Cancer and Sleep Apnea: Cutaneous Melanoma as a Case Study

Sleep apnoea increases biomarkers of immune evasion, lymphangiogenesis and tumour cell aggressiveness in high-risk patients and those with established lung cancer

Background

Intermittent hypoxaemia and obstructive sleep apnoea (OSA) have been linked to lung cancer through as yet unidentified pathophysiological mechanisms. This study evaluates the effect of OSA on serum levels of biomarkers of immunosurveillance, lymphangiogenesis and intrinsic tumour cell aggressiveness in high-risk individuals screened for lung cancer and patients with established lung cancer.

Methods

Serum samples from individuals participating in a lung cancer screening cohort (SAILS study) or with newly diagnosed lung cancer (SAIL study) were analysed. All patients underwent home sleep apnoea testing. Soluble levels of programmed cell death-1 (PD-1), programmed cell death ligand-1 (PD-L1), cytotoxic T-lymphocyte antigen-4, midkine (MDK), paraspeckle component-1 (PSPC1), transforming growth factor-β1 (TGF-β1), SMAD3, matrix metalloproteinase-2 and co-stimulus receptor of the tumour necrosis factor family of receptors (CD137) were determined by ELISA.

Results

The presence of moderate-to-severe OSA was associated with increased levels of PSPC1, MDK, PD-L1 and PD-1 in screened individuals, and with higher values of PSPC1, TGF-β1, PD-L1 and PD-1 in patients with established lung cancer. The findings correlated with nocturnal intermittent hypoxaemia indices.

Conclusion

Moderate-to-severe OSA is associated with increased expression of serum biomarkers of immune evasion, lymphangiogenesis and tumour cell aggressiveness in high-risk individuals screened for lung cancer and those with established disease.

Linking obstructive sleep apnoea and lung cancer: a further step down the road

There are various pathophysiological pathways linking obstructive sleep apnoea and lung cancer https://bit.ly/48qtqOO.

Role of Sleep Apnea and Long-Term CPAP Treatment in the Prognosis of Patients With Melanoma: A Prospective Multicenter Study of 443 Patients

BACKGROUND

OSA has been associated with increased incidence and aggressiveness of melanoma. However, the long-term impact of OSA and CPAP treatment on the prognosis of melanoma remains unexplored.

RESEARCH QUESTION

Are OSA and CPAP treatment associated independently with a poor prognosis for cutaneous melanoma?

STUDY DESIGN AND METHODS

Four hundred forty-three patients with a diagnosis of cutaneous melanoma (2012-2015) underwent a sleep study within 6 months of diagnosis. The main 5-year outcome of the study was a composite of melanoma recurrence, metastasis, or mortality. Patients were divided into four groups: baseline apnea-hypopnea index (AHI) of fewer than 10 events/h (no OSA; control group), OSA treated with CPAP and good adherence, untreated or poor CPAP adherence in moderate (AHI, 10-29 events/h), and severe OSA (AHI, ≥ 30 events/h). Survival analysis was used to determine the independent role of OSA and CPAP treatment on melanoma composite outcome.

RESULTS

Three hundred ninety-one patients (88.2%) were available for analysis at 5-year follow-up (mean age, 65.1 ± 15.2 years; 49% male; Breslow index, 1.7 ± 2.5 mm). One hundred thirty-nine patients had AHI of fewer than 10 events/h (control group); 78 patients with OSA were adherent to CPAP; and 124 and 50 patients had moderate and severe OSA, respectively, without CPAP treatment. Median follow-up was 60 months (interquartile range, 51-74 months). During follow-up, 32 relapses, 53 metastases, and 52 deaths occurred (116 patients showed at least one of the main composite outcomes). After adjusting for age, sex, sentinel lymph nodes affected at diagnosis, BMI, diabetes, nighttime with an oxygen saturation below 90%, Breslow index, Epworth sleepiness scale scores, and melanoma treatment, moderate (hazard ratio [HR], 2.45; 95% CI, 1.09-5.49) and severe OSA (HR, 2.96; 95% CI, 1.36-6.42) were associated with poorer prognosis of melanoma compared with the control group. However, good adherence to CPAP avoided this excess risk (HR, 1.66; 95% CI, 0.71-3.90).

INTERPRETATION

Moderate to severe untreated OSA is an independent risk factor for poor prognosis of melanoma. Treatment with CPAP is associated with improved melanoma outcomes compared with untreated moderate to severe OSA.

