Chromosomal patterns in human benign uterine leiomyomas

Several Fusion Genes Identified in a Spermatic Cord Leiomyoma With Rearrangements of Chromosome Arms 3p and 21q

BACKGROUND/AIM

Benign smooth-muscle tumors, leiomyomas, occur in nearly every organ but are most common in the uterus. Whereas much is known about the genetics of uterine leiomyomas, little genetic information exists about leiomyomas of other organs. Here, we report and discuss the genetic findings in a para-testicular leiomyoma.

MATERIALS AND METHODS

Cytogenetic, array comparative genomic hybridization (aCGH) RNA sequencing, reverse-transcription polymerase chain reaction (RT- PCR), and Sanger sequencing analyses were performed on a leiomyoma of the spermatic cord removed from a 61-year-old man.

RESULTS

The karyotype was 48~50,XY,add(3) (p21),+4,+7,+8,+9,add(21)(q22)[cp9]/46,XY[2]. aCGH confirmed the trisomies and also detected multiple gains and losses from 3p and 21q. RNA sequencing detected the chimeras ARHGEF3-CACNA2D2, TRAK1-TIMP4, ITPR1- DT-NR2C2, CLASP2-IL17RD, ZNF621-LARS2, CNTN4- RHOA, and NR2C2-CFAP410. All chimeras were confirmed by RT-PCR and Sanger sequencing.

CONCLUSION

Our data, together with those previously published, indicate that a group of leiomyomas may be cytogenetically characterized by aberrations of 3p and the formation of fusion genes.

Identification of the molecular relationship between intravenous leiomyomatosis and uterine myoma using RNA sequencing

The purpose of this study was to explore the potential relationship between intravenous leiomyomatosis (IVL) and uterine myoma (UM) at the molecular level. RNA-sequencing was performed on IVL tumours, UM tumours, and adjacent normal uterine muscle. We compared the gene expression levels between IVL and normal uterine muscle, UM and normal uterine muscle, to identify differentially expressed genes (DEGs). Then we used Gene Ontology Enrichment Analysis to determine the functions of the DEGs and performed specimen cluster analysis. We obtained 98 DEGs between IVL and adjacent normal uterine muscle, and 61 DEGs between UM and adjacent normal uterine muscle. Functional enrichment of both IVL and UM DEGs showed that they are associated with hormone stimulus, extracellular matrix, and cell adhesion. Unsupervised clustering analysis showed that IVL and UM could not be separated completely. Among these dysregulated genes, we found that HOXA13 showed a distinct dysregulated status between IVL and UM. HOXA13 may therefore serves as a biomarker to distinguish IVL and UM. Our results showed that IVL and UM may have similar dysregulated gene networks. They may be closely related, and HOXA13 may serves as a biomarker to distinguish between IVL and UM.

Genetic heterogeneity in leiomyomas of deep soft tissue

Leiomyoma of deep soft tissue is a rare type of benign smooth muscle tumor that mostly occurs in the retroperitoneum or abdominal cavity of women, and about which very little genetic information exists. In the present study, eight leiomyomas of deep soft tissue were genetically analyzed. G-banding showed that three tumors carried rearrangements of the long arm of chromosome 12, three others had 8q rearrangements, the 7^th tumor had deletion of the long arm of chromosome 7, del(7)(q22), and the 8^th had aberrations of chromosome bands 3q21∼23 and 11q21∼22. The target genes of the 12q and 8q aberrations were HMGA2 and PLAG1, respectively. In the leiomyomas with 12q rearrangements, both HMGA2 and PLAG1 were expressed whereas in the tumors with 8q aberrations, only PLAG1 was expressed. In the cases without 12q or 8q aberrations, the expression of HMGA2 was very low and PLAG1 was expressed only in the case with del(7)(q22). All eight leiomyomas of deep soft tissue expressed MED12 but none of them had mutation in exon 2 of that gene. In two tumors with 12q rearrangements, RPSAP52 on 12q14.3 was fused with non-coding RNA (accession number XR_944195) from 14q32.2 or ZFP36L1 from14q24.1. In a tumor with inv(12), exon 3 of HMGA2 was fused to a sequence in intron 1 of the CRADD gene from 12q22. The present data together with those of our two previous studies in which the fusions KAT6B-KANSL1 and EWSR1-PBX3 were described in two retroperitoneal leiomyomas carrying a t(10;17)(q22;q21) and a t(9;22)(q33;q12) translocation, respectively, show that leiomyomas of deep soft tissue are genetically heterogenous but have marked similarities to uterine leiomyomas.

Benign metastasizing leiomyoma: A review of current literature in respect to the time and type of previous gynecological surgery

INTRODUCTION

Benign metastasizing leiomyoma (BML) is a rare disorder that affects women with a history of uterine leiomyoma, which is found to metastasise within extrauterine sites. The aetiology of BML remains unexplained. Because BML is rare, and most publications contain descriptions of single cases, no statistically determined time relations were found between the primary and secondary surgeries, which may have aetiological implications.

OBJECTIVES

To determine age before BML surgery, age during diagnosis of BML, type of prior surgery, and location of metastasis based on the literature.

METHODS

A systematic review of four databases (Medline/PubMed, Embase, Web of Science, and Cochrane) covering articles published from 1 January 1965 to 10 April 2016. The inclusion criteria were full-text articles in English and articles containing case reports. Articles in languages other than English (39), articles containing incomplete data (14), i.e. no information regarding the time of surgery and/or the site of metastasis, articles bereft of case studies (25), and articles with access only to summaries, without access to the complete text (10) were excluded. Of 321 titles identified, only 126 articles met the aforementioned criteria.

