Clonal Structural Abnormalities Research Articles

Labial Mucosa Stem Cells: Isolation, Characterization, and Their Potential for Corneal Epithelial Reconstruction.

PurposeThe purpose of this study was to characterize labial mucosa stem cells (LMSCs) and to investigate their potential for corneal epithelial reconstruction in a rabbit model of total limbal stem cell deficiency (LSCD).MethodsRabbit LMSCs (rLMSCs) and human (hLMSCs) LMSCs were derived from labial mucosa and characterized in terms of their proliferation activity by the evaluation of proliferation index (PI) and colony forming efficiency (CFE), cell senescence, and differentiation abilities. The expression of various limbus-specific, stem cell-specific, and epithelial markers was assessed via immunocytochemistry. Flow cytometry was used to evaluate mesenchymal and hematopoietic cell surface markers expression. Chromosomal stability of the derived cells was examined using the conventional GTG-banding technique. To assess the impact of LMSCs on corneal epithelial reconstruction, rLMSCs were seeded onto a decellularized human amniotic membrane (dHAM), thereafter their regeneration potential was examined in the rabbit model of total LSCD.ResultsBoth rLMSCs and hLMSCs showed high proliferation and differentiation abilities, entered senescence at later passages, and expressed different stem cell-specific (ABCB5, ALDH3A1, ABCG2, and p63α), mesenchymal (vimentin), and epithelial (CK3/12, CK15) markers. Cell surface antigen expression was similar to other described mesenchymal stem cells. No clonal structural chromosome abnormalities (CSCAs) and the low percentage of non-clonal structural chromosome abnormalities (NSCAs) were observed. Transplantation of rLMSCs promoted corneal epithelial reconstruction and enhanced corneal transparency.ConclusionsLMSCs have significant proliferation and differentiation abilities, display no detrimental chromosome aberrations, and demonstrate considerable potential for corneal repair.

Cancer chromosome breakpoints cluster in gene-rich genomic regions.

Cancer cells are characterized by chromosome abnormalities, of which some, in particular balanced rearrangements, are associated with distinct tumor entities and/or with specific gene rearrangements that represent important steps in the carcinogenic process. However, the vast majority of cytogenetically detectable structural aberrations in cancer cells have not been characterized at the nucleotide level; hence, their importance and functional consequences are unknown. By ascertaining the chromosomal breakpoints in 22 344 different clonal structural chromosome abnormalities identified in the karyotypes of 49 626 cases of neoplastic disorders we here show that the distribution of breakpoints is strongly associated (P < 0.0001) with gene content within the affected chromosomal bands. This association also remains highly significant in separate analyses of recurrent and nonrecurrent chromosome abnormalities as well as of specific subtypes of cancer (P < 0.0001 for all comparisons). In contrast, the impact of band length was negligible. The breakpoint distribution is thus not stochastic—gene‐rich regions are preferentially affected. Several genomic features relating to transcription, replication, and chromatin organization have been found to enhance chromosome breakage frequencies; this indicates that gene‐rich regions may be more break‐prone. The salient finding in the present study is that a substantial fraction of all structural chromosome abnormalities, not only those specifically associated with certain tumor types, may affect genes that are pathogenetically important. If this interpretation is correct, then the prevailing view that the great majority of cancer chromosome aberrations is cytogenetic noise can be seriously questioned.

Human Angiosarcoma: A Histological and Biological Phenotyping Using Xenografts in Nude Mice: Analysis of Five Cases

