The Role of Epicardial Adipose Tissue in Acute Coronary Syndromes, Post-Infarct Remodeling and Cardiac Regeneration.

Epicardial adipose tissue (EAT) is a fat deposit surrounding the heart and located under the visceral layer of the pericardium. Due to its unique features, the contribution of EAT to the pathogenesis of cardiovascular and metabolic disorders is extensively studied. Especially, EAT can be associated with the onset and development of coronary artery disease, myocardial infarction and post-infarct heart failure which all are significant problems for public health. In this article, we focus on the mechanisms of how EAT impacts acute coronary syndromes. Particular emphasis was placed on the role of inflammation and adipokines secreted by EAT. Moreover, we present how EAT affects the remodeling of the heart following myocardial infarction. We further review the role of EAT as a source of stem cells for cardiac regeneration. In addition, we describe the imaging assessment of EAT, its prognostic value, and its correlation with the clinical characteristics of patients.

Therapeutic adherence and assessment of satisfaction patients with multiple myeloma treated with immunomodulatory drugs in a "real-world" study: Experiences of the Polish Myeloma Group.

INTRODUCTION: Therapeutic adherence (TA) is one of the most important factors influencing the effectiveness of treatment. Oral anti-cancer drugs are increasingly used to treat malignancy including multiple myeloma (MM). Our study aimed to determine TA of patients with MM treated with IMiDs, to identify TA risk factors, and to determine satisfaction with medical care during the treatment with IMiDs. METHODS: A cross-sectional survey-based study involving adult patients with MM treated with IMiDs. RESULTS: Between January 2021 and May 2021, 267 patients with MM were enrolled in the study. The dosing schedule was declared as easy by 71.8% of patients, as standard for 24.0%, and difficult for 4.2% of patients. During MM treatment, 85.0% of patients did not skip any IMiDs dose, and 87.6% did not skip the IMiDs dose in the last cycle of chemotherapy. Identified factors affecting TA included the treatment duration and education level. In addition, depending on the patient's well-being, gender, and household companionship influenced TA. Satisfaction with medical care during the treatment with IMiDs was declared by 95.5% of patients with MM. In our cohort, 95.5% of patients were satisfied with the information they received from the hematologist during treatment with IMiDs. CONCLUSIONS: Patients with MM treated with IMiDs are highly adherent to treatment. With time from the beginning of treatment, patients need more attention and motivation to adhere to the therapy rules.

In Search of the Holy Grail: Stem Cell Therapy as a Novel Treatment of Heart Failure with Preserved Ejection Fraction.

Heart failure, a leading cause of hospitalizations and deaths, is a major clinical problem. In recent years, the increasing incidence of heart failure with preserved ejection fraction (HFpEF) has been observed. Despite extensive research, there is no efficient treatment for HFpEF available. However, a growing body of evidence suggests stem cell transplantation, due to its immunomodulatory effect, may decrease fibrosis and improve microcirculation and therefore, could be the first etiology-based therapy of the disease. In this review, we explain the complex pathogenesis of HFpEF, delineate the beneficial effects of stem cells in cardiovascular therapy, and summarize the current knowledge concerning cell therapy in diastolic dysfunction. Furthermore, we identify outstanding knowledge gaps that may indicate directions for future clinical studies.

Evaluation of Nitrosative/Oxidative Stress and Inflammation in Heart Failure with Preserved and Reduced Ejection Fraction.

Heart failure (HF) is a complex syndrome characterized by impaired cardiac function. Two common subtypes of HF include heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). In this study, we aimed to evaluate and compare the plasma levels of 3-nitrotyrosine (3-NT)-as a marker of nitrosative/oxidative stress and myeloperoxidase (MPO)-as an indicator of inflammation between HFpEF and HFrEF. Twenty-seven patients diagnosed with HFpEF and twenty-two with HFrEF were enrolled in this study. Additionally, forty-one patients were recruited for the control group. An echocardiographic assessment was conducted, followed by the collection of blood samples from all participants. Subsequently, the levels of 3-NT and MPO were quantified using the ELISA method. Comprehensive clinical characteristics and medical histories were obtained. Circulating levels of 3-NT were significantly higher in the HFpEF patients than in the control and the HFrEF groups. Nitrosative/oxidative stress is significantly intensified in HFpEF but not in HFrEF.