RESULTS AND CONCLUSIONS

The mean age during primary surgery and BML diagnosis was 38.5 years and 47.3 years, respectively. The most common surgery was total hysterectomy. The most frequent site of metastasis was the lungs; other organs were affected less frequently.The site of metastases and their number were not related to the longer time span between the patient's initial surgery and occurrence of metastasis. The analysed data, such as the age during primary surgery, age during BML diagnosis, site and type of metastasis, do not provide us a clear answer. Thus, BML pathogenesis is most probably complex in nature and requires further multidirectional research.

Microchimeric Cells, Sex Chromosome Aneuploidies and Cancer

The phenomenon of feta-maternal microchimerisms inspires numerous questions. Many questions remain to be answered regarding this new avenue of genetics. The X and Y chromosomes have been associated with malignancy in different types of human tumors. We aimed to investigate the numerical aberrations of chromosomes X and Y in lung cancer (LC) and bladder cancer (BC) and review recent evidence for possible roles of microchimeric cells (McCs) in these cancers. We carried out cytogenetic analysis of the tumor and blood sampling in 52 cases of people with BC and LC, and also with 30 healthy people. A total of 48 (92.3 %) of the patients revealed sex chromosome aneuploidies (SCAs). A total SCAs was found in 9.8 % of 2282 cells that were analyzed as one or more cells in each case. The 68 and 95 SCAs were found in the 1952 (8.4 %) cells in peripheral blood, and 41 and 19 SCAs in the 330 (18.2 %) cells in the tumoral tissues respectively. There was a significant difference in the frequencies of SCAs between the patients and the control groups determined by the Fischer's Exact Test (p < 0.0001). The frequencies of SCAs were higher in the tumoral tissues than in the blood (p < 0.0001). There was a significant difference in the frequencies of SCAs between the tumor and blood tissues, and this was higher in the tumor tissue (p < 0.0001). In general, 78.9 % (41) of the 52 patients with LC and BC had X and Y chromosome monosomies. Largely a Y chromosome loss was present in 77.8 % of the men, and the 47, XXY karyotype was found in 33.3 % of them. The second most common SCA was monosomy X, and was found in 71.4 % of the women. McCs were observed in 26.9 % of the 52 patients, and the frequencies of McCs were higher in the blood than in the tissues (p < 0.0001). XY cells were identified in the lung and bladder tissues of the women who had been pregnant with boys, but not in those who had not. There was a significant difference in the frequencies of McCs between the LC and BC patients (p < 0.0005). We speculate that the microchimerism could have a general beneficial role in cancer, in which some sites may not be evident because of an allogeneic maternal immune reaction that hastens cancer development. A further understanding of McCs may help in anticipating its implications in cancer. Our results may suggest that SCAs may be contributing factors in the development of LC and BC, and aneuploidies of X and Y chromosomes play a role in the pathogenesis of cancers.

Chromosome imbalances and alterations in the p53 gene in uterine myomas from the same family members: familial leiomyomatosis in Turkey

Uterine leiomyomas (UL) are extremely common neoplasms in women of reproductive age, and are associated with a variety of characteristic choromosomal aberrations (CAs). The p53 gene has been reported to play a crucial role in suppressing the growth of a variety of cancer cells. Therefore, the present study investigated the effects of CAs and the p53 gene on ULs. We performed cytogenetic analysis by G-banding in 10 cases undergoing myomectomy or hysterectomy. Fluorescence in situ hybridization (FISH) with a p53 gene probe was also used on interphase nuclei to screen for deletions. In patients, CAs were found in 23.4% of 500 cells analysed, significantly more frequent than in the control group (p<0.001). In the patients, 76% of the abnormalities were structural aberrations (deletions, translocations and breaks), and only 24% were numerical. Deletions were the most common structural aberration observed in CAs. Among these CAs, specific changes in five loci 1q11, 1q42, 2p23, 5q31 and Xp22 have been found in our patients and these changes were not reported previously in UL. The chromosome breaks were more frequent in cases, from high to low, 1, 2, 6, 9, 3, 5, 10 and 12. Chromosome 22, X, 3, 17 and 18 aneuploidy was observed to be the most frequent among all numerical aberrations. We observed a low frequency of p53 losses (2-11%) in our cases. The increased incidence of autosomal deletions, translocations, chromatid breaks and aneuploidy, could contribute to the progression of the disease along with other chromosomal alterations.

Recurrent chromosomal aberrations in intravenous leiomyomatosis of the uterus: high-resolution array comparative genomic hybridization study