Human angiosarcoma (AS) is an infrequent soft tissue malignancy that may be difficult to diagnose, especially the solid, epithelioid or pleomorphic variant. A broad panel of antibodies is often necessary to determine the phenotype by Immunohistochemistry (IHC). To improve our knowledge of the morphology, immunophenotype, genetics and molecular biology, we constructed an in vivo xenograft platform using human soft tissue AS in nude mice. Tissue Microarrays (TMAs) were built from the original tumors and subsequent passages. The study included four original human AS, plus one secondary (a primary Malignant Peripheral Nerve Sheath Tumor (MPNST) which became an angiosarcoma), followed over successive tumor transfers for several generations. Endothelial marker expression (CD31, CD34, FVIII, CD105 (endoglin), Caveolin (CAV-1), D2-40, V-cadherin, FLI1 and ERG n-terminal) was evaluated by IHC. Molecular and cytogenetics studies were also performed. Only three out of the five AS (60%), grew in nude mice. Between 30 and 52 passages were achieved. Cytogenetically, the tumors showed complex karyotypes with many clonal numerical and structural abnormalities. Molecular biology showed p53 wild-type and KDR in all the cases. The WWTR1-CAMTA fusion was absent, which may be helpful in distinguishing epithelioid AS from epithelioid hemangioendothelioma (EHE), as it has been described as a hallmark in the latter. CD31, ERG, D2-40 and V-cadherin were the most sensitive, and ERG and FLI1 the most specific markers in the present series. This is the first study to combine nude mice xenografts and TMA studies in human AS, and describes for the first time an angiosarcomatous differentiation of an MPNST which occurred during the late passages generating a Kasabach-Merritt-like syndrome in the animal.

Adult rhabdomyoma: A challenging diagnosis on cytology

Adult rhabdomyoma: A challenging diagnosis on cytology

Characterization of a new human melanoma cell line with CD133 expression

A novel human malignant melanoma cell line, designated MEL-RC08, was established from a pericranial metastasis of a malignant melanoma of the skin. The cell line has been subcultured for more than 150 passages and is tumorigenic in nude mice. Growth kinetics, cytogenetics, flow cytometry, and molecular techniques for analysis of the genes implicated in cell cycle control; mutations in BRAF, NRAS, C-KiT, RB, and TP53 genes; and amplification of MDM2, CDK4, and cyclin D1 have been studied. Cytogenetically, the tumor and the cell line showed a hypertriploid karyotype with many clonal numeric and structural abnormalities. DNA flow cytometry showed an aneuploid peak with a DNA index value of 1.5. Mutations in TP53 and BRAF genes were demonstrated in both tumor and cell line. Furthermore, stem cell marker CD133 expression was detected in most cells, together with other stem cell markers, suggesting the presence of cells with tumor-initiating potential in this cell line.

Chromosomal imbalances in oral squamous cell carcinoma: Examination of 31 cell lines and review of the literature

Classical and molecular cytogenetic analysis, including fluorescence in situ hybridization (FISH) and chromosomal comparative genomic hybridization (CGH), were used to examine genetic changes involved in the development and/or progression of oral squamous cell carcinoma (OSCC). Of 31 OSCC cell lines studied, more than one-third expressed clonal structural abnormalities involving chromosomes 3, 7, 8, 9, and 11. Eleven OSCC cell lines were evaluated using CGH to identify novel genome-wide gains, losses, or amplifications. By CGH, more than half of the cell lines showed loss of 3p, gain of 3q, 8q, and 20q. Further, molecular cytogenetic analyses by FISH of primary tumors showed that the karyotypes of cell lines derived from those tumors correlated with specific gains and losses in the tumors from which they were derived. The most frequent nonrandom aberration identified by both karyotype and CGH analyses was amplification of chromosomal band 11q13 in the form of a homogeneously staining region. Our data suggest that loss of 9p and 11q13 amplification may be of prognostic benefit in the management of OSCC, which is consistent with the literature. The results of this study validate the relationship between these OSCC cell lines and the tumors from which they were derived. The results also emphasize the usefulness of these cell lines as in vitro experimental models and provide important genetic information on these OSCC cell lines that were recently reported in this journal.

A novel immortalized human endometrial stromal cell line with normal progestational response.

