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Despite a general role for the HIF hydroxylase system in cellular oxygen sensing and tumour hypoxia, cancer-associated mutations of genes in this pathway, including PHD2, PHD1, EPAS1 (encoding HIF-2α) are highly tissue-restricted, being observed in pseudohypoxic pheochromocytoma and paraganglioma (PPGL) but rarely, if ever, in other tumours. In an effort to understand that paradox and gain insights into the pathogenesis of pseudohypoxic PPGL, we constructed mice in which the principal HIF prolyl hydroxylase, Phd2, is inactivated in the adrenal medulla using TH-restricted Cre recombinase. Investigation of these animals revealed a gene expression pattern closely mimicking that of pseudohypoxic PPGL. Spatially resolved analyses demonstrated a binary distribution of two contrasting patterns of gene expression among adrenal medullary cells. Phd2 inactivation resulted in a marked shift in this distribution towards a Pnmt-/Hif-2α+/Rgs5+ population. This was associated with morphological abnormalities of adrenal development, including ectopic TH+ cells within the adrenal cortex and external to the adrenal gland. These changes were ablated by combined inactivation of Phd2 with Hif-2α, but not Hif-1α. However, they could not be reproduced by inactivation of Phd2 in adult life, suggesting that they arise from dysregulation of this pathway during adrenal development. Together with the clinical observation that pseudohypoxic PPGL manifests remarkably high heritability, our findings suggest that this type of tumour likely arises from dysregulation of a tissue-restricted action of the PHD2/HIF-2α pathway affecting adrenal development in early life and provides a model for the study of the relevant processes.

Hypoxia-inducible factor (HIF) is strikingly upregulated in many types of cancer, and there is great interest in applying inhibitors of HIF as anticancer therapeutics. The most advanced of these are small molecules that target the HIF-2 isoform through binding the PAS-B domain of HIF-2α. These molecules are undergoing clinical trials with promising results in renal and other cancers where HIF-2 is considered to be driving growth. Nevertheless, a central question remains as to whether such inhibitors affect physiological responses to hypoxia at relevant doses. Here, we show that pharmacological HIF-2α inhibition with PT2385, at doses similar to those reported to inhibit tumor growth, rapidly impaired ventilatory responses to hypoxia, abrogating both ventilatory acclimatization and carotid body cell proliferative responses to sustained hypoxia. Mice carrying a HIF-2α PAS-B S305M mutation that disrupts PT2385 binding, but not dimerization with HIF-1β, did not respond to PT2385, indicating that these effects are on-target. Furthermore, the finding of a hypomorphic ventilatory phenotype in untreated HIF-2α S305M mutant mice suggests a function for the HIF-2α PAS-B domain beyond heterodimerization with HIF-1β. Although PT2385 was well tolerated, the findings indicate the need for caution in patients who are dependent on hypoxic ventilatory drive.

