Three cases of rare salivary gland tumours: a molecular study of TP53, CDKN2A/ARF, RAS, BRAF, PTEN, MAPK2 and EGFR genes.

Salivary gland tumours are rare tumours characterized by histopathologic complexity and a wide variety of morphologic features. Studies on genetic changes in different histological subtypes of salivary gland tumours are important to better understand molecular pathogenetic mechanisms and to identify diagnostic and prognostic markers. Data are even more scanty dealing with unusual subtypes of these tumours. The aim of the present study was to analyse two high grade transformation adenoid cystic carcinomas (hgACC) and one hybrid tumour in order to identify, by mutational and microsatellite analysis, genetic alterations in TP53, CDKN2A/ARF, RAS, BRAF, PTEN, MAPK2 and EGFR genes. The two hgACCs showed snps missense in RAS genes and alterations with allelic instability in CDKN2A/ARF; moreover, a double mutation in TP53 was detected in one case. The hybrid tumour showed alterations in CDKN2A/ARF gene and snps missense in NRAS genes. Our data suggest that CDKN2A/ARF pathway might be involved in pathogenesis of the salivary gland tumours analysed. Further molecular analyses of these very rare tumours are necessary to better understand the role of other genetic alterations detected in our study.

The Italian external quality control program for familial adenomatous polyposis of the colon: five years of experience.

Familial adenomatous polyposis is a rare autosomal dominant inherited disease (incidence, 1/8000). More than 90% of families affected by familial adenomatous polyposis have a mutation in the tumor suppressor gene adenomatous polyposis coli (APC). Mutations in this gene are characterized by 100% penetrance, although there is a variation in phenotypic expression of the disease. According to a 2004 survey of the Italian Human Genetic Society, about 264 APC gene molecular genetic tests were performed by Italian laboratories per year. The Italian External Quality Assessment (IEQA), financially supported by the Ministry of Health and coordinated by the Istituto Superiore di Sanità, was started in 2000 to improve the quality of molecular genetic tests in Italy. In the frame of the IEQA, about 50% of public laboratories performing APC gene tests have been monitored. The number of responding public laboratories during the 5 years was 6, 7, 7, 7, and 5 from 2001 to 2006, respectively; on average, 96.3% of samples completely analyzed were correctly genotyped. Methods used by laboratories to detect mutation were direct sequencing, single-strand conformation polymorphism, protein truncation test, and denaturing high-performance liquid chromatography. Written reports were not homogeneous among laboratories, although a new form of written report was proposed to laboratories in 2004. It will be interesting to monitor the effects of the reporting model and the output of this educational action in the future.

The Italian scheme of External Quality Assessment for beta-thalassemia: genotyping and reporting results and testing strategies in a 5-year survey.

The Italian scheme of External Quality Assessment for beta-thalassemia started in 2001 as part of a project twice funded by the Italian Ministry of Health and coordinated by the Istituto Superiore di Sanità. To date, five trials have been performed (2001-2004 and 2006). The aim of the Italian scheme is to help public laboratories in improving and reaching a high standard of quality when performing a molecular test. Many laboratories took part in the 5-year project, and their participation was constant during the whole period. The aims of this paper are to describe the genotyping and reporting results as well as focusing on the techniques and the testing strategies adopted to detect mutations. Almost 99% of the alleles analyzed were correctly detected by laboratories, while 0.33% of the analyses gave a wrong result. Reverse dot blot was the most used technique, and it was always used in the strategies adopted by laboratories to detect mutations. The reports sent by laboratories showed incompleteness and heterogeneity; thus, a new model for written reports has been introduced since 2004. It will be interesting to monitor the effects of the reporting model and the output of this educational action in the future.

The Italian External Quality Assessment scheme for fragile x syndrome: the results of a 5-year survey.

The Italian External Quality Assessment scheme for fragile X syndrome started in 2001 as an activity funded by the National Health System and coordinated by the National Institute of Public Health. The aim of this work is to present the data of 5 years (2001--2004 and 2006) of survey. The External Quality Assessment scheme was designed to cover the following points: (a) genotyping and (b) interpretation and reporting of results. Overall, the scheme covered about 65% of all Italian public laboratories. The average reporting of results was 91.6%, with an overall success rate of 76%. The rate of diagnostic errors observed was on average 5%. Inaccuracy in sizing of CGG repeats of normal and premutated alleles was reported. During the survey the proportion of laboratories using a Southern blotting, polymerase chain reaction, and ABI sizing kit in combination rose from 36.8% to 70.6%. The reports from laboratories showed incompleteness and considerable variations in expected outcomes. For this reason, in 2004 a model for written reports was introduced. In conclusion, these data underscore the need to participate in External Quality Assessment schemes as an educational resource to ensure quality in molecular genetic testing.

EQUAL-qual: a European program for external quality assessment of genomic DNA extraction and PCR amplification.

