed potential associations between genetic susceptibility of COVID-19 and spinal stenosis (OR = 1.03; p-value = 0.028), diffuse brain injury (OR = 1.21; p-value = 0.040) and focal brain injury (OR = 1.12; p-value = 0.040). By testing for heterogeneity and pleiotropy, the above causal conclusions are robust. In summary, our analysis shows that COVID-19 has an independent and powerful causal influence on multiple neurosurgical disorders.

Spontaneous regression of recurrent pulmonary large cell neuroendocrine carcinoma with alteration of PD-L1 expression after surgical resection: A case report

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive subtype of non-small cell lung cancer with a poor prognosis. Spontaneous regression, that is, partial or complete disappearance of a malignancy without medical intervention, is extremely rare in LCNEC. Herein, we present a case of spontaneous complete regression in a 71-year-old male patient with recurrent LCNEC after surgical resection. The patient was diagnosed with stage IB LCNEC and underwent surgical resection. At 1-year follow-up, chest computed tomography revealed a recurrent lesion next to the stump site and enlargement of lymph nodes 4R and 7; recurrent LCNEC was confirmed. The patient declined chemoradiation therapy. One year after recurrence, the patient experienced severe multifocal necrotizing pneumonia and was treated with antibiotics, resulting in a gradual decrease in the size of the recurrent lesion. Five years after the initial diagnosis, positron emission tomography/computed tomography revealed no hypermetabolic lesions, indicating the spontaneous complete regression of LCNEC.

Dysregulated phosphate metabolism in autism spectrum disorder: associations and insights for future research

Studies of autism spectrum disorder (ASD) related to exposure to toxic levels of dietary phosphate are lacking. Phosphate toxicity from dysregulated phosphate metabolism can negatively impact almost every major organ system of the body, including the central nervous system. The present paper used a grounded theory-literature review method to synthesise associations of dysregulated phosphate metabolism with the aetiology of ASD. Cell signalling in autism has been linked to an altered balance between phosphoinositide kinases, which phosphorylate proteins, and the counteracting effect of phosphatases in neuronal membranes. Glial cell overgrowth in the developing ASD brain can lead to disturbances in neuro-circuitry, neuroinflammation and immune responses which are potentially related to excessive inorganic phosphate. The rise in ASD prevalence has been suggested to originate in changes to the gut microbiome from increasing consumption of additives in processed food, including phosphate additives. Ketogenic diets and dietary patterns that eliminate casein also reduce phosphate intake, which may account for many of the suggested benefits of these diets in children with ASD. Dysregulated phosphate metabolism is causatively linked to comorbid conditions associated with ASD such as cancer, tuberous sclerosis, mitochondrial dysfunction, diabetes, epilepsy, obesity, chronic kidney disease, tauopathy, cardiovascular disease and bone mineral disorders. Associations and proposals presented in this paper offer novel insights and directions for future research linking the aetiology of ASD with dysregulated phosphate metabolism and phosphate toxicity from excessive dietary phosphorus intake.

Interaction of reproductive tract infections with estrogen exposure on breast cancer risk and prognosis

BACKGROUND

Reproductive tract infections influenced a series of inflammatory processes which involved in the development of breast cancer, while the processes were largely affected by estrogen. The present study aimed to explore the associations of breast cancer risk and prognosis with reproductive tract infections and the modification effects of estrogen exposure.

METHODS

We collected history of reproductive tract infections, menstruation and reproduction from 1003 cases and 1107 controls and a cohort of 4264 breast cancer patients during 2008-2018 in Guangzhou, China. We used logistic regression model to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for risk; Cox model was applied to estimate the hazard ratios (HRs) and 95% CIs for progression-free survival (PFS) and overall survival (OS).

RESULTS

It was found that previous reproductive tract infections were negatively associated with breast cancer risk (OR = 0.80, 95%CI, 0.65-0.98), particularly for patients with more menstrual cycles (OR = 0.74, 95%CI, 0.57-0.96). Patients with previous reproductive tract infections experienced better OS (HR = 0.61; 95% CI, 0.40-0.94) and PFS (HR = 0.84; 95% CI, 0.65-1.09). This protective effect on PFS was only found in patients with more menstrual cycles (HR = 0.52, 95% CI:0.34-0.79, P_interaction = 0.015).

CONCLUSIONS

The findings suggested that reproductive tract infections may be protective for the initiation and development of breast cancer, particularly for women with a longer interval of lifetime estrogen exposure.