Adaptive responses to chronic intermittent hypoxia: contributions from the European Sleep Apnoea Database (ESADA) Cohort

Obstructive sleep apnoea (OSA) is a common disease in the general population, and is associated with increased cardiovascular risk and several comorbidities. Obesity favours upper airway collapsibility, but other pathophysiological traits have been identified, i.e. upper airway muscle activity, modulation of the respiratory drive, and the arousal threshold. OSA causes chronic intermittent hypoxia, inflammatory activation and autonomic imbalance with diurnal and nocturnal sympathetic hyperactivity. Disentangling so many components to investigate the pathogenesis of OSA's consequences is very hard clinically. However, albeit imperfect, clinical medicine constitutes a major source of inspiration for basic research, and a mutual exchange of information is essential between clinicians and physiologists to improve our understanding of disease states. OSA is no exception, and this narrative review will summarize the results of clinical studies performed over the years by the European Sleep Apnoea Database (ESADA) Study Group, to explore the variables linked to markers of intermittent hypoxia as opposed to the traditional assessment of OSA severity based on the frequency of respiratory events during sleep (the Apnoea Hypopnoea Index). The results of the clinical studies indicate that intermittent hypoxia variables are associated with several comorbidities, although evidence of a cause-effect relationship is still missing in many cases. It is also possible that adaptive rather than maladaptive responses could be evoked by intermittent hypoxia. The intensity, duration and frequency of intermittent hypoxia episodes causing adaptive rather than maladaptive responses, and their clinical implications, deserve further investigation.

Obstructive sleep apnoea is related to melanoma aggressiveness through paraspeckle protein-1 upregulation

BACKGROUND

In patients with obstructive sleep apnoea (OSA), intermittent hypoxia induces overexpression of paraspeckle component (PSPC)1, a master modulator of transforming growth factor (TGF)-β signalling, which promotes cell cancer progression through epithelial-mesenchymal transition (EMT) and acquisition of cancer stem cell (CSC)-like features. However, the persistence of intermittent hypoxia-induced effects on PSPC1, and their consequences in cancer patients are not known. To this effect, circulating PSPC1 levels were compared in patients with cutaneous melanoma with or without OSA, and their relationship with tumour aggressiveness along with the in vitro effects of soluble PSPC1 and intermittent hypoxia on melanoma cell aggressiveness mechanisms were assessed.

METHODS

In 292 cutaneous melanoma patients, sleep studies and serum levels of PSPC1 and TGF-β were evaluated. The effect of PSPC1 on expression of EMT and CSC transcription factors was assessed using melanoma cell lines with patient sera under both normoxia and intermittent hypoxia conditions.

RESULTS

PSPC1 levels were higher in patients with moderate-severe OSA compared with mild OSA or non-OSA patients. Serum levels of PSPC1 were associated with several cutaneous melanoma clinical aggressiveness indicators. Both intermittent hypoxia exposures and serum from OSA patients upregulated TGF-β expression and amplified the expression of transcription factors associated with EMT activation and acquisition of CSC characteristics.

CONCLUSION

In cutaneous melanoma patients, OSA severity is associated with higher PSPC1 serum levels, which jointly with intermittent hypoxia would enhance the self-reprogramming capabilities of EMT and CSC feature acquisition of melanoma cells, promoting their intrinsic aggressiveness.

Expression profile and prognostic values of LSM family in skin cutaneous melanoma

Background

The like-Smith (LSM) family is a group of RNA-binding proteins involved in RNA metabolism. However, their involvement in tumors, particularly skin cutaneous melanoma (SKCM), is not fully understood. In this study, we focused on the expression profiles and prognostic values of the LSM family in SKCM.

Methods

Raw data were downloaded from The Cancer Genome Atlas. The expression profile and prognostic value of LSM genes in SKCM were explored using the GEPIA, cBioPortal, and HPA databases. Protein–protein and gene–gene interaction analyses were performed using STRING and GeneMANIA. Enrichment and Cox regression analysis were conducted using R software. The TISIDB database was used to explore the relationship between LSMs and immunomodulators. Receiver operating characteristic curves and nomogram models were constructed to validate prognostic values.

Results

mRNA and protein expression levels of LSM2, LSM4, and LSM12 were significantly elevated in SKCM. The upregulated mRNA expression of LSM2 (p = 0.0013) and LSM4 (p = 0.0043) was significantly correlated with poor overall survival in patients with SKCM, whereas only LSM2 (p = 0.049) overexpression was markedly associated with worse disease-free survival. LSM2 overexpression was an independent risk factor (p = 0.013) and was confirmed to have a high prognostic value in SKCM using the receiver operating characteristic curve (AUC = 0.942) and nomogram models. All LSM genes were identified as genomic mutations, whereas alteration of LSM2 (p = 0.0153) significantly affected the overall survival in patients with SKCM. Significant correlations were observed between LSM family expression, immune cell infiltration, and immunomodulator. Furthermore, function and pathway enrichment analysis showed that the LSM family was mainly RNA binding proteins and involved in RNA splicing and degradation.

