Karyotypic changes in the preclinical and subsequent stages of malignant mesothelioma: a case report.

The karyotypic evolution was evaluated in cells from recurring pleural effusions in a patient previously exposed to asbestos. Pleural malignant mesothelioma (MM) was diagnosed 4 years after the first cytogenetic examination. The primary cytogenetic changes consisted of loss of chromosomes 1p,14,21, Y, both 22, and derivative chromosomes involving 1, 2, and 14. The modal chromosome number was 44. Sixty-seven percent of the cells had a normal karyotype. After 4 years of spontaneous remission, only 6% of the cells had a normal karyotype, 42% had the same karyotypic changes as found previously, whereas 52% had additional derivative chromosomes involving chromosomes 1, 3, 5, 7, 8, and 12, trisomy 7, 7p, and 11, and partial or whole monosomy 3, 8, and 9. The chromosomal changes are in agreement with the main findings in previous reports. The karyotype remained quite stable for 7 months in vitro. After 23 months in culture, all the cells were near-triploid. Cells established in culture were cytokeratin positive. All derivative and marker chromosomes identified in the cultured cells had previously been observed in direct preparations from the pleural effusions. We conclude that chromosomes 1, 14, 21, and 22 may be involved in the preclinical stage of development of asbestos-induced mesothelioma, whereas the later chromosomal changes may be related to progression of the tumor.