Silvano Presciuttini

TT virus in the nasal secretions of children with acute respiratory diseases: relations to viremia and disease severity.

ABSTRACT The natural history and pathogenic potential of the recently identified TT virus (TTV) are currently a matter of intensive investigation. In an attempt to shed some light on these issues, nasal and blood specimens of 1- to 24-month-old children hospitalized with a clinical diagnosis of acute respiratory disease (ARD) were examined for the presence, load, and genetic characteristics of TTV. The results have indicated that at least in young children, the respiratory tract not only represents a route by which abundant TTV can be shed into the environment but also may be a site of primary infection and continual replication. Although we found no compelling evidence that TTV was the direct cause of ARD in some of the children studied, the average loads of TTV were considerably higher in patients with bronchopneumonia (BP) than in those with milder ARD, raising interesting questions about the pathophysiological significance of TTV at this site. Furthermore, group 4 TTV was detected almost exclusively in children with BP.

Germline mutations of the BRCA1‐associated ring domain (BARD1) gene in breast and breast/ovarian families negative for BRCA1 and BRCA2 alterations

BARD1 (BRCA1‐associated RING domain) was identified by yeast two‐hybrid screening as a protein interacting with BRCA1. Somatic and germline mutations of BARD1 have been detected in sporadic breast, ovarian, and endometrial cancers. The present study represents the first description of BARD1 germline mutations in hereditary breast and breast/ovarian cancer patients. We analyzed the BARD1 gene in 40 families with hereditary breast and breast/ovarian cancer, tested negative for BRCA1 and BRCA2 mutations. A mutational analysis by PCR‐SSCP on the coding region and the exon–intron splice boundaries of the BARD1 gene yielded four different germline mutations. A group of 20 patients diagnosed with sporadic breast cancer below the age of 40 was also examined and only one germline mutation was found. A study of loss of heterozygosity at the BARD1 locus in neoplastic tissues from patients with BARD1 germline mutations was carried out. In all cases, we were unable to find any evidence for allelic deletions. The involvement of BARD1 mutations in the susceptibility to hereditary breast and breast/ovarian cancer is discussed.

Survival of patients with hereditary colorectal cancer: Comparison of HNPCC and colorectal cancer in FAP patients with sporadic colorectal cancer

Conflicting data exist on the prognosis of hereditary colorectal cancer. HNPCC patients, in particular, are often reported to have a better survival. We examined 2,340 colorectal‐cancer patients treated in our Institution: 144 HNPCC patients (Amsterdam Criteria), 161 FAP patients and 2,035 patients with sporadic cancer. Data on hereditary‐cancer patients treated between 1980 and 1995 was collected in a registry. The 2,035 sporadic colorectal‐cancer patients (controls) included all new cases treated in the Department of Gastrointestinal‐Tract Surgery during the same period. Observed survival was estimated using the Kaplan‐Meier method. Cumulative survival probability was estimated at 5 years within each group and stratified by various clinical and pathological variables. The age distribution at diagnosis of sporadic patients was significantly higher than that of FAP and HNPCC patients (median 60 years vs. 43 and 49 years; p < 0.0001). In the HNPCC group, 40% had a right cancer location, vs. 14% in the FAP group and 13% in the sporadic‐cancer group. In the sporadic group, 51% were early‐stage cancers (Dukes A or B) vs. 48.4% and 52.1% in the FAP and HNPCC groups respectively. In the HNPCC, FAP and sporadic‐cancer groups, the 5‐year cumulative survival rate was 56.9%, 54.4% and 50.6% respectively. Survival analysis by the Cox proportional‐hazards method revealed no substantial survival advantage for HNPCC and FAP patients compared with the sporadic group, after adjustment for age, gender, stage and tumor location. The hazard ratio for HNPCC was 1.01 (95% CI 0.72–1.39) and 1.27 (95% CI 0.95–1.7) for FAP patients compared with the sporadic‐colorectal‐cancer group. Int. J. Cancer 80:183–187, 1999.

Penetrances of breast and ovarian cancer in a large series of families tested for BRCA1/2 mutations.