Uterine intravenous leiomyomatosis (IVL) is a distinct smooth muscle neoplasm with a potential of clinical aggressiveness due to its ability to extend into intrauterine and extrauterine vasculature. In this study, chromosomal alterations analyzed by oligonucleotide array comparative genomic hybridization were performed in 9 cases of IVL. The analysis was informative in all cases with multiple copy number losses and/or gains observed in each tumor. The most frequent recurrent loss of 22q12.3-q13.1 was observed in 6 tumors (66.7%), followed by losses of 22q11.23-q13.31, 1p36.13-p33, 2p25.3-p23.3, and 2q24.2-q32.2 and gains of 6p22.2, 2q37.3 and 10q22.2-q22.3, in decreasing order of frequency. Copy number variants were identified at 14q11.2, 15q11.1-q11.2, and 15q26.2. Genes mapping to the regions of loss include CHEK2, EWS, NF2, PDGFB, and MAP3K7IP1 on chromosome 22q, HEI10 on chromosome 14q, and succinate dehydrogenase subunit B, E2F2, ARID1A KPNA6, EIF3S2 , PTCH2, and PIK3R3 on chromosome 1p. Regional losses on chromosomes 22q and 1p and gains on chromosomes 12q showed overlaps with those previously observed in uterine leiomyosarcomas. In addition, presence of multiple chromosomal aberrations implies a higher level of genetic instability. Follow-up polymerase chain reaction (PCR) sequencing analysis of MED12 gene revealed absence of G> A transition at nucleotides c.130 or c.131 in all 9 cases, a frequent mutation found in uterine leiomyoma and its variants. In conclusion, this is the first report of high-resolution, genome-wide investigation of IVL by oligonucleotide array comparative genomic hybridization. The presence of high frequencies of recurrent regional loss involving several chromosomes is an important finding and likely related to the pathogenesis of the disease.

Identification of CUX1 as the recurrent chromosomal band 7q22 target gene in human uterine leiomyoma

Uterine leiomyomas are benign solid tumors of mesenchymal origin which occur with an estimated incidence of up to 77% of all women of reproductive age. The majority of these tumors remains symptomless, but in about a quarter of cases they cause leiomyoma-associated symptoms including chronic pelvic pain, menorrhagia-induced anemia, and impaired fertility. As a consequence, they are the most common indication for pre-menopausal hysterectomy in the USA and Japan and annually translate into a multibillion dollar healthcare problem. Approximately 40% of these neoplasms present with recurring structural cytogenetic anomalies, including del(7)(q22), t(12;14)(q15;q24), t(1;2)(p36;p24), and anomalies affecting 6p21 and/or 10q22. Using positional cloning strategies, we and others previously identified HMGA1, HMGA2, RAD51L1, MORF, and, more recently, NCOA1 as primary target (fusion) genes associated with tumor initiation in four of these distinct cytogenetic subgroups. Despite the fact that the del(7)(q22) subgroup is the largest among leiomyomas, and was first described more than twenty years ago, the 7q22 leiomyoma target gene still awaits unequivocal identification. We here describe a positional cloning effort from two independent uterine leiomyomas, containing respectively a pericentric and a paracentric chromosomal inversion, both affecting band 7q22. We found that both chromosomal inversions target the cut-like homeobox 1 (CUX1) gene on chromosomal band 7q22.1 in a way which is functionally equivalent to the more frequently observed del(7q) cases, and which is compatible with a mono-allelic knock-out scenario, similar as was previously described for the cytogenetic subgroup showing chromosome 14q involvement.

Pulmonary benign metastasizing leiomyoma associated with intravenous leiomyomatosis of the uterus: clinical behavior and genomic changes supporting a transportation theory

Benign metastasizing leiomyoma is a rare lesion characterized by benign-appearing smooth muscle tumor most frequently involving the lung and usually associated with a benign leiomyoma or intravenous leiomyomatosis of the uterus. The pathogenetic mechanism of the tumor has not been clarified, but the possibilities including hormone-sensitive in situ proliferations of smooth muscle bundles, mechanical displacement or intravascular spread of preexisting benign uterine tumor tissue, and metastasized very low-grade uterine leiomyosarcoma have been proposed. We described a case of pulmonary benign metastasizing leiomyoma associated with a uterine intravenous leiomyomatosis in a 46-year-old woman with a result of comparative genomic hybridization study. The 2 lesions showed significantly overlapping, if not identical, complex genomic changes in the comparative genomic hybridization, suggesting that the 2 lesions are closely related to each other. Unresected pulmonary nodules were left untreated for 13 months after the hysterectomy and wedge biopsy of 3 pulmonary nodules to show no further growth, suggesting clinical behavior of nonmalignant tumor in our case. Benign metastasizing leiomyomas may comprise a heterogeneous group of tumors in terms of their malignant potential and pathogenetic mechanism.

The genetic heterogeneity of uterine leiomyomata

Research investigating the genetics of UL has already been successful in gathering epidemiologic evidence for heritability, establishing the clonal and mosaic nature of these tumors, correlating genotypic and phenotypic characteristics, defining cytogenetic subgroups, and identifying specific genes involved in tumorigenesis. Although UL are known to be benign tumors, the impact they have on the lives of so many women can only be described as "malignant". For this reason, continuing the quest to ascertain the genes, functions, and mechanisms integral to UL development is absolutely imperative. Genetic tests for personalized medical management of women with fibroids is at the threshold for providing the most appropriate treatments (Fig. 3), and combined with developing less invasive therapies portends a brighter future for a major health problem for women.

Independent clonal origin of multiple uterine leiomyomas that was determined by X chromosome inactivation and microsatellite analysis

OBJECTIVE

In an attempt to clarify the clonality and genetic relationships that are involved in the tumorigenesis of uterine leiomyomas, we used a total of 43 multiple leiomyomas from 14 patients and analyzed the allelic status with 15 microsatellite markers and X chromosome inactivation analysis.

STUDY DESIGN

We have used a set of 15 microsatellite polymorphism markers mapped on 3q, 7p, 11, and 15q by automated analysis. The X chromosome inactivation was evaluated by the methylation status of the X-linked androgen receptor gene.

