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Gerrit Meijer

Publications and source records attributed to Gerrit Meijer.

6 recordsLinked to original sources
PubMed2005

Centromeric chromosomal translocations show tissue-specific differences between squamous cell carcinomas and adenocarcinomas.

Structural chromosomal aberrations are common in epithelial tumors. Here, we compared the location of centromeric breaks associated with whole arm translocations in seven adenocarcinoma cell lines and nine squamous cell carcinoma cell lines using SKY, microarray-based comparative genomic hybridization (array CGH) and fluorescence in situ hybridization (FISH). Whole arm translocations were more frequent in squamous cell carcinomas (112 in nine cell lines and nine in one short-term culture) than in adenocarcinomas (13 in seven cases) and most often resulted in copy number alterations. Array CGH analysis demonstrated that in all squamous cell carcinomas and in most adenocarcinomas, the breakpoints of unbalanced whole arm translocations occurred between the two clones on the array flanking the centromeres. However, FISH with centromeric probes revealed that in squamous cell carcinomas, the marker chromosomes with whole arm translocations contained centromeres comprised of material from both participating chromosomes, while in adenocarcinomas centromeric material from only one of the chromosomes was present. These observations suggest that different mechanisms of centromeric instability underlie the formation of chromosomal aberrations in adenocarcinomas and squamous cell carcinomas.

Adenocarcinoma↗
PubMed2005

Chromosomal changes in relation to clinical outcome in larynx and pharynx squamous cell carcinoma.

Invasive head and neck squamous carcinomas are among the cytogenetically most complex tumors. Perhaps for this reason, there is little consensus on the prognostic value of specific chromosomal aberrations. Here we present results of CGH analysis of 56 clinically well-characterized set of head and neck cancers, consisting of larynx and pharynx only. The aim was to find possible associations with clinical outcome. The major chromosome arms showing gains were (in decreasing order): 3q, 7q, 8q, 5p, 11q13, 17q and 18p, and losses occurred at 3p, 11qter, 4p, 18q, and 5q. The segments most frequently amplified were 3q26-qter, 11q13, 11q22, 3q12-13, 18p11.3, 18q11.2 and 8q24.3. Tumors with stages III and IV, and lymph node positive tumors had a worse clinical outcome. Surprisingly, no specific chromosomal abnormality correlated with disease-free survival. The only aberration that correlated to one of the clinico-pathological parameters was amplification 11q13, that occurred solely in lymph node positive, stage IV tumors. However 11q13 amplification did not correlate with disease-free survival. These results seem to indicate that genetic alterations at the level of chromosomes have limited prognostic value in patients with invasive larynx and pharynx squamous cell carcinomas.

Adult↗
PubMed2004

Breakpoint identification and smoothing of array comparative genomic hybridization data.

SUMMARY: We describe a tool, called aCGH-Smooth, for the automated identification of breakpoints and smoothing of microarray comparative genomic hybridization (array CGH) data. aCGH-Smooth is written in visual C++, has a user-friendly interface including a visualization of the results and user-defined parameters adapting the performance of data smoothing and breakpoint recognition. aCGH-Smooth can handle array-CGH data generated by all array-CGH platforms: BAC, PAC, cosmid, cDNA and oligo CGH arrays. The tool has been successfully applied to real-life data. AVAILABILITY: aCGH-Smooth is free for researchers at academic and non-profit institutions at http://www.few.vu.nl/~vumarray/.

Algorithms↗
PubMed2003

LOH of PTPRJ occurs early in colorectal cancer and is associated with chromosomal loss of 18q12-21.

Recently, the gene PTPRJ (protein tyrosine phosphatase receptor type J) was identified as the candidate gene for the mouse colon cancer susceptibility locus Scc1. Its human homologue PTPRJ is frequently deleted in several cancer types, including colorectal cancer. To elucidate the role of PTPRJ loss in different stages of colorectal cancer and in its pathways of progression, we expanded the previously published comparative genomic hybridization results with novel data on loss of heterozygosity (LOH) at the PTPRJ locus. We identified a strong association between the LOH of PTPRJ and the loss of chromosomal region 18q12-21 (P=0.009). This observation is specific for progressed colorectal adenomas, suggesting that an interaction between LOH of PTPRJ and loss of 18q12-21 may be involved in the development of a more progressed form of adenomas.

Adenoma↗
PubMed2002

Colorectal adenoma to carcinoma progression follows multiple pathways of chromosomal instability.

BACKGROUND & AIMS: Current models of colorectal adenoma to carcinoma progression do not fully reflect the genetic heterogeneity and complexity of the disease. The aim of the present study was to identify genetic changes discriminating adenomas that have progressed to carcinoma from adenomas that have not progressed, and to refine the current genetic models of colorectal adenoma to carcinoma progression, based on a genome-wide analysis of chromosomal aberrations. METHODS: Sixty-six nonprogressed colorectal adenomas, 46 progressed adenomas (malignant polyps), and 36 colorectal carcinomas were screened for chromosomal aberrations by comparative genomic hybridization, and for mutations in the adenomatous polyposis coli (APC) and K-ras gene. Data analysis focused on cancer-associated genetic changes in adenomas. RESULTS: Accumulation of losses in 8p21-pter, 15q11-q21, 17p12-13, and 18q12-21, and gains in 8q23-qter, 13q14-31, and 20q13 were strongly associated with adenoma-to-carcinoma progression, independent of the degree of dysplasia. Hierarchic cluster analysis demonstrated the presence of 3 distinct subgroups of adenomas, characterized by unique combinations of genetic aberrations in the adenomas (17p loss and K-ras mutation, 8q and 13q gain, and 18q loss and 20q gain, respectively). CONCLUSIONS: The presence of 2 or more of the aforementioned 7 chromosomal changes was associated with progressed colorectal adenomas and colorectal cancer. In addition, evidence was found that these chromosomal abnormalities occurred in specific combinations of a few abnormalities rather than as a mere accumulation of events, indicating the existence of multiple independent chromosomal instability pathways of colorectal cancer progression.

Adenoma↗