Capecitabine as Adjuvant Treatment for Stage III Colon Cancer

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Validation of selected molecular methods for the mutations determination in codons 12 and 13 of K-RAS gene in five Polish oncological research centers

Chorzy na raka jelita grubego z przerzutami mogą osiągnąć korzyść z leczenia panitumumabem jedynie, jeśli w guzie nie stwierdzono mutacji w genie K-RAS. W związku z tym konieczne jest zbadanie statusu tego genu w celu wyłonienia chorych, którzy mogą być poddani takiemu leczeniu. Celem pracy było opracowanie standardowej procedury oznaczania statusu genu K-RAS w materiale izolowanym z bloczków parafinowych. Kolejnym celem była walidacja wybranych technik molekularnych oznaczania mutacji w pięciu ośrodkach w Polsce, w których odbywa się leczenie chorych na raka jelita grubego. Ocenie poddano cztery różne techniki oznaczania mutacji: SSCP, DHPLC, RFLP/PCR i bezpośrednie sekwencjonowanie. Stwierdzono, że wszystkie jednostki uczestniczące w procesie walidacji są odpowiednio przygotowane do podjęcia działalności diagnostycznej w zakresie oznaczania statusu genu K-RAS. Przyjęto następujące zalecenia dla laboratoriów diagnostycznych: 1. Materiał do izolacji DNA powinien zawierać przynajmniej 70% utkania nowotworowego; 2. Ujednolicenie procedury izolacji DNA ze skrawków parafinowych wymaga stosowania gotowego zestawu do izolacji DNA; 3. W przypadku braku jednoznacznego wyniku konieczne jest stosowanie dwóch metod oznaczania mutacji, przy czym jedną z nich powinno być sekwencjonowanie bezpośrednie.Metastatic colorectal cancer patients will benefit from treatment with panitumumab only when they don't have mutation in K-RAS gene. Therefore, estimation of mutational status of K-RAS is necessary for the selection of patients, who should be treated with panitumumab. The aim of this study was to evolve a standard method of estimation of K-RAS mutational status in the material isolated from paraffin blocs. The second aim was the validation of selected molecular methods of K-RAS mutation evaluation in five Polish oncological centers where mCRC patients are treated. Four methods were evaluated: SSCP, DHPLC, RFLP/PCR and direct sequencing. We found that all groups in five selected oncological centers, who took part in the validation process, were well prepared for molecular diagnosis of K-RAS mutational status. The following recommendations for diagnostic laboratories were approved: 1. At least 70% of cancer cells should be present in a tissue for DNA isolation; 2. The method of DNA isolation should be standardized, the most appropriate is usage of DNA isolation kits; 3. In case of equivocal results two independent molecular methods should be employed, one of them should be direct sequencing

Capecitabine as adjuvant treatment for stage III colon cancer

BACKGROUND: Intravenous bolus fluorouracil plus leucovorin is the standard adjuvant treatment for colon cancer. The oral fluoropyrimidine capecitabine is an established alternative to bolus fluorouracil plus leucovorin as first-line treatment for metastatic colorectal cancer. We evaluated capecitabine in the adjuvant setting. METHODS: We randomly assigned a total of 1987 patients with resected stage III colon cancer to receive either oral capecitabine (1004 patients) or bolus fluorouracil plus leucovorin (Mayo Clinic regimen; 983 patients) over a period of 24 weeks. The primary efficacy end point was at least equivalence in disease-free survival; the primary safety end point was the incidence of grade 3 or 4 toxic effects due to fluoropyrimidines. RESULTS: Disease-free survival in the capecitabine group was at least equivalent to that in the fluorouracil-plus-leucovorin group (in the intention-to-treat analysis, P<0.001 for the comparison of the upper limit of the hazard ratio with the noninferiority margin of 1.20). Capecitabine improved relapse-free survival (hazard ratio, 0.86; 95 percent confidence interval, 0.74 to 0.99; P=0.04) and was associated with significantly fewer adverse events than fluorouracil plus leucovorin (P<0.001). CONCLUSIONS: Oral capecitabine is an effective alternative to intravenous fluorouracil plus leucovorin in the adjuvant treatment of colon cancer

A functional study of genes essential for autogamy and nuclear reorganization in Paramecium

Like all ciliates, Paramecium tetraurelia is a unicellular eukaryote that harbors two kinds of nuclei within its cytoplasm. At each sexual cycle, a new somatic macronucleus (MAC) develops from the germline micronucleus (MIC) through a sequence of complex events, which includes meiosis, karyogamy and assembly of the MAC genome from MIC sequences. The latter process involves developmentally programmed genome rearrangements controlled by non-coding RNAs and a specialized RNA interference machinery. We describe our first attempts to identify genes and biological processes that contribute to the progression of the sexual cycle. Given the high percentage of unknown genes annotated in the P. tetraurelia genome, we applied a global strategy to monitor gene expression profiles during autogamy, a self-fertilization process. We focused this pilot study on the genes carried by the largest somatic chromosome and designed dedicated DNA arrays covering 484 genes from this chromosome (1.2% of all genes annotated in the genome). Transcriptome analysis revealed four major patterns of gene expression, including two successive waves of gene induction. Functional analysis of 15 up-regulated genes revealed four that are essential for vegetative growth, one of which is involved in the maintenance of MAC integrity and another in cell division or membrane trafficking. Two additional genes, encoding a MIC-specific protein and a putative RNA helicase localizing to the old, then to the new MAC, are specifically required during sexual processes. Our work provides a proof of principle that genes essential for meiosis and nuclear reorganization can be uncovered following genome-wide transcriptome analysis

Global trends of whole-genome duplications revealed by the ciliate Paramecium tetraurelia.

The duplication of entire genomes has long been recognized as having great potential for evolutionary novelties, but the mechanisms underlying their resolution through gene loss are poorly understood. Here we show that in the unicellular eukaryote Paramecium tetraurelia, a ciliate, most of the nearly 40,000 genes arose through at least three successive whole-genome duplications. Phylogenetic analysis indicates that the most recent duplication coincides with an explosion of speciation events that gave rise to the P. aurelia complex of 15 sibling species. We observed that gene loss occurs over a long timescale, not as an initial massive event. Genes from the same metabolic pathway or protein complex have common patterns of gene loss, and highly expressed genes are over-retained after all duplications. The conclusion of this analysis is that many genes are maintained after whole-genome duplication not because of functional innovation but because of gene dosage constraints