Key Points: The carotid body is a peripheral arterial chemoreceptor that regulates ventilation in response to both acute and sustained hypoxia. Type I cells in this organ respond to low oxygen both acutely by depolarization and dense core vesicle secretion and, over the longer term, via cellular proliferation and enhanced ventilatory responses. Using lineage analysis, the present study shows that the Type I cell lineage itself proliferates and expands in response to sustained hypoxia. Inactivation of HIF-2α in Type I cells impairs the ventilatory, proliferative and cell intrinsic (dense core vesicle) responses to hypoxia. Inactivation of PHD2 in Type I cells induces multilineage hyperplasia and ultrastructural changes in dense core vesicles to form paraganglioma-like carotid bodies. These changes, similar to those observed in hypoxia, are dependent on HIF-2α. Taken together, these findings demonstrate a key role for the PHD2-HIF-2α couple in Type I cells with respect to the oxygen sensing functions of the carotid body., Abstract: The carotid body is a peripheral chemoreceptor that plays a central role in mammalian oxygen homeostasis. In response to sustained hypoxia, it manifests a rapid cellular proliferation and an associated increase in responsiveness to hypoxia. Understanding the cellular and molecular mechanisms underlying these processes is of interest both to specialized chemoreceptive functions of that organ and, potentially, to the general physiology and pathophysiology of cellular hypoxia. We have combined cell lineage tracing technology and conditionally inactivated alleles in recombinant mice to examine the role of components of the HIF hydroxylase pathway in specific cell types within the carotid body. We show that exposure to sustained hypoxia (10% oxygen) drives rapid expansion of the Type I, tyrosine hydroxylase expressing cell lineage, with little transdifferentiation to (or from) that lineage. Inactivation of a specific HIF isoform, HIF-2α, in the Type I cells was associated with a greatly reduced proliferation of Type I cells and hypoxic ventilatory responses, with ultrastructural evidence of an abnormality in the action of hypoxia on dense core secretory vesicles. We also show that inactivation of the principal HIF prolyl hydroxylase PHD2 within the Type I cell lineage is sufficient to cause multilineage expansion of the carotid body, with characteristics resembling paragangliomas. These morphological changes were dependent on the integrity of HIF-2α. These findings implicate specific components of the HIF hydroxylase pathway (PHD2 and HIF-2α) within Type I cells of the carotid body with respect to the oxygen sensing and adaptive functions of that organ., (© 2018 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Ventilatory sensitivity to hypoxia increases in response to continued hypoxic exposure as part of acute acclimatisation. Although this process is incompletely understood, insights have been gained through studies of the hypoxia-inducible factor (HIF) hydroxylase system. Genetic studies implicate these pathways widely in the integrated physiology of hypoxia, through effects on developmental or adaptive processes. In keeping with this, mice that are heterozygous for the principal HIF prolyl hydroxylase, PHD2, show enhanced ventilatory sensitivity to hypoxia and carotid body hyperplasia. Here we have sought to understand this process better through comparative analysis of inducible and constitutive inactivation of PHD2 and its principal targets HIF-1α and HIF-2α. We demonstrate that general inducible inactivation of PHD2 in tamoxifen-treated Phd2(f/f);Rosa26(+/CreERT2) mice, like constitutive, heterozygous PHD2 deficiency, enhances hypoxic ventilatory responses (HVRs: 7.2 ± 0.6 vs. 4.4 ± 0.4 ml min(-1) g(-1) in controls, P < 0.01). The ventilatory phenotypes associated with both inducible and constitutive inactivation of PHD2 were strongly compensated for by concomitant inactivation of HIF-2α, but not HIF-1α. Furthermore, inducible inactivation of HIF-2α strikingly impaired ventilatory acclimatisation to chronic hypoxia (HVRs: 4.1 ± 0.5 vs. 8.6 ± 0.5 ml min(-1) g(-1) in controls, P < 0.0001), as well as carotid body cell proliferation (400 ± 81 vs. 2630 ± 390 bromodeoxyuridine-positive cells mm(-2) in controls, P < 0.0001). The findings demonstrate the importance of the PHD2/HIF-2α enzyme-substrate couple in modulating ventilatory sensitivity to hypoxia., (© 2015 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Oxygen-dependent prolyl hydroxylation of hypoxia-inducible factor (HIF) by a set of closely related prolyl hydroxylase domain enzymes (PHD1, 2 and 3) regulates a range of transcriptional responses to hypoxia. This raises important questions about the role of these oxygen-sensing enzymes in integrative physiology. We investigated the effect of both genetic deficiency and pharmacological inhibition on the change in ventilation in response to acute hypoxic stimulation in mice. Mice exposed to chronic hypoxia for 7 days manifest an exaggerated hypoxic ventilatory response (HVR) (10.8 ± 0.3 versus 4.1 ± 0.7 ml min(-1) g(-1) in controls; P < 0.01). HVR was similarly exaggerated in PHD2(+/-) animals compared to littermate controls (8.4 ± 0.7 versus 5.0 ± 0.8 ml min(-1) g(-1); P < 0.01). Carotid body volume increased (0.0025 ± 0.00017 in PHD2(+/-) animals versus 0.0015 ± 0.00019 mm(3) in controls; P < 0.01). In contrast, HVR in PHD1(-/-) and PHD3(-/-) mice was similar to littermate controls. Acute exposure to a small molecule PHD inhibitor (PHI) (2-(1-chloro-4-hydroxyisoquinoline-3-carboxamido) acetic acid) did not mimic the ventilatory response to hypoxia. Further, 7 day administration of the PHI induced only modest increases in HVR and carotid body cell proliferation, despite marked stimulation of erythropoiesis. This was in contrast with chronic hypoxia, which elicited both exaggerated HVR and cellular proliferation. The findings demonstrate that PHD enzymes modulate ventilatory sensitivity to hypoxia and identify PHD2 as the most important enzyme in this response. They also reveal differences between genetic inactivation of PHDs, responses to hypoxia and responses to a pharmacological inhibitor, demonstrating the need for caution in predicting the effects of therapeutic modulation of the HIF hydroxylase system on different physiological responses.