Obtaining primary human endometrial stromal cells (HESCs) for in vitro studies is limited by the scarcity of adequate human material and the inability to passage these cells in culture for long periods. Immortalization of these cells would greatly facilitate studies; however, the process of immortalization often results in abnormal karyotypes and aberrant functional characteristics. To meet this need, we have introduced telomerase into cultured HESCs to prevent the normal shortening of telomeres observed in adult somatic cells during mitosis. We have now developed and analyzed a newly immortalized HESC line that contains no clonal chromosomal structural or numerical abnormalities. In addition, when compared with the primary unpassaged parent cells, the new cell line displayed similar biochemical endpoints after treatment with ovarian steroids. Classical decidualization response to estradiol plus medroxyprogesterone acetate were seen in both morphologically, and progestin was seen to induce or regulate the expression of IGF binding protein-1, fibronectin, prolactin, tissue factor, plasminogen activator inhibitor-1, and Fas/Fas ligand. In summary, an immortalized HESC line has been developed that is karyotypically, morphologically, and phenotypically similar to the primary parent cells, and it is a powerful and consistent resource for in vitro work.

Spectral karyotype (SKY) analysis of human prostate carcinoma cell lines.

Well-characterized in vitro model systems provide an invaluable tool for studying prostate cancer in the laboratory. Detailed karyotypes have been reported using modern techniques such as multiplex fluorescence in situ hybridization (M-FISH) and spectral karyotyping (SKY) for LNCaP, DU 145, NCI-H660, and PC-3 cell lines. However, karyotypic data for more recently established prostate carcinoma cell lines are still limited. Classical (G-banding) and SKY analyses were performed on ten prostate carcinoma cell lines: 22Rv1, CWR-R1, DuCaP, LAPC-4, MDA PCa 1, MDA PCa 2a, MDA PCa 2b, PC-346C, PSK-1, and VCaP. Chromosomal abnormalities were identified in all cell lines, although the number and complexity varied greatly among them. PC-346C, established from a primary tumor, exhibited the lowest number (3) of clonal structural abnormalities, while DuCaP, established from a metastasis from a hormone-refractory patient, exhibited both the highest number (31) and largest complexity of structural abnormalities. In various subsets of these models, breakpoints were identified in chromosomal regions previously described as being involved in prostate cancer (e.g., 8p, 10q, 13q, and 16q). The present study provides a comprehensive karyotypic analysis of a large number of prostate carcinoma cell lines, and offers a valuable resource for future investigations.

Establishment and Characterization of a Continuous Human Chondrosarcoma Cell Line, ch-2879: Comparative Histologic and Genetic Studies with Its Tumor of Origin

Chondrosarcomas are malignant cartilage-forming tumors that represent the second most common malignant solid tumor of bone. These biologically poorly understood neoplasms vary considerably in clinical presentation and biologic behavior. Chemotherapy and radiation therapy are generally ineffective. Here we describe the establishment and characterization of a new human chondrosarcoma cell line named ch-2879, and we compare the cell line with its tumor of origin. The cell line was established from a recurrent grade 3 chondrosarcoma of the chest wall and characterized by growth kinetics and morphologic studies. Immunocytochemistry and RT-PCR were performed to examine the expression of cartilage-specific phenotypes. Genetic characterization was performed using cytogenetics, fluorescence in situ hybridization, flow cytometry, and molecular techniques for analysis of the genes implicated in cell cycle control, amplification of MDM2, CDK4, and Cyclin D1, and mutations in the p53 gene. ch-2879 cells were subcultured for more than 80 passages. They expressed vimentin, HNK-1, HBA-71, Ki-67, cyclin D1, Fli-1, S-100, p21, p27, and p53 and were negative for cytokeratin, EMA, p14, p16, MDM2, Rb, and c-erb-b2 antigens. Cytogenetically the recurrent tumor showed a hyperhaploid karyotype with clonal numerical and structural abnormalities. The sole structural abnormality was a chromosome derivative of a t(1;21) translocation. The cell line at passage 3 showed two populations: the hyperhaploid and an exactly duplicated, hypotriploid population. After the 18th passage, only the hypotriploid population was present. The cells expressed collagen 2. Molecular comparison of the primary and recurrent tumor evidenced an in vivo molecular change consisting of a deletion of 9p21 genes in the recurrence, probably caused by a selection process. Because of its gene expression profile, including expression of genes implicated in chondrogenesis in uncoated plastic dishes, this cell line may prove useful for cellular and molecular studies as well as studies of chondrosarcoma characterization and treatment.