COVID-19-related Gastrointestinal Bleeding in a Pediatric Patient With ALL.

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus-2. Patients with hematologic malignancies have been shown to have higher risk of mortality due to COVID-19 than reported in the general adult population. Reports on acute lymphoblastic leukemia and COVID in children are scarce. We present a case of an 11-year-old male patient undergoing treatment for B-cell acute lymphoblastic leukemia with an atypical course of COVID-19. The patient received a positive result of the syndrome coronavirus-2 polymerase chain reaction test performed due to epidemiologic reasons. The chemotherapy was continued since the patient had no clinical signs of COVID-19. The disease started with intensive gastrointestinal bleeding, followed by severe respiratory tract infection over 2 weeks later.

Grade migration and important prognostic factors in a pathology specimen for radical radiotherapy in prostate cancer patients.

The study aimed to evaluate grade migration and prognosis depending on pathologic features in patients with prostate cancer treated with radical external beam radiotherapy. The study included 139 patients with an initial Gleason score of 7 (3+4 or 4+3) i.e., Grade Group 2-3 (GG2-GG3) treated between 2008 and 2013. The clinical outcome was assessed with respect to biochemical control (BC) and biochemical disease-free survival (bDFS). After re-evaluation, the majority of patients (96 patients - 69%) were up-graded from GG2-3. Finally, there were 4 patients (3%) with grade GG1, 12 patients (9%) - GG2, 27 patients (19%) - GG3, 51 patients (37%) - GG4 and 45 patients (32%) - GG5. In 42 patients (30%) a cribriform pattern was observed. Among the analyzed factors only the GGs were important for BC (p = 0.011) and the cribriform pattern was of borderline significance (p = 0.06). The 5-year biochemical control was 100% in GG1-3 and 84% in GG4-5. The 5-year biochemical control was 81% and 93%, if cribriform or no cribriform pattern was detected, respectively. In conclusion, re-evaluation and verification of pathology specimens in accordance with contemporary rules upgraded the Gleason score in the majority of patients. The aggressive behavior of prostate cancer starts to occur from GG 4. Cribriform pattern almost tripled the biochemical failure rate.

Data Integration-Possibilities of Molecular and Clinical Data Fusion on the Example of Thyroid Cancer Diagnostics.

(1) Background: The data from independent gene expression sources may be integrated for the purpose of molecular diagnostics of cancer. So far, multiple approaches were described. Here, we investigated the impacts of different data fusion strategies on classification accuracy and feature selection stability, which allow the costs of diagnostic tests to be reduced. (2) Methods: We used molecular features (gene expression) combined with a feature extracted from the independent clinical data describing a patient's sample. We considered the dependencies between selected features in two data fusion strategies (early fusion and late fusion) compared to classification models based on molecular features only. We compared the best accuracy classification models in terms of the number of features, which is connected to the potential cost reduction of the diagnostic classifier. (3) Results: We show that for thyroid cancer, the extracted clinical feature is correlated with (but not redundant to) the molecular data. The usage of data fusion allows a model to be obtained with similar or even higher classification quality (with a statistically significant accuracy improvement, a p-value below 0.05) and with a reduction in molecular dimensionality of the feature space from 15 to 3-8 (depending on the feature selection method). (4) Conclusions: Both strategies give comparable quality results, but the early fusion method provides better feature selection stability.

Dynamics of Arabic gum aqueous solutions as revealed by NMR relaxometry.

BACKGROUND: The purpose of this article is to study molecular dynamics through nuclear magnetic relaxation (NMR) dispersion of Arabic gum aqueous solutions analysed in terms of two-fraction exchange model. RESULTS: The experiments revealed that relaxation of water molecules was non-monoexponential, which was interpreted in terms of a model describing the magnetization transfer due to exchange of water and polysaccharide protons. The analysis showed that water dynamics decreased slightly with gum content. Polymer-chain dynamics was assigned to regime II of the tube/reptation model. Peculiar temperature dependence of exchange rate was observed in the whole concentration range of Arabic gum solutions. CONCLUSION: NMR relaxation probed in a broad frequency and temperature range allows probing of the molecular dynamics of complex food systems. © 2022 Society of Chemical Industry.

Beliefs and sentiments of parents vaccinating their children - small town perspective in Poland: a preliminary study.