Background: Patients with malignant tumours of the upper gastrointestinal tract tumours exhibit important alarm symptoms such as dysphagia that warrant clinical investigations. An endoscopic examination of the upper gastrointestinal tract will be required in most cases. This study evaluates the diagnostic potential of index endoscopy in a random population of patients with dysphagia., Methods: This is a retrospective analysis of prospectively collected data over 10 years. Patients with previous endoscopic evaluation or upper gastrointestinal pathology were excluded from the study. Data was analysed to see the number and frequency of abnormal findings in upper gastrointestinal tract, and their significance in relation to the presenting symptoms., Results: Total number of index endoscopies was 13, 881. 913 patients were included in the study including 465 males (age range: 17-92 years, median: 55 years) and 448 females (age range: 18-100, median: 59 years), with male to female ratio of 1.04: 1. Oesophagus was abnormal in 678 cases (74%) and biopsies were taken in 428 patients (47%). Superficial oesophagitis, Barrett's oesophagus, oesophageal cancer, and oesophageal ulcer were main histological findings. Age more than 50 years and weight loss were significant predictors of oesophageal cancer (p < 0.0001). Male gender, heartburn, epigastric pain, weight loss and vomiting were significantly related to Barrett's oesophagus. A total of 486 gastric and 56 duodenal biopsies were also taken. There were 20 cases of gastric adenocarcinoma., Conclusion: OGD is an effective initial investigation to assess patients with dysphagia, especially males above the age of 50 years. Patients may be started on treatment or referred for further investigations, for example, a barium meal in the absence of any anatomical abnormality.

The prognosis of gastric cancer is closely related to the stage of disease at diagnosis. Early gastric cancer, whereby disease is limited to mucosa and submucosa, confers a survival rate of greater than 90% in 5 years in many centres. Gastric cancer is still a major cause of cancer mortality worldwide. In high incidence areas such as Japan, screening of asymptomatic population has been advocated. However, in Western countries, mass screening is not cost-effective. Hence, strategy has been directed to screen symptomatic individuals who are at higher risk of gastric cancer. Most patients with early gastric cancer present with symptoms indistinguishable from benign peptic ulcer disease. Screening for this group of patients improves detection rate of early gastric cancer and therefore its prognosis. Endoscopy for surveillance of premalignant lesions has been explored with this objective in mind. Serology testing for biomarkers such as pepsinogen, anti-Helicobacter pylori antibody and gastrin has been studied as an alternative to endoscopy. There is compelling evidence for the role of H. pylori in the initiation of Correa's cascade (stepwise progression from chronic active gastritis, atrophic gastritis, intestinal metaplasia, dysplasia and finally adenocarcinoma). Regression of premalignant lesions has been demonstrated with H. pylori eradication. However, it is not known whether this might effectively prevent gastric cancer in either low or high-risk population.

