Ductal carcinoma in situ develops within clonal fields of mutant cells in morphologically normal ducts.

Mutations are abundantly present in tissues of healthy individuals, including the breast epithelium. Yet it remains unknown whether mutant cells directly induce lesion formation or first spread, leading to a field of mutant cells that is predisposed towards lesion formation. To study the clonal and spatial relationships between morphologically normal breast epithelium adjacent to pre-cancerous lesions, we developed a three-dimensional (3D) imaging pipeline combined with spatially resolved genomics on archival, formalin-fixed breast tissue with the non-obligate breast cancer precursor ductal carcinoma in situ (DCIS). Using this 3D image-guided characterization method, we built high-resolution spatial maps of DNA copy number aberration (CNA) profiles within the DCIS lesion and the surrounding normal mammary ducts. We show that the local heterogeneity within a DCIS lesion is limited. However, by mapping the CNA profiles back onto the 3D reconstructed ductal subtree, we find that in eight out of 16 cases the healthy epithelium adjacent to the DCIS lesions has overlapping structural variations with the CNA profile of the DCIS. Together, our study indicates that pre-malignant breast transformations frequently develop within mutant clonal fields of morphologically normal-looking ducts. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Evidence for etiologic field changes in tongue distant from tumor in patients with squamous cell carcinoma of the oral tongue.

Oral cancer is a paradigm of Slaughter's concept of field cancerization, where tumors are thought to originate within an area of cells containing genetic alterations that predispose to cancer development. The field size is unclear but may represent a large area of tissue, and the origin of mutations is also unclear. Here, we analyzed whole exome and transcriptome features in contralateral tumor-distal tongue (i.e. distant from the tumor, not tumor-adjacent) and corresponding tumor tissues of 15 patients with squamous cell carcinoma of the oral tongue. The number of point mutations ranged from 41 to 237 in tumors and from one to 78 in tumor-distal samples. Tumor-distal samples showed mainly clock-like (associated with aging) or tobacco smoking mutational signatures. Tumors additionally showed mutations that associate with cytidine deaminase AID/APOBEC enzyme activities or a UV-like signature. Importantly, no point mutations were shared between a tumor and the matched tumor-distal sample in any patient. TP53 was the most frequently mutated gene in tumors (67%), whereas a TP53 mutation was detected in only one tumor-distal sample, and this mutation was not shared with the matched tumor. Arm-level copy number variation (CNV) was found in 12 tumors, with loss of chromosome (Chr) 8p or gain of 8q being the most frequent events. Two tumor-distal samples showed a gain of Chr8, which was associated with increased expression of Chr8-located genes in these samples, although gene ontology did not show a role for these genes in oncogenic processes. In situ hybridization revealed a mixed pattern of Chr8 gain and neutral copy number in both tumor cells and adjacent nontumor epithelium in one patient. We conclude that distant field cancerization exists but does not present as tumor-related mutational events. The data are compatible with etiologic field effects, rather than classical monoclonal field cancerization theory. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Prognosis of oral epithelial dysplasia in individuals with and without oral lichen planus.

OBJECTIVES: To investigate the role of oral lichen planus (OLP) on the long-term prognosis of oral epithelial dysplasia (OED). METHODS: Retrospective single-centre cohort study using the 2007-2019 database of the Head and Neck Cancer and Oral Medicine units of University College London Hospital. The exposure of interest was the presence of OLP, and the prognostic outcomes included the development of new primary episodes of OED, progression to malignancy and mortality. Cox proportional hazard and Poisson regression models were performed. RESULTS: A total of 299 patients, of whom 144 had OED arising on the background of OLP (OLP/OED) and 155 had OED without underlying OLP (non-OLP/OED), were included. A pre-existing diagnosis of OLP was significantly associated with a twofold increased risk of subsequent primary OED events (HR = 2.02, p = 0.04), which also developed faster (1.46 vs. 2.96 years, p = 0.04) and with more involvement of non-cancer-prone sites (p = 0.001) than in the non-OLP/OED group. There was no difference between groups in the progression to malignancy or mortality. CONCLUSIONS: Oral lichen planus/OED patients are at higher risk of multiple episodes of primary OED, which can develop faster and at non-cancer-prone sites as compared to non-OLP/OED individuals. Further research is needed to clarify the effects of OLP upon progression to OSCC and mortality.

