Raffaele Palmirotta

APC gene mutations and colorectal adenomatosis in familial adenomatous polyposis

Correlations between germline APC mutation sites and colorectal pathophenotypes, as evaluated by the direct count of adenomas at colectomy, were investigated analysing colectomy specimens from 29 FAP patients carrying one mis-sense (codon 208) and 14 frame-shift or non-sense APC mutations (codons 232, 367, 437, 623, 876, 995, 1061, 1068, 1075, 1112, 1114, 1309, 1324, 1556). The mis-sense mutation at codon 208 was associated with a relatively mild colorectal pathophenotype. The mutation at codon 367, subject to alternative splicing, was associated with attenuated FAP. The mutation at codon 1309 was associated with the profuse colorectal adenomatosis. For 13 mutations, predicted to result in null alleles or truncated APC proteins, we correlated density and distribution of colorectal adenomas with the predicted functional effects of the mutation. The most severe colorectal pathophenotype was significantly associated with the truncating mutation at codon 1309, which is located downstream to the I β-catenin binding domain but upstream II β-catenin-binding domain. Mutations between codons 867 and 1114, which affect the I β-catenin binding domain, as well as mutations occurring in exons 6 and 9, predicted to result in null alleles, were associated with a less severe colorectal pathophenotype. Overall, the highest number of adenomas was detected in the right colon, followed by the left colon, transverse colon sigma and rectum. However, the highest density of adenomas was observed in the left colon, followed by the right colon, sigma, transverse colon and rectum. Colorectal carcinomas, observed in only five patients, were all in the left colon.

Genetics of ischemic stroke, stroke-related risk factors, stroke precursors and treatments

Stroke remains a leading cause of death worldwide and the first cause of disability in the western world. Ischemic stroke (IS) accounts for almost 80% of the total cases of strokes and is a complex and multifactorial disease caused by the combination of vascular risk factors, environment and genetic factors. Investigations of the genetics of atherosclerosis and IS has greatly enhanced our knowledge of this complex multifactorial disease. In this article we sought to review common single-gene disorders relevant to IS, summarize candidate gene and genome-wide studies aimed at discovering genetic stroke risk factors and subclinical phenotypes, and to briefly discuss pharmacogenetics related to stroke treatments. Genetics of IS is, in fact, one of the most promising research frontiers and genetic testing may be helpful for novel drug discoveries as well as for appropriate drug and dose selection for treatment of patients with cerebrovascular disease.

Pharmacodynamic Effect of Switching Therapy in Patients With High On-Treatment Platelet Reactivity and Genotype Variation With High Clopidogrel Dose Versus Prasugrel The RESET GENE Trial

Background—High on-treatment platelet reactivity (HTPR) is associated with adverse outcomes. We aim to compare the novel thienopyridine prasugrel versus double-dose clopidogrel in patients with HTPR and explore the interaction between CYP2C19 genotype and both drugs. Methods and Results—Consecutive stable patients undergoing percutaneous coronary intervention were screened with the Multiplate Analyzer P2Y12 assay, defining HTPR as area under the curve >450. Those with HTPR were randomized to prasugrel (10 mg/day) or high-dose clopidogrel (150 mg/day) for 2 weeks and then crossed-over to, respectively, clopidogrel and prasugrel, repeating the P2Y12 assay at the end of each cycle. Clinical follow-up (until 3 months) and CYP2C19 genotyping was performed in all patients. The primary end point was platelet reactivity after 14 days of prasugrel versus high-dose clopidogrel. Thirty-two patients were randomized to prasugrel and then high-dose clopidogrel or to high-dose clopidogrel followed by prasugrel. Prasugrel was associated with a significantly lower platelet reactivity than high-dose clopidogrel was (325.8 versus 478.5 area under the curve, P=0.028). No patient treated with prasugrel exhibited HTPR, whereas 9 (28.1%) receiving high-dose clopidogrel still had prevalence of HTPR (P=0.001). Similar findings were obtained changing cutoffs or considering platelet reactivity as a continuous variable. Genotyping showed the same efficacy between high-dose clopidogrel and prasugrel in the 18 (56.3%) CYP2C19*2 noncarriers (HTPR in 12.5% versus 0, P=0.274), whereas it was significantly worse in the 14 (43.7%) carriers (HTPR in 43.7% versus 0, P=0.003). Conclusions—HTPR is successfully abolished by therapy with prasugrel irrespective of CYP2C19 genotype. Conversely, high-dose clopidogrel can address HTPR only in CYP2C19*2 noncarriers. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT01465828.