OBJECTIVES: Since 2009 the number of unvaccinated children in Poland has been regularly increasing. The purpose of the study was to learn what parents who decide to vaccinate their children feel and believe about their children's vaccines and in particular to find out how these sentiments and beliefs affect their attitude and decision-making with reference to vaccinations. METHODS: The interviews were conducted during an immunization visit of parents whose children are covered by immunization schedule; 53 parents aged 23 to 48 years took part in the study. Most study participants were high school or university graduates living in rural areas. Children were 1 week to 5 years old. Thematic analysis was used to analyse interview data. RESULTS: Identified factors shaping the parents' positive attitude to vaccination included conviction of necessity of vaccines (effective disease prevention, safety, favourable benefit-to-risk ratio, and concerns about the child). The general anti-vaccination belief was that vaccines are unnecessary. External factors, mainly authority figures and media broadcasts, affect parents' beliefs and decisions. CONCLUSIONS: Various factors affect parents' decision concerning immunization of their children. Both compulsory and recommended vaccines should be provided free-of-charge. Choice overload should be reduced. Paediatricians should address parental vaccine hesitancy.

The effect of depressive-like behavior in pregnant rat dams on the cardiovascular system in their offspring.

Maternal depression during pregnancy affects 18-20% of women and is often associated with comorbidities and adverse health outcomes for the offspring. We have previously reported on neurodevelopmental delays in a rat model of maternal depression during pregnancy; current report presents echocardiographic (ECHO) data derived from the same experiment and focuses on cardiovascular response in the offspring to maternal perinatal depression. Rat dams were exposed to chronic mild stress (CMS) with repeated restraint before pregnancy. Cardiac functions were assessed in the 35-day-old offspring, derived from control (CO, n = 11) and stress-exposed dams (SO, n = 16), using echocardiography (ECHO). The expression of cardiac failure marker - B-type natriuretic peptide (BNP) was measured in the myocardium by RT-PCR. ECHO analysis revealed a significant increase in heart rate (HR) and impairment of left ventricular diastolic function parameters. Importantly, a significant increase in mitral valve flow E wave velocity (MVE) and a decrease of mitral valve deceleration time of E wave (MV DT) were observed in SO. The expression of BNP was significantly higher in SO. These results suggest that maternal depression during pregnancy impacts offspring cardiovascular function, and specifically the diastolic cardiac functions of the left ventricle.

Analysis of the Role of FRMD5 in the Biology of Papillary Thyroid Carcinoma.

BACKGROUND: Thyroid carcinoma (TC) is the most common endocrine system malignancy, and papillary thyroid carcinoma (PTC) accounts for >80% of all TC cases. Nevertheless, PTC pathogenesis is still not fully understood. The aim of the study was to elucidate the role of the FRMD5 protein in the regulation of biological pathways associated with the development of PTC. We imply that the presence of certain genetic aberrations (e.g., BRAF V600E mutation) is associated with the activity of FRMD5. METHODS: The studies were conducted on TPC1 and BCPAP (BRAF V600E) model PTC-derived cells. Transfection with siRNA was used to deplete the expression of FRMD5. The mRNA expression and protein yield were evaluated using RT-qPCR and Western blot techniques. Proliferation, migration, invasiveness, adhesion, spheroid formation, and survival tests were performed. RNA sequencing and phospho-kinase proteome profiling were used to assess signaling pathways associated with the FRMD5 expressional status. RESULTS: The obtained data indicate that the expression of FRMD5 is significantly enhanced in BRAF V600E tumor specimens and cells. It was observed that a drop in intracellular yield of FRMD5 results in significant alternations in the migration, invasiveness, adhesion, and spheroid formation potential of PTC-derived cells. Importantly, significant divergences in the effect of FRMD5 depletion in both BRAF-wt and BRAF-mutated PTC cells were observed. It was also found that knockdown of FRMD5 significantly alters the expression of multidrug resistant genes. CONCLUSIONS: This is the first report highlighting the importance of the FRMD5 protein in the biology of PTCs. The results suggest that the FRMD5 protein can play an important role in controlling the metastatic potential and multidrug resistance of thyroid tumor cells.

Impact of the Tumor Microenvironment on the Gene Expression Profile in Papillary Thyroid Cancer.

