Giovanna Piras

Risk of malignant lymphoma following viral hepatitis infection

We investigated lymphoma risk following hepatitis infection in a case-control study of 274 incident lymphoma cases, defined according to the WHO classification, and 336 population controls in Sardinia, Italy. Part of our study population (198 cases and 219 controls) was included in the EPILYMPH study of Hepatitis C virus (HCV) infection in relation to non-Hodgklin’s lymphoma risk. Based on questionnaire information on whether and at what age a diagnosis of hepatitis was posed by a physician, systematic anti-HCV antibodies testing in cases and controls by enzyme-linked immunoassay, and HCV-RNA assessment by PCR analyses in positive samples, we investigated more in detail whether hepatitis non-C is also associated with lymphoma risk, and whether risk varies by clinical form of hepatitis (acute or chronic infection). After adjusting by age, gender, education, and area of birth whether from the study area or elsewhere in Italy, a previous generic diagnosis of hepatitis was associated with a significantly elevated lymphoma risk [odds ratio (OR) = 1.8; 95% CI 1.1, 2.8], which was equally increased for hepatitis B (OR = 1.8; 95% CI 0.9, 3.5), for HCV positive subjects overall (OR = 2.0; 95% CI 0.8, 4.8), and for hepatitis non-B non-C (OR = 1.6; 95% CI 0.7, 3.9). Once concurrent infection from other hepatitis viruses was excluded, acute or chronic hepatitis C was the only one showing a consistent risk increase in all lymphoma subtypes, but follicular lymphoma. Some indications of an excess risk of lymphoma were observed also for acute, but not chronic forms of hepatitis B and hepatitis non-B, non C. Self-limited hepatitis C did not show an association. No significant heterogeneity in the risk of major lymphoma subtype was observed. Our results confirm a role of either acute or chronic active HCV infection in lymphomagenesis. Further studies are warranted to test the hypothesis that acute infection from other hepatitis viruses might also increase lymphoma risk.

A role of BRCA1 and BRCA2 germline mutations in breast cancer susceptibility within Sardinian population

BackgroundIn recent years, numerous studies have assessed the prevalence of germline mutations in BRCA1 and BRCA2 genes in various cohorts. We here extensively investigated the prevalence and geographical distribution of BRCA1-2 mutations in the entire genetically-homogeneous Sardinian population. The occurrence of phenotypic characteristics which may be predictive for the presence of BRCA1-2 germline mutations was also evaluated.MethodsThree hundred and forty-eight breast cancer patients presenting a familial recurrence of invasive breast or ovarian carcinoma with at least two affected family members were screened for BRCA1-2 mutations by DHPLC analysis and DNA sequencing. Association of BRCA1 and BRCA2 mutational status with clinical and pathological parameters was evaluated by Pearsons Chi-Squared test.Results and ConclusionOverall, 8 BRCA1 and 5 BRCA2 deleterious mutations were detected in 35/348 (10%) families; majority (23/35;66%) of mutations was found in BRCA2 gene. The geographical distribution of BRCA1-2 mutations was related to three specific large areas of Sardinia, reflecting its ancient history: a) the Northern area, linguistically different from the rest of the island (where a BRCA2 c.8764_8765delAG mutation with founder effect was predominant); b) the Middle area, land of the ancient Sardinian population (where BRCA2 mutations are still more common than BRCA1 mutations); and c) the South-Western area, with many Phoenician and Carthaginian locations (where BRCA1 mutations are prevalent). We also found that phenotypic features such as high tumor grading and lack of expression of estrogen/progesterone receptors together with age at diagnosis and presence of ovarian cancer in the family may be predictive for the presence of BRCA1-2 germline mutations.