Background: Gastric cancer has in the past proven to be a difficult disease to cure. Surgery is the most effective treatment, although the extent of lymphadenectomy undertaken is controversial. This paper examines trends in the detection and treatment of gastric cancer, the move toward targeted surgery, and their impact on survival., Methods: From 1982 to 2001, 430 patients with gastric cancer were under the care of a single surgeon at the same institution. Copies of the operation records, discharge summaries, and histology reports were retained and subsequently reviewed., Results: Thirty-six patients were excluded from the analysis. Two hundred and five patients (52%) had potentially curative surgery for adenocarcinoma and 189 had incurable disease. During the 20-year period, overall 5-year survival increased significantly, from 15% to 41% (P < 0.01). The number of curative procedures also increased significantly, from 33% to 73% (P1 < 0.001) as disease was detected earlier, and 5-year survival in these patients increased from 26% to 46%. Eighty-seven D1, 92 D2, and 26 targeted procedures were performed, with 30-day mortalities of 5%, 9%, and 5%, respectively. The 5-year survival was 47% for D1, 42% for D2, and 66% for targeted surgery., Conclusion: This paper demonstrates an improvement in the stage at which disease was detected and improvement in long-term survival for patients with gastric cancer. The development of targeted surgery has shown promising early results.

Background: In the surgical management of gastric carcinoma, regional lymphatic spread is of prognostic importance. The fifth edition of the Union Internacional Contra la Cancrum classification has been shown to be reproducible, practical and of significant prognostic use. The tumour node metastasis (TNM) system requires at least 15 lymph nodes to be acquired and examined for staging to be accurate. This has raised concern over the consistency with which the requisite numbers of nodes would be acquired. This study was performed to assess how consistently surgically managed cases of gastric cancer in the West Midlands fulfilled this requirement to allow accurate staging., Methods: Data from the West Midlands Cancer Intelligence Unit on all cases of gastric cancer registered from 1998 to 1999 were obtained and the number of lymph nodes documented for each surgically managed case was assessed., Results: Overall, only 31.0 per cent of surgically resected cases could be assessed accurately according to the TNM system. The proportion staged accurately varied widely across hospitals from 10.9 to 76.0 per cent., Conclusion: These results reflect the need for improved N staging across the region to aid the appropriate multimodal treatment of patients.

This randomised, double-blind, placebo-controlled study was designed to evaluate the ability of the orally administered matrix metalloproteinase inhibitor, marimastat, to prolong survival in patients with non-resectable gastric and gastro-oesophageal adenocarcinoma. Three hundred and sixty-nine patients with histological proof of adenocarcinoma, who had received no more than a single regimen of 5-fluorouracil-based chemotherapy, were randomised to receive either marimastat (10 mg b.d.) or placebo. Patients were treated for as long as was tolerable. The primary endpoint was overall survival with secondary endpoints of time to disease progression and quality of life. At the point of protocol-defined study completion (85% mortality in the placebo arm) there was a modest difference in survival in the intention-to-treat population in favour of marimastat (P=0.07 log-rank test, hazard ratio=1.23 (95% confidence interval 0.98-1.55)). This survival benefit was maintained over a further 2 years of follow-up (P=0.024, hazard ratio=1.27 (1.03-1.57)). The median survival was 138 days for placebo and 160 days for marimastat, with 2-year survival of 3% and 9% respectively. A significant survival benefit was identified at study completion in the pre-defined sub-group of 123 patients who had received prior chemotherapy (P=0.045, hazard ratio=1.53 (1.00-2.34)). This benefit increased with 2 years additional follow-up (P=0.006, hazard ratio=1.68 (1.16-2.44)), with 2-year survival of 5% and 18% respectively. Progression-free survival was also significantly longer for patients receiving marimastat compared to placebo (P=0.009, hazard ratio=1.32 (1.07-1.63)). Marimastat treatment was associated with the development of musculoskeletal pain and inflammation. Events of anaemia, abdominal pain, jaundice and weight loss were more common in the placebo arm. This is one of the first demonstrations of a therapeutic benefit for a matrix metalloproteinase inhibitor in cancer patients. The greatest benefit was observed in patients who had previously received chemotherapy. A further randomised study of marimastat in these patients is warranted., (Copyright 2002 Cancer Research UK)

