Chromosomal alterations in early stages of malignant mesotheliomas.

In a case of a 67-year-old man with two different early stages of a predominantly epithelioid mesothelioma ("mesothelioma in situ", "early-stage mesothelioma"), chromosomal imbalances were determined by comparative genomic hybridisation (CGH), a molecular cytogenetic technique to detect chromosomal gains and losses in tumour cells. In the case of the mesothelioma in situ cells, nine different chromosomal alterations could be detected (losses on 3p, 5q, 6q, 8p, 9p, 15q, 22q, Y; gain on 7q), whereas the early-stage mesothelioma showed the same defects except for the gain on 7q. The simultaneous losses of 6q, 9p and 22q, as well as other chromosomal regions, correlate well with the most common defects previously found in 90 cases of more-advanced-stage mesotheliomas using CGH.

Pathological anatomy and molecular pathology.

The incidence of malignant mesotheliomas in Germany has increased since about the mid 1980s, and a further increase is expected until about 2020 due to the peak in asbestos processing in Germany between 1965 and 1980. About 90% of the mesotheliomas recorded in the files of the German Mesothelioma Registry in Bochum are asbestos-related and therefore possibly due to an occupational exposure. In 2003, 717 mesotheliomas were newly diagnosed at the German Mesothelioma Registry.

Mutational analysis of the nf2 tumour suppressor gene in three subtypes of primary human malignant mesotheliomas.

Fourteen primary human malignant mesothelioma (HMM) samples obtained from 14 patients were screened for point mutations and microdeletions/microinsertions in exons 1-16 of the chromosome 22q-located tumour suppressor gene neurofibromin 2 (nf2) by single strand conformation polymorphism (SSCP) analysis. In one tumour (7%) a 10 basepair microdeletion of exon 10 was detected by SSCP and subsequently characterised in detail by sequencing. Deletion of the second nf2 allele in laser-microdissected regions of the 10 bp mutation-harbouring tumour was demonstrated by denaturing gradient gel electrophoresis (DGGE) analysis.

Molecular cytogenetic differences between histological subtypes of malignant mesotheliomas: DNA cytometry and comparative genomic hybridization of 90 cases.

It is established that subtypes of human malignant mesotheliomas (MM) are associated with different survival times. Ninety cases of MM were examined using DNA cytometry and comparative genomic hybridization (CGH), with emphasis on the main histological subtypes; epithelioid, sarcomatoid and biphasic. A comparison by DNA cytometry revealed moderate differences, with the rare subgroup of mesodermomas having the highest and the sarcomatoid group the lowest rate of aneuploidy.