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Pancreatic Neoplasms: HELP
Articles by Tomás Lopez
Based on 5 articles published since 2010
(Why 5 articles?)

Between 2010 and 2020, Tomàs López wrote the following 5 articles about Pancreatic Neoplasms.
+ Citations + Abstracts
1 Review How useful is it clinically to analyse the K-ras mutational status for the diagnosis of exocrine pancreatic cancer? A systematic review and meta-analysis. 2011

Parker, Lucy A / Lumbreras, Blanca / Lopez, Tomás / Hernández-Aguado, Ildefonso / Porta, Miquel. ·Department of Public Health, Miguel Hernández University, Alicante, Spain. ·Eur J Clin Invest · Pubmed #21391995.

ABSTRACT: BACKGROUND: More clinically meaningful diagnostic tests are needed in exocrine pancreatic cancer (EPC). K-ras mutations are the most frequently acquired genetic alteration in EPC. We analysed the diagnostic utility of detecting K-ras mutations through a systematic analysis of the literature. METHODS: We searched PubMed using suitable medical subject headings and text words. Original research articles that evaluated the diagnostic accuracy of detecting K-ras mutations for diagnosis of EPC were selected. Two investigators independently extracted data from each study regarding the methodology used, the methodological quality of the study, the diagnostic accuracy reported and the authors' conclusions about clinical applicability of the test. Combined estimates for the sensitivity and specificity of K-ras were determined using bivariate meta-analysis; heterogeneity was explored using meta-regression. RESULTS: We assessed 34 studies from 30 published articles. The research reports were prone to numerous methodological biases and often lacked vital information for assessing external validity. The sensitivity of detecting K-ras status ranged from 0% through 100%, and the specificity from 58% through 100%. Diagnostic accuracy was highest when cytohistological samples were used: sensitivity and specificity were 76·5% (66·7-84·2) and 91·8% (87·6-94·1), respectively. Studies conducted in a clinically relevant population observed lower accuracy than case-control designs (68·4% vs. 82·7%). CONCLUSIONS: Because of the numerous methodological limitations of studies, the utility of analysing K-ras mutations for the diagnosis of EPC remains unknown. Flaws in diagnostic biomarkers with well-established biological properties, as K-ras, become even more relevant when the promises of 'personalized medicine' are pondered.

2 Article Adjusting serum concentrations of organochlorine compounds by lipids and symptoms: a causal framework for the association with K-ras mutations in pancreatic cancer. 2014

López, Tomàs / Pumarega, José A / Pollack, Anna Z / Lee, Duk-Hee / Richiardi, Lorenzo / Jacobs, David R / Schisterman, Enrique F / Porta, Miquel. ·Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain; Facultat de Medicina, Universitat Autònoma de Barcelona, Catalonia, Spain. · Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain; CIBER en Epidemiología y Salud Pública (CIBERESP), Spain. · Epidemiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, MD, USA. · Department of Preventive Medicine and Health Promotion Research Center, School of Medicine, Kyungpook National University, Daegu, Republic of Korea. · Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin and CPO-Piemonte, Torino, Italy. · Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, MN, USA. · Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain; Facultat de Medicina, Universitat Autònoma de Barcelona, Catalonia, Spain; CIBER en Epidemiología y Salud Pública (CIBERESP), Spain. Electronic address: mporta@imim.es. ·Chemosphere · Pubmed #25113205.

ABSTRACT: In clinically aggressive diseases, patients experience pathophysiological changes that often alter concentrations of lipids and environmental lipophilic factors; such changes are related to disease signs and symptoms. The aim of the study was to compare the effects of correcting for total serum lipids (TSL) and other clinical factors on the odds of mutations in the K-ras oncogene by organochlorine compounds (OCs), in logistic models, in 103 patients with exocrine pancreatic cancer (EPC) using a causal directed acyclic graph (DAG) framework. Results and likelihood of bias were discussed in the light of possible causal scenarios. The odds of K-ras mutated EPC was associated with some TSL-corrected OCs, including p,p'-DDT (p-value: 0.008) and polychlorinated biphenyl 138 (p-trend: 0.024). When OCs were not corrected by TSL, the OR of a K-ras mutation was significant for p,p'-DDT (p-trend: 0.035). Additionally adjusting for cholestatic syndrome increased the ORs of TSL-corrected OCs. When models were adjusted by the interval from first symptom to blood extraction (ISE), the ORs increased for both TSL-corrected and uncorrected OCs. Models with TSL-corrected OCs and adjusted for cholestatic syndrome or ISE yielded the highest ORs. We show that DAGs clarify the covariates necessary to minimize bias, and demonstrate scenarios under which adjustment for TSL-corrected OCs and failure to adjust for symptoms or ISE may induce bias. Models with TSL-uncorrected OCs may be biased too, and adjusting by symptoms or ISE may not control such biases. Our findings may have implications as well for studying environmental causes of other clinically aggressive diseases.

3 Article Pancreatic cancer risk and levels of trace elements. 2012

Amaral, André F S / Porta, Miquel / Silverman, Debra T / Milne, Roger L / Kogevinas, Manolis / Rothman, Nathaniel / Cantor, Kenneth P / Jackson, Brian P / Pumarega, José A / López, Tomàs / Carrato, Alfredo / Guarner, Luisa / Real, Francisco X / Malats, Núria. ·Genetic and Molecular Epidemiology Group, Spanish National Cancer Research Centre (CNIO), C/ Melchor Fernández Almagro 3, Madrid, Spain. ·Gut · Pubmed #22184070.