Analysis of adenomatous polyposis coli gene in thyroid tumours

Familial adenomatous polyposis (FAP) is known to be associated with neoplasia of various tissues, including thyroid carcinoma. Germline mutations of the tumour-suppressor gene APC, responsible for the predisposition to FAP, may therefore be involved in the pathogenesis of these tumours. In this report the structure of the APC gene has been investigated in 26 thyroid tumours, at different stages of dedifferentiation, that were surgically excised from patients with a negative history of FAP. Approximately 35% of the APC gene coding region, where most of the mutations are clustered, has been analysed by a combination of single-strand conformation polymorphism and direct sequencing. No significant alterations could be demonstrated in any sample examined. It is concluded that, at least in patients not affected by FAP, APC gene abnormalities do not seem to play a relevant role in the pathogenesis of thyroid carcinoma.

Prognostic value of soluble P‐selectin levels in colorectal cancer

Measurement of soluble (s) P‐selectin levels has been proposed as a diagnostic tool for monitoring the clinical course of human neoplasms. Thus, our study was aimed at analyzing the role of sP‐selectin in association with clinicopathological variables in 181 patients with primary (n=149) or metastatic (n=32) colorectal cancer (CRC), 34 patients with benign diseases and 181 control subjects. The results obtained showed that sP‐selectin levels were higher in patients with CRC compared either to patients with benign disease (p= 0.006) or controls (p= 0.003). No differences were observed between the latter and patients with benign diseases. Increased median sP‐selectin levels were significantly associated with the presence of distant metastasis (68.2 ng/ml vs. 48.6 ng/ml, p= 0.002). Of interest, carcinoembryonic antigen (CEA) levels were independently associated to sP‐selectin (regression coefficient= 0.28, p< 0.002). Coxs proportional hazards survival analysis of primary CRC patients demonstrated that beside the stage of disease sP‐selectin levels had an independent prognostic role in predicting recurrent disease (HR= 2.22, p= 0.019) and mortality from CRC (HR= 3.44, p= 0.017). These results suggest that measurement of plasma sP‐selectin might represent a prognostic indicator in the management of patients with CRC.

Microsatellite instability in thyroid tumours and tumour- like lesions

SummaryFifty-one thyroid tumours and tumour-like lesions were analysed for instability at ten dinucleotide microsatellite loci and at two coding mononucleotide repeats within the transforming growth factor β (TGF-β) type II receptor (TβRII) and insulin-like growth factor II (IGF-II) receptor (IGFIIR) genes respectively. Microsatellite instability (MI) was detected in 11 out of 51 cases (21.5%), including six (11.7%) with MI at one or two loci and five (9.8%) with Ml at three or more loci (RER+ phenotype). No mutations in the TβRII and IGFIIR repeats were observed. The overall frequency of MI did not significantly vary in relation to age, gender, benign versus malignant status and tumour size. However, widespread MI was significantly more frequent in follicular adenomas and carcinomas than in papillary and Hürthle cell tumours: three out of nine tumours of follicular type (33.3%) resulted in replication error positive (RER+), versus 1 out of 29 papillary carcinomas (3.4%, P = 0.01), and zero out of eight Hürthle cell neoplasms. Regional lymph node metastases were present in five MI-negative primary cancers and resulted in MI-positive in two cases.