Transcriptome of papillary thyroid cancer (PTC) is well characterized and correlates with some prognostic and genotypic factors, but data addressing the interaction between PTC and tumor microenvironment (TME) are scarce. Therefore, in the present study, we aimed to assess the impact of TME on gene expression profile in PTC. We evaluated the gene expression profile in PTC and normal thyroid cells isolated by laser capture microdissection and in whole tissue slides corresponding to the entire tumor. We included 26 microdissected samples for gene expression analysis (HG-U133 PLUS 2.0, Affymetrix, currently Thermo Fisher Scientific USA): 15 PTC samples, 11 samples of normal thyrocytes, and 30 whole slides (15 PTC and 15 normal thyroid). Transcripts were divided into three groups: differentially expressed both in microdissected and whole slides, transcripts differently expressed in microdissected samples and not changed in whole slides, and transcripts differentially expressed in whole slides and not changed in microdissected samples. Eleven genes were selected for validation in an independent set of samples; among them, four genes differentiated only microdissected PTC and normal cells. Two genes (PTCSC and CTGF) were confirmed. One gene (FOS) was not confirmed by the validation, whereas EGR1 was also significant in whole slide analysis. The other seven genes (TFF3, FN1, MPPED2, MET, KCNJ2, TACSTD2, and GALE) showed differentiated expression in microdissected thyrocytes and in whole tumor slides. Most of identified genes were related to the tumor-microenvironment interaction and confirmed the crosstalk between TME and cancer cells.

DASH diet decreases CXCL4 plasma concentration in patients diagnosed with coronary atherosclerotic lesions.

BACKGROUND AND AIMS: Aim of this study involved assessment of the intensive intervention concerning lifestyle based on the DASH diet model on plasma concentration of CXCL4 chemokine among patients with coronary atherosclerosis. METHODS AND RESULTS: The Dietary Intervention to Stop Coronary Atherosclerosis in Computed Tomography Study randomized patients with stable CAD to an interventional group (n = 41), where DASH diet was implemented and the control group (n = 40) without dietary intervention. Dietary counselling was provided to DASH group during all 6 control visits within 6 months of observation. During the study, body weight and body composition were controlled using the bioimpedance method. CXCL4 concentration was determined with the use of ELISA test. Within the DASH group, a significant decrease in body weight, a decrease in high sensitivity C-reactive protein concentration (-0.32 ± 2.8 mg/l; p < 0.05), as well as a decrease in CXCL4 concentration (-3.35 ± 3.4 ng/ml; p < 0.0001) were observed. Occurring changes were not statistically significant within the control group. CONCLUSIONS: DASH diet lessens CXCL4 concentration among patients with a stable CAD, however, further research is necessary in order to confirm aforementioned results and evaluate the impact on atherosclerotic plaque. THIS TRIAL WAS REGISTERED AT: www.clinicaltrials.gov as NCT02571803.

FGF-1 modulates pancreatic ß-cell functions/metabolism: An in vitro study.

Fibroblast growth factor 1 (FGF-1), also known as acidic fibroblast growth factor (aFGF), is a growth factor and signaling protein encoded by the Fgf1 gene. Previous studies have shown that FGF-1 may also participate in the regulation of glucose metabolism, both in healthy organisms and in pathological conditions such as diabetes. Because insulin the main regulator of glucose metabolism is secreted from pancreatic beta cells, we investigated whether FGF-1 directly affects the secretion of this hormone and regulates the metabolism of beta cells and isolated pancreatic islets. By using insulin-producing INS-1E cells and isolated pancreatic islets, we investigated the effect of FGF-1 on cell proliferation, viability, apoptosis, and insulin expression and secretion. Our study showed that FGF1 and fibroblast growth factor receptors (FgfRs: FgfR1, FgfR2, FgfR3, and FgfR4) are present on mRNA level in INS-1E cells and isolated rat pancreatic islets. We also proved that FGF1 stimulates the proliferation of INS-1E beta cells and enhances the viability of these cells and that of isolated pancreatic islet cells, and that ERK1/2 kinase is involved in the regulation of INS-1E cell proliferation. Moreover, we found that FGF1 can stimulate insulin secretion from both INS-1E cells and isolated rat pancreatic islets. Thus, the FGF1 peptide increases cell survival and decreases cell death. The obtained results indicate that FGF1 may play a role in controlling the physiology and metabolism of pancreatic beta cells as well as glycemia.