RESULTS

Loss of heterozygosity analysis showed a different pattern in 7 of the 8 cases with allelic loss for at least 1 of 15 microsatellite markers that were analyzed. A similar loss of heterozygosity findings at 7p22-15 was detected in 3 samples from the same patient. X chromosome inactivation analysis demonstrated the same inactivated allele in all tumors of the 9 of 12 informative patients; different inactivation patterns were observed in 3 cases.

CONCLUSION

Our data support the concept that uterine leiomyomas are derived from a single cell but are generated independently in the uterus. Loss of heterozygosity findings at 7p22-15 are consistent with previous data that suggested the relevance of chromosomal aberrations at 7p that were involved in individual uterine leiomyomas.

Expression of the HMGA2-LPP fusion transcript in only 1 of 61 karyotypically normal pulmonary chondroid hamartomas

The HMGA2 gene has been found to be rearranged in a variety of benign solid tumors. However, in all tumor entities where aberrations of the corresponding chromosomal region have been found, a large percentage of tumors do not show any detectable cytogenetic deviation. Thus, the question arises whether or not in some of these cases, small subpopulations of tumor cells characterized by HMGA2 rearrangements exist. The existence of these populations would strongly suggest a secondary nature of the chromosomal aberrations. Herein, we have addressed this question by RT-PCR analyses of the HMGA2-LPP fusion resulting from t(3;12)(q27 approximately q28;q14 approximately q15) in a series of 61 pulmonary chondroid hamartomas (PCH) with an apparently normal karyotype. As a result, the HMGA2-LPP fusion transcript was amplified in only one of 61 PCH with a normal karyotype. In this case, fluorescence in situ hybridization analysis revealed a hidden chromosomal aberration. The absence of the HMGA2-LPP fusion in small populations of tumors with a normal karyotype suggests the primary nature of chromosomal rearrangements in the development of PCH affected by those aberrations.

Identification of differentially expressed genes in human uterine leiomyomas using differential display

In searching of differentially expressed genes in human uterine leiomyomas, differential display was used with twelve pairs of primers to compare human uterine leiomyomas with matched myometrium. False positives were eliminated by reverse Northern analysis. Positives were confirmed by Northern blot analysis.

RESULTS

Four of 69 cDNA fragments (3 up-regulated named L1, L2 and L3 and 1 down-regulated named M1 in leiomyoma) were confirmed by Northern analysis. Sequence comparison and Northern analysis proved that L1 is exactly the human ribosomal protein S19. It was present ubiquitously in 13 tissues tested but in various levels and even in different size. L1 was highly expressed in parotidean cystadenocarcinoma, pancreatic cancer and breast cancer examined. No mutations have been found in human uterine leiomyomas (n=6).

CONCLUSIONS

hRPS19 overexpression might be a universal signal in rapid cell growth tissues.

The cytogenetic and molecular characterization of benign and malignant soft tissue tumors

Cytogenetic analyses of benign and malignant soft tissue tumors have led to the description of recurrent, specific, and even pathognomonic chromosomal translocations and/or other rearrangements in most types of soft tissue tumors. The consistent karyotypic rearrangements have provided critical diagnostic information in this group of neoplasms that often presents significant diagnostic challenges to the clinician and the pathologist. These findings have also been instrumental in the characterization of the abnormalities at the molecular level. Novel genes have been isolated from the translocation junctions and the mechanisms of their deregulation identified. This has increased our understanding of the histogenesis of these tumors, paved the way for the molecular diagnosis of many sarcomas, aided in directing therapy, and also provided important prognostic information.

Molecular cytogenetic analysis of uterine leiomyoma and leiomyosarcoma by comparative genomic hybridization

Uterine leiomyomata are among the most common of human neoplasms and are associated with abnormal uterine bleeding, infertility, and abdominal pain. Uterine leiomyosarcomata are presumed to be the malignant counterpart to uterine leiomyomata and are very rare. Transformation of uterine leiomyoma (ULM) into uterine leiomyosarcoma (ULMS) is yet to be conclusively confirmed, and each type of tumor may represent a distinct genetic entity. We used comparative genomic hybridization (CGH) to evaluate DNA sequence copy-number changes in 12 specimens of ULM and 8 of ULMS. CGH analysis of ULM demonstrated chromosomal imbalances in 8 of 12 (66. 7%) specimens. The most frequent ULM gains were observed at 9q34 (a novel finding) and on chromosome 19. Other ULM imbalances included gains and losses of chromosome 1p, losses on 7q, and gains on 12q. All ULMS specimens demonstrated chromosomal aberrations. Chromosome 1 imbalances were very prominent. The most frequent losses were detected on 14q and 22q. Losses on 14q are rarely seen in other types of leiomyo-sarcoma and may be a distinctive feature of ULMS. Gains on chromosomes 8, 17, and X were observed in half the cases and were accompanied by high-level amplification. Other chromosome arms overrepresented included 12q and 19p. The absence of specific anomalies common to all ULM and ULMS argues against their being benign-malignant counterparts.

Multiple uterine leiomyomas: cytogenetic analysis

Six uterine leiomyomas were studied cytogenetically. The material comprised two uterine myomas from one patient and four tumors from a second patient. In all cases the modal number was 46. The clonal numerical alterations were monosomies involving chromosomes X, 6, 8, 13, 19, and trisomy of 12. The only clonal structural alteration was der(11)t(10;11)(q11;q24). Although two monosomies (X and 8) were shared by two of four leiomyomas from the same uterus, the results suggested that each leiomyoma was the product of a separate clonal development.

