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 malign ant mesothelioma (MM) was diagnosed 4 years after the first cytogeneti c examination. The primary cytogenetic changes consisted of loss of ch romosomes 1p,14,21, Y, both 22, and derivative chromosomes involving 1 , 2, and 14. The modal chromosome number was 44. Sixty-seven percent o f the cells had a normal karyotype. After 4 years of spontaneous remis sion, only 6% of the cells had a normal karyotype, 42% had the same ka ryotypic changes as found previously, whereas 52% had additional deriv ative 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 chromos omal changes are in agreement with the main findings in previous repor ts. The kazyotype remained quite stable for 7 months in vitro. After 2 3 months in culture, all the cells were near-triploid. Cells establish ed in culture were cytokeratin positive. All derivative and marker chr omosomes identified in the cultured cells had previously been observed in direct preparations from the pleural effusions. We conclude that c hromosomes 1, 14, 21, and 22 may be involved in the preclinical stage of development of asbestos-induced mesothelioma, whereas the later chr omosomal changes may be related to progression of the tumor.