Maria Grazia Piva

Analysis of Helicobacter pylori vacA and cagA genotypes and serum antibody profile in benign and malignant gastroduodenal diseases.

Background—Helicobacter pylori species comprise different strains, cytotoxic and non-cytotoxic, which can be identified on the basis of their genomic pattern. Aims—(1) To evaluate the polymorphism of the vacA gene and to ascertain whether thecagA gene is present in patients with gastric adenocarcinoma. (2) To study the anti-H pylori antibody profile using western blotting. Patients—Twenty one patients with gastric adenocarcinoma and 71 with H pyloriassociated benign disease (nine gastric ulcer, 29 duodenal ulcer, 25 antral gastritis, and eight duodenitis). Methods—The polymerase chain reaction was used to verify the presence or absence ofcagA and to study the polymorphism of vacA in gastric mucosal samples obtained during endoscopy for patients with benign diseases and at surgery for patients with gastric adenocarcinoma. Fasting sera were used to assess anti-H pylori antibodies against different H pyloriantigens by western blotting. Results—cagAgene and the allele s1 of vacAwere significantly less frequent in patients with antral gastritis (60% and 60%) compared with patients with gastric adenocarcinoma (94% and 100%) and with other non-malignant gastroduodenal diseases (93% and 87%) (χ2=16.01, p<0.001; and χ2=13.97, p<0.01). In patients with gastric adenocarcinoma, antibodies against a 74 kDa H pylori antigen were less frequently found than in patients with benign diseases. Conclusions—H pylori infection caused bycagApositive/vacA s1 strains is a frequent finding in patients with gastric adenocarcinoma. Prospective studies are needed to confirm whether the low incidence of positive serological response to the 74 kDa H pyloriantigen in patients with gastric adenocarcinoma is important.

CEA mRNA identification in peripheral blood is feasible for colorectal, but not for gastric or pancreatic cancer staging.

Objective: It has been suggested that the molecular identification of cancer cells in the circulation may be useful in predicting the presence of micrometastasis in several cancer types. The aim of the present study was therefore to assess the feasibility of CEA mRNA identification in blood for diagnosing and staging colorectal, gastric and pancreatic cancer. Methods: We studied 16 control subjects, 69 patients with colorectal (CRC), 30 with gastric (GC), 27 with pancreatic cancer (PC) and 8 with benign diseases of the pancreatobiliary tree. At diagnosis CEA mRNA was identified in peripheral blood by means of a RT-PCR procedure. Results: The specificity of this test in control subjects was 94%, and its sensitivity in identifying CRC, GC and PC were 34, 37 and 41%, respectively. False-positive findings were recorded in 25% patients with benign diseases. No association was found between CEA mRNA and stage in patients with GC or PC. In CRC patients, positive CEA mRNA findings were correlated with local spread (χ2 = 14.6, p < 0.01), lymph node (χ2 = 18.95, p < 0.001) and distant metastasis (χ2 = 11.3, p < 0.001). In these cases, CEA mRNA, but not CEA, was entered in stepwise discriminant analysis to classify the presence of lymph node metastasis. Conclusions: The molecular detection of micrometastasis in the blood by means of CEA mRNA identification is feasible for colorectal, but not for gastric or pancreatic cancer staging. Further studies are needed in order to define the clinical utility of this marker also in follow-up protocols.

Helicobacter pylori Infection in Children and Adults: A Single Pathogen But a Different Pathology

Background. The aims of this retrospective study were to ascertain in large series of children and adults: the relationship of the infecting strain to gastric mucosal lesions; and the relationship of the infecting strain to its duodenal localization.

Serum antibodies anti-H. pylori and anti-CagA: a comparison between four different assays.

