Epistemology of the Origin of Cancer II: Fibroblasts Are the First Cells to Undergo Neoplastic Transformation.

BACKGROUND/AIMS: Many questions in cancer biology remain unanswered. Perhaps the most important issues remaining to be addressed focus on the molecular basis of carcinogenesis. Today's cancer focus lies on genetics and gene expression, which is unlikely to explain the true cause of most cancers or lead to a cure. METHODS: Earlier, we provided a plausible mechanism for this process, specifically, that most cancers develop in response to pathogenic stimuli that induce chronic inflammation, fibrosis, and remodeling of the cellular microenvironment. Collectively, these changes generate a precancerous niche (PCN) in which fibrosis and remodeling are ongoing secondary to persistent inflammation, followed by the deployment of a chronic stress escape strategy (CSES). If the CSES is unsuccessful, the cell undergoes a normal cell to cancer cell transformation (NCCT). RESULTS: Here, we highlight the critical role of fibroblasts as the first cells to undergo neoplastic transformation to a cancerous phenotype which is based on several critical findings. First, persistent disruption of homeostatic crosstalk increases lysyl oxidase activity and lysine oxidation which leads to increased collagen stiffness and decreased elasticity. If unresolved, chronic tissue stress will lead to an escape strategy that involves the recruitment of fibroblasts and fibrocytes from the bone marrow as well as cells undergoing an epithelial-mesenchymal transition (EMT). This yields a heterogeneous pool of cells that express both epithelial and mesenchymal markers and that will ultimately differentiate into cancer-associated fibroblasts (CAFs). Finally, CAFs undergo a mesenchymalepithelial transition (MET) and express epithelial markers that facilitate their integration into the target tissue. CONCLUSION: Here, we review the published findings that led us to this conclusion which is the most plausible answer to this critical question.

Physics Essentials Enable Deeper Understanding in Signaling and Crosstalk of the Carcinogenesis Paradigm "Epistemology of the Origin of Cancer".

Radioactivity and radiation-induced mutations are believed to be primary causal examples of cancer-initiating events (stimulus). The assumption that an increase in cancer risk develops from any amount of radiation gave rise to the linear no-threshold model. This also led to the assumption that cancer is caused by somatic mutations as described by the somatic mutation theory. Against this backdrop, in actuality only ~5%-10% of cancers result from somatic mutations or its various modifications, while ~80% of cancers are still termed as 'sporadic', meaning that their cause is unknown. Therefore, both the linear no-threshold model and the somatic mutation theory have resulted in an incongruity in thinking. Decades of molecular and clinical research since 2012 led to the development of the cancer paradigm, "Epistemology of the origin of cancer", which explains why the majority of cancers originate as a result of a sixstep sequence of events. An understanding of the essentials of physics helps to explain the interconnections between physics and the biology of cancer. This allows for a much-needed reconciliation of past errors and leads to a deeper understanding of carcinogenesis.

Somatic Mutation Theory - Why it's Wrong for Most Cancers.

Hysteron proteron reverses both temporal and logical order and this syllogism occurs in carcinogenesis and the somatic mutation theory (SMT): the first (somatic mutation) occurs only after the second (onset of cancer) and, therefore, observed somatic mutations in most cancers appear well after the early cues of carcinogenesis are in place. It is no accident that mutations are increasingly being questioned as the causal event in the origin of the vast majority of cancers as clinical data show little support for this theory when compared against the metrics of patient outcomes. Ever since the discovery of the double helical structure of DNA, virtually all chronic diseases came to be viewed as causally linked to one degree or another to mutations, even though we now know that genes are not simply blueprints, but rather an assemblage of alphabets that can, under non-genetic influences, be used to assemble a business letter or a work of Shakespearean literature. A minority of all cancers is indeed caused by mutations but the SMT has been applied to all cancers, and even to chemical carcinogenesis, in the absence of hard evidence of causality. Herein, we review the 100 year story of SMT and aspects that show why genes are not just blueprints, how radiation and mutation are associated in a more nuanced view, the proposed risk of cancer and bad luck, and the in vitro and in vivo evidence for a new cancer paradigm. This paradigm is scientifically applicable for the majority of non-heritable cancers and consists of a six-step sequence for the origin of cancer. This new cancer paradigm proclaims that somatic mutations are epiphenomena or later events occurring after carcinogenesis is already underway. This serves not just as a plausible alternative to SMT and explains the origin of the majority of cancers, but also provides opportunities for early interventions and prevention of the onset of cancer as a disease.