Conclusion

Expression profiles and prognostic values of LSM in SKCM were inconsistent. Among the LSM family, only LSM2 may serve as a potential poor prognosticator and immunotherapeutic target of SKCM.

Mechanical ventilation promotes lung tumor spread by modulation of cholesterol cell content

Mechanical stretch of cancer cells can alter their invasiveness. During mechanical ventilation, lungs may be exposed to an increased amount of stretch, but the consequences on lung tumors have not been explored. To characterize the influence of mechanical ventilation on the behavior of lung tumors, invasiveness assays and transcriptomic analyses were performed in cancer cell lines cultured in static conditions or under cyclic stretch. Mice harbouring lung melanoma implants were submitted to mechanical ventilation and metastatic spread was assessed. Additional in vivo experiments were performed to determine the mechano-dependent specificity of the response. Incidence of metastases was studied in a cohort of lung cancer patients that received mechanical ventilation compared with a matched group of non-ventilated patients. Stretch increases invasiveness in melanoma B16F10luc2 and lung adenocarcinoma A549 cells. We identified a mechanosensitive upregulation of pathways involved in cholesterol processing in vitro, leading to an increase in PCSK9 and LDLR expression, a decrease in intracellular cholesterol and preservation of cell stiffness. A course of mechanical ventilation in mice harboring melanoma implants increased brain and kidney metastases two weeks later. Blockade of PCSK9 using a monoclonal antibody increased cell cholesterol and stiffness and decreased cell invasiveness in vitro and metastasis in vivo In patients, mechanical ventilation increased PCSK9 abundance in lung tumors and the incidence of metastasis, thus decreasing survival. Our results suggest that mechanical stretch promote invasiveness of cancer cells, which may have clinically relevant consequences. Pharmacological manipulation of cholesterol endocytosis could be a novel therapeutic target in this setting.

Polysomnographic Markers of Obstructive Sleep Apnea Severity and Cancer-Related Mortality: A Large Retrospective Multicenter Clinical Cohort Study

RATIONALE

The evidence for an association between cancer survival and obstructive sleep apnea (OSA) remains under-explored.

OBJECTIVES

To evaluate an association between markers of OSA severity (respiratory disturbances, hypoxemia, and sleep fragmentation) and cancer-related mortality in individuals with previously diagnosed cancer.

METHODS

We conducted a multicenter retrospective cohort study using linked clinical and provincial health administrative data on consecutive adults who underwent a diagnostic sleep study between 1994 and 2017 in four Canadian academic hospitals and were previously diagnosed with cancer through the Ontario Cancer Registry. Multivariable cause-specific Cox regressions were utilized to address the research objective.

RESULTS

We included 2,222 subjects. Over a median follow-up time of 5.6 years (IQR: 2.7-9.1), 261/2,222 (11.7%) individuals with prevalent cancer died from cancer-related causes, which accounted for 44.2% (261/590) of all-cause death. Controlling for age, sex, alcohol use disorder, prior heart failure, COPD, hypertension, diabetes, treatment for OSA, clinic site, year of the sleep study, and time since the cancer diagnosis, measures of hypoxemia and sleep fragmentation, but not apnea-hypopnea index were significantly associated with the cancer-specific mortality: % time spent with SaO2 <90% (HR per 5% increase: 1.05; 95% CI: 1.01-1.09); mean SaO2 (HR per 3% increase: 0.79; 0.68-0.92); and % of Stage 1 Sleep (HR per 16% increase: 1.27; 1.07-1.51).

CONCLUSION

In a large clinical cohort of adults with suspected OSA and previously diagnosed cancer, measures of nocturnal hypoxemia and sleep fragmentation as markers of OSA severity were significantly associated with cancer-related mortality, suggesting the need for more targeted risk awareness.

