Biomedical subjects
Publications and source records attributed to J Limon.
A de novo translocation (X;1)(q13.1;p36.33) was found in a 2-year-old girl with typical clinical features of X-linked anhidrotic ectodermal dysplasia (EDA). The breakpoint at Xq13.1 is approximately the same as has been described in 2 other EDA females with X;autosome translocations.
Cytogenetic analysis of 30 renal cell carcinomas showed 3p aberrations in nine tumors, trisomy 7 in 17 tumors, and clonal loss of one sex chromosome in 14 tumors. The 3p aberrations and trisomy 7 were present in the same clone in two tumors and in separate clones in three tumors. Loss of one sex chromosome was present together with 3p aberrations in the same clone in one tumor and occurred in seemingly unrelated clones in two tumors. It occurred as the sole change in five tumors. Clones with trisomy 7 as the only change were present in six tumors. Trisomy 7 and loss of one sex chromosome were present in separate clones in four tumors and in the same clone in one tumor. Because +7 and -X/-Y were thus rarely present together with clonal structural abnormalities, in particular 3p changes, our findings make it highly unlikely that loss of one sex chromosome or trisomy 7 represents a primary change in renal cell carcinoma. We instead suggest that there is a tendency for normal kidney cells to lose an X or a Y chromosome and also to gain an extra copy of chromosome 7. This tendency is retained by renal carcinoma cells; therefore, trisomy 7 and sex chromosome loss should not be viewed as tumor-specific abnormalities in this context. Whether these simple numerical aberrations reflect in vivo mosaicism or are acquired in vitro remains unresolved.
Cytogenetic analysis was performed after short-term tissue culture of a thecoma of the ovary. Trisomy of chromosome 12 was revealed as the sole chromosome abnormality. This is the first report of a chromosomal aberration in thecoma of the ovary.
An improved technique for cytogenetic analysis of malignant prostatic tissue is described. This method is based on 1) prolonged mild collagenase treatment, 2) careful washing and repeated centrifugation and sedimentation of the disaggregated material to isolate viable prostatic epithelial cells, 3) short-term culture on collagen R-coated chamber slides with PFMR-4 medium supplemented with mitogenic factors, and 4) daily inspection of the cultured cells to determine the optimal time for harvesting. Twenty consecutive primary prostatic adenocarcinomas were cultured and processed for cytogenetic analysis. Outgrowth of pure epithelial colonies was obtained in 16 cases; in three there was a mixture of epithelial colonies and fibroblasts, and in one there was no cell growth. More than 25 metaphases with chromosomes of high banding quality could be analyzed per case, in particular in cultures from the final pellet fraction. Clonal chromosome aberrations were present in four tumors, and nonclonal structural changes were present in nine. Six tumors showed only normal diploid karyotypes.
Numerical chromosome aberrations are common in several types of malignant tumors. Recently, trisomy 7 and loss of the Y chromosome were described in cultures from nonneoplastic tissue, making the significance of these aberrations as cancer-associated changes doubtful. We herein report the mosaic occurrence of trisomy 7 in four consecutive short-term cultures initiated from normal kidney tissue. Smaller clones with trisomy 10 were present in three cases, and the only culture established from a male also showed mosaic loss of the Y chromosome.
The clinical and cytogenetic findings of a patient with refractory anemia with excess of blasts are presented. Trisomy 13 was present as the sole numerical aberration in all analyzed bone marrow metaphases; this finding has not been reported previously in myelodysblastic syndrome.
Double minute chromosomes were found in metaphases from short-term tissue cultures of two primary prostatic adenocarcinomas. This is the first cytogenetic evidence of gene amplification in this tumor type.
Cytogenetic analysis was performed after short-term tissue culture of two recurrent synovial sarcomas. The tumors were classified on the basis of morphology, location, and immunohistochemistry. In a poorly differentiated tumor, the karyotype 49,XY, +7, +8, +19,t(5:18) (q11.2;q11.2), and in a biphasic tumor two clonal cell lines with common translocations t(X;18)(p11.2;q11.2) and t(12;17)(p11.2;q11.2) were present. In the predominant cell line several other structural aberrations including t(1;12)(q21;q24.3), t(3;18)(p23;q21), and 17p+ were found. A comparison of our results with previously published studies suggests that in addition to t(X;18), translocations of chromosome 18 with other chromosomes may represent a consistent feature of chromosomal changes in synovial sarcoma.
Clonal chromosome abnormalities in short-term cultures were found in 18 of 51 nonfamilial renal cell carcinomas. The breakpoints on chromosome 3 in seven specimens clustered in region 3p11-3p24.2, confirming its importance in the genesis of renal cell carcinoma. An i(5p) and involvement of band 5q21 were other frequent structural chromosome changes. Two additional nonrandom karyotype changes, the gain of one chromosome 7 and the loss of one sex chromosome, were also observed.