Telomere shortening in uterine leiomyomas

OBJECTIVE

To gain a better understanding of proliferation control mechanisms in a common benign tumor, we investigated the mean telomere length and the clonality of uterine leiomyomas.

STUDY DESIGN

Deoxyribonucleic acid from uterine leiomyomas and from the adjacent normal myometrium of 51 patients (total number of uterine leiomyomas 107; 28 patients with single leiomyoma, 23 patients with multiple leiomyomas ranging from 2 to 8 myoma nodules per case) was hybridized to a telomeric oligonucleotide probe by Southern blot and chemiluminescent detection. The mean telomere length was evaluated by densitometry. Clonality was assessed with use of the phosphoglycerokinase gene polymorphism.

RESULTS

The mean telomere length was significantly shorter in uterine leiomyomas (median 7950 bp, interquartile range 7261 to 8372 bp) than in normal myometrium (median 9688 bp, interquartile range 8528 to 10535 bp) (P < .001). There was no correlation between tumor size and telomere attrition. Multiple uterine leiomyomas were found to have an independent clonal origin.

CONCLUSIONS

Telomere attrition in uterine leiomyomas reflects enhanced proliferation activity in the course of tumor evolution. The basic telomere lengths differ in the myocytes from which the uterine leiomyomas originate, probably explaining the lack of correlation between telomere attrition and tumor size.

Clinical significance of cytogenetic abnormalities in uterine myomas

OBJECTIVE

To investigate the clinical characteristics of uterine myomas with cytogenetic rearrangements.

DESIGN

Comparative study of myomas with normal and abnormal karyotype.

SETTING

University hospital.

PATIENTS

Premenopausal, GnRH-agonist (GnRH-a) treated and menopausal patients.

INTERVENTIONS

Myomectomy or hysterectomy.

MAIN OUTCOME MEASURES

Karyotype analysis and clinical characteristics.

RESULTS

Clonal abnormalities occurred in 29% of uterine myomas but were not related to the age of the patient or, in untreated menopausal patients, to the size of the myoma. In GnRH-a treated and menopausal women, 48% of the myomas larger than 4 cm were associated with clonal abnormalities. Submucous myomas had significantly fewer clonal abnormalities (12%) than subserosal (29%) or intramural myomas (35%).

CONCLUSIONS

The data support the hypothesis that cytogenetic rearrangements in uterine myomas are associated with loss of steroid hormones dependency and alter the growth potential of the tumor.

Analysis of genetic alterations in uterine leiomyomas and leiomyosarcomas by comparative genomic hybridization

Uterine leiomyomas are the most prevalent tumor type in women of reproductive age and are the most common reason for hysterectomies. Although uterine leiomyomas are considered to be benign, they are a major public health concern for women. In contrast, leiomyosarcomas are rare but highly malignant uterine tumors. They may arise in uteri with preexisting leiomyomas and histologically sometimes resemble leiomyomas, thus causing controversy about whether leiomyosarcomas arise within leiomyomas. In this study, we used comparative genomic hybridization (CGH) to identify genetic alterations unique to each tumor type and alterations that are common between the two tumors. We analyzed 14 cases of uterine leiomyomas and eight cases of uterine leiomyosarcomas. Only two of the 14 leiomyomas exhibited genetic alterations, and those were restricted to gains on chromosomes 14 and 19 and losses on chromosomes 1 and 4. In addition, 68 leiomyomas were examined for loss of heterozygosity on chromosomes 1 and 4, and only three tumors exhibited any losses. In contrast, all eight leiomyosarcomas showed gains and losses of DNA by CGH, and in many cases multiple changes were observed. The most commonly observed genetic aberration, occurring in five tumors, was gains on both arms of chromosome 1, suggesting that this chromosome contains loci involved in the development of leiomyosarcoma. Our results do not provide evidence for the progression from benign leiomyoma to malignant leiomyosarcoma. Moreover, the large number of random chromosomal alterations in the leiomyosarcomas suggests that increased genetic instability plays a role in the formation of these tumors.

Metastatic renal cell carcinoma in a child: 11-year disease-free survival following surgery

A child with metastatic renal cell carcinoma (RCC) is presented. This case is unusual in that the patient has remained disease free for 11 years following surgery and only one course of chemotherapy prior to thoracotomy. The management of metastatic RCC is reviewed and the genetic mechanisms leading to its development briefly discussed.

An angiomyoma with t(X;10)(q22;q23.2)

A t(X;10)(q22;q23.2) translocation was detected as the only chromosomal aberration in primary short-term cultured cells from an angiomyoma of a 58-year-old woman; 6p, 13q, and 21q rearrangements have been previously demonstrated by others in two cases of angiomyoma. This type of translocation has not been reported in other benign tumors including leiomyomas and angiomyomas, although it has been detected in an ependymoma. This is thought to be a third case of angiomyoma showing karyotypic abnormalities.

