Chromosome 16 abnormalities associated with myeloid malignancies

Twenty-six patients who had cytogenetic analyses performed for myeloid malignancies at St. Vincent's Hospital over a 6-year period were found to have an inversion abnormality of chromosome 16 (25 patients) or t(16;16) (1 patient). Only 16 patients had all the features of M4Eo, while the other 10 patients had diagnoses of M2, M4, M5, RAEB, and RAEB-T; six of these had abnormal eosinophils. Thus, abnormal eosinophils were present in 22 of 26 patients (85%). Thirteen patients had additional cytogenetic abnormalities at diagnosis, the commonest being +8 in 5, del(7q) in 4, and +21 in 3. Twenty-three patients received chemotherapy and 20 (87%) achieved complete remission. The median survival of the treated group was 188 weeks with a 61% 2-year and 45% 5-year survival. No significant difference in survival was observed between those patients with a diagnosis of M4Eo and those with other diagnoses suggesting that it is the abnormality of chromosome 16 which confers an improved prognosis. Additional cytogenetic abnormalities present at diagnosis did not affect prognosis. CNS relapse was observed in only two patients (8%), thus indicating no increased incidence of this complication. This study supports the premise that a chromosome abnormality involving 16p13 and 16q22 defines a good prognosis subset of myeloid leukemia despite morphological variations.     

Molecular genetic diagnosis of the familial myxoma syndrome (Carney complex)

We describe an individual in whom molecular genetic testing provided a diagnosis of the Carney complex, an autosomal dominant syndrome comprising cutaneous and cardiac myxomas, spotty pigmentation of the skin, and endocrinopathy. Recently, we localized the Carney complex disease gene to chromosome region 17q2. Our patient was a member of a family segregating the Carney complex, but was not, himself, initially thought to be affected. Haplotype analysis based on genotyping studies with 17q2 microsatellites predicted that this individual was, in fact, affected by Carney complex and was at risk for development of myxomas. Further clinical evaluation and re-review of prior pathologic studies, then, confirmed the DNA-based diagnosis. This report highlights the difficulty in establishing a diagnosis of Carney complex based on clinical and pathologic findings alone, and we suggest that molecular genetic analyses provide an important diagnostic method for this familial myxoma syndrome. Am. J. Med. Genet. 86:62–65, 1999. © 1999 Wiley-Liss, Inc.     

Chromosome abnormalities in neuroblastoma

The case is briefly reported of a 7-month-old boy with a disseminated neuroblastoma, whose marrow showed neuroblastoma rosettes and on direct examination on two occasions revealed a high proportion of cells with 48 chromosomes forming an abnormal cell line.     

Chromosome abnormalities in leiomyosarcomas

Short-term cultures from seven soft tissue leiomyosarcomas were investigated cytogenetically. Sufficient mitoses for chromosome analysis were obtained in six cases, four of which had only normal karyotypes. In one tumor, an intramuscular leiomyosarcoma of the lower arm, a variety of nonclonal structural and numerical aberrations were found in two thirds of the metaphases. Another tumor, a subcutaneous leiomyosarcoma of the knee, had clonal abnormalities resulting in the karyotype 46,X,der(X)t(X;4)(:Xq26----cen----Xp22::4q23----4qter) , del(4)(q23)/47,X,der(X)t(X;4),del(4)(q23), + 20. Flow cytofluorometric measurements of the DNA content in the six leiomyosarcomas successfully karyotyped revealed diploid values in five tumors. The leiomyosarcoma displaying numerous nonclonal changes had two cytofluorometric peaks, 1.01 and 1.39, indicating that the metaphases available for cytogenetic study cannot have been fully representative of the tumor stemline.     

Chromosome abnormalities in meningiomas

Cytogenetic analyses of eight meningiomas grown in culture for 1 week are reported. Normal karyotypes were found in three cases and hypodiploidy in the remaining five. In the five hypodiploid meningiomas, one chromosome #22 was missing in four cases, and one case exhibited a 22q- deletion. In four of these five cases, chromosome #14 was either lost or altered. Chromosome #1 was lost or altered in three, and chromosome #6 in two. These findings lend further support for the association of total or partial loss of chromosome #22 in meningiomas and suggest the involvement of other chromosomes in the clonal evolution of these tumors.     