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Two cases of a nonfluorescent Y (Ynf) chromosome were diagnosed: one in a male, the other in a female. Both had similar complex mosaic chromosome constitutions with a 45,X cell line. DNA studies were applied in both cases for verification of the cytogenetic diagnosis. The results on the two patients were compared with data obtained from seven healthy men (46,XY), three healthy women (46,XX), two females with 46,XY karyotype, and from cell lines with 49,XXXXY and 48,XXXX chromosome constitution. The highly repetitive Y-specific DNA sequences located in the heterochromatic region of the long arm were absent in these patients. Differences in the composition of the euchromatic part of the Y chromosome were demonstrable in both patients. The highly repetitive Y-specific DNA sequences located in the heterochromatic region of the long arm were absent in these patients. Differences in the composition of the euchromatic part of the Y chromosome were demonstrable in both patients. The suggestion that the Ynf chromosome originates from a dicentric Y chromosome cannot be accepted as a complete explanation of the phenomenon, as it probably involves more complex molecular alterations of the abnormal Y chromosome. The presence of Ynf is associated with the presence of a 45,X cell line more often than in cases of simple Y chromosome deletions with the breakpoint localized in or below the Y euchromatin/heterochromatin junction.
A poorly differentiated sarcoma in a 32-year-old female revealed a large, abnormally banded region in one chromosome #8 in all metaphases. The modal karyotype was 46,XX, -8, +mar. Southern blot hybridization was performed with probes for two protooncogenes located in chromosome 8q (c-MYC and c-MOS). No amplification or rearrangement was observed to account for the cytogenetic abnormality.
Cytogenetic studies were performed on human malignant melanoma cells from eight metastatic lesions. Five tumors displayed near-triploid and three near-diploid chromosome numbers. Chromosomes #1, #6, #7, followed by #2 and #9, were found to be most frequently involved in structural aberrations. Aberrations involving chromosome #1, with deletions or translocations of 1p, involving region 1p12-1p22 in seven of eight breakpoints of the p arm were observed. Seven of nine breakpoints of 6q were located at region 6q15-6q21. Most of the breakpoints on chromosome #7 occurred near the centromeric region. All tumors had additional chromosome material involving 1q, chromosome #7 (7q in two tumors), and in five tumors an increased dose of chromosome #6 (6p in one tumor). The nonrandom breakpoints of these and other chromosomes involved diverse bands, including loci of oncogenes and fragile sites. The observation of nonrandom chromosomal changes in advanced malignant melanoma suggests that genes important in the progression of melanoma are located on chromosomes #1, #6, and #7.
A cytogenetic study was performed on short-term cultures from fresh surgical specimens obtained from 41 patients with soft-tissue sarcomas of various histologic origins. The results demonstrated that myxoid liposarcomas (five tumors) were associated with a specific translocation between chromosomes 12 and 16 and that synovial sarcomas (six tumors) were associated with a specific translocation between the X chromosome and chromosome 18. These chromosomal data have been used to differentiate myxoid liposarcoma from other myxoid tumors exhibiting a non-characteristic histologic picture, as well as to ascertain the diagnosis of synovial sarcoma in undifferentiated soft-tissue sarcomas. The results to date indicate that identification of specific chromosomal changes in sarcomas may provide a new diagnostic criterion for these tumors and possibly improve prognostication with regard to survival and response to treatment.
Cytogenetic analysis of a primary adrenocortical carcinoma revealed clonal rearrangements of several autosomes and sex chromosomes. In all metaphases the following marker chromosomes were present: 4p+,t(3;12)(p14;p13),14q+, t(15;20)(p11;q11), t(5;18) (p13.3;p11.2), psu dic(18)t(18.3)(p11.39;p12), and psu dic(20)t(20;9)(q11.2;p11). The results are discussed in relation to the cytogenetic findings in other solid tumors, especially of the kidney.
The chromosome constitutions of black-melanotic (Ma), brown-melanotic (MI), and amelanotic (Ab) melanomas of the Syrian hamster were compared. The MI and Ab melanomas arose through a spontaneous phenotypic alteration of the Ma tumor. All three variants differ in their growth rates, with MI showing the slowest, Ab the fastest, and Ma intermediate growth rate. Cytogenetic examination revealed that each tumor line shows a distinct karyotype. The Ma tumor is near-diploid, whereas, Ab and MI tumors are hypertriploid and near-tetraploid, respectively. Each tumor line shows a unique set of marker chromosomes, though some markers are shared by two different tumor lines. No single marker chromosome was common for all three melanoma variants. We conclude that the spontaneous phenotypic variation of transplantable hamster melanomas is associated with profound changes in the chromosome constitution of the neoplastic cells. The general direction of these changes is toward increased ploidy and increased complexity of the structural abnormalities.
Chromosome studies were performed on an adrenocortical carcinoma extending into the kidney. The following karyotype was present in all metaphases: 46,XX,t(4;11)(q35;p13). Two metaphases with an additional del(1)(q23) were found. The results are briefly discussed in relation to specific karyotypic changes in cancer, in general, and to those of adrenocortical tumors, in particular.
A translocation that involves chromosome X (band p11.2) and chromosome 18 (band q11.2) was observed in short-term in vitro cultures of cells from five synovial sarcomas and one malignant fibrous histiocytoma. In four of these tumors, the translocation t(X;18)(p11.2;q11.2) was reciprocal. The two other tumors had complex translocations: t(X;18;21)(p11.2;q11.2;p13) and t(X;15;18)(p11.2;q23;q11.2). A translocation between chromosomes X and 18 was not detected in other histological types of soft tissue sarcoma. The X;18 rearrangement appears to characterize the synovial sarcoma and is the first description of a primary, nonrandom change in the sex chromosome of a human solid tumor.