PARP-1, EpCAM, and FRα as potential targets for intraoperative detection and delineation of endometriosis: a quantitative tissue expression analysis.

BACKGROUND: Endometriosis is a gynecological disease characterized by the presence of endometrial tissue in abnormal locations, leading to severe symptoms, inflammation, pain, organ dysfunction, and infertility. Surgical removal of endometriosis lesions is crucial for improving pain and fertility outcomes, with the goal of complete lesion removal. This study aimed to analyze the location and expression patterns of poly (ADP-ribose) polymerase 1 (PARP-1), epithelial cell adhesion molecule (EpCAM), and folate receptor alpha (FRα) in endometriosis lesions and evaluate their potential for targeted imaging. METHODS: Gene expression analysis was performed using the Turku endometriosis database (EndometDB). By immunohistochemistry, we investigated the presence and distribution of PARP-1, EpCAM, and FRα in endometriosis foci and adjacent tissue. We also applied an ad hoc platform for the analysis of images to perform a quantitative immunolocalization analysis. Double immunofluorescence analysis was carried out for PARP-1 and EpCAM, as well as for PARP-1 and FRα, to explore the expression of these combined markers within endometriosis foci and their potential simultaneous utilization in surgical treatment. RESULTS: Gene expression analysis revealed that PARP-1, EpCAM, and FOLR1 (FRα gene) are more highly expressed in endometriotic lesions than in the peritoneum, which served as the control tissue. The results of the immunohistochemical study revealed a significant increase in the expression levels of all three biomarkers inside the endometriosis foci compared to the adjacent tissues. Additionally, the double immunofluorescence analysis consistently demonstrated the presence of PARP-1 in the nucleus and the expression of EpCAM and FRα in the cell membrane and cytoplasm. CONCLUSION: Overall, these three markers demonstrate significant potential for effective imaging of endometriosis. In particular, the results emphasize the importance of PARP-1 expression as a possible indicator for distinguishing endometriotic lesions from adjacent tissue. PARP-1, as a potential biomarker for endometriosis, offers promising avenues for further investigation in terms of both pathophysiology and diagnostic-therapeutic approaches.

The role of HOTAIR in the modulation of resistance to anticancer therapy.

Leading anti-tumour therapeutic strategies typically involve surgery and radiotherapy for locally advanced (non-metastatic) cancers, while hormone therapy, chemotherapy, and molecular targeted therapy are the current treatment options for metastatic cancer. Despite the initially high sensitivity rate to anticancer therapies, a large number of patients develop resistance, leading to a poor prognosis. The mechanisms related to drug resistance are highly complex, and long non-coding RNAs appear to play a crucial role in these processes. Among these, the lncRNA homeobox transcript antisense intergenic RNA (HOTAIR), widely implicated in cancer initiation and progression, likewise plays a significant role in anticancer drug resistance. It can modulate cell activities such as proliferation, apoptosis, hypoxia, autophagy, as well as epithelial-mesenchymal transition, thereby contributing to the development of resistant tumour cells. In this manuscript, we describe different mechanisms of antitumor drug resistance in which HOTAIR is involved and suggest its potential as a therapeutic predictive biomarker for the management of cancer patients.

Transoral surgery with Thunderbeat© for hemangioma of the tongue base: A novel procedure. Case report.

INTRODUCTION: Hemangiomas are the most common benign tumors of the head-neck region in children and mainly affect the face, oral mucosa, lips, and tongue. The base of tongue is an extremely rare site of involvement. The incidence is higher in women and occur more frequently in infants and childhood. PRESENTATION OF CASE: We present a rare case of cavernous hemangioma of the base of tongue in a 70-year-old male patient surgically removed by Transoral Ultrasonic Surgery (TOUSS). 1-year follow up didn't show sign of recurrence. DISCUSSION: Hemangiomas are benign proliferations of endothelial cells common in the head and neck. The etiology is uncertain: an imbalance in angiogenesis related to substances such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (BFGF) with uncontrolled proliferation of vascular elements is proposed. It can be asymptomatic or, when affecting the tongue, lead to difficulty swallowing, pain, bleeding and dyspnea. CONCLUSION: This case report aims to stress that hemangioma should be considered in differential diagnosis in case of richly vascularized tongue base lesion, also in adult population. It would like to highlight the role of transoral ultrasonic surgery (TOUSS), which is able to achieve the same advantages as TORS with lower costs and shorter learning curve.