Carcinoma-associated fibroblasts: orchestrating the composition of malignancy.

The tumor stroma is no longer seen solely as physical support for mutated epithelial cells but as an important modulator and even a driver of tumorigenicity. Within the tumor stromal milieu, heterogeneous populations of fibroblast-like cells, collectively termed carcinoma-associated fibroblasts (CAFs), are key players in the multicellular, stromal-dependent alterations that contribute to malignant initiation and progression. This review focuses on novel insights into the contributions of CAFs to disease progression, emergent events leading to the generation of CAFs, identification of CAF-specific biomarkers predictive of disease outcome, and recent therapeutic approaches aimed at blunting or reverting detrimental protumorigenic phenotypes associated with CAFs.

Ex Vivo Analysis of Cell Differentiation, Oxidative Stress, Inflammation, and DNA Damage on Cutaneous Field Cancerization.

Cutaneous field cancerization (CFC) refers to a skin region containing mutated cells' clones, predominantly arising from chronic exposure to ultraviolet radiation (UVR), which exhibits an elevated risk of developing precancerous and neoplastic lesions. Despite extensive research, many molecular aspects of CFC still need to be better understood. In this study, we conducted ex vivo assessment of cell differentiation, oxidative stress, inflammation, and DNA damage in CFC samples. We collected perilesional skin from 41 patients with skin cancer and non-photoexposed skin from 25 healthy control individuals. These biopsies were either paraffin-embedded for indirect immunofluorescence and immunohistochemistry stain or processed for proteins and mRNA extraction from the epidermidis. Our findings indicate a downregulation of p53 expression and an upregulation of Ki67 and p16 in CFC tissues. Additionally, there were alterations in keratinocyte differentiation markers, disrupted cell differentiation, increased expression of iNOS and proinflammatory cytokines IL-6 and IL-8, along with evidence of oxidative DNA damage. Collectively, our results suggest that despite its outwardly normal appearance, CFC tissue shows early signs of DNA damage, an active inflammatory state, oxidative stress, abnormal cell proliferation and differentiation.

Association between continuous cessation or reduction of drinking alcohol and improvement of multiple dysplastic lesions in patients with esophageal squamous cell carcinoma after endoscopic resection.

BACKGROUND: Multiple development of squamous cell carcinoma (SCC) in the upper aerodigestive tract has been explained by the 'field cancerization phenomenon' associated with alcohol drinking. Squamous dysplastic lesion is clinically visualised as a Lugol-voiding lesion (LVL) by chromoendoscopy. Whether cessation or reduction of alcohol drinking improves multiple LVL and reduces the risk of field cancerization has not been elucidated. METHODS: We analysed 330 patients with newly diagnosed superficial esophageal SCC (ESCC) enrolled in the cohort study. The grade of LVL was assessed in all patients every 6 months. We instructed the patients to stop smoking and drinking and recorded their drinking and smoking status every 6 months. RESULTS: Among 330 patients, we excluded 98 with no LVL or no drinking habit. Of the remaining 232 patients, 158 continuously ceased or reduced their drinking habit. Patients who ceased or reduced their drinking habit significantly showed improvement in the grade of LVL. Multivariate analysis showed that continuous cessation or reduction of drinking habit improved the grade of LVL (hazard ratio [HR] = 8.5, 95% confidence interval [CI] 1.7-153.8, p = 0.0053). Higher grade of LVL carried a high risk of multiple ESCC and head and neck SCC (HNSCC) (HR = 3.7, 95% CI 2.2-6.4, p < 0.0001). Improvement in LVL significantly decreased the risk of multiple ESCC and HNSCC (HR = 0.2, 95% CI 0.04-0.7, p = 0.009). CONCLUSIONS: This is the first report indicating that field cancerization was reversible and cessation or reduction of drinking alcohol could prevent multiple squamous dysplastic lesion and multiple ESCC and HNSCC development. CLINICAL TRIALS REGISTRY NUMBER: UMIN000001676.