Accurate estimates of breast and ovarian cancer penetrance in BRCA1/2 mutation carriers are crucial in genetic counseling. Estimation is difficult because of the low frequency of mutated alleles and the often-uncertain mechanisms of family ascertainment. We estimated the penetrances of breast and ovarian cancers in carriers of BRCA1/2 mutations by maximizing the retrospective likelihood of the genetic model, given the observed test results, in 568 Italian families screened for germline mutations. The software BRCAPRO was used as a probability calculation tool in a Markov Chain Monte Carlo approach. Breast cancer penetrances were 27% (95% CI 20–34%) at age 50 years and 39% (27–52%) at age 70 in BRCA1 carriers, and 26% (0.18–0.34%) at age 50 and 44% (29–58%) at age 70 in BRCA2 carriers, and ovarian cancer penetrances were 14% (7–22%) at age 50 and 43% (21–66%) at age 70 in BRCA1 carriers and 3% (0–7%) at age 50 and 15% (4–26%) at age 70 in BRCA2 carriers. The new model gave a better fit than the current default in BRCAPRO, the likelihood being 70 log units greater; in addition, the observed numbers of mutations in families stratified by gene and by cancer profile were not significantly different from those expected. Our new penetrance functions are appropriate for predicting breast cancer risk, and for determining the probability of carrying BRCA1/2 mutations, in people who are presently referred to genetic counseling in Italy. Our approach could lead to country-customized versions of the BRCAPRO software by providing appropriate population-specific estimates.

Cancer risk among the relatives of patients with pancreatic ductal adenocarcinoma.

Background/Aims: Pancreatic cancer is a leading cause of cancer-related death; the most consistently identified risk factors are smoking and family history. Our aims were to examine familial aggregations of pancreas and other cancers, and to determine the relative risk of the family members. Methods: We prospectively collected data on the families of patients presenting with pancreatic ductal adenocarcinoma. Smoking habits and alcohol consumption of the probands were compared with the available statistics on the Italian population. Mortality from cancer was investigated in first-degree relatives, and age-dependent risks of dying from pancreatic cancer and other tumors were compared with background population levels. Results: Data for 570 families were collected, including 9,204 relatives. Probands were 3- to 5-fold more often heavy smokers than the general population, and 9.3% of them reported a positive family history of pancreatic cancer. In first-degree relatives, only mortality from pancreatic cancer was significantly increased (relative risk at age 85 years = 2.7). Lifetime risk of dying of pancreas cancer was 4.1% for the relatives of all probands, and was 7.2% for the relatives of probands who developed disease before 60 years of age. Conclusions: The data suggest that genetic susceptibility to pancreatic cancer may be attributable, in addition to BRCA2, to moderate- to low-penetrance gene(s).

Evaluation of widely used models for predicting BRCA1 and BRCA2 mutations

Deleterious mutations of the BRCA1 and BRCA2 genes are a major risk factor for the development of breast and ovarian cancers.1–4 Mutation tests for these two genes commonly are now offered in specialised clinics.5,6 As a result, a large number of women with personal or family histories of breast or ovarian cancer seek genetic counselling. Accurate evaluation of the probability that a woman carries a germline pathogenic mutation at BRCA1 or BRCA2 therefore is essential to help counsellors and those being counselled to decide whether testing is appropriate. In this context, the questions of practical interest are: Given the pedigree, what is the chance of a mutation being present? and What is the chance of the DNA laboratory finding a mutation? After testing became available, several models were developed to assess the pre-test probability of identifying carriers of mutations. Broadly speaking, two different approaches have been used to develop predictive models: the “empirical approach” and the “Mendelian approach”.7 In empirical models, families are stratified according to variables that describe their family history; regression or other approaches are used to predict the results of Mendelian testing. In some cases, this approach simply consists of observing the proportion of mutations found in different strata. Mendelian models, in contrast, address the probability that a proband is a mutation carrier on the basis of explicit assumptions about the genetic parameters (allele frequencies and cancer penetrances in carriers and non-carriers) and the Mendelian rules of gene transmission. A consequence of the two different strategies is that the Mendelian models evaluate the probability that a proband is a gene carrier, whereas the empirical models evaluate the probability of identifying a mutation. The main purpose of this study was to compare the performances of published models in predicting mutation test results in …

TT virus loads and lymphocyte subpopulations in children with acute respiratory diseases

ABSTRACT TT virus (TTV) produces chronic plasma viremia in around 90% of healthy individuals of all ages and has, therefore, been proposed as a commensal human virus. We recently demonstrated that in children hospitalized for acute respiratory diseases high TTV loads were associated with severe forms of disease. Here, we report that in such children TTV loads showed an inverse correlation with the percentage of circulating total T and helper T cells and a direct correlation with the percentage of B cells. Thus, florid TTV replication might contribute to lymphocyte imbalances and, possibly, immunosuppressive effects, thus resembling related animal viruses.