Case report: Spontaneous remission in lung carcinoma with a late relapse after adjuvant immunotherapy: Exceptional tumor micro-environment

Spontaneous remission (SR) of local recurrence after adjuvant immunotherapy has rarely been reported, and the underlying mechanism is poorly understood. Herein, we reported a patient with stage cT2aN2M0 squamous cell lung carcinoma who received neoadjuvant and adjuvant treatment with nivolumab plus chemotherapy. The patient experienced a late relapse in the subcarinal lymph node seven months after the last dosage of treatment but achieved SR in the next three months without additional antitumor therapy. The complete response lasted for eleven months and counting. Notably, high copies of pathogenic microorganisms were detected in the patient's bronchoalveolar lavage fluid along with the recurrence but disappeared after SR. The patient also experienced a lymph node puncture-induced fever but had no other symptoms. A longitudinal analysis of infiltrated immune cells in the recurrent lymph node was performed by multiplex immunofluorescence and whole transcriptome sequencing, which revealed that CD8+ T cells were recruited during the initial relapse, specifically in the stromal area, then migrated into the tumor tissue, and continued to increase after elimination of tumor cells. Meanwhile, the initial recruitment of CD8+ T cells was coupled with a higher proportion of B cells, and the abundant neutrophil population was synchronous with the infiltration of CD8+ T cells into tumor cells. This is the first report on an Non-small cell lung cancer (NSCLC) patient with a late relapse after adjuvant immune checkpoint inhibitor (ICI) therapy who achieved SR. Our case highlights the complexity and plasticity of antitumor immunity and is expected to help find efficient strategies against the resistance of ICI treatment.

Resolution of pituitary microadenoma after coronavirus disease 2019: a case report

Background

This report describes the case of a patient whose pituitary microadenoma resolved after he contracted coronavirus disease 2019. To our knowledge, this is one of the first reported cases of pituitary tumor resolution due to viral illness. We present this case to further investigate the relationship between inflammatory response and tumor remission.

Case presentation

A 32-year-old man in Yemen presented to the hospital with fever, low blood oxygen saturation, and shortness of breath. The patient was diagnosed with coronavirus disease 2019. Past medical history included pituitary microadenoma that was diagnosed using magnetic resonance imaging and secondary adrenal insufficiency, which was treated with steroids. Due to the severity of coronavirus disease 2019, he was treated with steroids and supportive care. Three months after his initial presentation to the hospital, brain magnetic resonance imaging was performed and compared with past scans. Magnetic resonance imaging revealed changes in the microadenoma, including the disappearance of the hypointense lesion and hyperintense enhancement observed on the previous scan.

Conclusions

Pituitary adenomas rarely undergo spontaneous resolution. Therefore, we hypothesized that tumor resolution was secondary to an immune response to coronavirus disease 2019.

New Insights into the Role of Glutathione in the Mechanism of Fever

Glutathione is one of the most important and potent antioxidants. The development of pharmacological compounds that can either increase or decrease glutathione concentrations has allowed investigation into the role of glutathione in various biological processes, including immune responses. Recent findings have shown that glutathione not only affects certain factors involved in immunological processes but also modifies complex immune reactions such as fever. Until recently, it was not known why some patients do not develop fever during infection. Data suggest that fever induction is associated with oxidative stress; therefore, antioxidants such as glutathione can reduce pyrexia. Surprisingly, new studies have shown that low glutathione levels can also inhibit fever. In this review, we focus on recent advances in this area, with an emphasis on the role of glutathione in immune responses accompanied by fever. We describe evidence showing that disturbed glutathione homeostasis may be responsible for the lack of fever during infections. We also discuss the biological significance of the antipyretic effects produced by pharmacological glutathione modulators.

Sepsis inhibits tumor growth in mice with cancer through Toll-like receptor 4-associated enhanced Natural Killer cell activity

Sepsis-induced immune dysfunctions are likely to impact on malignant tumor growth. Sequential sepsis-then-cancer models of tumor transplantation in mice recovering from sepsis have shown that the post-septic immunosuppressive environment was able to promote tumor growth. We herein addressed the impact of sepsis on pre-established malignancy in a reverse cancer-then sepsis experimental model. Mice previously inoculated with MCA205 fibrosarcoma cells were subjected to septic challenges by polymicrobial peritonitis induced by cecal ligation and puncture or endotoxinic shock. The anti-tumoral immune response was assessed through the distribution of tumor-infiltrating immune cells, as well as the functions of cytotoxic cells. As compared to sham surgery, polymicrobial sepsis dampened malignant tumor growth in wild-type (WT) mice, but neither in Toll-like receptor 4 (Tlr4)^-/- nor in Myd88^-/- mice. Similar tumor growth inhibition was observed following a LPS challenge in WT mice, suggesting a regulatory role of Tlr4 in this setting. The low expression of MHC class 1 onto MCA205 cells suggested the involvement of Natural Killer (NK) cells in sepsis-induced tumor inhibition. Septic insults applied to mice with cancer promoted the main anti-tumoral NK functions of IFNγ production and degranulation. The anti-tumoral properties of NK cells obtained from septic mice were exacerbated when cultured with MHC1^low MCA205 or YAC-1 cells. These results suggest that sepsis may harbor dual effects on tumor growth depending on the sequential experimental model. When applied in mice with cancer, sepsis prevents tumor growth in a Tlr4-dependent manner by enhancing the anti-tumoral functions of NK cells.