Field cancerization in breast cancer.

Breast cancer affects one in seven women worldwide during their lifetime. Widespread mammographic screening programs and education campaigns allow for early detection of the disease, often during its asymptomatic phase. Current practice in treatment and recurrence monitoring is based primarily on pathological evaluations but can also encompass genomic evaluations, both of which focus on the primary tumor. Although breast cancer is one of the most studied cancers, patients still recur at a rate of up to 15% within the first 10 years post-surgery. Local recurrence was originally attributed to tumor cells contaminating histologically normal (HN) tissues beyond the surgical margin, but advances in technology have allowed for the identification of distinct aberrations that exist in the peri-tumoral tissues themselves. One leading theory to explain this phenomenon is the field cancerization theory. Under this hypothesis, tumors arise from a field of molecularly altered cells that create a permissive environment for malignant evolution, which can occur with or without morphological changes. The traditional histopathology paradigm dictates that molecular alterations are reflected in the tissue phenotype. However, the spectrum of inter-patient variability of normal breast tissue may obfuscate recognition of a cancerized field during routine diagnostics. In this review, we explore the concept of field cancerization focusing on HN peri-tumoral tissues: we present the pathological and molecular features of field cancerization within these tissues and discuss how the use of peri-tumoral tissues can affect research. Our observations suggest that pathological and molecular evaluations could be used synergistically to assess risk and guide the therapeutic management of patients. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Lost expression of AT-rich interaction domain 1A in the gastric mucosa-A constituent of field cancerization in the stomach.

Abnormalities of the AT-rich interaction domain 1A (ARID1A) occur in cancer tissues and precursors or premalignant lesions in various organs. To investigate the significance of ARID1A abnormalities in the early phase of cancer development in the stomach, we screened for ARID1A loss and p53 overexpression in glands in non-neoplastic gastric mucosa using immunohistochemistry. We tested 230 tissue blocks of 77 patients with gastric carcinoma, and in 10% of non-neoplastic mucosa we detected ARID1A-lost and in 3.7% p53-overexpressed foci. Loss of ARID1A expression occurred in the scales of several glands, which were morphologically characterized as authentic, pseudo-pyloric, or intestinal metaplastic glands devoid of dysplastic changes. In contrast, p53-overexpressed foci were detected in dysplastic intestinal metaplasia. In early gastric cancer cases (n = 46), ARID1A-lost foci were frequent in samples of patients with Epstein-Barr virus-associated gastric carcinoma (p = 0.037). Ultra-deep DNA sequencing of ARID1A-lost foci revealed frameshift and nonsense mutations in ARID1A. Mapping abnormal glands in the entire resected stomach of the three selected patients demonstrated that ARID1A-lost foci clustered with p53 abnormal glands. ARID1A-lost epithelial cells may develop clonal growth through the pathway, different from p53-abnormal intestinal metaplasia, and require one or more events to develop into an overt carcinoma, such as EBV infection.

Is OLP potentially malignant? A clue from ZNF582 methylation.

