hMSH2 is the most commonly mutated MMR gene in a cohort of Greek HNPCC patients

Germline mutations in genes encoding proteins involved in DNA mismatch repair are responsible for the autosomal dominantly inherited cancer predisposition syndrome hereditary nonpolyposis colorectal cancer (HNPCC). We describe here analysis of hMLH1 and hMSH2 in nine Greek families referred to our centre for HNPCC. A unique disease-causing mutation has been identified in seven out of nine (78%) families. The types of mutations identified are nonsense (five out of seven) (hMLH1: E557X, R226X; hMSH2: Q158X, R359X and R711X), a 2 bp deletion (hMSH2 1704_1705delAG) and a 2.2 kb Alu-mediated deletion encompassing exon 3 of the hMSH2 gene. The majority of mutations identified in this cohort are found in hMSH2 (77.7%). Furthermore, four of the mutations identified are novel. Finally, a number of novel benign variations were observed in both genes. This is the first report of HNPCC analysis in the Greek population, further underscoring the differences observed in the various geographic populations.

Staging of ampullary and pancreatic carcinoma: comparison between endosonography and surgery

BACKGROUND

The aim of the study was to update our previously published data on the clinical TNM staging of ampullary and pancreatic carcinoma by endosonography.

METHODS

Endosonography was performed in 70 patients with pancreatic cancer and in 32 patients with ampullary carcinoma. TNM staging was carried out before surgery and compared with findings of histology and/or surgery.

RESULTS

Endosonography was accurate in staging the depth of tumor invasion. Early-stage carcinomas could be distinguished from advanced cancers. Nonresectability was accurately assessed on the basis of vascular involvement using real-time ultrasound. Tumor compression due to peritumoral pancreatitis and direct tumor invasion into the base of the mesocolon could not be diagnosed by endosonography. The overall accuracy in tumor staging for pancreatic and ampullary carcinomas was 83.6% and 84.4%, respectively. Endosonography was accurate in diagnosing regional lymph node metastases but not accurate in defining nonmetastatic lymphadenopathy and distant metastases.

CONCLUSION

Endosonography was accurate in staging tumor stage and lymph node metastases. Minimally invasive methods of resection for superficial ampullary cancers should be based on endosonography staging.

Prognosis of esophageal cancers preoperatively staged to be locally invasive (T4) by endoscopic ultrasound (EUS): a multicenter retrospective cohort study

BACKGROUND

Endosonography is a significant advance in the preoperative staging (TNM classification) of esophageal cancer. Its accuracy for evaluating depth of tumor invasion is over 80%.

METHODS

A multicenter retrospective cohort study of patients with esophageal carcinomas defined to be invasive (T4) by endosonography was performed to compare the survival of surgically and nonsurgically treated patients. Median survival time, overall mortality, and Kaplan-Meier survival curves were compared by treatment group. Univariate and Cox regression analysis were used to evaluate the effects of various prognostic factors and treatment on the risk of death.

RESULTS

A total of 79 patients were studied. The surgical group (Group I, n = 42) was significantly younger and had more distal tumors (adenocarcinomas) than the nonsurgical group (Group II, n = 37). Endosonography was significantly more accurate than CT scanning in identifying tumor invasion (87.5% versus 43.8%, respectively, p = .0002). Overall mortality rate was not significantly different between treatment groups; 59.5% of the surgical group and 64.9% of the nonsurgical group were dead at follow-up (p = 0.65). Similarly, the median survival times of Group I and Group II patients were similar (5.2 and 7.0 months, respectively, p = 0.50). Survival curves for the two groups were almost overlapping (log rank test, p = 0.84). Even after adjusting for age, histologic diagnosis, tumor location, and regional lymph node status, surgical treatment did not significantly influence survival (p = 0.24).

CONCLUSIONS

Endosonography accurately identifies patients with invasive T4 tumors who have a poor prognosis. This prognosis is independent of mode of therapy.

Functional evidence for the presence of nitric oxide synthase in the dorsal motor nucleus of the vagus

BACKGROUND & AIMS

Histochemical studies indicate that reduced nicotinamide adenine dinucleotide phosphate diaphorase, the nitric oxide synthase-related enzyme, is present in the dorsal motor nucleus of the vagus of the cat. We have previously shown in vitro that NO synthase is present in this nucleus in the rat and that the excitatory effect of N-methyl-D-aspartate on these neurons is in part caused by NO formation. The aim of this study was to obtain functional evidence for the presence of NO synthase in the cat dorsal motor nucleus of the vagus.

METHODS

L-Glutamate, L-arginine, D-arginine, the NO donor S-nitroso-N-acetyl-penicillamine, and the NO synthase inhibitor NG-nitro-L-arginine-methyl ester were unilaterally microinjected into the rostral dorsal motor nucleus of anesthetized cats, and antral and pyloric motility were monitored using extraluminal force transducers.

RESULTS

Microinjection of L-arginine increased gastric motility, whereas D-arginine had no effect. Vagotomy eliminated the L-arginine-induced increases. Microinjection of S-nitroso-N-acetyl-penicillamine increased antral motility. NG-Nitro-L-arginine-methyl ester prevented L-arginine from exerting an effect on gastric motility.

CONCLUSIONS

Motility increases obtained after microinjection of L-arginine into the dorsal motor nucleus and prevention of these motility increases with microinjection of a NO synthase inhibitor provide functional evidence for the presence of NO synthase in the dorsal motor nucleus of the vagus in the cat.

The role of endoscopic ultrasonography in diagnosis of benign lesions of the upper GI tract

The contribution of endoscopic ultrasonography (EUS) in the diagnosis of benign lesions of the upper gastrointestinal (UGI) tract was studied in 46 patients with polypoid lesions which were not thought to have invaded adjacent tissues or organs. Precise visualization of the five layers of the UGI tract was possible with EUS. The site of origin of the tumour was also determined. The diameter of the hypochoic lesions ranged between 1-4 cm, with well-defined margins, and were demarcated precisely from adjacent tissues. Lesions included: (1) leiomyoma of the esophagus, stomach, duodenum (n = 7); (2) ectopic pancreatic tissues (n = 3); (3) polyp of the esophagus, stomach or duodenum (n = 12); (4) hypertrophic gastric folds (n = 19); (5) extra gastric compression (n = 5). Patients from groups 1, 2 and 3 had the diagnosis confirmed and staged surgically. It was possible to differentiate between polypoid lesions of the UGI tract and extra gastric compression. The sensitivity of EUS in the diagnosis of benign tumours was 92%.