Heterogeneity of Melanoma Cell Responses to Sleep Apnea-Derived Plasma Exosomes and to Intermittent Hypoxia

Obstructive sleep apnea (OSA) is associated with increased cutaneous melanoma incidence and adverse outcomes. Exosomes are secreted by most cells, and play a role in OSA-associated tumor progression and metastasis. We aimed to study the effects of plasma exosomes from OSA patients before and after adherent treatment with continuous positive airway pressure (CPAP) on melanoma cells lines, and also to identify exosomal miRNAs from melanoma cells exposed to intermittent hypoxia (IH) or normoxia. Plasma-derived exosomes were isolated from moderate-to-severe OSA patients before (V1) and after (V2) adherent CPAP treatment for one year. Exosomes were co-incubated with three3 different melanoma cell lines (CRL 1424; CRL 1619; CRL 1675) that are characterized by genotypes involving different mutations in BRAF, STK11, CDKN2A, and PTEN genes to assess the effect of exosomes on cell proliferation and migration, as well as on pAMK activity in the presence or absence of a chemical activator. Subsequently, CRL-1424 and CRL-1675 cells were exposed to intermittent hypoxia (IH) and normoxia, and exosomal miRNAs were identified followed by GO and KEG pathways and gene networks. The exosomes from these IH-exposed melanoma cells were also administered to THP1 macrophages to examine changes in M1 and M2 polarity markers. Plasma exosomes from V1 increased CRL-1424 melanoma cell proliferation and migration compared to V2, but not the other two cell lines. Exposure to CRL-1424 exosomes reduced pAMPK/tAMPK in V1 compared to V2, and treatment with AMPK activator reversed the effects. Unique exosomal miRNAs profiles were identified for CRL-1424 and CRL-1675 in IH compared to normoxia, with six miRNAs being regulated and several KEGG pathways were identified. Two M1 markers (CXCL10 and IL6) were significantly increased in monocytes when treated with exosomes from IH-exposed CRL-1424 and CRL-1625 cells. Our findings suggest that exosomes from untreated OSA patients increase CRL-1424 melanoma malignant properties, an effect that is not observed in two other melanoma cell lines. Exosomal cargo from CRL-1424 cells showed a unique miRNA signature compared to CRL-1675 cells after IH exposures, suggesting that melanoma cells are differentially susceptible to IH, even if they retain similar effects on immune cell polarity. It is postulated that mutations in STK-11 gene encoding for the serine/threonine kinase family that acts as a tumor suppressor may underlie susceptibility to IH-induced metabolic dysfunction, as illustrated by CRL-1424 cells.

Cancer risk in patients with sleep apnoea following adherent 5-year CPAP therapy

BACKGROUND

Increasing evidence suggests that obstructive sleep apnoea (OSA) contributes to cancer risk; however, limited data are available on the impact of continuous positive airway pressure (CPAP) therapy on cancer incidence. We aimed to determine whether adherence to CPAP therapy is associated with a reduction in all-cancer incidence compared to non-adherent patients with OSA.

METHODS

The study relied on the data collected by the multicentre study Pays de la Loire Sleep Cohort, linked to health administrative data, such as to identify new-onset cancer. We included patients who were prescribed CPAP for OSA, with no history of cancer before the diagnostic sleep study or during the first year of CPAP. Patients with documented CPAP use for at least 4 h per night were defined as adherent. Those who discontinued or used CPAP less than 4 h at night constituted the non-adherent group. A propensity-score inverse probability of treatment weighting analysis was performed to assess the effect of CPAP adherence on cancer risk.

RESULTS

After a median [inter-quartile range] follow-up of 5.4 [3.1-8.0] years, 437 (9.7%) of 4,499 patients developed cancer, 194 (10.7%) in the non-adherent group (n=1817) and 243 (9.1%) in adherent patients (n=2682). The final weighted model showed no significant impact of CPAP adherence on all-cause cancer risk (sub distribution hazard ratio [95% confidence interval]): 0.94 [0.78; 1.14]).

CONCLUSIONS

Adherence to CPAP therapy in OSA patients was not associated with a reduction in all-cancer incidence. Whether adherent CPAP therapy of OSA might reduce the risk of specific cancer sites should be further evaluated.

Intermittent Hypoxia Mediates Paraspeckle Protein-1 Upregulation in Sleep Apnea

Simple Summary

Patients with obstructive sleep apnea (OSA) exhibit an intermittent hypoxia-dependent paraspeckle protein-1 (PSPC1) increase, which is eventually delivered to the plasma through its cleavage from OSA monocytes by matrix metalloprotease-2, promoting tumor growth factor (TGFβ) expression and increasing epithelial-to-mesenchymal transition in a tumor functional model using a melanoma cell line. These results connect the phenomena of sleep apnea with increased plasma PSPC1 levels, which has a functional effect on the TGFβ pathway and accelerates tumor progression.