Alterations of CDKN2 (p16) in non-small cell lung cancer

The cyclin-dependent kinase inhibitor known as p16 (CDK41, CDKN2, INK4A, MTS1) has been proposed as a tumor suppressor gene on chromosome segment 9p21. We have evaluated CDKN2 alterations in 34 non-small cell lung cancers (NSCLCs) with matched normal tissue controls and in 9 NSCLC cell lines by Southern blotting, single-strand conformation polymorphism (SSCP) with the polymerase chain reaction, and direct sequencing. In addition, loss of heterozygosity at chromosome segment 9p21, with the use of the microsatellite marker D9S171, was studied in these samples. Whereas CDKN2 was either deleted or mutated in NSCLC cell lines at a high frequency (6/9, 67%), alterations were much less frequent (7/34, 21%) in primary tumor samples. Only one sample contained a point mutation in exon 1 of CDKN2. In addition, two samples had homozygous deletions of CDKN2 in exon 1; one had a homozygous and three a hemizygous deletion of exon 2. Possibly normal tissue contaminating our tumor samples may have masked homozygous deletions in these cases. Four patient samples had LOH in the region of CDKN2 on chromosome segment 9p21; two of these samples had potentially inactivating alterations of CDKN2; one sample had a mutation of CDKN2, and the other had a homozygous deletion of exon 1. In summary, inactivation of CDKN2 is implicated in the development of about 20% of NSCLC, but the possibility of another tumor suppressor gene on chromosome segment 9p21 important in lung cancer cannot be eliminated.     

Chromosome abnormalities in pancreatic adenocarcinoma

Adenocarcinoma of the pancreas is the fifth most common cause of cancer deaths in the United States, yet few cytogenetic studies of this tumor have been reported. We analyzed 26 primary tumors to identify which chromosome abnormalities occur most frequently in this neoplasm. One carcinoma was well differentiated and mucin producing, 18 were moderately well differentiated, and seven were poorly differentiated. Only normal karyotypes were obtained from nine carcinomas. The remaining 17 carcinomas frequently had normal metaphase cells in addition to simple to highly complex karyotypes. The modal chromosome number in 20 carcinomas was diploid or near-diploid; four carcinomas had both a major near-diploid and near-triploid or near-tetraploid component, and two were near-tetraploid. Numerical abnormalities included loss of whole copies of chromosomes 6, 17, and 18, and gains of chromosome 20. Structural abnormalities were frequent, with 1p, 2p, 3p, 4q, 6q, 7q, 1 1q, and 17p recurrently involved. Results of this study were combined with karyotypes of 19 other primary adenocarcinomas of the pancreas reported in the literature. The combined data involving 1 17 breakpoints suggest that careful analysis of chromosome 20, proximal 1 q. 6q, proximal 8p. and proximal 17p could be productive in defining genes involved in adenocarcinoma of the pancreas. Genes Chrom Cancer 9:93-100 (1994).© 1994 Wiley-Liss, Inc.     

Chromosome abnormalities in human embryos

The presence of numerical chromosome abnormalities in human embryos was studied using fluorescence in-situ hybridization with four or more chromosome-specific probes. When most cells of an embryo are analysed, this technique allows differentiation to be made between aneuploidy, mosaicism, haploidy and polyploidy. Abnormal types of fertilization, such as unipronucleated, tripronucleated zygotes and zygotes with uneven pronuclei, were studied using this technique. We have found a strong correlation between some types of dysmorphism with chromosomal abnormalities. In addition, the more impaired the development of an embryo, the more chromosomal abnormalities were detected in those embryos. Maternal age and other factors were linked to an increase in chromosome abnormalities (hormonal regimes, temperature changes), but not to intracytoplasmic sperm injection.     

