Karin A. Oien

Helicobacter pylori infection and chronic gastric acid hyposecretion

BACKGROUND & AIMS We have identified a subgroup of Helicobacter pylori-infected subjects with low or absent gastric acid output. The aim of this study was to document the morphological and functional abnormalities in these subjects and to assess the effect of eradicating the infection. METHODS The 16 hypochlorhydric subjects (6 men) had a mean age of 55 years (range, 36-79 years). They underwent a 14C-urea breath test, H. pylori serology, fasting gastrin, gastric autoantibodies, gastroscopy with antral and body biopsies, and measurement of peak acid output to pentagastrin (PAO(PG)). Their histology was compared with that of age- and sex-matched duodenal ulcer and nonulcer dyspepsia patients (16 each). H. pylori infection was eradicated in the hypochlorhydric subjects, and the investigations were repeated 6 months later. RESULTS Compared with controls, the hypochlorhydric subjects had less dense H. pylori colonization, body-predominant colonization and gastritis, and increased prevalence of body atrophy and intestinal metaplasia. Median PAO(PG) before eradication in the hypochlorhydric subjects was 1.1 mmol/h and increased to 12.6 mmol/h after eradication (P < 0.001), with no significant change in body atrophy or intestinal metaplasia. CONCLUSIONS In some subjects, chronic H. pylori infection produces a body-predominant gastritis and profound suppression of gastric acid secretion that is partially reversible with eradication therapy.

Mutant p53 drives metastasis and overcomes growth arrest/senescence in pancreatic cancer

TP53 mutation occurs in 50–75% of human pancreatic ductal adenocarcinomas (PDAC) following an initiating activating mutation in the KRAS gene. These p53 mutations frequently result in expression of a stable protein, p53R175H, rather than complete loss of protein expression. In this study we elucidate the functions of mutant p53 (Trp53R172H), compared to knockout p53 (Trp53fl), in a mouse model of PDAC. First we find that although KrasG12D is one of the major oncogenic drivers of PDAC, most KrasG12D-expressing pancreatic cells are selectively lost from the tissue, and those that remain form premalignant lesions. Loss, or mutation, of Trp53 allows retention of the KrasG12D-expressing cells and drives rapid progression of these premalignant lesions to PDAC. This progression is consistent with failed growth arrest and/or senescence of premalignant lesions, since a mutant of p53, p53R172P, which can still induce p21 and cell cycle arrest, is resistant to PDAC formation. Second, we find that despite similar kinetics of primary tumor formation, mutant p53R172H, as compared with genetic loss of p53, specifically promotes metastasis. Moreover, only mutant p53R172H-expressing tumor cells exhibit invasive activity in an in vitro assay. Importantly, in human PDAC, p53 accumulation significantly correlates with lymph node metastasis. In summary, by using ‘knock-in’ mutations of Trp53 we have identified two critical acquired functions of a stably expressed mutant form of p53 that drive PDAC; first, an escape from KrasG12D-induced senescence/growth arrest and second, the promotion of metastasis.

Increased prevalence of precancerous changes in relatives of gastric cancer patients: critical role of H. pylori

BACKGROUND & AIMS Helicobacter pylori is believed to predispose to gastric cancer by inducing gastric atrophy and hypochlorhydria. First-degree relatives of patients with gastric cancer have an increased risk of developing gastric cancer. The aim of this study was to determine the prevalence of atrophy and hypochlorhydria and their association with H. pylori infection in first-degree relatives of patients with gastric cancer. METHODS H. pylori status, gastric secretory function, and gastric histology were studied in 100 first-degree relatives of patients with noncardia gastric cancer and compared with those of controls with no family history of this cancer. RESULTS Compared with healthy controls, relatives of patients with gastric cancer had a higher prevalence of hypochlorhydria (27% vs. 3%) but a similar prevalence of H. pylori infection (63% vs. 64%). Relatives of cancer patients also had a higher prevalence of atrophy (34%) than patients with nonulcer dyspepsia (5%) matched for H. pylori prevalence. Among the relatives of cancer patients, the prevalence of atrophy and hypochlorhydria was increased only in those with evidence of H. pylori infection, was greater in relatives of patients with familial cancer than in relatives of sporadic cancer index patients, and increased with age. Eradication of H. pylori infection produced resolution of the gastric inflammation in each subject and resolution of hypochlorhydria and atrophy in 50% of the subjects. CONCLUSIONS Relatives of patients with gastric cancer have an increased prevalence of precancerous gastric abnormalities, but this increase is confined to those with H. pylori infection. Consequently, prophylactic eradication of the infection should be offered to such subjects.

