1,424 research outputs found
Lynch syndrome (hereditary non-polyposis colorectal cancer): current concepts and approaches to management
No full textColorectal cancer is among the most frequent causes of cancer death worldwide. An inherited predisposition to cancer of the colon and other organs, Lynch syndrome-- also called hereditary non-polyposis colorectal cancer--is probably the most frequent cause of hereditary cancer and is often found in a colon cancer patient and traced through other family members. However, this syndrome is not only characterized by the early onset of colon cancers but also by a predisposition to a constellation of extraintestinal cancers that tend to be misdiagnosed. With new diagnostic technologies, the incidence of familial/inherited versus sporadic cases may appear to increase, due to the recognition of cancers in families that do not fulfill clinical guidelines developed prior to knowledge of the genetic basis of this disease. We now have the ability and the responsibility to detect and prevent this disease, and equally important, to direct patients to specifically targeted treatment. Specialists should be aware of the significance of inherited colon cancer and should become familiar with the molecular diagnostic tests now widely available
Constraints imposed by supercoiling on in vitro amplification of polyomavirus DNA
No full textPrevious attempts to identify oncogenic polyomaviruses in human cancers have yielded conflicting results, even with the application of PCR technology. Here, it was considered whether the topological features of the polyomavirus genome interfere with efficient PCR amplification. Plasmid and SV40 DNAs were used as a model system for comparing the amplification efficiency of supercoiled, circular relaxed and linear templates. It was found that detection of circular templates required 10 times more molecules than detection of identical but linear templates. Supercoiling hindered the in vitro amplification of SV40 circles by a factor of 10, and erratic amplification of supercoiled SV40 occurred with subpicogram amounts of template. Accordingly, topoisomerase I treatment of DNA improved the PCR detection of supercoiled SV40, significantly decreasing the number of false-negative samples. Previously described, yet controversial, polyomavirus presence in human tissues should be reconsidered and topoisomerase I-sensitive polyomavirus amplification might help to detect polyomavirus genomes in mammalian tissues
La politica della legalità : il ruolo del giurista nell'età contemporanea
No full textAs the author of this book shows as he tests his theses, impartiality and justice require specific and scrupulous forms of civil engagement which render obsolete the traditional call for neutrality. At the same time, citizens must be made to understand how formal features of law that usually evoke their hostility actually guarantee their rights. The legal professional must learn to be a "relativist", obliged - through his choices - to establish priorities among distinct and often irreconcilable value domains
Involvement of the Polyomavirus, JCV, in Colorectal Cancer
No full textThis chapter focuses on the possible role of the polyomavirus JC in the development of colorectal cancer. Based on recent findings from several international groups, there is increased evidence that JC virus might contribute to the developmet of colorectal cancer displaying chromosomal instability, which represent the majority of cases. The possibility that an oncogenic virus, JC virus, because of its ability to produce an oncoprotein named T antigen, is intriguing thus needing further cause-relationship association. However, both in vitro and in vivo data are now pointing to the direction that the virus might have a critical role
State-of-the-Art Lecture: Infection, inflammation and cancer – the future.
No full textThis chapter focuses on the role of infections in inflammations and cance
Steady-state regulation of the human DNA mismatch repair system
No full textSteady-state levels of human DNA mismatch repair (MMR) transcripts and proteins were measured in MMR-proficient and -deficient cell lines by the newly developed competitive quantitative reverse transcription- polymerase chain reaction and Western analysis normalized with purified proteins. In MMR-proficient cells, hMSH2 is the most abundant MMR protein and is expressed 3 to 5 times more than hMLH1. The hMLH1 protein was expressed 1.5 to 2.5 times more than hPMS2. Steady-state levels of mRNA expression correlated well with protein expression, hMSH2-mutated LoVo cells did not express detectable hMSH3 or hMSH6 proteins. Similarly, hMLH1-mutated HCT116 cells did not express detectable hMLH1 or hPMS2 protein, whereas in hMLH1 restored HCT116+ch3 cells, hPMS2 protein was reexpressed. In hMSH6-mutated HCT15 cells, both hMSH3 protein and mRNA were increased. In SV40-transformed lung fibroblasts, all MMR mRNAs and proteins examined were expressed at levels 1.5-5-fold higher than in their nontransformed counterpart. The steady-state levels of MMR proteins indicate that substantially more hMutS proteins, which are involved in DNA mismatch recognition, are present in comparison with the hMutL proteins. Stability of hMSH3 and hMSH6 proteins appears to depend upon the presence of the hMSH2 protein, and, similarly, the stability of the hPMS2 protein depends upon hMH1. When the hMSH6 is mutationally inactivated, hMSH3 increases by both transcriptional up-regulation and enhanced protein stability. A balanced up-regulation of all of the components was seen after vital transformation in a fibroblast model. Quantitative changes of the MMR components are a potential mechanism to modify the DNA MMR capabilities of a cell
A novel mechanism for aspirin-mediated growth inhibition of human colon cancer cells
No full textPurpose: The molecular mechanisms by which aspirin and other nonsteroidal anti-inflammatory drugs exert chemopreventative effects in colon cancer are unclear and complex. Current investigations focus on the chemopreventive properties of nonsteroidal anti-inflammatory drugs, independent of their ability to inhibit cyclooxygenase (COX) activity, and presumably, identification of non-COX pathways will suggest new targets for clinical use. It was demonstrated recently that aspirin results in reduced microsatellite instability in colorectal cancer cells. We hypothesized that aspirin treatment might alter expression of DNA mismatch repair (MMR) proteins, representing another potential non-COX mechanism for its action. Experimental Design: In this study, we have examined the effects of aspirin on the cellular growth rates, MMR protein levels, cell cycle analysis and apoptosis in MMR-deficient (HCT116) and MMR-proficient (HCT116+chr3 and SW480) human colon cancer cell lines. Results: We found that treatment with aspirin inhibited the growth of these three cancer cell lines. In HCT116+chr3 cells, treatment with 1 mM of aspirin increased expression of the hMLH1 and hPMS2 proteins by 2.5-fold and 2-fold, respectively, and increased expression of the hMSH2 and hMSH6 proteins by 2-3-fold. For SW480 cells, treatment with 1 and 5 mM of aspirin increased expression of the hMLH1 and hPMS2 proteins by 2-4-fold and 3-5-fold, respectively, and increased expression of the hMSH2 and hMSH6 proteins by 3-7-fold. For all three of the cell lines, treatment with 1 and 2.5 mM of aspirin induced apoptosis at 48 and 72 h. Aspirin induced G0/G1 cell cycle arrest in HCT116 cells. Conclusions: We conclude that aspirin acts through COX-independent mechanisms by resulting in an increase in MMR protein expression and subsequent apoptosis, which might serve as an additional means of growth inhibition in aspirin-treated human colon cancer cells
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