A conservative treatment for eosinophilic cystitis.

Introduction: Eosinophilic cystitis is a rare condition which causes common symptoms and may mimic other conditions. Eosinophilic cystitis has several causes such as hypereosinophilic syndrome, inflammatory diseases, neoplasia, parasites or fungal infection, IgE-related diseases, Drug Reaction and Eosinophilia and Systemic Symptoms (DRESS) syndrome, or Churg-Strauss syndrome. Therefore, differential diagnosis is difficult. Case presentation: We report the case of a middle-aged man affected by eosinophilic cystitis with persistent hematuria and other peculiar symptoms that may be brought back to hypereosinophilic crisis. Conclusion: Conservative approach is preferred, avoiding radical cystectomy rather than corticosteroid, antihistaminic and second line therapy. Hyperbaric therapy is an innovative approach for severe relapsing gross hematuria without specific literature and should be studied for further indications.

The Inflammatory Feed-Forward Loop Triggered by the Complement Component C3 as a Potential Target in Endometriosis.

The complement system is a major component of humoral innate immunity, acting as a first line of defense against microbes via opsonization and lysis of pathogens. However, novel roles of the complement system in inflammatory and immunological processes, including in cancer, are emerging. Endometriosis (EM), a benign disease characterized by ectopic endometrial implants, shows certain unique features of cancer, such as the capacity to invade surrounding tissues, and in severe cases, metastatic properties. A defective immune surveillance against autologous tissue deposited in the peritoneal cavity allows immune escape for endometriotic lesions. There is evidence that the glandular epithelial cells found in endometriotic implants produce and secrete the complement component C3. Here, we show, using immunofluorescence and RT-qPCR, the presence of locally synthesized C3 in the ectopic endometriotic tissue, but not in the eutopic tissue. We generated a murine model of EM via injection of minced uterine tissue from a donor mouse into the peritoneum of recipient mice. The wild type mice showed greater amount of cyst formation in the peritoneum compared to C3 knock-out mice. Peritoneal washings from the wild type mice with EM showed more degranulated mast cells compared to C3 knock-out mice, consistent with higher C3a levels in the peritoneal fluid of EM patients. We provide evidence that C3a participates in an auto-amplifying loop leading to mast cell infiltration and activation, which is pathogenic in EM. Thus, C3 can be considered a marker of EM and its local synthesis can promote the engraftment of the endometriotic cysts.

The Ferroxidase Hephaestin in Lung Cancer: Pathological Significance and Prognostic Value.

Hephaestin (HEPH) belongs to a group of exocytoplasmic ferroxidases which contribute to cellular iron homeostasis by favouring its export. Down-regulation of HEPH expression, possibly by stimulating cell proliferation due to an increase in iron availability, has shown to correlate with poor survival in breast cancer. The lung is particularly sensitive to iron-induced oxidative stress, given the high oxygen tension present, however, HEPH distribution in lung cancer and its influence on prognosis have not been investigated yet. In this study we explored the prognostic value of HEPH and its expression pattern in the most prevalent histotypes of lung cancers, namely lung adenocarcinoma and lung squamous cell carcinoma. In silico analyses, based on UALCAN, Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan-Meier plotter bioinformatics, revealed a significant correlation between higher levels of HEPH expression and favorable prognosis, in both cancer histotypes. Moreover, TIMER web platform showed a statistically significant association between HEPH expression and cell elements belonging to the tumor microenvironment identified as endothelial cells and a subpopulation of cancer-associated fibroblasts, further confirmed by double immunohistochemical labeling with cell type specific markers. Taken together, these data shed a light on the complex mechanisms of local iron handling lung cancer can exploit to support tumorigenesis.

TTF-1/p63-Positive Poorly Differentiated NSCLC: A Histogenetic Hypothesis from the Basal Reserve Cell of the Terminal Respiratory Unit.