Markers of Adenocarcinoma Characteristic of the Site of Origin: Development of a Diagnostic Algorithm

Purpose: Patients with metastatic adenocarcinoma of unknown origin are a common clinical problem. Knowledge of the primary site is important for their management, but histologically, such tumors appear similar. Better diagnostic markers are needed to enable the assignment of metastases to likely sites of origin on pathologic samples. Experimental Design: Expression profiling of 27 candidate markers was done using tissue microarrays and immunohistochemistry. In the first (training) round, we studied 352 primary adenocarcinomas, from seven main sites (breast, colon, lung, ovary, pancreas, prostate and stomach) and their differential diagnoses. Data were analyzed in Microsoft Access and the Rosetta system, and used to develop a classification scheme. In the second (validation) round, we studied 100 primary adenocarcinomas and 30 paired metastases. Results: In the first round, we generated expression profiles for all 27 candidate markers in each of the seven main primary sites. Data analysis led to a simplified diagnostic panel and decision tree containing 10 markers only: CA125, CDX2, cytokeratins 7 and 20, estrogen receptor, gross cystic disease fluid protein 15, lysozyme, mesothelin, prostate-specific antigen, and thyroid transcription factor 1. Applying the panel and tree to the original data provided correct classification in 88%. The 10 markers and diagnostic algorithm were then tested in a second, independent, set of primary and metastatic tumors and again 88% were correctly classified. Conclusions: This classification scheme should enable better prediction on biopsy material of the primary site in patients with metastatic adenocarcinoma of unknown origin, leading to improved management and therapy.

Co-amoxiclav jaundice: clinical and histological features and HLA class II association

BACKGROUND AND AIMS Jaundice associated with co-amoxiclav has been increasingly recognised. We aimed to characterise its clinical and histological features and to investigate linkage with human leucocyte antigen class II haplotypes. METHODS We identified cases in the west of Scotland in the period 1991–1997 and performed polymerase chain reaction amplification and oligonucleotide probing on whole blood. RESULTS Twenty two cases were identified (10 male, mean age 59.1 years). Jaundice occurred a median of 17 days after drug commencement, with a median peak bilirubin level of 225 μmol/l (range 84–598) and median duration of jaundice 69 days (range 29–150). Two patients had primary biliary cirrhosis and two other patients had persistently abnormal liver biochemistry on follow up. One death occurred in a frail elderly woman despite resolving jaundice. The frequency of jaundice was 1 in 78 209 co-amoxiclav prescriptions. Liver biopsy, available in 12 patients, showed perivenular bilirubinostasis, accompanying reactive ceroid laden macrophages, and portal inflammation with focal injury to interlobular bile ducts. Fourteen of 20 patients had DRB1*1501 compared with 27 of 134 controls (p<2.5×10–6; odds ratio (OR) 9.25; relative risk (RR) 6.43). Of these, seven patients were homozygous for DRB1*1501(p< 10–8; OR 35.54; RR=8.68) compared with two of 134 controls. All patients with DRB1*1501 had the extended haplotype DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602. There were no clinical or histological differences between genotypes. CONCLUSIONS Co-amoxiclav associated hepatotoxicity may have a genetic basis and be delayed, severe, and prolonged, although complete recovery is usual.