Genomics, microRNA, epigenetics, and proteomics for future diagnosis, treatment and monitoring response in upper GI cancers.

One major objective for our evolving understanding in the treatment of cancers will be to address how a combination of diagnosis and treatment strategies can be used to integrate patient and tumor variables with an outcome-oriented approach. Such an approach, in a multimodal therapy setting, could identify those patients (1) who should undergo a defined treatment (personalized therapy) (2) in whom modifications of the multimodal therapy due to observed responses might lead to an improvement of the response and/or prognosis (individualized therapy), (3) who might not benefit from a particular toxic treatment regimen, and (4) who could be identified early on and thereby be spared the morbidity associated with such treatments. These strategies could lead in the direction of precision medicine and there is hope of integrating translational molecular data to improve cancer classifications. In order to achieve these goals, it is necessary to understand the key issues in different aspects of biotechnology to anticipate future directions of personalized and individualized diagnosis and multimodal treatment strategies. Providing an overview of translational data in cancers proved to be a challenge as different methods and techniques used to obtain molecular data are used and studies are based on different tumor entities with different tumor biology and prognoses as well as vastly different therapeutic approaches. The pros and cons of the available methodologies and the potential response data in genomics, microRNA, epigenetics and proteomics with a focus on upper gastrointestinal cancers are considered herein to allow for an understanding of where these technologies stand with respect to cancer diagnosis, prognosis and treatment.

Therapeutic approaches to gastroesophageal junction adenocarcinomas.

The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the distinction between adenocarcinomas above, below, or within the gastroesophageal junction; combined modality therapy; tumor markers for use in personalized medicine; PET-CT and endoscopic biopsies in the evaluation of response to neoadjuvant chemoradiation therapy; a standardized grading system for tumor regression in squamous cell cancer and adenocarcinoma; the experimental basis for new approaches to medical treatment; the criteria measuring response in esophageal cancer; and the impact of novel imaging on staging and response assessment.

Undervalued criteria in the evaluation of multimodal trials for upper GI cancers.

Global economies and their health systems face a huge challenge from cancer: 1 in 3 women and 1 in 2 men will develop cancer in their lifetime. In the less developed countries, the volume of cancer patients will overwhelm the existing healthcare systems. Even in developed regions, patients with upper gastrointestinal (GI) cancer usually present with locally advanced tumors that their prognosis is poor. A detailed knowledge of anatomy, embryology, epidemiology, tumor classifications and tumor growth is key understanding and evaluating the relevant research. We review undervalued criteria necessary to evaluate the response to multimodal therapy for upper GI cancers.

Cell-cell communication in the tumor microenvironment, carcinogenesis, and anticancer treatment.

The delineation of key molecular pathways has enhanced our knowledge of the biology of tumor microenvironment, tumor dissemination, and carcinogenesis. The complexities of cell-cell communication and the possibilities for modulation provide new opportunities for treating cancers. Cells communicate by direct and indirect signaling. Direct cell-cell communication involves both, self-self-communication (intracrine and autocrine), and adjacent communication with nearby cells (juxtacrine), which themselves are regulated by distinct pathways. Indirect intercellular communication involves local communication over short distances (paracrine and synaptic signaling) or over large distances via hormones (endocrine). The essential components of cell-cell communication involve communication junctions (Connexins, Plasmodesmata, Ion Channels, Chemical Synapses, and Pannexins), occluding junctions (Tight Junctions), and anchoring junctions (Adherens, Desmosomes, Focal Adhesions, and Hemidesmosomes). The communication pathways pass through junctions at physical cell-cell attachments, and they go, as well, through the extracellular matrix (ECM) via the different transmembrane adhesion proteins (Cadherins and Integrins). We have here reviewed cell-cell communication involving (1) the components of junctions and their dynamic interplay with the other aspects of communication, including (2) the tumor microenvironment and carcinogenesis, (3) coupling and migration, (4) the underlying cell-cell and sub-cellular communication mechanisms (signaling) of anticancer treatments, and finally, (5) aspects of recent research on cell-cell communication.

Imagine a world without cancer.