The authors compare efficacy of two ELISA assays (one supplied by DIAMEDIX [Delta Biological s.r.l.], and the other by RADIM [RADIM I]) in detecting total anti‐H. pylori antibodies, and of two further ELISA methods (one supplied by EUROSPITAL [Helori CTX IgG] and the other by RADIM [RADIM 2]) in identifying anti‐CagA antibodies, using sera from 69 controls (20 adults and 49 children) and from 96 patients, obtained before endoscopy. Seventy‐three of the patients had H. pylori infection, while the remaining 23 were H. pylori negative (histology and polymerase chain reaction [PCR]). Fifty‐two of the H. pylori positive patients, had cagA‐positive strain infection, identified by PCR. The DIAMEDIX assay was found to be more sensitive (92%) than RADIM 1 (79%) in identifying H. pylori positive patients, irrespective of the infecting strain. On the other hand, the DIAMEDIX assay was less specific than RADIM 1 for H. pylori‐negative patients (43% vs. 83%). However, when patients already treated for H. pylori infection were excluded from the group of H. pylori‐negative patients, the DIAMEDIX assay had a specificity of 89%. In identifying anti‐CagA antibodies, the kit supplied by RADIM (RADIM 2) had a sensitivity of 90% and a specificity of 94%, whereas that supplied by EUROSPITAL had a sensitivity of 100% and a specificity of 76%. The performances of the two methods in the identification of anti‐CagA antibodies were found to be similar. The authors conclude that, in view of its high sensitivity, the DIAMEDIX assay may be useful in screening for H. pylori infection. J. Clin. Lab. Anal. 13:194–198, 1999.

Retrovirus-mediated herpes simplex virus thymidine kinase gene transfer in pancreatic cancer cell lines: an incomplete antitumor effect.

Introduction The transfer of drug-susceptible (suicide) genes to tumor cells by retroviral or adenoviral vectors is a novel approach to the treatment of human tumors. Aims To ascertain the antitumor effect of retroviral transduction of the pancreatic cancer cell lines MIA PaCa 2, CAPAN-1, PANC1, and PSN1 with the herpes simplex virus thymidine kinase (HSV-TK) gene. Methodology The vector carried a neoselectable marker gene, the human interleukin-2 gene, an internal ribosome entry coding site, and the region coding HSV-TK. Results Twenty micromoles or less of ganciclovir did not modify nontransduced TK− cell growth, whereas ≥100 &mgr;mol completely inhibited TK− cell growth, indicating that this dosage is cytotoxic per se. The 4 TK− and the 4 transduced cell lines were treated daily with 0.001, 0.01, 0.1, 1, 10, and 20 &mgr;mol of ganciclovir for 13 days. CAPAN-1 cell growth was completely inhibited by 0.1 &mgr;mol of ganciclovir; higher doses were required to kill PANC1 (10 &mgr;mol) and PSN1 (20 &mgr;mol). MIA PaCa 2 cell growth decreased following a 20-&mgr;mol ganciclovir dosing. The bystander effect was great in the CAPAN-1 cell line and moderate in PANC1; no bystander effect was recorded in MIA PaCa 2 and PSN1 cell lines. Conclusion Gene therapy with HSV-TK for pancreatic cancer seems effective in only a limited number of tumor-derived cell lines, and this limits its application in vivo.

Portal but not peripheral serum levels of interleukin 6 could interfere with glucose metabolism in patients with pancreatic cancer

UNLABELLED Interleukin 6 (IL-6), an autocrine growth factor for many tumors, seems to favour tumor spread to the liver. Our aims were first to evaluate the pattern of portal and systemic IL-6 levels in patients with pancreatic cancer (PC, n = 18) and chronic pancreatitis (CP, n = 22) compared with controls (CS, n = 20); and second, to ascertain whether there was any relation between IL-6 levels and tumor spread or PC-associated Diabetes mellitus. For all subjects, a fasting serum sample was obtained from a cubital vein; a portal serum sample was obtained from nine PC and three CP patients. In cubital and portal sera we measured IL-6, interleukin 1 beta (IL-1b), CA 19-9, c-reactive protein (CRP) and amylase. Systemic IL-6 levels were significantly higher in PC patients than in CS. In PC, portal IL-6 levels were significantly higher than the corresponding systemic values. The same pattern was found in the three CP patients, whereas IL-1b, CA 19-9, CRP and amylase portal levels were the same as systemic values. No correlation was found between PC stage and systemic or portal IL-6 levels. Portal IL-6 levels were correlated with the corresponding fasting serum glucose values. A significant correlation was found between IL-6 values and CRP, ALT, total bilirubin, GGT and creatinine, but not amylase. IN CONCLUSION (1) Portal IL-6, which is partly of pancreatic origin, is first metabolised in the liver; (2) Systemic IL-6 reflects hepatic and renal functions rather than local conditions in the pancreas; (3) IL-6 does not appear to influence PC spread; (4) IL-6, which is released in large amounts by the inflamed pancreas, may contribute to determining diabetes, thus interfering with the signal transducing pathways involved in glucose metabolism in liver cells.