Acute lymphoblastic leukaemia: diagnosis and classification

Acute lymphoblastic leukaemia (ALL) is a heterogeneous disease with distinct biological and prognostic groupings. Diagnosis relies on traditional cytomorphological and immunohistochemical evaluation of the leukaemic blasts. Subsequently, cytogenetic analysis identifies clonal numeric and/or structural chromosomal abnormalities that may be present, thus confirming the subtype classification and providing important prognostic information for treatment planning. The major chromosomal abnormalities in ALL are t(9;22)(q34;q11), t(12;21)(p13;q22), t(4;11)(q21;q23), t(1;19)(q23;p13), 8q24 translocations and hyperdiploidy. Generally, hyperdiploidy, occurring most frequently in paediatric cases, is associated with a good prognosis, while hypodiploidy confers a poor prognosis. Among structural chromosomal abnormalities, the t(9;22)(q34;q11) resulting in the BCR/ABL fusion protein, and rearrangements of the MLL gene, confer a poor prognosis in both children and adults, while t(12;21)(p13;q22), resulting in the TEL/AML1 fusion protein, and del (12p) confer a good prognosis. More recently, additional diagnostic and prognostic information has been gained from fluorescence in situ hybridization (FISH) and DNA microarray techniques.

CHARACTERIZATION OF A NEW RAT CELL LINE ESTABLISHED FROM 2′AAF-INDUCED COMBINED HEPATOCELLULAR CHOLANGIOCELLULAR CARCINOMA

A rat cell line-nominated CC-62 derived from a combined hepatocellular and cholangiocellular carcinoma obtained by administration of 2-acetylaminofluorene to male Wistar rats, has been established. Using light and electron microscopy it was determined that morphologically the tumor consisted of a mixed population of hepatocytes and cholangiolar neoplastic cells, intermingled with small, undifferentiated oval-like cells. The CC-62 line has been maintained through 90 passages in culture adopting a paving stone arrangement. Doubling time at the 12th passage was 23 h. Immunostaining with a panel of antisera was performed to identify the cytological profiles of the cell line. There was no k-ras or p53 expression by immunohistochemistry, and molecular biology failed to detect mutations. Molecular analysis by reverse transcriptase-polymerase chain reaction revealed transcripts for c-met but no expression of HGF messenger ribonucleic acid. Three cell lines cloned from CC-62 showed the same immunohistochemical and molecular pattern as the parental line. Cytogenetic analysis revealed a chromosome number ranging from 74 to 82 with a modal number of 79 but no clonal structural abnormalities were found. Deoxyribonucleic acid ploidy analysis showed an aneuploid peak. CC-62 caused tumors 1 mo after subcutaneous transplantation into nude mice, with morphological patterns of mucosecretory solid and spindle-shaped carcinoma. This cell line is the first established from a primary rat combined hepatocellular and cholangiocellular neoplasm. The resulting cells expressed biological and morphological markers of hepatocytes and cholangiolar cells. Therefore this cell line may contribute to a better understanding of the histogenesis of liver cancer.

Cytogenetic Analysis of a Parachordoma

We report the cytogenetic and histopathological findings in a 7-year-old female child with an intranasal tumor that is most consistent with a parachordoma. Karyotypic analysis of the tumor revealed clonal numerical and structural chromosome abnormalities. Seven cells displayed recurrent changes: der(2)t(2;4), del(3q), and the loss of chromosomes 9, 10, 20, and 22. Four cells showed a loss of chromosome 17. To the best of our knowledge, these are the first clonal chromosome abnormalities described in parachordoma.