BACKGROUND: Despite the rapid transition into routine clinical practice of molecular techniques based on PCR, external quality assessment (EQA) is still not widely available. The European Union and European Communities Confederation of Clinical Chemistry have supported the EQUAL project as a series of 3 different EQA programs for the assessment of molecular methods independently from analytes. We present the results from the EQUAL-qual program designed to evaluate the analytical aspects of DNA analysis by means of a conventional qualitative PCR experiment. METHODS: The EQUAL-qual program provided DNA, blood samples, and primer sets to participant laboratories to assess DNA extraction and PCR amplification. We have developed statistical procedures to identify laboratories performing poorly in DNA extraction (quality and quantity), PCR efficiency, and data interpretation after electrophoresis. RESULTS: An application to participate was obtained from 213 laboratories (from 25 countries), and 175 (82%) of laboratories submitted results for assessment. Questionable results in terms of quality and/or quantity of DNA derived from blood extractions were returned by 27% of laboratories (46 of 166). PCR efficiency showed high variability, with 3% of laboratories (5 of 163) showing a consistently low rate of amplification and 10% (18 of 175) not reporting the expected number of bands of the amplified targets. CONCLUSIONS: The results showed considerable variability in all phases of the experiment. The approach confirms the validity of EQA as a method for evaluating analytical aspects of PCR-based tests.

The Italian External Quality Control Programme for cystic fibrosis molecular diagnosis: 4 years of activity.

BACKGROUND: The Italian External Quality Control Programme for cystic fibrosis molecular diagnosis started in 2001; public laboratories distributed throughout Italy participated on a voluntary basis. METHODS: The Italian Public Health Institute (Istituto Superiore di Sanità) sent six validated DNA samples to participating laboratories: technical and clinical information was provided for each sample. Laboratories were required to analyse all six samples. For each sample the laboratories had to provide the results (including raw data) and a report of molecular analysis within 2 months using current methods and nomenclature. Raw data and reports were evaluated by a Steering Committee and their comments were sent to each laboratory. RESULTS: Genotyping results indicated a general good level of quality for all laboratories, i.e., approximately 1% of alleles were incorrectly assigned each year due to analytical (45%) and misinterpretation (45%) errors. During the first 2 years, more than 70% of laboratories did not test for some regional Italian mutations. Commercial kits for reverse dot-blot and oligonucleotide ligation assay PCR were used to detect mutations by 52.8% and 29.5%, respectively, of the participating laboratories. Reporting of results was still inadequate; in 2004 a model for the written report was introduced, but not all laboratories used it. CONCLUSIONS: Our data show that few genotyping errors were made by laboratories and were principally due to misinterpretation and analytical reasons. However, reports are still inadequate and it will be interesting to evaluate the introduction of the reporting model in future years.

Identification of plasmids by PCR-based replicon typing.

The epidemiological importance of tracing plasmids conferring drug resistance prompted us to develop a PCR method based on replicons (inc/rep PCR) of the major plasmid incompatibility groups among Enterobacteriaceae. Eighteen pairs of primers were designed to perform 5 multiplex- and 3 simplex-PCRs, recognizing FIA, FIB, FIC, HI1, HI2, I1-Igamma, L/M, N, P, W, T, A/C, K, B/O, X, Y, F, and FIIA. The specificity of the method was tested on a collection of 61 reference plasmids and on 20 Salmonella enterica strains of different serotypes isolated in Italy. Results indicated that the inc/rep PCR method demonstrates high specificity and sensitivity in detecting replicons on reference plasmids and also revealed the presence of recurrent and common plasmids in epidemiologically unrelated Salmonella isolates of different serotypes. These results suggest that the method is potentially applicable to a large number of strains to trace the diffusion of specific multi-drug resistance plasmids in different environments.

Quality assessment in cytogenetic and molecular genetic testing: the experience of the Italian Project on Standardisation and Quality Assurance.

The first Italian national trial of external quality assessment in genetic testing was organised within the framework of the "Italian National Project for Standardisation and Quality Assurance of Genetic Tests". Sixty-eight Public Health Service laboratories volunteered for the trial, which involved molecular genetic tests (cystic fibrosis, beta-thalassaemia, familial adenomatous polyposis coli and fragile-X syndrome) and cytogenetic tests (prenatal and postnatal, the latter included cancer cytogenetics). The response rate was high (88.2%). The level of analytical accuracy was good, i.e., the percentage of laboratories that correctly genotyped all samples was 89.3% for cystic fibrosis, 90.9% for beta-thalassaemia, 100% for familial adenomatous polyposis coli (despite two laboratories did not complete the analysis because the amount of DNA was considered insufficient), and 90.5% for fragile-X syndrome. Written reports differed widely and were judged "inadequate" in over 50% of cases. Most laboratories from the present study already have experience in previous European external quality assessments for at least one genetic test; this can explain the higher analytical accuracy in the Italian external quality assessment with respect to quality control programmes in other countries. Collaborative networks are strongly suggested to improve the quality of the reports.

Organization and integration sites in the human genome of endogenous retroviral sequences belonging to HERV-E family.

The present paper reports the characterization of HERV-E endogenous retroviral sequences in the human genome by using three complementary approaches. Firstly, we identified genomic clones containing HERV-E by BLAST screening of human DNA databases by using the entire sequence of a characterized HERV-E clone (M10976) as a query. The genomic structure and integration sites of the HERV-E elements were characterized. Secondly, new integration sites of HERV-E elements were revealed by a retroviral LTR-arbitrary primer-PCR (RELAP-PCR) technique. BLAST analysis of the PCR products identified a subgroup that shows low identity (75%) to the original clone M10976 and slightly higher identity (80%) to a closely related HERV-E (Ac. n. K02166). Finally, we performed FISH mapping, which revealed sites of integration of HERV-E not previously identified at the cytogenetic level. A preliminary analysis of genes mapping in the same bands as HERV-E integration sites was performed: several loci relevant to physiological and/or pathological processes were detected. Our findings may provide clues to identify HERV-E integration sites adjacent to genes with important biological roles.