Detection of chromosomal abnormalities in uterine leiomyoma using conventional cytogenetic method and interphase fluorescence in situ hybridization

Seventy-nine uterine leiomyomas were examined using a conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Nine (17.6%) of 51 tumor samples examined showed chromosomal abnormalities by conventional cytogenetic analysis. Rearrangements of chromosome 12 were detected in two tumors. Other tumors showed abnormalities affecting chromosomes 1, 4, 6, 7, 10, 13, 14, and 22. For FISH, the whole-chromosome painting probe and the D12Z3 probe specific for the centromeric region were used to detect structural and numerical abnormalities of chromosome 12. Of forty-one tumor samples, six showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the tumors with structural aberrations identified by FISH, two had normal karyotypes, two showed structural rearrangements of chromosome 12 cytogenetically, and two could not be analyzed because of an insufficient number of metaphases. There were no correlations between the cytogenetic data and clinical parameters. The results indicate that chromosomal abnormalities are important in the biology of at least some types of uterine leiomyomas, and that FISH is a useful complement to conventional cytogenetic analysis in the study of solid tumors.

Structural aberrations of chromosome 6 in three uterine smooth muscle tumors

Clonal karyotypic alterations of chromosome 6 in three uterine smooth muscle tumors are reported. In all cases an apparently identical breakpoint on the short arm of chromosome 6 was found. Two cases displayed the histologic features of cell-rich myomas with severe nuclear atypia but no clear evidence for malignancy. The remaining case was a primary uterine leiomyosarcoma of an 80-year-old patient showing an apparently balanced reciprocal chromosomal translocation, t(1;6)(p32-33;p21.3), as the sole karyotypic abnormality. This type of aberration has not been reported before in leiomyosarcomas. Because of the nuclear atypia in the other myomas with a breakpoint involving the short arm of chromosome 6 we feel that this cytogenetically recognizable but rare subgroup of uterine smooth muscle tumors warrants a careful clinical follow-up.

A new cytogenetic subgroup in uterine leiomyoma is characterized by a deletion of the long arm of chromosome 3

Our cytogenetic findings in 175 uterine leiomyomas revealed 52 tumors with clonal chromosome abnormalities, eight of which did not belong to any well-delineated cytogenetic abnormal subgroup. However, an interstitial deletion of the long arm of chromosome 3 was found, as the sole chromosome abnormality, in three cases. We believe that this involvement of 3q is significant enough to consider it as a new cytogenetic subgroup of uterine leiomyoma.

Cytogenetics and molecular genetics of human solid tumours

It is generally accepted that cancer is a genetic disease resulting from the accumulation of multiple genomic rearrangements. These rearrangements involve gross chromosomal abnormalities (e.g. translocations and deletions) as well as submicroscopic mutations affecting both oncogenes and tumour suppressor genes. Recent studies of several tumour specific translocations in sarcomas have shown that the translocations result in so-called fusion genes. In this review we will discuss the specificity and implications of different genetic alterations in both sporadic and hereditary human solid tumours, and provide examples of how these changes can be used as tumour specific markers of both diagnostic and prognostic significance.

Renal cell carcinoma with translocation (X;1). Further evidence for a cytogenetically defined subtype

A renal cell carcinoma from a 15-year-old male had a 49,Y,t(X;1)(p11.2;q21), +der(X)t(X;1) (p11.2;q21), +5, -16, +17, +18 karyotype. This is the third report of a translocation involving a breakpoint at Xp11.2 in a renal cell carcinoma in a child. A total of nine cases of renal cell carcinoma involving Xp11, including this case, have been reported. Of the eight cases for which there are genetics reports, all are male. Patients with renal cell carcinoma with abnormalities at Xp11 appear to be younger than renal cell carcinoma patients overall.

Identification of a YAC spanning the translocation breakpoints in uterine leiomyomata, pulmonary chondroid hamartoma, and lipoma: physical mapping of the 12q14-q15 breakpoint region in uterine leiomyomata

Uterine leiomyomata are the most common tumors in women and can cause abnormal uterine bleeding, pelvic pain, and infertility. Approximately 200,000 hysterectomies are performed annually in the U.S. to relieve patients of the medical sequelae of these benign neoplasms. Our efforts have focused on cloning the t(12;14)(q14-q15;q23-q24) breakpoint in uterine leiomyoma to further our understanding of the biology of these tumors. Thirty-nine YACs and six cosmids mapping to 12q14-q15 have been mapped by fluorescence in situ hybridization to tumor metaphase chromosomes containing a t(12;14). One YAC spanned the translocation breakpoint and was mapped to tumor metaphases from a pulmonary chondroid hamartoma containing a t(12;14)(q14-q15;q23-q24) and a lipoma containing a t(12;15)(q15;q24); this YAC also spanned the breakpoint in these two tumors, suggesting that the same gene on chromosome 12 may be involved in the pathobiology of these distinct benign neoplasms.

Physical mapping of the uterine leiomyoma t(12;14)(q13-15;q24.1) breakpoint on chromosome 14 between SPTB and D14S77

Uterine leiomyoma is the most common tumor of smooth muscle cell origin and is often associated with the recurrent balanced translocation t(12;14)(q13-15;q24). As an initial step toward finding the gene or genes that are interrupted by the translocation breakpoint, a somatic cell hybrid carrying the derivative 14 as the single t(12;14) translocated chromosome was constructed from a leiomyoma cell line with this translocation. Sequence tagged sites (STS) whose locations on the genetic map of chromosome 14 were known were used to map the breakpoint in the translocated chromosomes. The results of this analysis place the translocation breakpoint on the long arm of chromosome 14 between the proximal marker SPTB and the distal marker D14S77, narrowing the chromosomal translocation breakpoint to a region of approximately 7 cM. The identification of flanking markers on chromosome 14 lays the foundation for efforts to clone the breakpoint and to identify the genes involved in the formation of leiomyoma.