Abstract

As some evidence suggests that hypoxia might be an inducer of nuclear paraspeckle formation, we explore whether intermittent hypoxia (IH)-mediated paraspeckle protein-1 (PSPC1) overexpression might contribute to the activation of tumor growth factor (TGF)β-SMAD pathway in patients with obstructive sleep apnea (OSA). This activation would promote changes in intracellular signaling that would explain the increased cancer aggressiveness reported in these patients. Here, we show that patients with OSA exhibit elevated PSPC1 levels both in plasma and in monocytes. Our data suggest that PSPC1 is ultimately delivered to the plasma through its cleavage from OSA monocytes by matrix metalloproteinase-2 (MMP2). In addition, IH promotes PSPC1, TGFβ, and MMP2 expression in monocytes through the hypoxia-inducible factor. Lastly, both PSPC1 and TGFβ induce increased expression of genes that drive the epithelial-to-mesenchymal transition. Our study details the mechanism by which hypoxemia upmodulates the extracellular release of PSPC1 by means of MMP2, such that plasma PSPC1 together with TGFβ activation signaling further promotes tumor metastasis and supports cancer aggressiveness in patients with OSA.

Worldwide production on sleep apnea from 2009-2018. Analysis of the ability to secure funding and international collaboration networks

BACKGROUND

Obstructive sleep apnea (OSA) is an emerging health problem, but information on scientific production in this subject area is scarce. We aim to evaluate the scientific production on OSA from 2009 to 2018 to illustrate its worldwide distribution, topic areas, and ability to secure funding, as well as to describe international collaboration networks in this field.

METHODS

Articles published between 2009 and 2018 were extracted from the Science Citation Index Expanded via Web of Science (WoS) using the search term "obstructive sleep apn*". Publication year, number and country of authors, journal, subject category, key words, funding source and number of citations received were recorded. We also conducted network analyses for key words and international collaboration.

RESULTS

12,666 articles on OSA were located, which had increased from 895 documents in 2009 to 1592 in 2018. The progressive growth in scientific production on OSA had outpaced the growth rate of total WoS production since 2012.50% of the articles declared some type of funding, with a citation index higher than manuscripts that were not funded. The manuscripts were distributed in journals from 135 subject categories of the WoS, and keyword distribution showed a dispersed pattern with a high number of nodes. The international collaboration rate was 18.2%, and the country network showed the United States as the hegemonic node.

CONCLUSION

World production on OSA has grown at a higher rate than global production and shows notable thematic dispersion as well as a high ability to secure funding, which increases its impact.

Chronic intermittent hypoxia promoted lung cancer stem cell-like properties via enhancing Bach1 expression

BACKGROUND

An adverse role for obstructive sleep apnea (OSA) in cancer aggressiveness and mortality has recently emerged from clinical and animal studies, and the reasons have not been fully determined. Cancer stem cells (CSCs) are regarded as the main cause of carcinoma metastasis. So far, the relationship between OSA and lung CSCs has not been explored.

METHOD

In the present study, we established an orthotopic mouse model of primary lung cancer and utilized chronic intermittent hypoxia (CIH) exposure to mimic OSA status.

RESULTS

We observed that CIH endows lung cancer with greater metastatic potential, evidenced by increased tumor growth, tumor seeding, and upregulated CSC-related gene expression in the lungs. Notably, the transcription factor BTB and CNC homology 1 (Bach1), a key factor in responding to conditions of oxidative stress, is increased in lung cancer after CIH exposure in vitro and in vivo. Meanwhile, exposing lung cancer cells to CIH promoted cell proliferation, clonal diversity, induced stem-like cell marker expression, and gave rise to CSCs at a relatively higher frequency. Furthermore, the increase of mitochondrial ROS (mtROS) and CSC-marker expression induced by CIH exposure was abolished in Bach1 shRNA-treated lung cancer cells.

CONCLUSIONS

Our results indicated that CIH promoted lung CSC-like properties by activating mtROS, which was partially mediated by Bach1.

Obstructive Sleep Apnea and Incident Cancer: A Large Retrospective Multicenter Clinical Cohort Study

BACKGROUND

To examine the association between the severity of obstructive sleep apnea (OSA) and nocturnal hypoxemia with incident cancer.

METHODS

This was a multicenter retrospective clinical cohort study using linked clinical and provincial health administrative data on consecutive adults who underwent a diagnostic sleep study between 1994 and 2017 in four academic hospitals (Canada) who were free of cancer at baseline. Cancer status was derived from the Ontario Cancer Registry. Cox cause-specific regressions were utilized to address the objective and to calculate the 10-year absolute risk difference (ARD) in the marginal probability of incident cancer and the number needed to harm (NNH).

