25 research outputs found

    Genome characteristics of primary carcinomas, local recurrences, carcinomatoses, and liver metastases from colorectal cancer patients

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    BACKGROUND: Colorectal cancer (CRC) is one of the most common causes of cancer-related deaths in the Western world, and despite the fact that metastases are usually the ultimate cause of deaths, the knowledge of the genetics of advanced stages of this disease is limited. In order to identify potential genetic abnormalities underlying the development of local and distant metastases in CRC patients, we have, by comparative genomic hybridization, compared the DNA copy number profiles of 10 primary carcinomas, 14 local recurrences, 7 peritoneal carcinomatoses, and 42 liver metastases from 61 CRC patients. RESULTS: The median number of aberrations among the primary carcinomas, local recurrences, carcinomatoses, and liver metastases was 10, 6, 13, and 14, respectively. Several genetic imbalances, such as gains of 7, 8q, 13q, and 20, and losses of 4q, 8p, 17p, and 18, were common in all groups. In contrast, gains of 5p and 12p were more common in the carcinomatoses than in other stages of the disease. With hierarchical cluster analysis, liver metastases could be divided into two main subgroups according to clusters of chromosome changes. CONCLUSIONS: Each stage of CRC progression is characterized by a particular genetic profile, and both carcinomatoses and liver metastases are more genetically complex than local recurrences and primary carcinomas. This is the first genome profiling of local recurrences and carcinomatoses, and gains of 5p and 12p seem to be particularly important for the spread of the CRC cells within the peritoneal cavity

    Molecular detection (k-ras) of exfoliated tumour cells in the pelvis is a prognostic factor after resection of rectal cancer?

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    <p>Abstract</p> <p>Background</p> <p>After total mesorectal excision (TME) for rectal cancer around 10% of patients develops local recurrences within the pelvis. One reason for recurrence might be spillage of cancer cells during surgery. This pilot study was conducted to investigate the incidence of remnant cancer cells in pelvic lavage after resection of rectal cancer. DNA from cells obtained by lavage, were analysed by denaturing capillary electrophoresis with respect to mutations in hotspots of the <it>k-ras </it>gene, which are frequently mutated in colorectal cancer.</p> <p>Results</p> <p>Of the 237 rectal cancer patients analyzed, 19 had positive lavage fluid. There was a significant survival difference (p = 0.006) between patients with <it>k-ras </it>positive and negative lavage fluid.</p> <p>Conclusion</p> <p>Patients with <it>k-ras </it>mutated cells in the lavage immediately after surgery have a reduced life expectation. Detection of exfoliated cells in the abdominal cavity may be a useful diagnostic tool to improve the staging and eventually characterize patients who may benefit from aggressive multimodal treatment of rectal cancer.</p

    Pseudomyxoma peritonei – two novel orthotopic mouse models portray the PMCA-I histopathologic subtype

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    <p>Abstract</p> <p>Background</p> <p>Pseudomyxoma peritonei (PMP) is a rare malignant disease, most commonly originating from appendiceal lesions and characterized by accumulation of mucinous tumor tissue in the peritoneal cavity. Since the disease is infrequent, the task of carrying out studies of treatment efficacy and disease biology in the clinical setting is challenging, warranting the development of relevant <it>in vitro </it>and <it>in vivo </it>PMP models.</p> <p>Methods</p> <p>Human tumor tissue was implanted in the peritoneal cavity of nude mice to establish two orthotopic models exhibiting noninvasive intraperitoneal growth without metastasis development.</p> <p>Results</p> <p>Xenograft tissues have retained essential properties of the original human tumors, such as macro- and microscopic growth patterns, mucin production as well as expression of carcinoembryonal antigen, cytokeratins 20 and 7 and the proliferation marker pKi67. Upon microscopic examination, the human tumors were categorized as the PMCA-I (peritoneal mucinous carcinomatosis of intermediate features) subtype, which was conserved through 14 examined passages in mice, for the first time modeling this particular histopathologic category.</p> <p>Conclusion</p> <p>In conclusion, two novel orthotopic models of human PMP have been established that consistently portray a distinct histopathologic subtype and reflect essential human tumor properties. Xenografts can easily and reproducibly be transferred to new generations of mice with acceptable passage periods, rendering the models as attractive tools for further studies of PMP biology and treatment.</p

    Hyperoxia increases the uptake of 5-fluorouracil in mammary tumors independently of changes in interstitial fluid pressure and tumor stroma

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    <p>Abstract</p> <p>Background</p> <p>Hypoxia is associated with increased resistance to chemo- and radiation-therapy. Hyperoxic treatment (hyperbaric oxygen) has previously been shown to potentiate the effect of some forms of chemotherapy, and this has been ascribed to enhanced cytotoxicity or neovascularisation. The aim of this study was to elucidate whether hyperoxia also enhances any actual uptake of 5FU (5-fluorouracil) into the tumor tissue and if this can be explained by changes in the interstitium and extracellular matrix.</p> <p>Methods</p> <p>One group of tumor bearing rats was exposed to repeated hyperbaric oxygen (HBO) treatment (2 bar, pO<sub>2 </sub>= 2 bar, 4 exposures à 90 min), whereas one group was exposed to one single identical HBO treatment. Animals housed under normal atmosphere (1 bar, pO<sub>2 </sub>= 0.2 bar) served as controls. Three doses of 5FU were tested for dose response. Uptake of [<sup>3</sup>H]-5FU in the tumor was assessed, with special reference to factors that might have contributed, such as interstitial fluid pressure (P<sub>if</sub>), collagen content, oxygen stress (measured as malondialdehyd levels), lymphatics and transcapillary transport in the tumors.</p> <p>Results</p> <p>The uptake of the cytostatic agent increases immediately after a single HBO treatment (more than 50%), but not 24 hours after the last repeated HBO treatment. Thus, the uptake is most likely related to the transient increase in oxygenation in the tumor tissue. Factors like tumor P<sub>if </sub>and collagen content, which decreased significantly in the tumor interstitium after repeated HBO treatment, was without effect on the drug uptake.</p> <p>Conclusion</p> <p>We showed that hyperoxia increases the uptake of [<sup>3</sup>H]-5FU in DMBA-induced mammary tumors <it>per se</it>, independently of changes in P<sub>if</sub>, oxygen stress, collagen fibril density, or transendothelial transport alone. The mechanism by which such an uptake occur is still not elucidated, but it is clearly stimulated by elevated pO<sub>2</sub>.</p

    A knowledge model for situation‐handling

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