ABSTRACT: BACKGROUND AND AIMS: Knowledge on the aetiology of exocrine pancreatic cancer (EPC) is scant. The best established risk factor for EPC is tobacco smoking. Among other carcinogens, tobacco contains cadmium, a metal previously associated with an increased risk of EPC. This study evaluated the association between concentrations of trace elements in toenails and EPC risk. METHODS: The study included 118 EPC cases and 399 hospital controls from eastern Spain. Levels of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. OR and 95% CI, adjusted for potential confounders, were calculated using logistic regression. RESULTS: Significantly increased risks of EPC were observed among subjects whose concentrations of cadmium (OR 3.58, 95% CI 1.86 to 6.88; p(trend)=5×10(-6)), arsenic (OR 2.02, 95% CI 1.08 to 3.78; p(trend)=0.009) and lead (OR 6.26, 95% CI 2.71 to 14.47; p(trend)=3×10(-5)) were in the highest quartile. High concentrations of selenium (OR 0.05, 95% CI 0.02 to 0.15; p(trend)=8×10(-11)) and nickel (OR 0.27, 95% CI 0.12 to 0.59; p(trend)=2×10(-4)) were inversely associated with the risk of EPC. CONCLUSION: Novel associations are reported of lead, nickel and selenium toenail concentrations with pancreas cancer risk. Furthermore, the results confirm previous associations with cadmium and arsenic. These novel findings, if replicated in independent studies, would point to an important role of trace elements in pancreatic carcinogenesis.

4 Article Clinical validity of detecting K-ras mutations for the diagnosis of exocrine pancreatic cancer: a prospective study in a clinically-relevant spectrum of patients. 2011

Parker, Lucy A / Porta, Miquel / Lumbreras, Blanca / López, Tomàs / Guarner, Luisa / Hernández-Aguado, Ildefonso / Carrato, Alfredo / Corominas, Josep M / Rifà, Juli / Fernandez, Esteve / Alguacil, Joan / Malats, Núria / Real, Francisco X. ·Department of Public Health, Miguel Hernández University, Alicante, Spain. ·Eur J Epidemiol · Pubmed #21298467.

ABSTRACT: The diagnostic utility of detecting K-ras mutations for the diagnosis of exocrine pancreatic cancer (EPC) has not been properly studied, and few reports have analysed a clinically relevant spectrum of patients. The objective was to evaluate the clinical validity of detecting K-ras mutations in the diagnosis of EPC in a large sample of clinically relevant patients. We prospectively identified 374 patients in whom one of the following diagnoses was suspected at hospital admission: EPC, chronic pancreatitis, pancreatic cysts, and cancer of the extrahepatic biliary system. Mutations in the K-ras oncogene were analysed by PCR and artificial RFLP in 212 patients. The sensitivity and specificity of the K-ras mutational status for the diagnosis of EPC were 77.7% (95% CI: 69.2-84.8) and 78.0% (68.1-86.0), respectively. The diagnostic accuracy was hardly modified by sex and age. In patients with either mutated K-ras or CEA > 5 ng/ml, the sensitivity and specificity were 81.0% (72.9-87.6) and 62.6% (72.9-87.6), respectively. In patients with mutated K-ras and CEA > 5 ng/ml the sensitivity was markedly reduced. In comparisons with a variety of non-EPC patient groups sensitivity and specificity were both always greater than 75%. In this clinically relevant sample of patients the sensitivity and specificity of K-ras mutations were not sufficiently high for independent diagnostic use. However, it seems premature to rule out the utility of K-ras analysis in conjunction with other genetic and 'omics' technologies.

5 Article Relationships between occupational history and serum concentrations of organochlorine compounds in exocrine pancreatic cancer. 2011

Bosch de Basea, Magda / Porta, Miquel / Alguacil, Joan / Puigdomènech, Elisa / Gasull, Magda / Garrido, José A / López, Tomàs / Anonymous6460679. ·Clinical and Molecular Epidemiology of Cancer Unit, Institut Municipal d'Investigació Mèdica, Universitat Autònoma de Barcelona, Carrer del Dr Aiguader 88, E-08003 Barcelona, Catalonia, Spain. ·Occup Environ Med · Pubmed #21098829.

ABSTRACT: BACKGROUND: Previous studies investigating associations between occupational history and risk of exocrine pancreatic cancer (EPC) did not use biomarkers of exposure. The only two studies that measured internal concentrations of organochlorine compounds (OCs) in EPC did not analyse their relationship with occupation. OBJECTIVE: To analyse the relationship between occupational history and blood concentrations of seven OCs in patients with EPC. METHODS: Incident cases of EPC were prospectively identified, and during hospital admission were interviewed face-to-face on occupational history and life-style factors (n = 135). Occupations were coded according to the International Standard of Occupations 1988. Some occupational exposures were also assessed with the Finnish job-exposure matrix (Finjem). Serum concentrations of OCs were analysed by high-resolution gas chromatography with electron-capture detection. RESULTS: Craftsmen and related trades workers had significantly higher concentrations of polychlorinated biphenyl (PCB) congeners 138, 153 and 180. Years worked in agriculture did not influence concentrations of p,p'-DDT, p,p'-DDE, hexachlorobenzene or β-hexachlorocyclohexane. Subjects who ever worked in agriculture had lower concentrations of PCBs (all p < 0.05). Occupational exposure to lead, nickel and low frequency magnetic fields was significantly associated with higher concentrations of PCBs. CONCLUSIONS: Certain occupations were associated with higher concentrations of PCBs, suggesting that these compounds may account for some increased risks found in previous studies. The lack of association between work in agriculture and concentrations of OC pesticides is consistent with occupation playing a lesser role than diet in influencing OC concentrations. Occupational studies on the relationships among exposure to industrial agents and EPC risk may need to consider adjusting for exposure to PCBs.