Differences in Gene Expression Profile of Primary Tumors in Metastatic and Non-Metastatic Papillary Thyroid Carcinoma-Do They Exist?

Molecular mechanisms of distant metastases (M1) in papillary thyroid cancer (PTC) are poorly understood. We attempted to analyze the gene expression profile in PTC primary tumors to seek the genes associated with M1 status and characterize their molecular function. One hundred and twenty-three patients, including 36 M1 cases, were subjected to transcriptome oligonucleotide microarray analyses: (set A-U133, set B-HG 1.0 ST) at transcript and gene group level (limma, gene set enrichment analysis (GSEA)). An additional independent set of 63 PTCs, including 9 M1 cases, was used to validate results by qPCR. The analysis on dataset A detected eleven transcripts showing significant differences in expression between metastatic and non-metastatic PTC. These genes were validated on microarray dataset B. The differential expression was positively confirmed for only two genes: IGFBP3, (most significant) and ECM1. However, when analyzed on an independent dataset by qPCR, the IGFBP3 gene showed no differences in expression. Gene group analysis showed differences mainly among immune-related transcripts, indicating the potential influence of tumor immune infiltration or signal within the primary tumor. The differences in gene expression profile between metastatic and non-metastatic PTC, if they exist, are subtle and potentially detectable only in large datasets.

Novel TG-FGFR1 and TRIM33-NTRK1 transcript fusions in papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC) is most common among all thyroid cancers. Multiple genomic alterations occur in PTC, and gene rearrangements are one of them. Here we screened 14 tumors for novel fusion transcripts by RNA-Seq. Two samples harboring RET/PTC1 and RET/PTC3 rearrangements were positive controls whereas the remaining ones were negative regarding the common PTC alterations. We used Sanger sequencing to validate potential fusions. We detected 2 novel potentially oncogenic transcript fusions: TG-FGFR1 and TRIM33-NTRK1. We detected 4 novel fusion transcripts of unknown significance accompanying the TRIM33-NTRK1 fusion: ZSWIM5-TP53BP2, TAF4B-WDR1, ABI2-MTA3, and ARID1B-PSMA1. Apart from confirming the presence of RET/PTC1 and RET/PTC3 in positive control samples, we also detected known oncogenic fusion transcripts in remaining samples: TFG-NTRK1, ETV6-NTRK3, MKRN1-BRAF, EML4-ALK, and novel isoform of CCDC6-RET.

Cardioprotective Mechanisms of Cocoa.

Cardiovascular diseases are the main cause of deaths in highly developed countries. Dietetic interventions that involve recommendations for consumption of products with a confirmed health-improving action are an important aspect of prevention of cardiovascular diseases. Cocoa is an alimentary product with significant cardioprotective potential due to its high content of bioactive compounds. The aim of the present study was to review the most recent literature concerning the effectiveness and mechanisms of action of compounds contained in cocoa with regard to selected cardiovascular risk factors and cardiometabolic markers. Study results indicate that cocoa consumption, especially in the form of dark chocolate with high flavonoid content, may be a good strategy to diminish cardiovascular risk due to its beneficial effect on platelet aggregation, decreasing blood pressure, diminishing dyslipidemia, and decreasing blood plasma glucose concentration. Many studies have shown that cocoa-derived flavonoids have antioxidant and anti-inflammatory activity and also play a significant role in preventing insulin resistance. However, in order to completely confirm the potential cardiovascular benefits, it is necessary to conduct larger and longer studies, also with regard to potential dangers associated with long-term consumption of large amounts of flavonoids and determination of a safe and effective dose. Key teaching points Cocoa consumption may be a good strategy in diminishing cardiovascular risk. Beneficial effects on platelet aggregation, blood pressure, dyslipidemia, glycemia, as well as antioxidant and anti-inflammatory activity are observed. There is a need to conduct larger and longer studies to determine a safe and effective dose of cocoa flavonoids.

Efficacy and safety of BRAF inhibitors and anti-CTLA4 antibody in melanoma patients-real-world data.