OBJECTIVE: Whether oral lichen planus (OLP) was potentially malignant remains controversial. Here, we examined associations of ZNF582 methylation (ZNF582m ) with OLP lesions, dysplastic features and squamous cell carcinoma (OSCC). MATERIALS AND METHODS: This is a case-control study. ZNF582m was evaluated in both lesion and adjacent normal sites of 42 dysplasia, 90 OSCC and 43 OLP patients, whereas ZNF582m was evaluated only in one mucosal site of 45 normal controls. High-risk habits affecting ZNF582m such as betel nut chewing and cigarette smoking were also compared in those groups. RESULTS: OLP lesions showed significantly lower ZNF582m than those of dysplasia and OSCC. At adjacent normal mucosa, ZNF582m increased from patients of OLP, dysplasia, to OSCC. In addition, ZNF582m at adjacent normal sites in OLP patients was comparable to normal mucosa in control group. Dysplasia/OSCC patients with high-risk habits exhibited significantly higher ZNF582m than those without high-risk habits. However, ZNF582m in OLP patients was not affected by those high-risk habits. CONCLUSIONS: OLP is unlikely to be potentially malignant based on ZNF582m levels. ZNF582m may also be a potential biomarker for distinguishing OLP from true dysplastic features and OSCC, and for monitoring the malignant transformation of OLP, potentially malignant disorders with dysplastic features and OSCC.

Expressional variations of Kaiso: an association with pathological characteristics and field cancerization of OSCC.

BACKGROUND: A group of genetically altered cells that have not transformed into a clinical or histologically identifiable state of malignancy but contains a higher risk of transforming into one is known as the field of cancerization. Numerous molecules are being investigated for their significance in the development of this phenomenon. One such protein of this family is Kaiso also known as ZBTB33 (Zinc Finger and BTB Domain containing 33). This protein belongs to the POZ-ZF family of transcription factors and may have functional tasks similar to its other siblings such as the growth and development of vertebrates and the pathogenesis of neoplastic diseases. Nevertheless, its role in the pathogenesis, progression, epithelial mesenchyal transition and field cancerization in case of oral cancer still needs exploration. Hence, this study was designed to explore the expressional differences between the mucosa of controls and those diagnosed with oral squamous cell carcinoma (OSCC). METHODS: Soft tissue samples were obtained from the main tumor, tumor periphery and opposite buccal mucosa of 50 oral cancer patients, whereas normal mucosa was taken from 50 volunteers undergoing elective tooth removal. The acquired samples were subjected to Immunohistochemical exploration for expression of Kaiso and E-Cadherin. The expression was measured using Image-J IHC profiler and summed as Optical density. The Optical density values were then subjected to statistical analysis. RESULTS: Results revealed a significant differential expression of Kaiso between the mucosal tissues taken from oral cancer patients and controls (p-value: < 0.0001), showing almost 50% down-regulation of Kaiso in all three tissue samples taken from oral cancer patients as compared to normal mucosa. CONCLUSION: Kaiso has a significant difference of expression in the mucosa of oral cancer patients as compared to the mucosa of normal patients, making it a probable contributor to disease pathogenesis and field cancerization.

AHNAK Contributes to Hepatocellular Carcinoma Growth by Interacting with IGF-1R.

Neuroblast differentiation-associated protein AHNAK, a large structural scaffold protein, remains mysterious in biological processes. AHNAK plays a suppressive or progressive role in different types of cancers. To investigate the role of the AHNAK in hepatocellular carcinoma (HCC), cell viability assays were performed to determine the cell proliferation of the stable AHNAK-knockdown HepG2 cell line; co-immunoprecipitation (Co-IP) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) were performed on HCC and matched paracancerous (MPC) tissues. The Metascape platform was used for enrichment analyses; the "ComplexHeatmap" package was applied for cluster analyses and visualization. Co-IP, Western botting and immunofluorescence double staining were performed to assess the interactions between AHNAK and insulin-like growth factor 1 receptor (IGF-1R). AHNAK silencing reduced the viability of HepG2 cells; the interactome in HCC and MPC tissues enriched 204 pathways and processes, which partially reflected the signature of HCC field cancerization. AHNAK could co-localize and interact with IGF-1R. These results suggested that the AHNAK complex contributes to HCC growth, potentially by interacting with IGF-1R.

The Overall Number of Actinic Keratosis Lesions Is Not Predictable by the Number of Visible Lesions: Consequences for Field-Directed Therapies.