Reduction of Raf-1 Kinase Inhibitor Protein Expression Correlates with Breast Cancer Metastasis

Purpose: Raf-1 kinase inhibitor protein (RKIP) was originally identified as the first physiologic inhibitor of the Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (ERK) pathway. This pathway regulates fundamental cellular functions, including those that are subverted in cancer cells, such as proliferation, transformation, survival, and metastasis. Recently, RKIP has been recognized as a strong candidate for a metastasis suppressor gene in cell and animal model systems. Therefore, we investigated whether RKIP expression is altered in clinical specimens of human primary breast cancers and their lymph node metastases. Experimental Design: Paraffin-embedded tumor samples from 103 breast cancer patients were examined immunohistochemically for the expression of RKIP, activated ERK, and apoptosis. The specificity of the antibodies used was validated by competition experiments with purified recombinant RKIP protein. Results: RKIP expression was high in breast duct epithelia and retained to varying degrees in primary breast tumors. However, in lymph node metastases, RKIP expression was highly significantly reduced or lost (P = 0.000003). No significant correlations were observed between RKIP expression and histologic type, tumor differentiation grade, size, or estrogen receptor status. Conclusion: This is the first study of RKIP expression in a large clinical cohort. It confirms the results of cell culture and animal studies, suggesting that in human breast cancer, RKIP is a metastasis suppressor gene whose expression must be down-regulated for metastases to develop. RKIP expression is independent of other markers for breast cancer progression and prognosis.

Loss of Apc allows phenotypic manifestation of the transforming properties of an endogenous K-ras oncogene in vivo

Oncogenic mutations in the K-ras gene occur in ≈50% of human colorectal cancers. However, the precise role that K-ras oncogenes play in tumor formation is still unclear. To address this issue, we have conditionally expressed an oncogenic K-rasV12 allele in the small intestine of adult mice either alone or in the context of Apc deficiency. We found that expression of K-rasV12 does not affect normal intestinal homeostasis or the immediate phenotypes associated with Apc deficiency. Mechanistically we failed to find activation of the Raf/MEK/ERK pathway, which may be a consequence of the up-regulation of a number of negative feedback loops. However, K-rasV12 expression accelerates intestinal tumorigenesis and confers invasive properties after Apc loss over the long term. In renal epithelium, expression of the oncogenic K-rasV12 allele in the absence of Apc induces the rapid development of renal carcinoma. These tumors, unlike those of intestinal origin, display activation of the Raf/MEK/ERK and Akt signaling pathways. Taken together, these data indicate that normal intestinal and kidney epithelium are resistant to malignant transformation by an endogenous K-ras oncogene. However, activation of K-rasV12 after Apc loss results in increased tumorigenesis with distinct kinetics. Whereas the effect of K-ras oncogenes in the intestine can been observed only after long latencies, they result in rapid carcinogenesis in the kidney epithelium. These data imply a window of opportunity for anti-K-ras therapies after tumor initiation in preventing tumor growth and invasion.

MicroRNA Molecular Profiles Associated with Diagnosis, Clinicopathologic Criteria, and Overall Survival in Patients with Resectable Pancreatic Ductal Adenocarcinoma

