Cytogenetic findings in mouse multiple myeloma and Waldenström's macroglobulinemia

Multiple myeloma (MM) and Waldenström's macroglobulinemia-like lymphoma (MW) appear spontaneously in C57BL/KaLwRij mice at a frequency of 0.5% and 0.2%, respectively. They can readily be propagated by intravenous transfer of mainly bone marrow or spleen cells into syngeneic recipients. Previous studies demonstrated that these mouse malignant monoclonal gammopathies (MMG) show clinical and biologic features that closely resemble those of the corresponding human diseases and thus could be used as experimental models. We report on cytogenetic analysis of two mouse MW and five MM in vivo cell lines of the 5TMM series propagated in syngeneic mice. These studies demonstrated clonal abnormalities in all cell lines, hyperdiploid karyotype in both MW and one MM lines, and hypotriploidy, hypertriploidy, or hypotetraploidy in the other lines. Structural abnormalities of chromosome 15 were observed in all MM lines. In the five MM lines, frequent rearrangements were also found for chromosome numbers 1, 2, 5, and 12. A single chromosomal abnormality, as found in induced mouse plasmacytomas and resembling Burkitt lymphoma, was not found in mouse MM and MW. It was concluded that spontaneously originating C57BL MM of the 5T series is a better model for human MM than pristane-induced BALB/c or NZB plasmacytoma

Cytogenetic studies of forty malignant mesotheliomas

Cytogenetic analyses of 40 confirmed malignant mesotheliomas are reported. Pleural effusion cells were studied in 90% of the cases by direct method, or after culture, or both. Biopsy and ascites fluid were also analysed in 11 cases and 2 cases, respectively. Clonal abnormalities were found in 30 cases, a normal karyotype in 9 and no analysable metaphase in one. All clonal changes were complex and heterogeneous. Karyotype evolution by duplication of the stemline was common and, as a consequence, most metaphases contained many chromosomes. In 13 patients a hypodiploid stemline was found in at least a few cells, whilst 11 patients had a hypotetraploid karyotype with a modal chromosome number varying from 67 to 90, and six patients had a hyperdiploid karyotype with 49 to 61 chromosomes. No consistent, presumably specific abnormality was detected. Nevertheless, two main patterns of nonrandom abnormalities were observed: (1) loss of chromosomes 4 and 22 and structural changes leading to (partial) deletion of 3p and 9p in the hypodiploid/hypotetraploid category; and (2) gain of 7, 5 and 20, together with deletion of 3p in the hyperdiploid type. Pattern (1), observed in 24 out of 30 abnormal cases, was characteristic enough to be of help in differentiating malignant mesothelioma from metastatic effusions of carcinoma. We found no correlation between the cytogenetic category and clinical variables such as age of onset, primary site, survival time and histological type of tumour. Asbestos exposure was also a general feature of our patients' history.</p

Cytogenetic studies of forty malignant mesotheliomas

Cytogenetic analyses of 40 confirmed malignant mesotheliomas are reported. Pleural effusion cells were studied in 90% of the cases by direct method, or after culture, or both. Biopsy and ascites fluid were also analysed in 11 cases and 2 cases, respectively. Clonal abnormalities were found in 30 cases, a normal karyotype in 9 and no analysable metaphase in one. All clonal changes were complex and heterogeneous. Karyotype evolution by duplication of the stemline was common and, as a consequence, most metaphases contained many chromosomes. In 13 patients a hypodiploid stemline was found in at least a few cells, whilst 11 patients had a hypotetraploid karyotype with a modal chromosome number varying from 67 to 90, and six patients had a hyperdiploid karyotype with 49 to 61 chromosomes. No consistent, presumably specific abnormality was detected. Nevertheless, two main patterns of nonrandom abnormalities were observed: (1) loss of chromosomes 4 and 22 and structural changes leading to (partial) deletion of 3p and 9p in the hypodiploid/hypotetraploid category; and (2) gain of 7, 5 and 20, together with deletion of 3p in the hyperdiploid type. Pattern (1), observed in 24 out of 30 abnormal cases, was characteristic enough to be of help in differentiating malignant mesothelioma from metastatic effusions of carcinoma. We found no correlation between the cytogenetic category and clinical variables such as age of onset, primary site, survival time and histological type of tumour. Asbestos exposure was also a general feature of our patients' history.</p