Actinic keratoses are keratotic lesions occurring on skin areas extensively damaged by sunlight. Using data from a previously published Phase III randomized, controlled clinical trial in patients with at least 5 actinic keratoses, we explored the potential link between the number of visible actinic keratosis lesions before any treatment and the total number of lesions of the field cancerization as revealed by 5-fluorouracil cream. Our analysis suggests that the baseline number of visible actinic keratoses is a poor indicator of the real number of lesions in the field of cancerization, reinforcing the need to explain the field cancerization concept to patients. (Curr Ther Res Clin Exp. 2022; 82:XXX-XXX) © 2022 Elsevier HS Journals, Inc.

Endoscopic findings in the soft palatal mucosa are associated with the risk of esophageal squamous cell carcinoma.

BACKGROUND AND AIM: We investigated endoscopic findings of the soft palatal mucosa to identify factors associated with esophageal squamous cell carcinoma (ESCC). METHODS: This study was conducted during endoscopic examinations of subjects at Osaka International Cancer Institute from January 2020 through May 2020. We took endoscopic images of the soft palate under non-magnifying and mild-magnifying observations. Subjects with ESCC or a history of ESCC were defined as the ESCC group. Two endoscopists who were blinded to subjects' clinical information interpreted 10 endoscopic findings: melanosis, brownish changes, whitish epithelium, vasodilation, circular alignment of dilated vessels, uneven surface, uneven epithelial color, uneven vessel visibility, palate ridge, and erosion. Subjects were interviewed about their alcohol use, smoking, and flushing reactions. RESULTS: Two hundred eighty-two subjects, including 151 in the ESCC group and 131 in the non-ESCC group, were included in the analysis. Univariate analyses and multivariate logistic regression demonstrated that melanosis, whitish epithelium, and vasodilation were significantly associated with ESCC. The positive likelihood ratios (PLRs) of melanosis, whitish epithelium, and vasodilation were 3.3, 4.2, and 2.8, respectively. Additionally, the PLRs for three of the endoscopic findings in subjects with drinking and smoking habits were higher than in those without these habits-PLRs ranging from 7.23 to 19.1. High PLRs for three endoscopic findings suggested a high possibility of ESCC. Interobserver agreement was substantial for whitish epithelium, moderate for melanosis, and fair for vasodilation. CONCLUSIONS: Three endoscopic findings in soft palate were considered to be useful as alarming signs that indicate ESCC risk.

Field cancerization in clinically solitary actinic keratosis: A pilot study.

Clinical studies have demonstrated that subclinical actinic keratoses (AKs) may be clinically evidenced following treatment of multiple AKs with a topical immunotherapy agent known to reveal a "field cancerization". The aim of our study was to investigate if subclinical AKs may be evidenced also in case of single AKs. Ten patients with single, solitary AKs were treated with IQ 3.75% cream applied on the lesion and on a 5 × 5 cm surrounding area once daily for two 2-week treatment cycles separated by a 2-week treatment-free period. Lesions were evaluated by clinical, dermoscopic and RCM examination. At the end of treatment, subclinical lesions were evidenced in 8 of 10 patients revealing the presence of a field cancerization. If larger studies will confirm these results, field cancerization could likely be considered also in case of solitary AKs, resulting in a different approach in terms of disease evolution and treatment.

Second primary tumors in head and neck cancer patients: The importance of a "tailored" surveillance.