TTF-1 is expressed in the alveolar epithelium and in the basal cells of distal terminal bronchioles. It is considered the most sensitive and specific marker to define the adenocarcinoma arising from the terminal respiratory unit (TRU). TTF-1, CK7, CK5/6, p63 and p40 are useful for typifying the majority of non-small-cell lung cancers, with TTF and CK7 being typically expressed in adenocarcinomas and the latter three being expressed in squamous cell carcinoma. As tumors with coexpression of both TTF-1 and p63 in the same cells are rare, we describe different cases that coexpress them, suggesting a histogenetic hypothesis of their origin. We report 10 cases of poorly differentiated non-small-cell lung carcinoma (PD-NSCLC). Immunohistochemistry was performed by using TTF-1, p63, p40 (ΔNp63), CK5/6 and CK7. EGFR and BRAF gene mutational analysis was performed by using real-time PCR. All the cases showed coexpression of p63 and TTF-1. Six of them showing CK7+ and CK5/6- immunostaining were diagnosed as "TTF-1+ p63+ adenocarcinoma". The other cases of PD-NSCLC, despite the positivity for CK5/6, were diagnosed as "adenocarcinoma, solid variant", in keeping with the presence of TTF-1 expression and p40 negativity. A "wild type" genotype of EGFR was evidenced in all cases. TTF1 stained positively the alveolar epithelium and the basal reserve cells of TRU, with the latter also being positive for p63. The coexpression of p63 and TTF-1 could suggest the origin from the basal reserve cells of TRU and represent the capability to differentiate towards different histogenetic lines. More aggressive clinical and morphological features could characterize these "basal-type tumors" like those in the better known "basal-like" cancer of the breast.

Fever and dyspnoea in a tracheostomised patient.

Pneumonia of unknown origin in tracheostomised patient https://bit.ly/3hZHBA0.

Prognostic Value of Complement Properdin in Cancer.

The complement system is readily triggered by the presence of damage-associated molecular patterns on the surface of tumor cells. The complement alternative pathway provides rapid amplification of the molecular stress signal, leading to complement cascade activation to deal with pathogens or malignant cells. Properdin is the only known positive regulator of the alternative pathway. In addition, properdin promotes the phagocytic uptake of apoptotic T cells by macrophages and dendritic cells without activating the complement system, thus, establishing its ability to recognize "altered-self". Dysregulation of properdin has been implicated in substantial tissue damage in the host, and in some cases, chronic unresolved inflammation. A corollary of this may be the development of cancer. Hence, to establish a correlation between properdin presence/levels in normal and cancer tissues, we performed bioinformatics analysis, using Oncomine and UALCAN. Survival analyses were performed using UALCAN and PROGgeneV2 to assess if properdin can serve as a potential prognostic marker for human lung adenocarcinoma (LUAD), liver hepatocellular carcinoma (LIHC), cervical squamous cell carcinoma (CESC), and pancreatic adenocarcinoma (PAAD). We also analyzed levels of tumor-infiltrating immune cells using TIMER, a tool for characterizing immune cell composition in cancers. We found that in LUAD and LIHC, there was a lower expression of properdin in the tumors compared to normal tissues, while no significant difference was observed in CESC and PAAD. Survival analysis demonstrated a positive association between properdin mRNA expression and overall survival in all 4 types of cancers. TIMER analysis revealed that properdin expression correlated negatively with tumor purity and positively with levels of infiltrating B cells, cytotoxic CD8+ T cells, CD4+ helper T cells, macrophages, neutrophils and dendritic cells in LUAD, CESC and PAAD, and with levels of B cells, CD8+ T cells and dendritic cells in LIHC. Immunohistochemical analysis revealed that infiltrating immune cells were the most likely source of properdin in the tumor microenvironment. Thus, complement protein properdin shows promise as a prognostic marker in cancer and warrants further study.

Prognostic Implications of the Complement Protein C1q in Gliomas.

The contribution of the complement system in the pathophysiology of brain cancers has been recently considered in light of its well-known involvement in carcinogenesis. Complement system represents an important component of the inflammatory response, which acts as a functional bridge between the innate and adaptive immune response. C1q, the first recognition subcomponent of the complement classical pathway, has recently been shown to be involved in a range of pathophysiological functions that are not dependent on complement activation. C1q is expressed in the microenvironment of various types of human tumors, including melanoma, prostate, mesothelioma, and ovarian cancers, where it can exert a protective or a harmful effect on cancer progression. Despite local synthesis of C1q in the central nervous system, the involvement of C1q in glioma pathogenesis has been poorly investigated. We, therefore, performed a bioinformatics analysis, using Oncomine dataset and UALCAN database in order to assess whether the expression of the genes encoding for the three chains of C1q (C1qA, C1qB, and C1qC) could serve as a potential prognostic marker for gliomas. The obtained results were then validated using an independent glioma cohort from the Chinese Glioma Genome Atlas datasets. Our bioinformatics analysis, coupled with immunohistochemistry and fluorescence microscopy, appears to suggest a positive correlation between higher levels of C1q expression and unfavorable prognosis in a diverse grade of gliomas.