BACKGROUND: Since the "War on Cancer" was declared in 1971, the United States alone has expended some $300 billion on research, with a heavy focus on the role of genomics in anticancer therapy. Voluminous data have been collected and analyzed. However, in hindsight, any achievements made have not been realized in clinical practice in terms of overall survival or quality of life extended. This might be justified because cancer is not one disease but a conglomeration of multiple diseases, with widespread heterogeneity even within a single tumor type. DISCUSSION: Only a few types of cancer have been described that are associated with one major signaling pathway. This enabled the initial successful deployment of targeted therapy for such cancers. However, soon after this targeted approach was initiated, it was subverted as cancer cells learned and reacted to the initial treatments, oftentimes rendering the treatment less effective or even completely ineffective. During the past 30 plus years, the cancer classification used had, as its primary aim, the facilitation of communication and the exchange of information amongst those caring for cancer patients with the end goal of establishing a standardized approach for the diagnosis and treatment of cancers. This approach should be modified based on the recent research to affect a change from a service-based to an outcome-based approach. The vision of achieving long-term control and/or eradicating or curing cancer is far from being realized, but not impossible. In order to meet the challenges in getting there, any newly proposed anticancer strategy must integrate a personalized treatment outcome approach. This concept is predicated on tumor- and patient-associated variables, combined with an individualized response assessment strategy for therapy modification as suggested by the patient's own results. As combined strategies may be outcome-orientated and integrate tumor-, patient- as well as cancer-preventive variables, this approach is likely to result in an optimized anticancer strategy. SUMMARY: Herein, we introduce such an anticancer strategy for all cancer patients, experts, and organizations: Imagine a World without Cancer.

Serum-based DNA methylation biomarkers in colorectal cancer: potential for screening and early detection.

Colorectal cancer (CRC) is the third most common cause of cancer-related death in the United States. Early identification and treatment of pre-cancerous colorectal lesions, or node-negative CRC are highly effective interventions that substantially reduce disease-specific mortality. Colonoscopy remains a highly effective primary screening tool based on its excellent diagnostic accuracy, and its ability to remove pre-cancerous lesions. However, the nature of the procedure limits compliance with colonoscopy intended for population-based CRC screening. A significant advance in the screening and care of these patients could be realized by blood-based biomarkers, which could accurately identify patients at-risk for CRC development whom might benefit from early and/or more frequent surveillance for disease. We reviewed and herein discuss the potential for serum based DNA methylation biomarkers for screening and early detection of CRC.

Randomized clinical trials for colorectal cancer peritoneal surface malignancy.

Upwards of 40% of patient with colorectal cancer develop peritoneal carcinomatosis (CRCPC). Of the 2500 patients reported in the literature, 1000 underwent cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC), resulting in median survival of 22 to 63 months. However, level I data from prospective randomized trials are limited. Further trials are indicated to identify peritoneal carcinomatosis in at-risk patients early in the natural history of the disease and confirm the efficacy of multimodality therapy (CRS/HIPEC/systemic therapy) in those with CRCPC amenable to CRS in the modern era of novel targeted and cytotoxic systemic therapy.

Peritoneal carcinomatosis: cytoreductive surgery and HIPEC--overview and basics.

Tumor involvement of the peritoneum-peritoneal carcinomatosis-is a heterogeneous form of cancer that had been generally regarded as a sign of systemic tumor disease and as a terminal condition. The multimodal treatment approach for patients with peritoneal carcinomatosis, which had been conceived and developed, consists of what is known as cytoreductive surgery, followed by hyperthermic intraperitoneal chemotherapy (HIPEC). Depending on the tumor mass as assessed intraoperatively and the histopathological differentiation, patients who undergo cytoreductive surgery and HIPEC have a significant survival benefit. Mean increases in the survival period ranging from six months to up to four years have now been reported. In view of the substantial logistic effort and the extent of the surgery involved, this treatment approach represents a major challenge both for patients and for surgical oncologists, as well as for the members of the overall interdisciplinary structure required, which includes oncology, anesthesiology and intensive care, psycho-oncology, and patient management. The surgical procedures alone may take 8-14 hr. The present paper provides an overview of the basis for the approach and the use of specialized classifications and quantitative prognostic indicators.

Application of laser microdissection and quantitative PCR to assess the response of esophageal cancer to neoadjuvant chemo-radiotherapy.