PURPOSE: In the management of melanoma, BRAF inhibitors yield fast disease control; however, the duration of response does not last very long. Ipilimumab-an anti-CTLA4 antibody on the other hand-provides longer-lasting results of treatment but achieves less favorable responses. The aim of this study was to assess the efficacy and safety of novel drugs for advanced melanoma in daily routine practice. METHODS: A retrospective observational study was conducted on all Polish patients (1170 patients), diagnosed with advanced metastatic melanoma, treated with the following drugs: vemurafenib, dabrafenib, and ipilimumab. The antitumor efficacy of these agents was retrospectively assessed by Response Evaluation Criteria in Solid Tumors in the case of BRAF inhibitors and by Immune-Related Response Criteria in the case of ipilimumab therapy. Adverse events were assessed in relation to the morphologic parameters of blood, nephrotoxicity, and hepatotoxicity. RESULTS: The overall response to treatment with BRAF inhibitors (vemurafenib and dabrafenib) was similar with a slightly better outcome in the group treated with vemurafenib. Compared to clinical trials, the objective response rate was slightly worse for both BRAF inhibitors (30% and 42% for dabrafenib and vemurafenib, respectively), as well as the immune-related response for ipilimumab (1%). There was no significant difference in patient's response rates regardless of what lines of treatment (first, second, or next) vemurafenib was applied in. A few severe adverse events (mostly anemia and hyperbilirubinemia) were observed during treatment. CONCLUSIONS: The lack of evidence in responses observed regardless of what line of treatment vemurafenib was applied in suggests there is no clinical reason for restricting BRAF inhibitors to only the first line of therapy. Our study confirms that novel agents brought about a major advancement in the management of melanoma. In line with literature, BRAF inhibitors and ipilimumab significantly improved the antitumor response rate with manageable adverse events.

Adherence to guidelines for pharmacological treatment of young adults with myocardial infarction in Poland: Data from Polish Registry of Acute Coronary Syndromes (PL-ACS).

WHAT IS KNOWN AND OBJECTIVE: Myocardial infarction (MI) in young adults accounts for up to 10% of all cases. Regarding life expectancy and professional activity, it is extremely important to restore and maintain young patients' full performance. Therefore, secondary prevention is especially vital in this group of patients. The paper focuses on the analysis of pharmacotherapy in young MI patients in Poland, assessing disparities between the European Society of Cardiology guidelines and clinical practice, and regional differences among the provinces. METHODS: The analysis was conducted using the data from a nationwide, observational, multicentre, prospective study-the Polish Registry of Acute Coronary Syndromes (PL-ACS). The data were collected from patients ≤45 years old with MI who were hospitalized in the period 2010-2014. RESULTS AND DISCUSSION: A retrospective study included 6367 MI patients. They constituted 3.9% of all the patients with MI in Poland. Despite the fact that during hospitalization regional differences were observed in case of acetylsalicylic acid (range 70.3%-93.8%), ß-blockers (range 50.0%-79.6%), statins (range 53.4%-85.7%) and angiotensin-converting enzyme inhibitors (range 46.9%-75.0%), the majority of patients received the drugs according to the guidelines. Regional differences found at discharge also regarded those medications, but the range of observed variations was smaller. On average, three-quarter of patients received guideline-recommended medications. Still, in some provinces, almost a quarter of patients were administered those medications only at discharge. WHAT IS NEW AND CONCLUSION: In the study population, there were significant differences between the provinces regarding pharmacotherapy during hospitalization, which concerned major groups of medications. However, pharmacotherapy indicated at discharge revealed fewer regional differences and adhered to guideline recommendations to a greater extent. Nevertheless, there is still some room for improvement, especially with regard to pharmacotherapy during hospitalization.

Heterogeneity of Thyroid Cancer.

There are 5 main histological types of thyroid cancers (TCs): papillary, follicular (also known as differentiated), poorly differentiated, anaplastic (the most aggressive form), and medullary TC, and only the latter arises from thyroid C cells. These different forms of TCs show significant variability, both among and within tumours. This great variation is particularly notable among the first 4 types, which all originate from thyroid follicular cells. Importantly, this heterogeneity is not limited to histopathological diversity only but is also manifested as variation in several genetic and/or epigenetic alterations, the numbers of interactions between the tumour and surrounding microenvironment, and interpatient differences, for example. All these factors contribute to the great complexity in the development of a tumour from cancer cells. In the present review, we summarise the knowledge accumulated about the heterogeneity of TCs. Further research in this direction should help to gain a better understanding of the underlying mechanisms contributing to the development and diversity of TCs, paving the way toward more effective treatment strategies.