Cytogenetics of tumors of soft tissue and bone. Implication for pathology

Pathologists should be aware of the existence of diagnostically useful chromosomal rearrangements in several soft tissue and bone tumors. They include rearrangement of 8q12 in lipoblastomas, ring chromosomes in atypical lipomas, ring and giant marker chromosomes in well differentiated liposarcomas, t(12;16)(q13;p11) in myxoid liposarcomas, rearrangement of 7p21-22 in low-grade endometrial stromal sarcomas, t(2;13)(q37;q14) in alveolar rhabdomyosarcomas, t(X;18)(p11.2;q11.2) in synovial sarcomas, t(12;22) (q13;q13) in clear cell sarcomas, t(11;22)(q24;q12) in Ewing's sarcomas and peripheral neuroepitheliomas, and t(9;22)(q21-31;q11-12) in extraskeletal myxoid chondrosarcomas.

Development of papillary renal cell tumours is associated with loss of Y-chromosome-specific DNA sequences

Twenty-two papillary renal cell tumours were analysed by Southern hybridization using eight DNA probes from homologous regions of the X and Y chromosomes and two Y-chromosome-specific DNA probes. Sixteen of the 19 papillary renal cell tumours of male patients showed the loss of Y-chromosome-specific sequences. No loss of heterozygosity was detected in three tumours that developed in females. The frequency of loss of the Y chromosome was established in 50 non-papillary renal cell carcinomas as well. Only seven of the 31 non-papillary renal cell carcinomas obtained from male patients had lost the Y-chromosome-specific sequences, whereas no allelic loss was found in 19 non-papillary tumours obtained from female patients. Papillary renal cell tumours show a strong male preponderance (6:1) and loss of Y chromosome in 84 per cent of the cases, whereas non-papillary renal cell carcinomas show only a slight male preponderance (1.5:1) and the Y chromosome is lost in only 22 per cent of the cases. These data suggest that a tumour suppressor gene is localized at one of the homologous regions of the X and Y chromosomes, the homozygous inactivation of which is associated with the development of papillary renal cell tumours.

Comparison of chromosome aberrations in leiomyoma and leiomyosarcoma using FISH on archival tissues

Fluorescence in situ hybridization (FISH) with chromosome-specific probes was used to study cytogenetic changes in five cases of leiomyosarcoma (LMS) and nine cases of uterine leiomyoma (LM). Biotinylated DNA probes for the centromeric regions of chromosomes 1, 6, 8, 9, 17, and 18, painting probes for chromosomes 1 and 22, and the cosmid probe for chromosome region 21q22.3 were used on nuclei isolated from paraffin blocks. Four of five LMS cases revealed major chromosomal aberrations, while the only case with minor clonal aberrations was subsequently found not to be a typical LMS. The most common numerical aberrations found in the LMS cases were extra copies of chromosome 8 (three of five cases), loss of chromosome 1 (three of five cases), and loss of chromosome 6 (two of five cases). One of two LMS cases studied with a chromosome 1 painting probe demonstrated translocations of chromosome 1. In contrast to LMS, only five of nine uterine LM cases had abnormal clones, and these were smaller than those in LMS. Two LM cases showed 9% tetrasomy 8 with 17 or 20% monosomy 6, and three other cases had monosomy 6 clones in 18-34% of cells. These results indicate that typical LMS is characterized by multiple chromosomal aberrations affecting most of the cells, whereas borderline LMS and LM have fewer affected chromosomes and less clonal involvement.

Recurrent t(12;19)(q13;q13.3) in intracranial and extracranial hemangiopericytoma

We report on a recurrent intracranial hemangiopericytoma cytogenetically studied after short-term culture. The tumor had a uniform karyotype 47,XX,add(7)(q21),t(12;19)(q13;q13.3),del(13)(q14q22), +21. Remarkably, one case with an identical reciprocal (12;19) translocation has been previously reported as the sole cytogenetic change in a recurrent retroperitoneal hemangiopericytoma. This nonrandom structural change may characterize a subentity of hemangiopericytoma and might be of diagnostic value.

Deletion 7q22 in uterine leiomyoma. A cytogenetic review

The cytogenetic patterns of uterine leiomyomas have been extensively investigated, and cases characterized by specific clonal changes have been documented in detail. In these tumors one of the cytogenetic changes frequently observed has been a del(7), particularly del(7)(q22), usually as a sole anomaly. This is confirmed by our experience and by reports in the literature. The fact that del(7) is one of the most common abnormalities in leiomyoma raises the question of its role in tumor development. The main purpose of this review is to analyze the above aspect and to interpret its possible meaning. Our findings on cytogenetic abnormalities of chromosome 7 in leiomyoma, together with those reported in the literature, are reviewed and discussed. A listing of the genes located at 7q22 is also presented.

The 12q13-q15 translocation breakpoints in pleomorphic adenoma and clear-cell sarcoma of tendons and aponeuroses are different from that in myxoid liposarcoma

The transcription factor gene CHOP was recently shown to be rearranged in myxoid liposarcoma with t(12;16)(q13;p11). We have analyzed whether the CHOP gene is the target of rearrangements in pleomorphic adenoma and clear-cell sarcoma of tendons and aponeuroses with chromosome abnormalities of 12q13-q15. Restriction fragment analysis showed that the CHOP gene and its flanking sequences were not rearranged in any of these tumor types, indicating that the 12q translocation breakpoints in pleomorphic adenoma and clear-cell sarcoma are different from that in myxoid liposarcoma.