Platinum-Based Compounds and Risk for Cardiovascular Toxicity in the Elderly: Role of the Antioxidants in Chemoprevention

Cancer in elderly patients is an increasingly common problem. Older patients have more co-morbidity, therefore the toxic effects of chemotherapy treatment are less tolerable compared to younger patients. Platinum-based compounds (PBCs) are commonly used cytotoxic agents in the treatment of several solid tumors; however, their application is still limited in elderly patients, due to the risks in cardiovascular toxicity. The increased risk for myocardial ischemia, stroke, and vascular thrombosis linked with PBCs treatment is mainly due to reactive oxygen species (ROS) production and the subsequent induction of oxidative stress and switch to a prothrombotic condition. Recently, studies have shown a different genetic susceptibility in cardiovascular toxicity induced by therapy with PBCs. Antioxidants, such as vitamin E, selenium, lycopene, melatonin, and resveratrol, have been implicated in cancer treatment by their property to suppress the oxidant injury. Resveratrol, especially, has been shown to increase the antineoplastic activity of cisplatin. In addition, resveratrols ability to activate the sirtuin1 (SIRT1) pathway has been heavily implicated in the mechanisms controlling longevity and quality of life in the aged population. This article reviews the current state of treatment with PBCs and their associated risk for cardiovascular disease. It discusses the most powerful antioxidant supplementation options as a possible strategy to reduce the cardiovascular toxicity effects of chemotherapy in the elderly.

Preanalytical Procedures for DNA Studies: The Experience of the Interinstitutional Multidisciplinary BioBank (BioBIM)

Preanalytical variables, including the anticoagulants and stabilizing agents, time, storage temperature, and methods of DNA extraction applied to blood samples, may affect quality and quantity of isolated nucleic acids for future genomic applications. Considering the large number of collected samples, standard operating procedure optimization for whole blood preservation before DNA extraction is a crucial step in a biological repository. Moreover, the future application of the biological material may not be known subsequent to its extraction. To define standard operating procedures for whole blood preservation before DNA extraction, we aimed to determine whether different combinations of anticoagulants, blood storage temperatures, and time intervals before storage at -80°C might have an impact on quality and quantity of subsequent extracted DNA. After spectrophotometer quantification, the quality and integrity of DNA were assessed by agarose gel electrophoresis, polymerase chain reaction, and real-time polymerase chain reaction methods. We observed that decrease in DNA recovery during blood storage time was more pronounced at room temperature than at 4°C. Based on our experience, we recommend as anticoagulants of choice sodium citrate and ethylenediaminetetraacetate, whereas sodium citrate theophylline adenosine dipyridamole could represent an alternative choice, excluding a priori lithium heparin and Fluoride-Oxalate. Based on the overall evaluation criteria, we conclude that the procedures necessary to preserve the whole blood before the DNA extraction may have a significant impact on downstream molecular biological applications.

Sirtuins and Cancer: Role in the Epithelial-Mesenchymal Transition

The human sirtuins (SIRT1–SIRT7) enzymes are a highly conserved family of NAD+-dependent histone deacetylases, which play a critical role in the regulation of a large number of metabolic pathways involved in stress response and aging. Cancer is an age-associated disease, and sirtuins may have a considerable impact on a plethora of processes that regulate tumorigenesis. In particular, growing evidence suggests that sirtuins may modulate epithelial plasticity by inducing transcriptional reprogramming leading to epithelial-mesenchymal transition (EMT), invasion, and metastases. Though commonly regarded as EMT inducers, sirtuins may also suppress this process, and their functional properties seem to largely depend on the cellular context, stage of cancer development, tissue of origin, and microenvironment architecture. Here, we review the role of sirtuins in cancer biology with particular emphasis on their role in EMT.

Pharmacogenomics and pharmacogenetics of thiazolidinediones: role in diabetes and cardiovascular risk factors

The most important goal in the treatment of patients with diabetes is to prevent the risk of cardiovascular disease (CVD), the first cause of mortality in these subjects. Thiazolidinediones (TZDs), a class of antidiabetic drugs, act as insulin sensitizers increasing insulin-dependent glucose disposal and reducing hepatic glucose output. TZDs including pioglitazone, rosiglitazone and troglitazone, by activating PPAR-γ have shown pleiotropic effects in reducing vascular risk factors and atherosclerosis. However, troglitazone was removed from the market due to its hepatoxicity, and rosiglitazone and pioglitazone both have particular warnings due to being associated with heart diseases. Specific genetic variations in genes involved in the pathways regulated by TDZs have demonstrated to modify the variability in treatment with these drugs, especially in their side effects. Therefore, pharmacogenomics and pharmacogenetics are an important tool in further understand intersubject variability per se but also to assess the therapeutic potential of such variability in drug individualization and therapeutic optimization.