OBJECTIVE: Head and neck cancer survivors have increased risk of developing second primary tumors compared to overall population. Because second primary represents a major cause of morbidity and mortality in this population, early detection is fundamental. MATERIALS AND METHODS: In this 10-year single-institution study, we investigated the following: incidence, clinical-pathological risk factors, and survival of patients with second primary tumor. We included all patients with diagnosis of squamous cell carcinoma of the head and neck seen at the Modena University Hospital from 2008 to 2018. RESULTS: Among 1,177 patients included, 222 (18.9%) developed second primary tumor; its survival probability at 5 years was 40.6%. Alcohol consumption (p = .0055) and index cancer in oropharynx (p = .0029), supraglottic larynx (p = .0000), glottic larynx (p = .0222) were associated with higher risk of second primary. The most common second primary sites were head and neck district and lung (70, 31.5%, and 67, 30.2%, respectively). Head and neck district were more common in oral cavity (18, 43%) and oropharynx index cancer (20, 31%); lung second primary in hypopharynx (4, 40%), supraglottic larynx (17, 43%), and glottic larynx index cancer (23, 35%). CONCLUSION: Head and neck cancer survivors developing a second primary tumor have dismal prognosis. Tailored surveillance is recommended.

Early Upper Aerodigestive Tract Cancer Detection Using Electron Microscopy to Reveal Chromatin Packing Alterations in Buccal Mucosa Cells.

A profound characteristic of field cancerization is alterations in chromatin packing. This study aimed to quantify these alterations using electron microscopy image analysis of buccal mucosa cells of laryngeal, esophageal, and lung cancer patients. Analysis was done on normal-appearing mucosa, believed to be within the cancerization field, and not tumor itself. Large-scale electron microscopy (nanotomy) images were acquired of cancer patients and controls. Within the nuclei, the chromatin packing of euchromatin and heterochromatin was characterized. Furthermore, the chromatin organization was quantified through chromatin packing density scaling. A significant difference was found between the cancer and control groups in the chromatin packing density scaling parameter for length scales below the optical diffraction limit (200 nm) in both the euchromatin (p = 0.002) and the heterochromatin (p = 0.006). The chromatin packing scaling analysis also indicated that the chromatin organization of cancer patients deviated significantly from the control group. They might allow for novel strategies for cancer risk stratification and diagnosis with high sensitivity. This could aid clinicians in personalizing screening strategies for high-risk patients and follow-up strategies for treated cancer patients.

Newly developed primary malignancies in long-term survivors who underwent curative esophagectomy for squamous cell carcinoma of the esophagus.

PURPOSE: We evaluated the efficacy of the long-term follow-up of patients who underwent radical esophagectomy for esophageal squamous cell carcinoma (ESCC) to screen for recurrence and new primary malignancies. METHODS: We retrospectively collected 448 ESCC patients who underwent radical esophagectomy. Esophagogastroduodenoscopy, computed tomography, a stool test and the assessment of the serum concentration of squamous cell carcinoma antigen and carcinoembryonic antigen were performed annually, even over 5 years after esophagectomy. The incidence of ESCC recurrence and new primary malignancies was investigated. RESULTS: We enrolled 222 patients who survived at least 5 years after esophagectomy. A total of 104 new primary malignancies occurred in 82 patients (36.9%) after esophagectomy. Twenty-one malignancies were in the head and neck region, 14 in the residual esophagus, 13 in the prostate and 11 in the gastric tube and lung. Patients who developed new primary malignancies after esophagectomy had a significantly higher Brinkman index than those without new malignancies. An endoscopic approach successfully treated 92.9% of carcinomas in the residual esophagus, 90.9% of cancers in the gastric tube and 42.9% of carcinomas in the head and neck region. CONCLUSION: The incidence of new primary malignancies was higher than the age-standardized incidence. Long-term follow-up and systemic screening may increase the probability of an early diagnosis and subsequent low-invasive treatment.

Field Cancerization in NSCLC: A New Perspective on MicroRNAs in Macrophage Polarization.