A case report of fibrolipoma with t(12;16)(q13;q24)

Chromosomal analysis of a fibrolipoma of the shoulder of a 55-year-old man showed the following abnormal complement: 46,XY,t(12;16)(q13;q24). Comparison with two previously characterized fibrolipomas showed abnormalities reportedly observed in "classic lipoma." A unique or distinguishing anomaly for fibrolipoma was not detected. Therefore, fibrolipoma appears to be distinct histologically but not cytogenetically.

Recombinations of chromosomal bands 6p21 and 14q24 characterise pulmonary hamartomas

Cytogenetic analysis of short-term cultures from seven pulmonary hamartomas revealed an abnormal karyotype in six of them. The most characteristic aberration was an exchange of material between 6p21 and 14q24, found in three tumours. Abnormalities of either 6p or 14q were seen in another two hamartomas. Other regions that were rearranged more than once were 12q (three times) and 17p (twice), sometimes in exchange with 6p or 14q and giving rise to complex derivative chromosomes. Only one tumour had aberrations that did not involve 6p, 12q, 14q, or 17p. These results-together with the data on three previously reported pulmonary hamartomas, two of which also had t(6;14)-show that recombinations between 6p21 and 14q24 are common, and hence probably pathogenetically important. The data support the view that these tumours are genuine neoplasms rather than developmental anomalies. The coexistence of a common 14q24 breakpoint in uterine leiomyomas and pulmonary hamartomas indicates that a gene important in the genesis of both tumours exists in this band.

Translocation (X;1) in papillary renal cell carcinoma. A new cytogenetic subtype

We report a consistent t(X;1)(p11.2;q21) that was observed in four cases of papillary renal tumors. In one of the cases, two cells showed the cytogenetic abnormality as the only change, whereas the other cases showed additional chromosomal anomalies particularly involving chromosomes 7 and 17. One identical t(X;1) has been reported previously in a papillary renal cell carcinoma. To date, all of the patients carrying this translocation have been males.

Inversion (X)(p22q13) in a uterine leiomyoma

We report a case of uterine leiomyoma which showed a karyotype 46,X,inv(X)(p22q13) as the only clonal change in most of the cells. A few cells had an additional del(7), though del(7) has been found to be a primary change in leiomyomas. These findings indicate that the abnormality involving the X chromosome and particularly Xp22 can be considered as a primary chromosomal abnormality. We discuss the findings together with few reports of cases involving chromosome X in leiomyomas.

INT1 and GLI genes are not rearranged or amplified in benign pleomorphic adenomas with chromosome abnormalities of 12q13-15

A subgroup of pleomorphic adenomas of the salivary glands is characterized by translocations involving chromosome 12, with consistent breakpoints at 12q13-15. Two proto-oncogenes, INT1 and GLI, have been assigned to this region of chromosome 12. We studied the possible involvement of these genes in pleomorphic adenomas with different karyotypic abnormalities, including cases with involvement of 12q13-15. Using detailed restriction fragment analysis of tumor DNAs from 25 cases, we found no evidence of rearrangement or amplification of INT1 or GLI. Because we previously found an adenoma with a del(12)(q13q15), we also analyzed normal and tumor DNAs from the 25 tumors separately to identify possible allelic losses at the GLI locus. Thirteen of the 25 tumors were informative, and none of these showed evidence of allelic losses. Collectively, these findings indicate that neither the INT1 nor the GLI gene appears to be the primary target gene for the translocations and deletions involving the 12q13-15 region in pleomorphic adenomas.

Chromosome aberrations and cancer

Cancer may be defined as a progressive series of genetic events that occur in a single clone of cells because of alterations in a limited number of specific genes: the oncogenes and tumor suppressor genes. The association of consistent chromosome aberrations with particular types of cancer has led to the identification of some of these genes and the elucidation of their mechanisms of action. Consistent chromosome aberrations are observed not only in rare tumor types but also in the relatively common lung, colon, and breast cancers. Identification of additional mutated genes through other chromosomal abnormalities will lead to a more complete molecular description of oncogenesis.

Leiomyosarcoma in a patient with trisomy 8 mosaicism

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Clonal chromosomal abnormalities in hemangiopericytoma

We report the cytogenetic findings in nine hemangiopericytomas studied after short-term culture. Clonal chromosome abnormalities were present in four cases. One case had a simple translocation (12;19)(q13;q13.3) as the sole abnormality whereas complex and multiple chromosomal abnormalities involving almost all chromosomes in the complement characterized tumors from the three other cases.

Intratumoral cytogenetic heterogeneity in a benign neoplasm

Cytogenetic findings are reported in a 64-year-old man who had a history of rapid growth of a mass in the left groin area. The histopathologic diagnosis of the tumor was consistent with that of a lipoma with atypia. Cytogenetic analysis was done on an incisional biopsy specimen. The initial biopsy specimen revealed, in addition to normal cells, three different clones: 46,XY,t(12;21)(q13;q21), 46,XY, t(2;12)(q11.2'1.2), t(19;20)(q13.1'3), and 47.XY,+ r. The subsequently excised specimen showed a normal male karyotype (46,XY) and a predominant clone with the karyotype, 47,XY,t(2;12)(q11.2'1.2),t(3;11)(p24'5), + r. One cell with 47,XY, + r was present. In addition, polyploid cells with large markers, rings, and a high frequency of telomeric associations were also observed.