Dynamics of Persistent TT Virus Infection, as Determined in Patients Treated with Alpha Interferon for Concomitant Hepatitis C Virus Infection

ABSTRACT TT virus (TTV) is a recently identified widespread DNA virus of humans that produces persistent viremia in the absence of overt clinical manifestations. In an attempt to shed light on the dynamics of chronic infection, we measured the levels of TTV in the plasma of 25 persistently infected patients during the first 3 months of alpha interferon (IFN-α) treatment for concomitant hepatitis C virus (HCV) infection. The first significant decline of TTV loads was observed at day 3 versus day 1 for HCV. Subsequently, the loads of TTV became progressively lower in most patients, but some initial responders relapsed before the end of the follow-up, suggesting that at least in some subjects the effects of IFN on TTV can be very short-lived. No correlation between the responses of TTV and HCV to therapy was found. Fitting the viremia data obtained during the first week of treatment into previously developed mathematical models showed that TTV sustains very active chronic infections, with over 90% of the virions in plasma cleared and replenished daily and a minimum of approximately 3.8 × 1010 virions generated per day. Low levels of TTV were occasionally detected in the peripheral blood mononuclear cells of patients who had cleared plasma viremia, thus corroborating previous results showing that these cells may support TTV replication and/or persistence.

Association Between Canine Malignant Lymphoma, Living in Industrial Areas, and Use of Chemicals by Dog Owners

A case-control study was carried out to determine whether residential exposure to environmental pollutants increased risk for canine lymphoma in pet dogs. One hundred one cases with cytologically or histologically confirmed lymphoma diagnosed at a veterinary teaching hospital between the middle of 1996 and the middle of 1998 were examined. Controls were obtained by choosing twice the number of dogs without neoplastic disease, with overlapping distributions of province of residence, age, sex, and breed. Information regarding animal management, residence type, professional or hobby use of chemicals by owners, and treatment with herbicides or other pesticides in the area frequently visited by the dogs was obtained with a multiple-choice questionnaire by telephone interview. Two variables were positively and independently associated with the disease, namely residency in industrial areas (odds ratio [OR]; = 8.5; 95% confidence interval [CI], 2.3-30.9) and use of chemicals by owners, specifically paints or solvents (OR = 4.6; 95% CI, 1.7-12.6). A significantly lower value of the mean age of disease onset was found in the group of dogs at risk in comparison with the group of all other dogs (6.1 +/- 0.4 years, n = 36 versus 7.5 +/- 0.4 years, n = 65, respectively; P = .008). Variables describing animal care and pesticide use were either not associated with the disease or were uninformative. We suggest that canine lymphoma may be considered a sentinel of potentially hazardous situations for humans, because of the relatively short latency between exposure and disease onset.

Mean age of tumor onset in hereditary nonpolyposis colorectal cancer (HNPCC) families correlates with the presence of mutations in DNA mismatch repair genes.

Fourteen Italian families affected with hereditary nonpolyposis colorectal cancer (HNPCC) were screened for germline mutations at three DNA mismatch repair (MMR) genes, MSH2, MLH1, and GTBP, by using a combination of different methods that included an in vitro synthesized protein assay, single‐strand conformation polymorphism analysis, and direct sequencing. DNA alterations were observed in six instances, including a single base deletion in MSH2 exon 14, an A‐to‐G transition in the splice donor site of MLH1 exon 6, and two missense mutations in MLH1 exons 5 and 9. A previously reported common mutation affecting the splice donor site of MSH2 exon 5 was identified in two families. No mutations were detected in the GTBP gene. In total, eight of 16 Italian HNPCC families (50%), including two previously reported kindreds, were found to carry a mutation in MMR genes. We compared the mean age of colorectal cancer onset in the index cases (three patients for each family) between the two groups of kindreds, those with identified mutation vs. those without, and found that the first had a significantly lower value (43.0 vs. 53.7 years, P = 0.014). This finding suggests that HNPCC families with a more advanced age of tumor onset are less likely to be associated with known MMR genes. Genes Chromsom. Cancer 19:135–142, 1997.