Band 1p36 Abnormalities and t(1;17) in Ovarian Carcinoma

In a series of 128 karyotyped ovarian carcinomas, 42% of cases with chromosome 1 clonal structural abnormalities had breaks at band 1p36 (usually involving translocations of unknown material). Fluorescent in situ hybridization (FISH) studies using combinations of 1 centromere and 1p36.3–specific probes (16 cases) or 1 centromeric and 17 whole-chromosome paint probes (11 cases with 1p+) revealed a trend toward deletion of 1pter relative to 1 centromere (63%); intratumor heterogeneity; and the origin of 1p+ in 3/11 cases (27%) from chromosome 17 [t(1;17)(p36;?)]. The frequency of this specific breakpoint and its involvement in recurrent translocations suggest that these regions are loci for genes important in the pathogenesis of a subset of sporadic ovarian carcinomas.

Haematological abnormalities in Shwachman-Diamond syndrome.

We have analysed the haematological parameters in 21 patients with Shwachman-Diamond syndrome (SDS) seen over a 25-year period at our institution. Neutropenia, although present in all patients, was intermittent in two-thirds, constant in the rest and was associated with impaired chemotaxis in all of those patients tested. Fetal haemoglobin (HbF) was elevated in 80% of the patients at some stage, and anaemia and thrombocytopenia was documented in 66% and 24% respectively. Bone marrow samples were taken in over half of the patients. Myelodysplastic syndrome (MDS) developed in seven (33%) patients, five of whom had acquired clonal structural chromosome abnormalities in their bone marrows. In five of the patients with MDS (24%) transformation to acute myeloid leukaemia occurred. Like other constitutional bone marrow failure syndromes. SDS has a predilection to leukaemic transformation hitherto assumed to be in the region of 5-10%. The data presented here suggest that this figure probably represents an underestimate. Shwachman-Diamond syndrome is an interesting model of leukaemia development and greater understanding of the clinical spectrum of this rare disorder should produce further insights into its pathobiology.

Chromosomal anomalies exclusive of telomeric associations in giant cell tumor of bone

The occurrence of telomeric associations in giant cell tumor of bone is well recognized. However, there has been little emphasis on clonal structural abnormalities that may be seen in addition to or in the absence of telomeric associations. Two cases of giant cell tumor of bone are presented in this study demonstrating clonal karyotypic anomalies other than telomeric association with a review of previously reported cases showing similar findings.

Karyotype correlates with peripheral blood morphology and immunophenotype in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is recognized as a distinct entity. However, morphologic and immunophenotypic heterogeneity exist. Twenty-six patients with CLL were studied to investigate whether an association exists among peripheral blood karyotype, morphology and immunophenotype. Clonal cytogenetic abnormalities were detected in 14 patients (53%), using conventional karyotyping techniques in addition to fluorescence in situ hybridization (FISH) for chromosome 12. By FAB guidelines, 7 of the 8 patients (88%) with trisomy 12 had mixed cell morphology compared to only 3 of 18 (17%) without trisomy 12 (P = .004). One patient (12%) with trisomy 12 had lymphocyte morphology typical for CLL. Six of the eight (75%) with trisomy 12 had atypical immunophenotype including one or more of the following: strong CD20 expression, strong surface light chain expression, or absence of CD23 expression. Only 2 of the 18 patients (11%) without trisomy 12 had atypical immunophenotype (P = .005). None of the three patients with clonal structural abnormalities of chromosome 13q14 had mixed cell morphology or atypical immunophenotype. One of the 12 patients (8%) without clonal cytogenetic abnormalities had mixed cell morphology and one had atypical immunophenotype. This study suggests that a correlation exists among karyotype, morphology, and immunophenotype in CLL, and that CLL subgroups can be identified based on laboratory parameters. Although normal karyotypes or clonal structural abnormalities of 13q14 are associated with morphology and immunophenotype considered typical for CLL, trisomy 12 is associated with mixed cell morphology and atypical immunophenotype. These findings may have implications for evaluating variation in both disease course and response to emerging therapies.

