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Malignant rhabdoid tumor (MRT): A highly malignant childhood tumor with minimal karyotypic changes
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Abstracts . 8 9 M A L I G N A N T RBABDOID TUMOR (MET): A HIGHLY MALIGN A N T C H I L D H O O D T U M O R WITH MINIMAL KARYOTYPIC CHANGES. Edwin C. Douglass, Marc Valentine, Susan T. Rowe, David M. Parham. Judith A. Wilimas. St. Jude Children's Research Hospital, Memphis TN 38105 MRT is a highly malignant tumor of childhood, o r i g i n a l l y d e s c r i b e d as an unfavorable variant of Wilms' tumor. Now, we recognize it as a separate cancer which also occurs in other organs such as liver, brain, and soft tissues. MRT is often widely metastatic at diagnosis and responds poorly to therapy. It is fatal except in children with localized disease. The cell of origin is unknown. We have found no reports of previous cytogenetlc studies in MRT. We have karyotyped 9 MRT's (of i0 attempted) and have found a surprisingly low incidence of karyotypic abnormalities. A l l cases w e r e s t u d i e d from m a t e r i a l obtained before treatment. Three cases (i liver, 2 kidney) have no detectable chromosomal rearranEements at an early to mld-metaphase stage of elongation. All three cell cultures contain only tumor cells. Electron microscopy (EM) demonstrates the accumulation of intermediate filaments characteristic of MRT. Two more cases (both kidney) also have no abnormalities, but did not persist in culture to allow EM studies. 4 cases demonstrated chromosomal abnormalities: i. soft tissue MRT with 46 XY, t(8;15)(q12;pll), 2. liver MRT with 47 XY, del(1)(ql2), de!(3)(p21), +mar, 3, brain MRT with 46 XX, +20, -22, and 4. kidney MRT with 46 XY/46 XY, del(13)(ql4). In summary, 3 of 9 cases of MRT had no detectable chromosomal rearrangements~ despite EM evidence that the cultured cells were of tumor origin. Two further cases were also normal but are unverified. 4 cases had minimal karyotypic changes characterized in 3 cases by loss of genetic material.
, CYTOGENETIC FINDINGS IN BENIGN BONE TUMORS. B10 Julia A. Bridge, M.D.*+, Warren Sanger, Ph.D.+ and James R. Neff, M.D.* *University of Kansas Medical Center - Kansas City, Kansas +University of Nebraska Medical Center - Omaha, Nebraska Few benign tumors have been described as having clonal chromosome abnormalities. Primary benign bone tumors have not previously been subjected to cytogenetic analysis. In this report, 26 different benign bone tumors were analyzed including 16 giant cell tumors, chondroblastomas, 1 nonossifying fibroma, i osteoblastoma, 1 enchondroma, 1 ossifying fibroma, i desmoDlastic fibroma, and I chondromyxoid fibroma. Cells from the tumors were disaggregated by mechanical mincing and/or by the addition of 0.8% collagenase. Culture times ranged from i-i0 days. Analyzable metaphase ~lates were obtained in all of the cases. Only chromosomally normal cells were observed in ii of the cases. Of the remaining 15 cases, clonal numerical abnormalities of chromosomes 3, 5, and 7 were mo~t frequent and structural abnormalities of chromosomes 2, ii, 13, and 18 were described. Increased telomeric association was apparent in i0 of the 15 giant cell tumors. Additional benign bone tumors are presently being analyzed and will be presented along with the above cases.
Abstracts . 8 9 M A L I G N A N T RBABDOID TUMOR (MET): A HIGHLY MALIGN A N T C H I L D H O O D T U M O R WITH MINIMAL KARYOTYPIC CHANGES. Edwin C. Douglass, Marc Valentine, Susan T. Rowe, David M. Parham. Judith A. Wilimas. St. Jude Children's Research Hospital, Memphis TN 38105 MRT is a highly malignant tumor of childhood, o r i g i n a l l y d e s c r i b e d as an unfavorable variant of Wilms' tumor. Now, we recognize it as a separate cancer which also occurs in other organs such as liver, brain, and soft tissues. MRT is often widely metastatic at diagnosis and responds poorly to therapy. It is fatal except in children with localized disease. The cell of origin is unknown. We have found no reports of previous cytogenetlc studies in MRT. We have karyotyped 9 MRT's (of i0 attempted) and have found a surprisingly low incidence of karyotypic abnormalities. A l l cases w e r e s t u d i e d from m a t e r i a l obtained before treatment. Three cases (i liver, 2 kidney) have no detectable chromosomal rearranEements at an early to mld-metaphase stage of elongation. All three cell cultures contain only tumor cells. Electron microscopy (EM) demonstrates the accumulation of intermediate filaments characteristic of MRT. Two more cases (both kidney) also have no abnormalities, but did not persist in culture to allow EM studies. 4 cases demonstrated chromosomal abnormalities: i. soft tissue MRT with 46 XY, t(8;15)(q12;pll), 2. liver MRT with 47 XY, del(1)(ql2), de!(3)(p21), +mar, 3, brain MRT with 46 XX, +20, -22, and 4. kidney MRT with 46 XY/46 XY, del(13)(ql4). In summary, 3 of 9 cases of MRT had no detectable chromosomal rearrangements~ despite EM evidence that the cultured cells were of tumor origin. Two further cases were also normal but are unverified. 4 cases had minimal karyotypic changes characterized in 3 cases by loss of genetic material.
, CYTOGENETIC FINDINGS IN BENIGN BONE TUMORS. B10 Julia A. Bridge, M.D.*+, Warren Sanger, Ph.D.+ and James R. Neff, M.D.* *University of Kansas Medical Center - Kansas City, Kansas +University of Nebraska Medical Center - Omaha, Nebraska Few benign tumors have been described as having clonal chromosome abnormalities. Primary benign bone tumors have not previously been subjected to cytogenetic analysis. In this report, 26 different benign bone tumors were analyzed including 16 giant cell tumors, chondroblastomas, 1 nonossifying fibroma, i osteoblastoma, 1 enchondroma, 1 ossifying fibroma, i desmoDlastic fibroma, and I chondromyxoid fibroma. Cells from the tumors were disaggregated by mechanical mincing and/or by the addition of 0.8% collagenase. Culture times ranged from i-i0 days. Analyzable metaphase ~lates were obtained in all of the cases. Only chromosomally normal cells were observed in ii of the cases. Of the remaining 15 cases, clonal numerical abnormalities of chromosomes 3, 5, and 7 were mo~t frequent and structural abnormalities of chromosomes 2, ii, 13, and 18 were described. Increased telomeric association was apparent in i0 of the 15 giant cell tumors. Additional benign bone tumors are presently being analyzed and will be presented along with the above cases.