Background: A large proportion of patients attending open access endoscopy have histological and gross pathological findings that are potentially premalignant. The proportion of these patients who go on to develop malignancies and the timescale over which this occurs are uncertain., Aims: This study aims to discover the incidence of gastric cancers in this "high risk" group and to examine the potential for their early diagnosis and treatment., Patients: A total of 1753 patients attended open access endoscopy. From these, 166 patients with dysplasia, intestinal metaplasia, atrophic gastritis, foveolar hyperplasia, regenerative changes, polyps, or ulcers who agreed to undergo annual surveillance endoscopy were studied., Methods: Patients were endoscoped annually. Additionally, patients with ulcers were re-examined at two monthly intervals until ulcer healing. Cancers detected were treated by gastrectomy., Results: Twenty two of 1753 patients attending open access endoscopy had gastric cancer (1.3%). In the study population, 14 cancers were detected over 10 years (8.4 %). These were of an earlier stage than those detected at open access (stage I and II 67% v 23%; p<0.05) and five year survival was significantly higher (50% v 10%; p=0.006). In atrophic gastritis and intestinal metaplasia the risk of malignancy was 11%., Conclusions: In patients with atrophic gastritis or intestinal metaplasia, annual surveillance can detect most new tumours at an early stage with a major improvement in survival. Potential benefits of such a surveillance programme are large and warrant further investigation in a multicentre randomised controlled trial.

Aims: Accurate staging of gastric, oesophageal and oesophagogastric cancer is essential to avoid unnecessary laparotomies in patients where only palliation is appropriate. This requires a multimodal approach utilizing endoscopy, computed tomography and laparoscopy. Previous authors have found that the presence of free peritoneal tumour cells (FPTCs) detected at laparoscopy or laparotomy confers a poorer prognosis. However, various methods of peritoneal lavage are described. The aim of this study was to evaluate the prognostic value of our technique of peritoneal lavage., Materials and Methods: 88 staging laparoscopies with peritoneal lavage were carried out between March 1997 and February 1999 on patients eligible for attempted curative resection of a gastric, oesophageal or oesophagogastric cancer. During laparoscopy the pelvis was irrigated with 200 ml of normal saline, with 100 ml aspirated and examined cytologically. Patients were followed-up until September, 1999., Results: 11 patients had FPTC-positive cytology with a median survival following laparoscopy of 122 days (95% CI 82-161) with only a single patient surviving more than one year. In the FPTC-negative group, median survival was 378 days (95% CI 256,-). Log-rank Chi(2)=16.7, P<0.001., Conclusions: The presence of FPTCs detected by our technique is a contraindication to attempted curative resection - palliation only (medical or surgical) is appropriate., (Copyright Harcourt Publishers Limited.)

BACKGROUND: Despite encouraging retrospective and non-randomized trials, two large prospective, randomized trials of D1 vs D2 resections show double the mortality in the D2 group, with no increase in long-term survival. However, the D2 resection still offers the only hope of cure when N2 nodes are involved. We propose a reclassification of the International Union Against Cancer TNM "N" staging to a system with an anatomical basis that is useful in defining the surgery performed. Junctional nodes lying between the N1 and N2 tiers will act as a guide to surgery. Where these nodes are uninvolved, the probability of gastric bed (N2) involvement is low and the radical D2 dissection with its higher mortality and morbidity can be avoided.CONCLUSION: Such "stage-appropriate" surgery will reduce the number of D2 resections while ensuring that patients with N2 disease are not denied curative surgery. A prospective, randomized, controlled trial of targeted surgery is required.