Tissues are complicated three-dimensional structures, composed of different types of interacting cells. Since the cell population of interest might constitute only a minor fraction of the total tissue volume, the problem of tissue heterogeneity has been a major barrier to the molecular analysis of normal versus diseased tissue. Thus, tissue microdissection represents one of the most promising techniques in molecular pathology offering the link between morphology and genetic analysis since it was established in the early 1970s. These first applications and further developments in the techniques enable preparation of morphologically well described and circumscribed cell populations of either tumor cells or surrounding tissue or even cytology specimens without contamination of unwanted cells. Laser capture microdissection is suitable for the dissection of both paraffin embedded and fresh frozen material. Further applications of the dissected genomic material are isolation of DNA and RNA as described later on followed by PCR or RT-PCR and sequencing.

Phosphoglycerate kinase 1 promoting tumor progression and metastasis in gastric cancer - detected in a tumor mouse model using positron emission tomography/magnetic resonance imaging.

BACKGROUND/AIMS: Tumor dissemination is frequent in gastric cancer and implies a poor prognosis. Cure is only achievable provided an accurate staging is performed at primary diagnosis. In previous studies we were able to show a relevant impact of increased phosphoglycerate kinase 1 expression (PGK1; a glycolytic enzyme) on invasive properties of gastric cancer in-vivo and in-vitro. Thus the aim of the present study was to evaluate the effect of enhanced PGK1 expression in gastric cancer employing magnetic resonance (MR)-imaging combined with positron emission tomography (PET), a recently emerging new high resolution imaging technique in a mouse model. METHODS: A metastatic nude mouse model simulating human gastric cancer behavior by orthotopic tumor implantation was established. Mice were divided into one control group (n=5) and two experimental groups (n=30) divided by half in animals baring tumors from MKN45-cells and MKN45-cells with plasmid-mediated overexpression of PGK1. In the course of tumor growth MR-imaging and PET/MRI fusion was performed. Successively experimental animals were examined macroscopically and histopathologically regarding growth, metastasis and PGK1 expression. RESULTS: Elevated PGK1 expression increased invasive and metastatic behavior of implanted gastric tumors significantly. MR/PET- imaging results in-vivoand subsequent ex-vivo findings concerning tumor growth and metastasis correlated excellently and could be underlined by concordant immuohistochemical PGK1 staining. CONCLUSION: Consistent in-vivo findings suggest that PGK1 might be crucially involved in gastric malignancy regarding growth and metastasis, which was also underlined by novel imaging techniques. Thus, PGK1 may be exploited as a prognostic marker and/or be of potential therapeutic value preventing malignant dissemination.

The predictive value of genes of the TGF-beta1 pathway in multimodally treated squamous cell carcinoma of the esophagus.

BACKGROUND AND AIM: Pretherapeutic identification of esophageal squamous cell carcinomas (ESCCs) that are likely to respond to neoadjuvant chemoradiotherapy is important in the attempt to improve the prognosis for patients. In the present study, expression of members of the transforming growth factor-beta1 (TGF-beta1) signaling pathway was investigated in pretherapeutic biopsies from 97 ESCCs (cT3, cN0/+, cM0) in patients who underwent neoadjuvant chemoradiotherapy (45 Gy plus cisplatin and 5-fluorouracil) and subsequent esophagectomy in the setting of a single-center prospective treatment trial. MATERIALS AND METHODS: Expression of TGF-beta1 and its downstream effectors Smad4 and Smad7 was assessed using quantitative reverse transcription polymerase chain reaction from RNA prepared from pretherapeutic tumor biopsies. The presence of phosphorylated Smad2 was assessed immunohistochemically. RESULTS: Expression of TGF-beta1 (mean 7.8; range 0.0-25.7 arb. units), Smad4 (mean 0.1; range 0.0-0.4 arb. units), and Smad7 (mean 1.6; range 0.4-16.1 arb. units) varied substantially between the patients. Tumors with total or subtotal regression, as determined by histopathological examination after neoadjuvant chemoradiotherapy, showed significantly higher levels of Smad4 mRNA expression than tumors with minor or no regression (P = 0.032). TGF-beta1 and Smad7 mRNA expression as well as Smad2 protein expression were of no prognostic value. Expression of the four genes under analysis also showed no impact on the overall survival. In contrast, the overall survival correlated significantly with histopathological regression (P < 0.0001) and to a minor degree also with clinical regression grading (P = 0.0254). INTERPRETATION: Among the parameters analyzed, only Smad4 was found to have possible predictive value for esophageal squamous cell carcinoma in patients receiving neoadjuvant chemoradiotherapy.