Seeding nerve sutures with minced nerve-graft (MINE-G): a simple method to improve nerve regeneration in rats.

BACKGROUND: The aim of this study was to assess the effect of seeding the distal nerve suture with nerve fragments in rats. METHODS: On 20 rats, a 15 mm sciatic nerve defect was reconstructed with a nerve autograft. In the Study Group (10 rats), a minced 1 mm nerve segment was seeded around the nerve suture. In the Control Group (10 rats), a nerve graft alone was used. At 4 and 12 weeks, a walking track analysis with open field test (WTA), hystomorphometry (number of myelinated fibers (n), fiber density (FD) and fiber area (FA) and soleus and gastrocnemius muscle weight ratios (MWR) were evaluated. The Student t-test was used for statistical analysis. RESULTS: At 4 and 12 weeks the Study Group had a significantly higher n and FD (p = .043 and .033). The SMWR was significantly higher in the Study Group at 12 weeks (p = .0207). CONCLUSIONS: Seeding the distal nerve suture with nerve fragments increases the number of myelinated fibers, the FD and the SMWR. The technique seems promising and deserves further investigation to clarify the mechanisms involved and its functional effects.

Cystic adenomyosis spreading into subserosal-peduncolated myoma: How to explain it?

INTRODUCTION: Cystic adenomyosis is a rare variant of adenomyosis characterized by well- circumscribed cavitated endometrial gland and stroma located within the myometrium. The cysts usually measure≥1cm in diameter, contain a "chocolate-colored" fluid and do not open into the overlaying endometrium. CASE PRESENTATION: We present a case of a peduncolated-subserosal cystic adenomyoma, namely cystic adenomyosis, correlated with pelvic MR imaging, laparoscopic surgery technique and histopathology findings. CONCLUSIONS: In this case, the peculiar growth pattern of cystic adenomyosis in a myoma represents a singular condition rarely reported in the medical literature. We therefore support the pathogenetic theory that the disease might have been caused by direct proliferation of endometrial cells within a peduncolated- subserosal myoma.

Intraperitoneal coated polypropylene hernia meshes: the dark side of the moon.

BACKGROUND: To date, the use of meshes in repairing abdominal wall defects has brought many advantages, especially in terms of recurrence prevention, but it is not exempt from complications, such as chronic pain, entero-cutaneous fistulas and intestinal obstruction. Here we report a case of intestinal obstruction in a patient with a large umbilical hernia treated laparoscopically by means of a composite polypropylene mesh, six year before. CASE REPORT: A 49-year-old man came to our care with a 3-day history of central and right lower abdominal quadrant pain and a clinical picture of intestinal obstruction. Six years before the patient underwent a laparoscopic intervention to repair his umbilical hernia, with the positioning of a polypropylene coated mesh. Abdominal ultrasonography (US) confirmed the obstruction and demonstrated adhesions between an intestinal loop and the mesh. Intraoperatively, obstruction was confirmed and an intestinal segment had to be resected. CONCLUSIONS: Small bowel obstruction is an uncommon but possible late complication after laparoscopic hernia repair with coated polypropylene mesh.

Changes in immunohistochemical levels and subcellular localization after therapy and correlation and colocalization with CD68 suggest a pathogenetic role of Hsp60 in ulcerative colitis.

In an earlier work, the role of heat shock protein (Hsp60) in the pathogenesis of ulcerative colitis (UC) was suggested by its significant increase in the pathological mucosa parallel with an increase in inflammatory cells. More data in this direction are reported in this work. We analyzed by immunohistochemistry biopsies of colon tissue from 2 groups of patients with UC and treated with either 5-aminosalicylic acid (5-ASA) alone or in combination with a probiotic. We looked for inflammatory markers and Hsp60. Both the treatments were effective in reducing symptoms but the group treated with both 5-ASA and probiotics showed better clinical results. Amelioration of symptoms was associated with reduction of both inflammation and Hsp60, a reduction that was most marked in the group treated with 5-ASA and probiotics. The levels of Hsp60 positively correlated with those of CD68-positive cells, and double immunofluorescence showed a high index of colocalization of the chaperonin and CD68 in lamina propria. Immunoelectron microscopy showed that Hsp60-classically a mitochondrial protein-was abundantly also present in cytosol in biopsies taken at the time of diagnosis, but not after the treatment. Our data suggest that Hsp60 is an active player in pathogenesis of UC and it can be hypothesized that the chaperonin is responsible, at least in part, for initiation and maintenance of disease.