RESULTS

Of 33,997 individuals considered, 33,711 with no missing OSA severity were included: median age, 50 years; 58% male; and 23% with severe OSA (apnea-hypopnea index >30). Of the 18,458 individuals with information on sleep time spent with oxygen saturation (SaO₂) <90%, 5% spent >30% of sleep with SaO₂ <90% (severe nocturnal hypoxemia). Over a median of 7 years, 2,498 of 33,711 (7%) individuals developed cancer, with an incidence rate of 10.3 (10.0-10.8) per 1,000 person-years. Controlling for confounders, severe OSA was associated with a 15% increased hazard of developing cancer compared with no OSA (HR = 1.15, 1.02-1.30; ARD = 1.28%, 0.20-2.37; and NNH = 78). Severe hypoxemia was associated with about 30% increased hazard (HR = 1.32, 1.08-1.61; ARD = 2.38%, 0.47-4.31; and NNH = 42).

CONCLUSIONS

In a large cohort of individuals with suspected OSA free of cancer at baseline, the severity of OSA and nocturnal hypoxemia was independently associated with incident cancer.

IMPACT

These findings suggest the need for more targeted cancer risk awareness in individuals with OSA.

Proangiogenic factor midkine is increased in melanoma patients with sleep apnea and induces tumor cell proliferation

Midkine (MDK) might mediate the proangiogenic effect of intermittent hypoxia (IH) in patients with obstructive sleep apnea (OSA) and cutaneous melanoma (CM). We compare circulating MDK in CM patients with and without OSA, and their relationship with tumor aggressiveness, while exploring in vitro effects of soluble MDK on human lymphatic endothelial (HLEC) and melanoma cell proliferation. In 360 CM patients, sleep studies and MDK serum level measurements were performed. The effect of MDK on cell proliferation was assessed using HLEC and melanoma cell lines with patient sera under both normoxia and IH. MDK levels were higher in severe OSA compared to mild OSA or non-OSA patients, whereas no differences in VEGF levels emerged. In OSA patients, MDK levels correlated with nocturnal hypoxemia and CM mitotic rate. In vitro, MDK promotes HLEC proliferation under IH conditions. Moreover, cultures of the human melanoma cell line C81-61 with sera from patients with the highest MDK levels promoted tumor cell proliferation, which was attenuated after the addition of MDK antibody. These responses were enhanced by IH exposures. In conclusion, in CM patients, OSA severity is associated with higher MDK levels, which, appear to enhance both the lymphangiogenesis as the intrinsic aggressiveness of CM tumor cells.

Sleep Apnoea Adverse Effects on Cancer: True, False, or Too Many Confounders?

Obstructive sleep apnoea (OSA) is a prevalent disorder associated with increased cardiovascular, metabolic and neurocognitive morbidity. Recently, an increasing number of basic, clinical and epidemiological reports have suggested that OSA may also increase the risk of cancer, and adversely impact cancer progression and outcomes. This hypothesis is convincingly supported by biological evidence linking certain solid tumours and hypoxia, as well as by experimental studies involving cell and animal models testing the effects of intermittent hypoxia and sleep fragmentation that characterize OSA. However, the clinical and epidemiological studies do not conclusively confirm that OSA adversely affects cancer, even if they hold true for specific cancers such as melanoma. It is likely that the inconclusive studies reflect that they were not specifically designed to test the hypothesis or because of the heterogeneity of the relationship of OSA with different cancer types or even sub-types. This review critically focusses on the extant basic, clinical, and epidemiological evidence while formulating proposed directions on how the field may move forward.

Obesity attenuates the effect of sleep apnea on active TGF-ß1 levels and tumor aggressiveness in patients with melanoma

Active transforming growth factor-β1 (TGF-β1), a cytokine partially regulated by hypoxia and obesity, has been related with poor prognosis in several tumors. We determine whether obstructive sleep apnea (OSA) increases serum levels of active TGF-β1 in patients with cutaneous melanoma (CM), assess their relationship with melanoma aggressiveness and analyze the factors related to TGF-β1 levels in obese and non-obese OSA patients. In a multicenter observational study, 290 patients with CM were underwent sleep studies. TGF-β1 was increased in moderate-severe OSA patients vs. non-OSA or mild OSA patients with CM. In OSA patients, TGF-β1 levels correlated with mitotic index, Breslow index and melanoma growth rate, and were increased in presence of ulceration or higher Clark levels. In CM patients, OSA was associated with higher TGF-β1 levels and greater melanoma aggressiveness only in non-obese subjects. An in vitro model showed that IH-induced increases of TGF-β1 expression in melanoma cells is attenuated in the presence of high leptin levels. In conclusion, TGF-β1 levels are associated with melanoma aggressiveness in CM patients and increased in moderate-severe OSA. Moreover, in non-obese patients with OSA, TGF-β1 levels correlate with OSA severity and leptin levels, whereas only associate with leptin levels in obese OSA patients.