Chromosome abnormalities in male infertility

On the basis of systematic cytogenetic studies carried out with men undergoing examination for infertility in the couple, it is now estimated that the incidence of chromosome anomalies is about 5 per cent. This rate is much higher than that observed in the general population (0.7 per cent). Anomalies in the sex chromosomes are the most frequently observed since they represent approximately 4 per cent of the cases, and the analysis of the various types of mutation shows a distinct predominance of the 47 chromosome composition, XXY, which is related to Klinefelter's syndrome. Autosome anomalies are also observed, notably Robertsonian and reciprocal translocations. They are more rare (about 1% of the cases), but the fact that they are linked with disturbances of spermatogenesis is an important element in understanding the control-mechanisms of this process. The occurrence in both man and animals of a non-random relationship between the forms of translocation and the X and Y chromosomes found in the seminal vesicle during the pachytene stage, suggests that this contact interferes with the normal process in which the X chromosome is inactivated. This interference could account for the observed deficits in spermatogenesis. The hypothesis is reinforced by the fact that female carriers of the same autosome translocations, whose two X chromosomes are normally active during the whole miotic prophase, have no fertility problems.     

Chromosome abnormalities in myelodysplastic syndrome

We performed chromosomal analysis in 18 patients with myelodysplastic syndrome (MDS). According to the French-American-British (FAB) cooperative study group and Research Group of Japanese Ministry of Welfare Classification, our cases with MDS were classified into four subtypes as follows; refractory anemia [RA], 6 cases; refractory anemia with excess of blasts [RAEB], 4; chronic myelomonocytic leukemia [CMML], 3; refractory anemia with excess of blasts in transformation [RAEB-T], 4; and refractory cytopenia [RC], 1. Thirteen patients (72%) had chromosomal abnormalities and frequently observed chromosomal abnormalities were trisomy 8, -7/7q-, 20q-, trisomy 1q and 5q-. The mean survival were as follows; RA: 22.5 months, RAEB: 13.2 months, CMML: 15 months, RAEB-T: 5.5 months. Progression to overt leukemia occurred in 5 patients (27.7%): 1 of four patients with RAEB, 1 of three patients with CMML and 3 of four patients with RAEB-T. In conclusion, chromosomal abnormalities were most frequently observed in the patient with RAEB-T who had shortest survival time among the patients with MDS. On the other hand, chromosomal abnormalities were less frequently observed in the patients with RA and they showed relatively better prognosis than the other types of MDS.     

Chromosome abnormalities in liposarcomas.

We performed a cytogenetic study of short-term cultures from fresh surgical specimens obtained from four patients with liposarcoma. Myxoid liposarcomas (cases 1-3) were associated with a specific translocation between chromosomes 12 and 16. Trisomy 8, a nonrandom secondary aberration in myxoid liposarcoma, was observed in the third case as the only additional change. Round cell liposarcoma (case 4) showed complex chromosomal aberrations affecting chromosomes 1, 2, 5, 6, 7, 13, 14, 17, 19, and 22. Neither band 12q13 nor 16p11 was visibly rearranged. Three subgroups of liposarcomas are proposed. The first group is characterized by t(12;16)(q13;p11), the second group by ring chromosomes, telomeric associations, and giant markers, and the last by complex numerical and structural aberrations.     

Chromosome abnormalities in breast fibroadenomas

A cytogenetic study on 25 breast fibroadenomas from 17 women is reported. Seven tumors in five patients showed clonal structural chromosome changes. In three patients the breaks involved chromosome 12, occurring in two tumors in band 12p12 and in band 12q15 in all three tumors of one patient. The finding of an identical aberration, t(11;12)(q21;q15), in three adenomas from the same patient strongly suggests a clonal origin of multiple fibroadenomas of the breast.     

Rubinstein-Taybi syndrome with de novo reciprocal translocation t(2;16) (p13.3; p13.3)

We describe a girl with typical Rubinstein-Taybi syndrome with apparently balanced reciprocal translocation between chromosome 2 and 16. The patient has a condition characterized by mental retardation, typical facial manifestations, broad thumbs and first toes. Cytogenetic studies of the patient showed a reciprocal translocation without visible deletion, karyotype: 46, XX, t(2;16) (p13.3; p13.3). Her parents had normal chromosomes. These results suggest that the locus of the gene for the Rubinstein-Taybi syndrome may be situated at 2p13.3 or 16p13.3.