Inflammatory mediator ultra-low-molecular-weight hyaluronan triggers necrosis of B-precursor leukemia cells with high surface CD44 expression

Acute lymphoblastic leukemia (ALL) with mixed lineage leukemia (MLL) gene rearrangements (MLL+ALL) has a dismal prognosis and is characterized by high surface CD44 expression. Known that CD44 has the specific binding sites for a natural ligand hyaluronan (HA), we investigated biological effects of HA with different molecular sizes on MLL+ALL cell lines, and found that the addition of ultra-low-molecular-weight (ULMW)-HA strongly suppressed their thymidine uptakes. The MLL+ALL cell line lacking surface CD44 expression established by genome editing showed no suppression of thymidine uptake. Surface CD44-high B-precursor ALL cell lines other than MLL+, but not T-ALL cell lines, were also suppressed in their thymidine uptakes. The inhibition of thymidine uptakes was because of induction of cell death, but dead cells lacked features of apoptosis on cytospin smears and flow cytometric analysis. The cell death was neither blocked by pan-caspase inhibitor nor autophagy inhibitor, but was completely blocked by necrosis inhibitor necrostatin-1. Necrotic cell death was further supported by a marked release of a high-mobility protein group B1 and morphological changes on transmission electron microscopy. Elevation of intracellular reactive oxygen species production suggested a role for inducing this necrotic cell death. ULMW-HA-triggered cell death was similarly demonstrated in surface CD44-high primary B-precursor leukemia cells. Assuming that ULMW-HA is abundantly secreted at the site of infection and inflammation, this study sheds light on understanding the mechanism of a transient inflammation-associated remission of leukemia. Further, the CD44-targeting may become an effective approach in future for the treatment of refractory B-precursor ALL by its capability of predominantly eradicating CD44-high leukemia-initiating cells.

Regression in primary cutaneous melanoma: etiopathogenesis and clinical significance

Though not required currently for staging, regression is a histopathologic parameter typically reported upon diagnosis of an invasive primary cutaneous melanoma. The studies examining the prognostic significance of regression in patient outcome have yielded controversial findings; likely because the definition and assessment of regression have not been consistent, in addition to subjectivity of pathologists' interpretation. Regression is histologically characterized by variable decrease in the number of melanoma cells accompanied by the presence of a host response consisting of dermal fibrosis, inflammatory infiltrate, melanophages, ectatic blood vessels, epidermal attenuation, and/or apoptosis of keratinocytes or melanocytes; the relative extent of these features depends on the stage of the regression. However, the magnitudes to which these individual changes must be present to meet the threshold of histologic regression have not been well defined or agreed upon, and thus, the definition and classification of histologic regression in melanoma varies considerably among institutions and even among individual pathologists. In order to determine the clinical significance of histologic analysis of regression, there is a compelling need for a universal scheme to objectively define and assess histologic regression in primary cutaneous melanoma, so that the biologic and prognostic significance of this process may be completely understood.Laboratory Investigation advance online publication, 27 February 2017; doi:10.1038/labinvest.2017.8.

Lorenz system in the thermodynamic modelling of leukaemia malignancy

The core idea of the proposed thermodynamic modelling of malignancy in leukaemia is entropy arising within normal haematopoiesis. Mathematically its description is supposed to be similar to the Lorenz system of ordinary differential equations for simplified processes of heat flow in fluids. The hypothetical model provides a description of remission and relapse in leukaemia as two hierarchical and qualitatively different states of normal haematopoiesis with their own phase spaces. Phase space transition is possible through pitchfork bifurcation, which is considered the common symmetrical scenario for relapse, induced remission and the spontaneous remission of leukaemia. Cytopenia is regarded as an adaptive reaction of haematopoiesis to an increase in entropy caused by leukaemia clones. The following predictions are formulated: a) the percentage of leukaemia cells in marrow as a criterion of remission or relapse is not necessarily constant but is a variable value; b) the probability of remission depends upon normal haematopoiesis reaching bifurcation; c) the duration of remission depends upon the eradication of leukaemia cells through induction or consolidation therapies; d) excessively high doses of chemotherapy in consolidation may induce relapse.

Protein-bound polysaccharides from Coriolus versicolor attenuate LPS-induced synthesis of pro-inflammatory cytokines and stimulate PBMCs proliferation

Protein-bound polysaccharides (PBP) isolated from Coriolus versicolor (CV) are classified as biological response modifiers capable of exhibiting various biological activities, such as anti-tumour and immunopotentiating activity. Since we have found in vivo studies that the tested PBP induced prolongation of endotoxin fever in rats, the aim of the present study was to investigate the in vitro effect of the PBP on the production of pro-inflammatory cytokines by the lipolysaccharide (LPS)-stimulated rat peripheral blood mononuclear cells (PBMCs). The results showed that the PBP affect the immunomodulating properties of the LPS-treated PBMCs by the enhancement of mitogenic activity and attenuation of the LPS-induced production of interleukin (IL)-1β and IL-6. Moreover, the tested polysaccharides peptides themselves also exhibit immunomodulatory properties manifested in the increased cell proliferation and pro-inflammatory cytokine release from PBMCs. The effect of PBP on the both phenomena was time-dependent and occurred in the U-shaped dose response manner. These findings are significant when considering the use of commercially available PBP from CV extract by cancer patients suffering from immunodeficiency, who may experience microbial infections during therapy.