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Janusz Jankowski

Publications and source records attributed to Janusz Jankowski.

13 recordsLinked to original sources
PubMed2006

Epidermal growth factor receptor kinase domain mutations in esophageal and pancreatic adenocarcinomas.

PURPOSE: Specific activating mutations within the epidermal growth factor receptor (EGFR) identify a subset of non-small cell lung cancers with dramatic sensitivity to the specific tyrosine kinase inhibitors (TKI), gefitinib and erlotinib. Despite the abundant expression of EGFR protein in a broad range of epithelial cancers, EGFR mutations have not been reported in a substantial fraction of other cancers. Given recent reports of TKI-responsive cases of esophageal and pancreatic cancer, this study was designed to determine the prevalence of EGFR mutations in these gastrointestinal cancers. EXPERIMENTAL DESIGN: We sequenced exons 18 to 21 of EGFR from 21 cases of Barrett's esophagus, 5 cases of high-grade esophageal dysplasia, 17 cases of esophageal adenocarcinoma, and 55 cases of pancreatic adenocarcinoma. Subsets of esophageal (n = 7) and pancreatic cancer cases (n = 5) were obtained from patients who were subsequently treated with gefitinib or erlotinib-capecitabine, respectively. RESULTS: Mutations of EGFR were identified in two esophageal cancers (11.7%), three cases of Barrett's esophagus (14.2%), and two pancreatic cancers (3.6%). The mutations consisted of the recurrent missense L858R and in-frame deletion delE746-A750, previously characterized as activating EGFR mutations in non-small cell lung cancer. We also identified the TKI drug resistance-associated EGFR T790M mutation in an untreated case of Barrett's esophagus and the corresponding adenocarcinoma. CONCLUSION: The presence of activating mutations within EGFR in both esophageal and pancreatic adenocarcinomas defines a previously unrecognized subset of gastrointestinal tumors in which EGFR signaling may play an important biological role. EGFR mutations in premalignant lesions of Barrett's esophagus also point to these as an early event in transformation of the esophageal epithelium. The role of genotype-directed TKI therapy should be tested in prospective clinical trials.

Adenocarcinoma↗
PubMed2005

Cancer prevention.

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Family Practice↗
PubMed2005

A family history of Barrett's oesophagus: another risk factor?

Barrett's oesophagus and oesophageal adenocarcinoma, although increasingly common, have no known genetic cause. In this report we describe a family with a remarkable history of Barrett's oesophagus and adenocarcinoma. The index case is a 76-year-old man with adenocarcinoma arising within Barrett's oesophagus. Two of his three brothers, aged 68 and 78 years, also developed adenocarcinoma arising in Barrett's oesophagus and the remaining 67-year-old brother has severe dysplasia in biopsies from Barrett's oesophagus. The sons and daughters of the index case requested screening and all had histologically confirmed short-segment Barrett's oesophagus. This kindred appears to be genetically susceptible to Barrett's oesophagus and oesophageal adenocarcinoma. Pooling of data from this and other Barrett's families may allow successful linkage analysis.

Adenocarcinoma↗
PubMed2004

An antiapoptotic role for gastrin and the gastrin/CCK-2 receptor in Barrett's esophagus.

Mechanisms by which premalignant Barrett's metaplasia (BM) progresses to esophageal adenocarcinoma are currently being sought. This study investigated the role played by the polypeptide hormone gastrin, specifically its antiapoptotic effects through activation of protein kinase B/Akt (PKB/Akt). In esophageal cell lines with low basal levels of activated PKB/Akt, phosphorylation could be induced by exogenous amidated gastrin. High basal levels of activated PKB/Akt were linked to endogenous gastrin expression and were reduced by treatment with a cholecystokinin-type 2 receptor (CCK-2R) antagonist. Expression of a constitutively active splice variant of the CCK-2R additionally increased basal activation of PKB/Akt. It is proposed that gastrin acting in an autocrine and endocrine manner via a CCK-2R isoform may activate PKB/Akt and that with expression of gastrin and CCK-2R isoforms increasing in BM samples, gastrin may aid progression of BM through amplification of antiapoptotic pathways. Evidence for this proposal was provided through the observed specific up-regulation of PKB/Akt in BM samples.