BRAF(V600E) mutation influences hypoxia-inducible factor-1alpha expression levels in papillary thyroid cancer.

Hypoxia-inducible factor-1alpha is found frequently overexpressed in solid tumors cells, exerting an important role in angiogenesis, glucose metabolism, cell proliferation, survival and invasion. In thyroid carcinomas, hypoxia-inducible factor-1alpha expression was found increased in differentiated, poorly differentiated, medullary and anaplastic variants. Hypoxia represents the principal stimulus responsible for hypoxia-inducible factor-1alpha induction. Other nonhypoxic stimuli increase hypoxia-inducible factor-1alpha synthesis through the activation of phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways in a cell-type-specific manner. We have previously shown the role of BRAF(V600E) mutation in papillary thyroid cancer cells as a factor that facilitates tumor cell growth and progression. In this study, we tested the hypothesis that BRAF(V600E) mutation influences hypoxia-inducible factor-1alpha expression in papillary thyroid carcinoma cells. We analyzed 27 papillary thyroid carcinomas, 13 of which presented BRAF(V600E) mutation. In tumor tissues, immunoreactivity for hypoxia-inducible factor-1alpha was detected in the majority of analyzed BRAF(V600E) mutated cases. Transcriptional analyses revealed elevated hypoxia-inducible factor-1alpha levels with significant differences between wild-type and mutated group. A BRAF wild-type papillary thyroid carcinoma cell line and a BRAF(V600E) mutated papillary thyroid carcinoma cell line were selected to study the effects of BRAF mutation on hypoxia-inducible factor-1alpha expression in vitro. Knockdown of mutant BRAF(V600E) or both the wild type and the BRAF(V600E) by RNA interference induced a significant reduction of hypoxia-inducible factor-1alpha expression at mRNA and protein levels. Pharmacological inhibition of BRAF significantly reduces hypoxia-inducible factor-1alpha expression levels in papillary thyroid carcinoma cell line harboring BRAF(V600E) mutation. Our results suggest that hypoxia-inducible factor-1alpha is expressed in papillary thyroid carcinomas and is regulated not only by hypoxia but also by BRAF(V600E)-mediated signaling pathway.

Hsp60 and Hsp10 increase in colon mucosa of Crohn's disease and ulcerative colitis.

The purpose of this work was to determine in colon mucosa of Crohn's disease (CD) and ulcerative colitis (UC) in relapse: a) the levels of the chaperonins Hsp60 and Hsp10; b) the quantity of inflammatory cells; and c) if the levels of chaperonins parallel those of inflammation cells. Twenty cases of CD and UC and twenty normal controls (NC) were studied using immunohistochemistry, Western blotting and immunofluorescence. Immunohistochemically, Hsp60 and Hsp10 were increased in both inflammatory bowel diseases (IBD) compared to NC. These results were confirmed by Western blotting. Hsp60 and Hsp10 occurred in the cytoplasm of epithelial cells in CD and UC but not in NC. Hsp60 and Hsp10 co-localised to epithelial cells of mucosal glands but not always in connective tissue cells of lamina propria, where only Hsp60 or, less often, Hsp10 was found. Cells typical of inflammation were significantly more abundant in CD and UC than in NC. Since chaperonins are key factors in the activation of the immune system leading to inflammation, we propose that they play a central role in the pathogenesis of the two diseases, which, consequently, ought to be studied as chaperonopathies.

Differing expression of metalloprotease and of adhesion molecules in signet-ring cell and intestinal colorectal carcinoma.

