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[This corrects the article DOI: 10.1186/s12014-016-9103-3.].
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BACKGROUND: Malignant mesothelioma is an aggressive, almost uniformly fatal tumor, caused primarily by exposure to asbestos. In this study, serum presence of mesothelioma-specific protein transcript variants of ecto-nicotinamide adenine dinucleotide oxidase disulfide-thiol exchanger 2 (ENOX2), a recently identified marker of malignancy, were investigated using the ONCOblot tissue of origin cancer detection test. METHODS: Sequential serum samples collected from asbestos-exposed individuals prior to the development of frank mesothelioma were assayed for ENOX2 presence by 2-D gel immunoblot analysis to determine how long in advance of clinical symptoms mesothelioma-specific ENOX2 transcript variants could be detected. RESULTS: Two mesothelioma-specific ENOX2 protein transcript variants were detected in the serum of asbestos-exposed individuals 4-10 years prior to clinical diagnosis of malignant mesothelioma (average 6.2 years). Either one or both ENOX2 protein transcript variants indicative of malignant mesothelioma were absent in 14 of 15 subjects diagnosed with benign pleural plaques either with or without accompanying asbestosis. CONCLUSIONS: In a population of asbestos-exposed subjects who eventually developed malignant mesothelioma, ENOX2 protein transcript variants characteristic of malignant mesothelioma were present in serum 4-10 years in advance of clinical symptoms. As with all biomarker studies, these observations require validation in a larger, independent cohort of patients and should include prospective as well as retrospective sampling.
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A proteomics approach with detection on western blots using an S-peptide tagged pan-tNOX (ENOX2) recombinant (scFv) antibody followed by alkaline phosphatase-linked anti S has revealed a family of more than 20 ENOX2 isoforms of varying molecular weights (34 to 94 kDa) and mostly of low isoelectric points (4.6 +/- 0.7) based on serum analysis. Different isoforms characterize cancers of different tissue origins indicative of both cancer presence and tissue site of origin. ENOX2 proteins are cancer-associated and differ from constitutive (CNOX or ENOX1) proteins primarily by the absence of a drug binding site to which the cancer-specific scFv is directed. All are located on the cell surface where they function both as terminal oxidases for plasma membrane electron transport and carry out protein disulfide-thiol interchange. These proteins are shed into the blood and can also be found in urine. The tNOX isoform technology is under development as a clinical aid to identify unknown or uncertain primary cancers, evaluation of metastatic spread in post surgery patients, monitoring remission following cessation of therapy and for early diagnosis in at-risk populations.
Assuntos
NADH NADPH Oxirredutases/análise , NADH NADPH Oxirredutases/metabolismo , Neoplasias/metabolismo , Isoformas de Proteínas/análise , Isoformas de Proteínas/metabolismo , Western Blotting , Neoplasias da Mama/metabolismo , Neoplasias do Colo/metabolismo , Eletroforese em Gel Bidimensional , Feminino , Humanos , Neoplasias Pulmonares/metabolismo , Linfoma não Hodgkin/metabolismo , Masculino , Melanoma/metabolismo , NADH NADPH Oxirredutases/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Pancreáticas/mortalidade , Neoplasias da Próstata/metabolismo , Isoformas de Proteínas/genética , Neoplasias do Colo do ÚteroRESUMO
ENOX proteins with an oscillatory pattern of production of superoxide (measured by ferricytochrome c reduction) and with a period length of 26 min increase linearity with age beginning at about 30 y to a maximum of about age 60. The proteins are shed and appear in serum, saliva and urine. Enhanced arNOX activity correlates with age and with oxidative changes contributing to skin aging. Topical cosmetic preparations containing substances that block arNOX activity are under evaluation to reduce visible symptoms of skin aging.