Lung cancer is currently the first cause of cancer-related death. The major lung cancer subtype is non-small cell lung cancers (NSCLC), which accounts for approximatively 85% of cases. The major carcinogenic associated with lung cancer is tobacco smoke, which produces long-lasting and progressive damage to the respiratory tract. The progressive and diffuse alterations that occur in the respiratory tract of patients with cancer and premalignant lesions have been described as field cancerization. At the level of tumor cells, adjacent tumor microenvironment (TME) and cancerized field are taking place dynamic interactions through direct cell-to-cell communication or through extracellular vesicles. These molecular messages exchanged between tumor and nontumor cells are represented by proteins, noncoding RNAs (ncRNAs) and microRNAs (miRNAs). In this paper, we analyze the miRNA roles in the macrophage polarization at the level of TME and cancerized field in NSCLC. Identifying molecular players that can influence the phenotypic states at the level of malignant cells, tumor microenvironment and cancerized field can provide us new insights into tumor regulatory mechanisms that can be further modulated to restore the immunogenic capacity of the TME. This approach could revert alterations in the cancerized field and could enhance currently available therapy approaches.

Genomic and transcriptomic profiling of carcinogenesis in patients with familial adenomatous polyposis.

OBJECTIVE: Familial adenomatous polyposis (FAP) is characterised by the development of hundreds to thousands of adenomas at different evolutionary stages in the colon and rectum that will inevitably progress to adenocarcinomas if left untreated. Here, we investigated the genetic alterations and transcriptomic transitions from precancerous adenoma to carcinoma. DESIGN: Whole-exome sequencing, whole-genome sequencing and single-cell RNA sequencing were performed on matched adjacent normal tissues, multiregionally sampled adenomas at different stages and carcinomas from six patients with FAP and one patient with MUTYH-associated polyposis (n=56 exomes, n=56 genomes and n=8,757 single cells). Genomic alterations (including copy number alterations and somatic mutations), clonal architectures and transcriptome dynamics during adenocarcinoma carcinogenesis were comprehensively investigated. RESULTS: Genomic evolutionary analysis showed that adjacent lesions from the same patient with FAP can originate from the same cancer-primed cell. In addition, the tricarboxylic acid cycle pathway was strongly repressed in adenomas and was then slightly alleviated in carcinomas. Cells from the 'normal' colon epithelium of patients with FAP already showed metabolic reprogramming compared with cells from the normal colon epithelium of patients with sporadic colorectal cancer. CONCLUSIONS: The process described in the previously reported field cancerisation model also occurs in patients with FAP and can contribute to the formation of adjacent lesions in patients with FAP. Reprogramming of carbohydrate metabolism has already occurred at the precancerous adenoma stage. Our study provides an accurate picture of the genomic and transcriptomic landscapes during the initiation and progression of carcinogenesis, especially during the transition from adenoma to carcinoma.

The cellular origins of cancer with particular reference to the gastrointestinal tract.

Stem cells or their closely related committed progenitor cells are the likely founder cells of most neoplasms. In the continually renewing and hierarchically organized epithelia of the oesophagus, stomach and intestine, homeostatic stem cells are located at the beginning of the cell flux, in the basal layer of the oesophagus, the isthmic region of gastric oxyntic glands and at the bottom of gastric pyloric-antral glands and colonic crypts. The introduction of mutant oncogenes such as KrasG12D or loss of Tp53 or Apc to specific cell types expressing the likes of Lgr5 and Mist1 can be readily accomplished in genetically engineered mouse models to initiate tumorigenesis. Other origins of cancer are discussed including 'reserve' stem cells that may be activated by damage or through disruption of morphogen gradients along the crypt axis. In the liver and pancreas, with little cell turnover and no obvious stem cell markers, the importance of regenerative hyperplasia associated with chronic inflammation to tumour initiation is vividly apparent, though inflammatory conditions in the renewing populations are also permissive for tumour induction. In the liver, hepatocytes, biliary epithelial cells and hepatic progenitor cells are embryologically related, and all can give rise to hepatocellular carcinoma and cholangiocarcinoma. In the exocrine pancreas, both acinar and ductal cells can give rise to pancreatic ductal adenocarcinoma (PDAC), although the preceding preneoplastic states are quite different: acinar-ductal metaplasia gives rise to pancreatic intraepithelial neoplasia culminating in PDAC, while ducts give rise to PDAC via. mucinous cell metaplasia that may have a polyclonal origin.