Purpose: MicroRNAs (miRNA) have potential as diagnostic and prognostic biomarkers and as therapeutic targets in cancer. We sought to establish the relationship between miRNA expression and clinicopathologic parameters, including prognosis, in pancreatic ductal adenocarcinoma (PDAC). Experimental Design: Global miRNA microarray expression profiling of prospectively collected fresh-frozen PDAC tissue was done on an initial test cohort of 48 patients, who had undergone pancreaticoduodenectomy between 2003 and 2008 at a single institution. We evaluated association with tumor stage, lymph node status, and site of recurrence, in addition to overall survival, using Cox regression multivariate analysis. Validation of selected potentially prognostic miRNAs was done in a separate cohort of 24 patients. Results: miRNA profiling identified expression signatures associated with PDAC, lymph node involvement, high tumor grade, and 20 miRNAs were associated with overall survival. In the initial cohort of 48 PDAC patients, high expression of miR-21 (HR = 3.22, 95% CI: 1.21–8.58) and reduced expression of miR-34a (HR = 0.15, 95% CI: 0.06–0.37) and miR-30d (HR = 0.30, 95% CI: 0.12–0.79) were associated with poor overall survival following resection independent of clinical covariates. In a further validation set of 24 patients, miR-21 and miR-34a expression again significantly correlated with overall survival (P = 0.031 and P = 0.001). Conclusion: Expression patterns of miRNAs are significantly altered in PDAC. Aberrant expression of a number of miRNAs was independently associated with reduced survival, including overexpression of miR-21 and underexpression of miR-34a. Summary: miRNA expression profiles for resected PDAC were examined to identify potentially prognostic miRNAs. miRNA microarray analysis identified statistically unique profiles, which could discriminate PDAC from paired nonmalignant pancreatic tissues as well as molecular signatures that differ according to pathologic features. miRNA expression profiles correlated with overall survival of PDAC following resection, indicating that miRNAs provide prognostic utility. Clin Cancer Res; 18(2); 534–45. ©2011 AACR.

Positive Mobilization Margins Alone Do Not Influence Survival Following Pancreatico-Duodenectomy for Pancreatic Ductal Adenocarcinoma

Objective:To determine the prognostic influence of residual tumor at or within 1 mm of the mobilization margins (R1Mobilization) compared with transection margins (R1Transection) following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC). Background:The prognostic strength of R1 status increases with frequency of margin positivity and is enhanced by protocol driven pathology reporting. Currently, margins are treated uniformly with tumor at or close to any margin considered of equal prognostic significance. The resection involves a mobilization phase freeing the posterior margin and anterior surface then a transection phase requiring lympho-vascular division forming the medial resection and pancreatic transection margin. The comparative assessment of the relative importance of tumor involvement of these different margins has not previously been investigated. Methods:Retrospective analysis of 148 consecutive resections for PDAC from 1996–2007 was performed. The individual (pancreatic transection, medial, posterior, and anterior surface) margins were separately identified and analyzed by a senior pathologist. An R1 resection was defined as microscopic evidence of tumor ≤1 mm from a resection margin. R1Mobilization tumor extension included both R1Anterior and R1Posterior cases; while R1Transection included pancreatic neck/body transection, R1Medial and adjacent transection margins. Results:R1 status was confirmed in 109 patients (74%). The medial (46%) and posterior (44%) margins were most commonly involved. R1 status was found to an independent predictor of poor outcome (P < 0.001). R1Mobilization involvement only (n = 48) was associated with a significantly longer median survival of 18.9 months (95% CI, 13.7–24.8) versus 11.1 months (95% CI, 7.1–15.0) for those with R1Transection tumor involvement (n = 61) (P < 0.001). There was no significant difference in the survival of the R1Mobilization compared with R0 group (P = 0.52). Conclusions:Following pancreaticoduodenectomy for PDAC, involvement of the transection margins in contrast to mobilization margins defines a group whose outcome is significantly worse. This may impact upon the allocation of adjuvant therapy within the setting of randomized controlled trials.

Cancers of unknown primary site: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

K. Fizazi1, F. A. Greco2, N. Pavlidis3, G. Daugaard4, K. Oien5 & G. Pentheroudakis3, on behalf of the ESMO Guidelines Committee* Department of Cancer Medicine, Institut Gustave Roussy, University of Paris Sud, Villejuif, France; Tennessee Oncology, Centennial Medical Center, Nashville, USA; Department of Medical Oncology, University of Ioannina, Ioannina, Greece; Department of Oncology 5073, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; University of Glasgow, Institute of Cancer Sciences, Glasgow, UK