Mortality and morbidity in obstructive sleep apnoea-hypopnoea syndrome: results from a 30-year prospective cohort study

Background

Obstructive sleep apnoea–hypopnoea syndrome (OSAHS) carries substantial negative health consequences. This study examines factors affecting mortality and morbidity according to continuous positive airway pressure (CPAP) use and predictors affecting CPAP adherence in a longitudinal cohort of OSAHS patients.

Materials and methods

This prospective, cohort study comprised 4502 patients who were diagnosed with OSAHS at a tertiary sleep disorders centre between 1982 and 2003. Of these, 1174 patients completed follow-up in 2012. Data collected included anthropometric, sleep and demographic characteristics, including comorbidities, ongoing medications and CPAP adherence. Patients were followed up for an average of 14.8±3.7 years.

Results

Imputation analysis showed that long-term CPAP users (>5 years) were 5.63 times more likely to be alive at study end than non-CPAP users (95% CI: 4.83–6.58, p<0.001) and 1.74-times more likely than short-term CPAP users (≤5 years) (95% CI: 1.49–2.02, p<0.001). Females had a significantly higher mortality rate during the follow-up period (26.8% versus 19.6%, p<0.001). Respiratory mortality was more common in patients with OSAHS, in particular those who did not use CPAP, compared to the general population (17.2% versus 12.2%, p=0.002 respectively), whereas deaths from cancer were less common compared to the general population (16.2% versus 25.6%, p<0.001). Compared to CPAP users, non-CPAP-users had a significantly increased incidence of type II diabetes mellitus (DMII) (27.9% versus 18.7%, p=0.003), ischaemic heart disease (IHD) (25.5% versus 12.7%, p<0.001) and myocardial infarction (MI) (14.7% versus 4.2%, p<0.001) at long-term follow-up.

Conclusions

Long-term CPAP use in men and women with OSAHS reduces mortality and decreases the incidence of DMII and cardiovascular disease.

In this first long-term prospective cohort study to use imputation analysis in OSAHS patients, all-cause morbidity and mortality were significantly reduced in long-term CPAP users (>5 years), and equivalent for both males and femaleshttps://bit.ly/3cKL2HK

The Association of Sleep Disorders, Obesity and Sleep-Related Hypoxia with Cancer

BACKGROUND

Sleep disorders have emerged as potential cancer risk factors.

OBJECTIVE

This review discusses the relationships between sleep, obesity, and breathing disorders with concomitant risks of developing cancer.

RESULTS

Sleep disorders result in abnormal expression of clock genes, decreased immunity, and melatonin release disruption. Therefore, these disorders may contribute to cancer development. Moreover, in sleep breathing disorder, which is frequently experienced by obese persons, the sufferer experiences intermittent hypoxia that may stimulate cancer cell proliferation.

DISCUSSION

During short- or long- duration sleep, sleep-wake rhythm disruption may occur. Insomnia and obstructive sleep apnea increase cancer risks. In short sleepers, an increased risk of stomach cancer, esophageal squamous cell cancer, and breast cancer was observed. Among long sleepers (>9 hours), the risk of some hematologic malignancies is elevated.

CONCLUSION

Several factors including insomnia, circadian disruption, obesity, and intermittent hypoxia in obstructive sleep apnea are contributing risk factors for increased risk of several types of cancers. However, further studies are needed to determine the more significant of these risk factors and their interactions.

Sleep Apnea and Skin

Purpose of the Review

Skin disease is associated with obstructive sleep apnea (OSA) both epidemiologically and mechanistically. In this review we highlight conditions which have a well-established link to obstructive sleep apnea, such as psoriasis and atopic dermatitis.

Recent findings

We describe putative mechanistic links between OSA and skin disease involving inflammatory pathways, obesity, mechanical upper airways obstruction, and hypoxia. In the context of these mechanisms we describe specific skin conditions, and other conditions which are associated with both skin manifestations (including hair/nail findings) and OSA. The risks/ benefits of CPAP in the context of skin disease are also reviewed.

Summary

We conclude that further research is needed to understand the mechanisms behind the associations between OSA and skin disease. Given the frequent co-occurrence of OSA and skin conditions, there would be great benefit for OSA clinical trials to consider improvement in skin disease as an outcome measure.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

This comprehensive review of the 2019 restorative dental literature is offered to inform busy dentists regarding remarkable publications and noteworthy progress made in the profession. Developed by the Scientific Investigation Committee of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to 1 of 8 sections of the report: (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information likely to influence day-to-day dental treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source material when greater detail is desired. As the profession moves toward evidence-based clinical decision-making, an incredible volume of potentially valuable dental literature continues to increase. It is the intention of this review and its authors to provide assistance in negotiating the extensive dental literature published in 2019. It is our hope that readers find this work useful in the clinical management of dental patients.