Cimetidine is thought to inhibit suppressor T-lymphocyte function and preliminary evidence from a randomized trial indicated that it might prolong survival for patients with operable and inoperable gastric cancer. The British Stomach Cancer Group conducted a randomized, double-blind, placebo-controlled trial examining the effects of cimetidine (400 mg or 800 mg twice a day) on the survival of patients with early (stages I, II and III: n = 229) and advanced (stages IVa and IVb: n = 201) gastric cancer. The primary end point was death. A total of 442 patients were randomized by 59 consultants in 39 hospitals between February 1990 and March 1995. Log-rank survival analysis was used to assess differences between the groups. Three hundred and forty patients died during the study: 166 (49%) in the cimetidine treatment groups and 174 (51%) in the placebo groups. Median survival for patients receiving cimetidine was 13 months (95% confidence interval (CI) 9-16 months) and 11 months in the placebo arm (95% CI 9-14 months). There was no significant difference in survival between the two treatment groups (P = 0.42) or between different doses of cimetidine tablets (P = 0.46). Five-year survival of those patients randomized to cimetidine was 21% compared to 18% for those patients randomized to placebo. Cimetidine at a dose of 400 mg or 800 mg twice a day does not have a significant influence on the survival of patients with gastric cancer compared to placebo.

Background: Reported operative mortality and survival rates following total pelvic exenteration (TPE) for recurrent pelvic neoplasia are now as good as those for many primary treatments. The currently accepted primary treatments for these tumours are, however, still either radiotherapy alone or radiotherapy and chemotherapy. The primary aim of this study was to evaluate the safety and tolerability of TPE and secondarily to ascertain survival after TPE., Methods: This was a phase II study of 50 patients with locally advanced pelvic tumours who underwent TPE., Results: Thirty-two patients (64 per cent) underwent TPE for recurrent carcinoma of the cervix, seven (14 per cent) for rectal cancer, three (6 per cent) for vulval carcinoma, three (6 per cent) for vaginal carcinoma, two (4 per cent) for prostate cancer and three (6 per cent) for other tumours. The 30-day mortality rate was 8 per cent with an in-hospital mortality rate of 16 per cent. The crude morbidity rate was 62 per cent, with 23 patients (46 per cent) having grade III or IV toxicity. A complete response was achieved in 63 per cent and a partial response in 37 per cent of patients. The overall median survival time was 86 weeks; it was 111 weeks in patients in whom a complete response was achieved., Conclusion: The survival and operative mortality rates that are now attainable with TPE are comparable to those achieved with chemoradiotherapy in advanced pelvic neoplasia. TPE should no longer be reserved for salvage therapy and should perhaps be compared with chemoradiotherapy as first-line treatment in a phase III randomized trial in patients with these tumours.

A questionnaire was sent to 53 patients who had undergone an upper gastrointestinal endoscopy under total intravenous anaesthesia (TIVA) using intermittent Propofol. All of the patients would accept the same technique again. Out of 20 patients who had previously had the procedure performed under Diazepam sedation, 18 preferred the use of Propofol. This technique can only be used with an anaesthetist present.

The role of radical surgery for early gastric cancer has become a topic of considerable debate. Despite excellent results from Japan and several retrospective and uncontrolled trials, results from two large prospective randomized trials appear to demonstrate no benefit from D2 compared to the D1 resections. These trials have prompted a move away from radical lymph-node dissection. We argue that this reasoning is flawed and based not on the lack of efficacy of the D2 resection but in an attempt to reduce post-operative mortality and morbidity. Post-operative complications are largely a result of distal pancreatectomy and splenectomy and the relative inexperience of surgeons performing the operations. By preserving these organs and concentrating surgery to specialized centres the complication rate of radical surgery can be significantly reduced to approximate that of non-radical surgery. Lymph-node metastasis to the N2 nodes in early gastric cancer has been shown to be as high as 23%. Non-radical surgery poses significant risks of leaving residual disease. Radical surgery must remain the operation of choice if non-curative surgery for a curable condition is to be avoided.