Dissecting the genetic make-up of North-East Sardinia using a large set of haploid and autosomal markers

Sardinia has been used for genetic studies because of its historical isolation, genetic homogeneity and increased prevalence of certain rare diseases. Controversy remains concerning the genetic substructure and the extent of genetic homogeneity, which has implications for the design of genome-wide association studies (GWAS). We revisited this issue by examining the genetic make-up of a sample from North-East Sardinia using a dense set of autosomal, Y chromosome and mitochondrial markers to assess the potential of the sample for GWAS and fine mapping studies. We genotyped individuals for 500K single-nucleotide polymorphisms, Y chromosome markers and sequenced the mitochondrial hypervariable (HVI–HVII) regions. We identified major haplogroups and compared these with other populations. We estimated linkage disequilibrium (LD) and haplotype diversity across autosomal markers, and compared these with other populations. Our results show that within Sardinia there is no major population substructure and thus it can be considered a genetically homogenous population. We did not find substantial differences in the extent of LD in Sardinians compared with other populations. However, we showed that at least 9% of genomic regions in Sardinians differed in LD structure, which is helpful for identifying functional variants using fine mapping. We concluded that Sardinia is a powerful setting for genetic studies including GWAS and other mapping approaches.

Methylation analysis of the phosphates and tensin homologue on chromosome 10 gene (PTEN) in multiple myeloma

BackgroundAberrant DNA methylation of promoter region CpG islands is an alternative mechanism that leads to genetic defects in the inactivation of tumor suppressor genes during myelomagenesis. The aim of this study was to examine the promoter methylation status of the phosphates and tensin homologue on chromosome 10 (PTEN) gene in a cohort of multiple myeloma patients.FindingsThe PTEN gene was hypermethylated in 7 out of 58 (12%) primary myeloma samples. The correlation between functional inactivation and PTEN mRNA levels was not statistically significant. The multiple myeloma subgroup with an aberrant PTEN status had a prevalence of the component IgG, Salmon Durie stage I, lower lactate dehydrogenase levels, intermediate-standard cytogenetic risk and longer overall survival with the respect to the unmethylated subgroup.ConclusionsThis is the first report demonstrating the presence of PTEN promoter hypermethylation in multiple myeloma.

Identification of a founder BRCA2 mutation in Sardinian breast cancer families

The population of Sardinia is characterized by a relatively low level of genetic heterogeneity: therefore ‘founder mutations’ can be expected to be found. We analysed 17 probands from families with high incidence of breast cancer or breast and ovarian cancer by sequencing the full-length coding regions of BRCA1 and BRCA2 genes. A novel BRCA2 frameshift mutation, 3951del3insAT, which produces a protein truncated at codon 1258, was observed in six patients with BC from the same village. The mutation was not found in unaffected females (matched on basis of ethnicity and age) with no family history of cancer. Haplotype analysis strongly suggests that all affected persons had a common ancestor. The identification of this clinically significant founder mutation may facilitate screening/testing for inherited risk of breast cancer.

Reassessing the evolutionary history of the 17q21 inversion polymorphism

A polymorphic inversion that lies on chromosome 17q21 comprises two major haplotype families (H1 and H2) that not only differ in orientation but also in copy-number. Although the processes driving the spread of the inversion-associated lineage (H2) in humans remain unclear, a selective advantage has been proposed for one of its subtypes. Here, we genotyped a large panel of individuals from previously overlooked populations using a custom array with a unique panel of H2-specific single nucleotide polymorphisms and found a patchy distribution of H2 haplotypes in Africa, with North Africans displaying a higher frequency of inverted subtypes, when compared with Sub-Saharan groups. Interestingly, North African H2s were found to be closer to “non-African” chromosomes further supporting that these populations may have diverged more recently from groups outside Africa. Our results uncovered higher diversity within the H2 family than previously described, weakening the hypothesis of a strong selective sweep on all inverted chromosomes and suggesting a rather complex evolutionary history at this locus.

Pomalidomide in heavily pretreated refractory multiple myeloma: a case report

We present the case of a 70-year-old man diagnosed with multiple myeloma in 2008, who after four therapy lines initiated a fifth-line treatment with pomalidomide (4 mg orally, days 1-21 of a 28-day cycle) and low-dose dexamethasone (40 mg weekly orally). The patient was treated with pomalidomide for almost 2 years achieving a complete remission after 12 cycles. Complete remission was maintained for 9 months. This case illustrates the potential of pomalidomide plus low-dose dexamethasone to overcome multiple myeloma refractoriness inducing a quick and very prolonged remission.