Epidemiological characteristics of obstructive sleep apnea in a hospital-based historical cohort in Lebanon

The objective of our study was to characterize and analyze the associations between OSA (obstructive sleep apnea) and other clinical variables in adult patients referred for sleep evaluation by polysomnography at a referral center in Beirut, Lebanon, in terms of sociodemographic features, symptoms presentation and comorbidities, and evaluate the burden of comorbidities associated with this disease. All individuals with suspected Sleep Apnea referred (January 2010-September 2017) for a one-night polysomnography were included. Demographics, self-reported symptoms and comorbidities were documented. The relationship between OSA severity and the presence of symptoms and comorbidities were evaluated using multivariate logistic regression. Overall, 663 subjects were assessed. Of these, 57.3% were referred from chest physicians, and sleep test results were abnormal in 589 subjects (88.8%) of whom 526 patients (89.3%) fulfilled diagnostic criteria for OSA; 76.3% were men and women were on average older. OSA was severe in 43.2% and more severe in men. Almost all patients were symptomatic with ~2–4 symptoms per patient and women presented with symptoms that are more atypical. Comorbidities were significantly higher in women. In the multivariate analysis, age, male sex, obesity, symptoms of snoring, excessive daytime somnolence and witnessed apneas were associated with OSA severity. Only age and obesity were associated with self-reported diagnosis of hypertension and diabetes. This is the first study in Lebanon to explore the characteristics of patients with polysomnography-diagnosed OSA. High prevalence of severe OSA and low referral rates in the medical community support promoting awareness for an earlier diagnosis and more personalized approach in this country.

Five-year relative survival in sleep apnea patients with a subsequent cancer diagnosis

STUDY OBJECTIVES

In vitro and animal studies suggest that intermittent hypoxia characterizing sleep apnea contributes to accelerated cancer progression. However, the impact of sleep apnea on survival subsequent to cancer diagnosis is unknown.

METHODS

We identified a cohort of 1,575 adults diagnosed with sleep apnea between 2005 and 2014 with a subsequent cancer diagnosis via linkage of the University of Washington Medicine system and a population-based cancer registry serving the same Seattle-Puget Sound region. We computed age-standardized 5-year relative survival after cancer diagnosis for all cancers combined, and for specific cancer sites, for both the sleep apnea cohort and the general Seattle-Puget Sound population, and we used US life tables as the reference population. Relative survival was estimated by sex, cancer stage, and health care engagement.

RESULTS

Five-year overall relative survival for cancer was more favorable in the sleep apnea cohort than in the general population [83.6%, 95% confidence interval (CI): 79.8%-86.8% vs 71.6%, 95% CI: 71.3%-71.9%]; this pattern was applicable to most specific cancer sites. However, 5-year relative survival was slightly less favorable in the sleep apnea cohort among patients with melanoma (97.7%, 95% CI: 84.6%-99.7% vs 99.2%, 95% CI: 98.8%-99.5%) and cancer of the corpus uteri (84.0%, 95% CI: 58.2%-94.5% vs 84.6%, 95% CI: 83.1%-86.0%).

CONCLUSIONS

The fact that survival after cancer, overall and for most cancer sites, was more favorable in patients with sleep apnea warrants larger community-based studies to further tease out effects of sleep apnea and treatment on site-specific survival for different cancer types, particularly in patients with melanoma or uterine cancer.

Obstructive sleep apnea syndrome and causal relationship with female breast cancer: a mendelian randomization study

Although observational studies have reported a positive association between obstructive sleep apnea syndrome (OSAS) and breast cancer (BC) risk, causality remains inconclusive. We aim to explore whether OSAS is associated with etiology of BC by conducting a two-sample Mendelian randomization (MR) study in a Chinese population and Asian population from the Breast Cancer Association Consortium (BCAC). We found a detrimental causal effect of OSAS on BC risk in the primary analysis of our samples (IVW OR, 2.47 for BC risk per log-odds increment in OSAS risk, 95% CI = 1.86-3.27; P = 3.6×10^-10). This was very similar to results of the direct observational case-control study between OSAS and BC risk (OR = 2.80; 95% CI = 2.24-3.50; P =1.4×10^-19). Replication in the Asian population of the BCAC study also supported our results (IVW OR, 1.33 for BC risk per log-odds increment in OSAS risk, 95% CI = 1.13-1.56; P = 0.0006). Sensitivity analyses confirmed the robustness of our findings. We provide novel evidence that genetically determined higher risk of OSAS has a causal effect on higher risk of BC. Further studies focused on the mechanisms of the relationship between OSAS and breast carcinogenesis are needed.