Non-acid gastroesophageal reflux measured using multichannel intraluminal impedance in older patients.

BACKGROUND: Diagnosing gastroesophageal reflux disease is challenging in the older population, as comorbid conditions can obscure the disease. METHODS: This prospective study included 97 participants: 25 healthy controls (group 1), 46 reflux patients aged 26-64 (group 2), and 26 patients over 65 (group 3). Esophageal motility was assessed using conventional esophageal manometry, and 24-h pH-metry and non-acid reflux episodes were assessed using multichannel intraluminal impedance. RESULTS: Among the older patients (group 3), 34% had reflux disease. The rate of lower esophageal sphincter insufficiency in group 3 was comparable with that in group 2 and significantly different from group 1. Gastric 24-h pH-metry showed no significant differences between the groups. Esophageal pH-metry results for groups 1 and 3 differed significantly from those in group 2. Impedance assessment showed that older patients have non-acid reflux episodes in the recumbent position significantly more often in comparison with controls and reflux patients. Reflux patients and older patients had proximal reflux episodes significantly more often than healthy volunteers. CONCLUSIONS: Patients aged over 65 have non-acid reflux, particularly in the recumbent position, significantly more often than normal individuals and patients with reflux disease. Non-acid reflux may mimic a negative DeMeester score in older patients with severe reflux disease.

Phosphoglycerate kinase 1 a promoting enzyme for peritoneal dissemination in gastric cancer.

Peritoneal carcinomatosis is a frequent finding in gastric cancer associated with a poor prognosis. The features that enable gastric tumors to disseminate are poorly understood until now. Previously, we showed elevated mRNA levels of phosphoglycerate kinase 1 (PGK1), an adenosine triphosphate-generating enzyme in the glycolytic pathway, the chemokine receptor 4 (CXCR4), the corresponding chemokine ligand 12 (CXCL12) and beta-catenin in specimens from gastric cancer patients with peritoneal carcinomatosis. In this study, the influence of PGK1 on CXCR4 and beta-catenin was assessed as well as the invasiveness of PGK1 overexpressing cancer cells. In this current study, we found that PGK1 regulates the expression of CXCR4 and beta-catenin at the mRNA and protein levels. On the other hand, CXCR4 regulates the expression of PGK1. Plasmid-mediated overexpression of PGK1 dramatically increased the invasiveness of gastric cancer cells. Interestingly, inhibition of CXCR4 in cells overexpressing PGK1 produced only a moderate reduction of invasiveness suggesting that, PGK1 itself has a critical role in tumor invasiveness. Immunohistochemistry in specimens from diffuse gastric cancer patients also revealed an overexpression of PGK1 in patients with development of peritoneal carcinomatosis. Therefore, PGK1 may be a crucial enzyme in peritoneal dissemination. Together these findings suggest that the enhanced expression of PGK1 and its signaling targets CXCR4 and beta-catenin in gastric cancer cells promote peritoneal carcinomatosis. Thus, PGK1 may serve as prognostic marker and/or be a potential therapeutic target to prevent dissemination of gastric carcinoma cells into the peritoneum.

Response to preoperative therapy in upper gastrointestinal cancers.

BACKGROUND: In cancer, a response to therapy implies a reduction in the volume or activity of localized and/or metastatic tumors. In localized upper gastrointestinal cancer, there is no accepted definition of clinical response; however, tumor shrinkage is frequently observed when preoperative therapy is administered. As patients with upper gastrointestinal cancers often undergo multimodal therapy, it is therefore imperative that new definitions for assessing the response to preoperative therapy be established. METHODS: We reviewed the development of response criteria from a historical perspective, with particular emphasis on the criteria used to assess upper gastrointestinal cancers. RESULTS: Observing the response to preoperative therapy appears to make it possible to distinguish between favorable and unfavorable clinical biology in the cancer. Patients who experience a response to preoperative treatment appear to fare better in terms of overall survival than those whose cancers do not respond. We reviewed the published results regarding the response to preoperative therapy and the implications of this for patients. CONCLUSIONS: This review of the literature suggests that a variety of tools are available for defining the response to preoperative therapy and that these need to be exploited. Developing reliable methods of assessing the response will improve the individualization of therapy for patients with gastroesophageal cancer. There is a strong need for surrogate markers for efficacy in order to assess responses that are capable of predicting patient outcome.