BACKGROUND: Pure signet-ring cell colorectal carcinoma (SRCC) is an infrequent and highly malignant histological variant of colorectal cancer (CRC), while it is present as a histological component in colorectal carcinomas more frequently. MATERIALS AND METHODS: The aim of this work was to widen the knowledge of the biological factors involved in the pathogenesis and aggressiveness of SRCC by the identification and evaluation of possible molecular abnormalities. By means of immunohistochemistry the expression of the proteolytic degradation enzyme matrix metalloprotease (MMP)-1, that is a collagenase specifically degrading collagens I, II, III and of the adhesion proteins E-cadherin, beta-catenin and fibronectin which are usually involved in the carcinogenesis of conventional colorectal tumours was investigated. RESULTS: SRCCs showed a significantly greater MMP-1 expression compared to the ordinary intestinal colorectal cancer (ICRC) and a significantly reduced E-cadherin, beta-catenin and fibronectin expression. CONCLUSION: The biological aggressiveness and strong metastatic behaviour of SRCC could be due to high MMP-1 and low expression of the adhesion molecules.

Oxidative stress induces myeloperoxidase expression in endocardial endothelial cells from patients with chronic heart failure.

Increased oxidative stress has been implicated in the pathogenesis of a number of cardiovascular diseases. Recent findings suggest that myeloperoxidase (MPO) may play a key role in the initiation and maintenance of chronic heart failure (CHF) by contributing to the depletion of the intracellular reservoir of nitric oxide (NO). NO consumption through MPO activity may lead to protein chlorination or nitration, leading to tissue damage. Primary cultures of human endocardial endothelial cells (EEC) obtained at heart transplantation of patients with CHF and human umbilical vein endothelial cells (HUVEC) were subjected to oxidative stress by incubation with hydrogen peroxide at non lethal (60 microM) dose for different exposure times (3 and 6 h). Treated and control cells were tested by immunohistochemistry and RT-PCR for MPO and 3-chlorotyrosine expression. Both endothelial cell types expressed myeloperoxidase following oxidative stress, with higher levels in EEC. Moreover, 3-chlorotyrosine accumulation in treated cells alone indicated the presence of MPO-derived hypochlorous acid. Immunohistochemistry on sections from post-infarcted heart confirmed in vivo the endothelial positivity to MPO, 3-chlorotyrosine and, to a minor extent, nitrotyrosine. Immunohistochemical observations were confirmed by detection of MPO mRNA in both stimulated EEC and HUVEC cells. This study demonstrates for the first time that EEC can express MPO after oxidative stress, both in vitro and in vivo, followed by accumulation of 3-chlorotyrosine, an end product of oxidative stress. Deregulation of endothelial functions may contribute to the development of a number of cardiovascular diseases, including CHF. The results also highlight the notion that endothelium is not only a target but also a key player in oxidative-driven cardiovascular stress.

Increased expression of transketolase-like-1 in papillary thyroid carcinomas smaller than 1.5 cm in diameter is associated with lymph-node metastases.

BACKGROUND: Patients with small papillary thyroid carcinoma (PTC) may have a high incidence of regional lymph-node (LN) metastases at presentation, and these are considered to be an independent risk factor for tumor recurrence. A mutated transketolase transcript (TKTL1) has been found up-regulated in different human malignancies, and strong TKTL1 protein expression has been associated with aggressiveness and poor patient survival in several epithelial cancers. METHODS: TKTL1 protein expression was analyzed in 256 consecutive cases of PTCs

Clonal diversity in carcinomas: its implications for tumour progression and the contribution made to it by epithelial-mesenchymal transitions.

The progression of tumours to malignancy is commonly considered to arise through lineal evolution, a process in which mutations conferring pro-oncogenic cellular phenotypes are acquired by a succession of ever-more dominant clones. However, this model is at odds with the persistent polyclonality observed in many cancers. We propose that an alternative mechanism for tumour progression, called interclonal cooperativity, is likely to play a role at stages of tumour progression when mutations cause microenvironmental changes, such as occur with epithelial-mesenchymal transitions (EMTs). Interclonal cooperativity occurs when cancer cell-cancer cell interactions produce an emergent malignant phenotype from individually non-malignant clones. In interclonal cooperativity, the oncogenic mutations occur in different clones within the tumour that complement each other and cooperate in order to drive progression. This reconciles the accepted genetic and evolutionary basis of cancers with the observed polyclonality in tumours. Here, we provide a conceptual basis for examining the importance of cancer cell-cancer cell interactions to the behaviour of tumours and propose specific mechanisms by which clonal diversity in tumours, including that provided by EMTs, can drive the progression of tumours to malignancy.