Adenocarcinoma↗
PubMed2004

A critical review of the diagnosis and management of Barrett's esophagus: the AGA Chicago Workshop.

BACKGROUND & AIMS: The diagnosis and management of Barrett's esophagus (BE) are controversial. We conducted a critical review of the literature in BE to provide guidance on clinically relevant issues. METHODS: A multidisciplinary group of 18 participants evaluated the strength and the grade of evidence for 42 statements pertaining to the diagnosis, screening, surveillance, and treatment of BE. Each member anonymously voted to accept or reject statements based on the strength of evidence and his own expert opinion. RESULTS: There was strong consensus on most statements for acceptance or rejection. Members rejected statements that screening for BE has been shown to improve mortality from adenocarcinoma or to be cost-effective. Contrary to published clinical guidelines, they did not feel that screening should be recommended for adults over age 50, regardless of age or duration of heartburn. Members were divided on whether surveillance prolongs survival, although the majority agreed that it detects curable neoplasia and can be cost-effective in selected patients. The majority did not feel that acid-reduction therapy reduces the risk of esophageal adenocarcinoma but did agree that nonsteroidal antiinflammatory drugs are associated with a cancer risk reduction and are of promising (but unproven) value. Participants rejected the notion that mucosal ablation with acid suppression prevents adenocarcinoma in BE but agreed that this may be an appropriate strategy in a subgroup of patients with high-grade dysplasia. CONCLUSIONS: Based on this review of BE, the opinions of workshop members on issues pertaining to screening and surveillance are at variance with published clinical guidelines.

Adenocarcinoma↗
PubMed2004

Acid suppression and chemoprevention in Barrett's oesophagus.

Barrett's oesophagus is a pre-malignant condition affecting 1% of the population in the West. Even though most patients with Barrett's will not develop oesophageal cancer, the incidence of adenocarcinoma is 0.45-1%, conferring a 40-fold increased risk compared with the general population. The risk rises to 40-50% within 5 years for those with high grade dysplasia. Currently, the only strategies available to diminish adenocarcinoma rates are surveillance endoscopy, endoscopic thermal or photodynamic ablation or tissue resection. The latter options are reserved for those who already have dysplasia. 10-50% of patients undergoing oesophagectomy for high grade dysplasia have been shown to have adenocarcinoma. Therefore approaches are needed to be that either remove or prevent stimuli propelling patients down the dysplasia-adenocarcinoma pathway. Both gastric acid and bile acids have been reported as potential insults involved in the pathogenesis of Barrett's oesophagus. This is thought to be mediated by a range of molecules including cyclo-oxygenase-2, c-myc and mitogen-activated protein kinase signalling. Proton pump inhibitors not only suppress acid but also bile reflux, although symptom control is a poor guide as to adequacy of acid suppression. There is some evidence that proton pump inhibitors cause partial regression in Barrett's oesophagus length, although the data is contradictory. Proton pump inhibitors have also been shown to increase cell differentiation and apoptosis, reduce proliferation and COX-2 levels, with the supposition that this may diminish cancer risk. However this role in decreasing cancer risk has not yet been evaluated. The use of NSAIDS and aspirin, most likely via inhibition of COX-2 and other inflammatory pathways, is associated with a reduction of adenocarcinoma rates. Both PPIs and NSAIDs/Aspirin may therefore be potential chemopreventative agents but further studies are required to appraise their use.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Barrett's esophagus: environmental influences in the progression of dysplasia.

Barrett's esophagus (BE) is composed of multiple lineages including Paneth cells and endocrine cells in addition to gastric and intestinal cells. Although the origin of the BE stem cell is a matter of conjecture, the stem cells are clearly multipotent, and therefore the phenotype is restricted by genomic imprinting (termed restricted potency). Recent evidence suggests that the microenvironment may select various lineages. In this regard the proportion of gastric and specialized intestinal metaplastic cells has been attributed to the composition of the refluxate, acid or bile, respectively. Experimental evidence also implicates specific xenobiotics in this process, including bile acids. In particular we discuss the potential biologic roles of bile acids in epithelial adaptation from in vivo and in vitro models.

Adaptation, Physiological↗
PubMed2002

Gastroenterology.

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Attitude of Health Personnel↗