Mitsuaki A. Yoshida

Translocation (9;22)(g22;ql2) A recurrent chromosome abnormality in extraskeletal myxoid chondrosarcoma

Cytogenetic analysis of a case of extraskeletal myxoid chondrosarcoma revealed a reciprocal translocation between 9q and 22q in almost all metaphases analyzed. Structural rearrangements involving 9q and 22q have been reported previously in three cases of extraskeletal myxoid chondrosarcoma. The breakpoints on chromosomes 9 and 22 in the present case were in regions 9q22-q31 and 22q11-q12.2, respectively. The same breakpoints were present in all three previously reported cases. Thus, this recently identified rearrangement of 9q and 22q may serve as a critical cytogenetic parameter for the diagnosis and classification of extraskeletal myxoid chondrosarcoma, as well as being a primary chromosomal event in the course of development of this rare malignancy.

Chromosome rearrangements at 12q13 in two cases of chondrosarcomas

We analyzed the karyotypes of two moderately differentiated (grade 2) chondrosarcomas. Case 1 had a reciprocal translocation between chromosomes 6 and 12, t(6;12)(q25;q13) in most of the cells analyzed, as well as trisomies of chromosomes 7, 8, 11, 17, 19, and 21 and tetrasomy of chromosome 19. A reciprocal translocation involving chromosomes 12 and 19, t(12;19)(q13;q13), was noted as a highly clonal abnormality in the other case. Some cells had t(12;19) as the sole chromosome abnormality. Thus, chromosome rearrangements involving the long arm of chromosome 12 at the same region (q13) were commonly identified in the two tumors. These findings suggest that the rearrangements at 12q13 are nonrandom acquired changes that characterize a subgroup of chondrosarcomas.

Newly established clear cell sarcoma (malignant melanoma of soft parts) cell line expressing melanoma-associated Melan-A antigen and overexpressing C-MYC oncogene

Clear cell sarcoma (CCS), malignant melanoma of soft parts, is a rare malignant tumor with a poor prognosis. In this study, a CCS cell line, designated MP-CCS-SY, was established from a metastatic tumor of a 17-year-old Japanese girl that originated in the left Achilles tendon. A small number of melanosomes were detected in the cytoplasm by electron microscopy. The melanosomes immunoreacted with two melanoma-associated antibodies, HMB45 and Melan-A. A Western blot demonstrated the existence of a Melan-A antigen in this cell line. Although a t(12;22)(q13;q12), which is characteristic of CCS, was not identified by a chromosomal analysis with conventional banding techniques, fluorescence in situ hybridization analysis with painting probes of chromosomes 12 and 22 revealed the insertion of a chromosome 12 fragment into one of the long arms of chromosome 22. The chimeric EWS/ATF1 transcript was detected by the reverse transcriptase polymerase chain reaction. Extra copies and structural abnormalities of chromosome 8 were observed. Overexpression of c-myc mRNA was detected by Northern blot analysis and may have a role in malignant progression of CCS. The availability of this MP-CCS-SY cell line will help to understand the molecular biology of this malignancy and should be useful as a tool for developing an immunotherapy.

Molecular cytogenetic analysis of 17 renal cancer cell lines: increased copy number at 5q31-33 in cell lines from nonpapillary carcinomas.

Comparative genomic hybridization (CGH) was used to screen for genomic imbalances in cell lines derived from 13 nonpapillary renal‐cell carcinomas (RCCs), two papillary RCCs, one renal squamous‐cell carcinoma, and one transitional‐cell carcinoma of the renal pelvis. Aberrations were found in all 17 lines. The most frequent changes in nonpapillary RCC cell lines were gains of 5q (85%), 7q (69%), 8q (69%) and 1q (54%) and losses of 3p (92%), 8p (77%), 4q (62%) and 14q (54%). High‐level gains (HLGs) were detected at 4q12, 5p, 5q23‐33, 7q22‐qter, 8q23‐24, 10q21‐qter, 12p and 12q13‐22. By means of fluorescence in situ hybridization (FISH) we narrowed the smallest common region involving 5q gains to the genomic segment between D5S642 and D5S673, and found that the HLG at 4q12 possibly involved amplifications of c‐kit and PDGFRA. Two papillary RCC cell lines showed gains of entire chromosomes 7, 12 and 17. The CGH data reported here should help to facilitate the choice of individual renal‐tumor cell lines for exploring target genes in regions of interest.

Functional evidence for involvement of multiple putative tumor suppressor genes on the short arm of chromosome 3 in human oral squamous cell carcinogenesis

Cytogenetic and restriction fragment length polymorphism (RFLP) analyses have suggested that a putative tumor suppressor genes(s), which may play an important role in the development of human oral squamous cell carcinoma (SCC), is located on the short arm of chromosome 3 (3p). We previously reported that introducing in intact human chromosome 3 into three different oral SCC tumorigenic cell lines completely suppresses the tumorigenicity of each cell line with significant decrease in the in vitro growth rate and morphological changes. To map the tumor suppressor gene(s) on 3p, we have now examined the tumorigenicity of microcell hybrid clones containing various fragments derived from 3p that were introduced by microcell-mediated chromosome transfer. Sixteen hybrid clones were obtained from four successful experiments, and these clones were classified into two groups: 4 fully tumorigenic clones and 12 suppressed phenotype clones. Analyses of the 3p segments in the series of hybrid clones with the use of RFLP or microsatellite markers revealed that the 3p21.2-p21.3 or 3p25 regions or both were consistently retained in the 12 clones with suppressed phenotype but not in the 4 tumorigenic clones. The more proximal 3p13 region also was retained in three nontumorigenic clones. The overall results are fairly compatible with recent evidence that there are three discrete regions on 3p showing frequent allelic losses on oral SCC, and they directly provide functional evidence for the presence of tumor-suppressor genes for oral SCC in these regions. The possibility that three genes, FHIT, VHL, and T beta R-II, recently identified on 3p may be significantly involved in oral SCC development is also discussed.

A case of chromophobe renal cell carcinoma associated with low chromosome number and microsatellite instability

Cytogenetic study in a case of a human chromophobe renal cell carcinoma revealed a hypodiploid chromosome number of 36 with loss of chromosomes 1, 2, 5, 6, 10, 13, 15, 17, 21, and X. The tumor DNA showed microsatellite instability in dinucleotide repeat microsatellite markers. This is the fourth case that has been fully karyotyped and showed a low chromosome number in a chromophobe renal cell carcinoma. Our data in the present study are consistent with those in the literature. It is suggested that human chromophobe renal cell carcinoma may possibly be characterized by tumor cells with low chromosome number or microsatellite instability.

Chromosome Changes in Desmoid Tumors Developed in Patients with Familial Adenomatous Polyposis

Chromosome analyses were performed on benign desmoid tumors obtained from two female patients with familial adenomatous polyposis (FAP), one of whom was diagnosed as having Gardner syndrome (GS). The modal chromosome number was 46 in both specimens, and detailed Q‐banding analysis in Case 1 (GS) revealed a clonal abnormality of an interstitial deletion of the long arm of chromosome 5, del(5)(q2lq31). The deleted region included an assigned locus for an FAP major gene (5q21‐q22). All of the metaphases analyzed in this case showed an extra segment of bright fluorescence on the short arm of chromosome 15, but this unusual chromosome (15p +) was observed in both peripheral lymphocyte and skin fibroblast cultures from the patient, indicating that the 15p+ was constitutional in nature. In Case 2, no clonal rearrangements were Identified and most cells had a normal karyotype. However, two cells showed rearrangements involving a 17q with non‐identical breakpoints, one of which was observed as a solitary chromosome change. Based on the present findings in Case 1 and those reported so far, the chromosomal defect on 5q might be one of the causal genetic events primarily associated with the development of both benign desmoid tumors and colorectal adenomas and carcinomas in FAP patients.

Rearrangements of Chromosome 3 in Nonfamilial Renal Cell Carcinomas from Japanese Patients

Cytogenetic studies were successfully carried out in 5 tumor tissues from Japanese patients with nonfamilial renal cell carcinoma, histologically diagnosed as clear cell subtype. Mitotic cells were obtained by a combined method of enzymatic disaggregation and short‐term culture (6–12 days). The modal chromosome numbers were found to be diploid or near‐diploid in all the cases examined. Every case showed characteristic structural and numerical abnormalities. Rearrangements in the short arm of chromosome 3 were observed as clonal abnormalities in all the cases, including a translocation t(3;6) resulting in a partial loss of 3p (3 cases), a terminal deletion of 3p (one case) and 2 different translocations involving 3p and 8p (one case). The other clonal abnormalities were a whole or partial trisomy of chromosome 7 and a loss of Y chromosome. The overall results in the present study were consistent with those of our previous data in American patients, and suggest that the rearrangements of chromosome 3 leading to a partial loss of its short arm may play primary and significant role(s) in the development of renal cell carcinoma.

Homozygous deletions on the short arm of chromosome 3 in human oral squamous cell carcinomas

Recent cytogenetic and allelic deletion analyses have demonstrated that deletions on the short arm of chromosome 3 (3p) are frequently found in various cancers, including oral squamous cell carcinomas (OSCCs). This suggests that one or more tumor suppressor gene(s) for these malignancies might be located on 3p. In the present study, to further define the region(s) on 3p that harbor putative tumor suppressor gene(s) for OSCCs, we have investigated the existence of homozygous deletions (HDs) at 34 loci on 3p, in 14 OSCC cell lines. HDs were detected within the FRA3B region at 3p14.2 in only two cell lines (HSC-4 and TSU). Recently, the human fragile histidine triad (FHIT) gene was isolated from this region, abnormalities of which have been found at high frequencies in several types of human cancers. We also examined the expression of the FHIT gene, using reverse transcription-polymerase chain reaction (RT-PCR) and exon-specific PCR, in the two OSCC cell lines which showed HDs at 3p14.2. There was no detectable expression of exon 5, which was the first protein-coding exon of FHIT gene, in HSC-4 cells, indicating that this region was homozygously deleted in this cell line. On the other hand, HD in the TSU cells did not affect the coding region of the FHIT gene, and the wild-type transcript was detected by RT-PCR. Therefore, several candidate tumor suppressor genes, including the FHIT gene, may reside in these homozygously deleted regions. To our knowledge, this is the first report of HDs on 3p in OSCCs.

Case Report: Upper Respiratory Tract Involvement in Adult T-Cell Leukemia

ABSTRACT Adult T-cell leukemia (ATL) is characterized by peripheral lymph node enlargement, hepatosplenomegaly and skin lesions. The association of local mass lesions of other organs with ATL is extremely rare. This report describes a 57-year-old woman with chronic type ATL with associated local tumor masses in the nasal cavity, paranasal sinuses and larynx as well as skin infiltration. Histologic investigation of the skin lesion and nasal mucosa revealed non-Hodgkin lymphoma, diffuse, mixed type. Her chief complaints were progressive dyspnea and hoarseness. Leukemic cell masses in her upper respiratory tract caused narrowing of the airway, which was responsible for her complaints.