No recurrent structural abnormalities apart from i(12p) in primary germ cell tumors of the adult testis

Malignant transformation may be caused by gene deregulation resulting from specific chromosomal rearrangements, by amplification, by mutations in proto-oncogenes, by loss of tumor suppressor genes, or a combination of these. We investigated the role of numerical and structural chromosomal abnormalities in 102 cytogenetically abnormal cases of primary testicular germ cell tumors of adolescents and adults (TGCT) [32 seminomas (SE) and 70 nonseminomatous germ cell tumors (NS)]. We confirmed that an isochromosome for 12p, i(12p), is the only consistent structural chromosomal abnormality in TGCT, present in about 70% of our cases. Both the frequency and the number of copies of i(12p) are higher in NS than in SE. This may suggest that i(12p) is involved in tumor progression. Besides i(12p), several clonal structural chromosomal abnormalities were found, but none appeared to be specific. SE and NS had chromosome numbers in the triploid range, with significantly higher numbers in SE than in NS (average modal chromosome numbers of 73.4 in SE and 65.0 in NS). Both in SE and NS, some chromosomes were significantly underrepresented (e.g., 11, 13, 18, and Y) and others overrepresented (e.g., 7, 8, 12, 21, and X). In SE, a significantly higher copy number of chromosomes 7, 15, 19, and 22 was found and a significantly lower number of chromosome 17, compared with NS. These chromosomes may play an important role in the differentiation of TGCT.

Cytogenetics of 158 patients with regional or disseminated melanoma Subset analysis of near-diploid and simple karyotypes

We report on the cytogenetic analyses of 158 cases of metastatic malignant melanoma, comprised of 63 cases with regional disease (RD) and 95 cases with distant (metastatic) disease (DD). Clonal structural abnormalities were identified in 126 (80%) cases and were significantly increased (< 0.01 after adjusting for multiple comparisons) on chromosomes (in order of frequency of involvement) 1, 6, 7, 11, 9, and 3. Clustering of breakpoints occurred at 1p36, 1p22-q21, 6p11-q21, 9p, 11q23-qter, 13p (especially for cases with DD), and 19q13. The most common clonal numerical abnormalities, in a subset of 49 near-diploid cases were −10, −22, −9, +7, −19, and −Y. Analysis of chromosome segment gains and losses (CSRP) showed frequent loss of chromosomes 6 and 10, followed by equal rates of involvement of chromosomes 1, 7, and 9. Whole or segmental losses of chromosome 9 (especially 9p) correlate well with recent molecular genetic studies identifying putative suppressor genes, and are also likely important genetic abnormalities. However, based on the frequency of abnormalities in this large series of metastatic melanomas, it is likely that structural abnormalities of 1 and 6, and −10 are important in the pathogenesis of sporadic advanced melanoma.

Mesenchymal chondrosarcoma A cytogenetic, immunohistochemical and ultrastructural study

A case of mesenchymal chondrosarcoma was studied. The tumor was near-tetraploid and the clonal structural chromosomal abnormalities included add(7)(p13), add(22)(q13), markers, and double minutes. The ultrastructural and immunohistochemical findings were consistent with the diagnosis. Strong immunoreactivity for desmin was an unusual, not previously reported, feature of the neoplasm.

Cytogenetic findings in 31 papillary thyroid carcinomas

Chromosome studies performed on 31 papillary thyroid carcinomas (PTCs) revealed clonal numerical and structural abnormalities in 12 tumors. The numerical clonal aberrations found were trisomy 2, trisomy 7, and loss of the Y chromosome. A nonrandom telomeric association, tas(15;16)(p13;p13), was observed in one carcinoma. Structural alterations with a breakpoint at 10q11.2 were detected in two tumors. Other chromosomes involved in rearrangements were chromosomes 1, 2, 3, 5, 7, 9, 11, 12, and 14. The observation of clonal changes of chromosome 2 [i(2)(q10) and trisomy 2] in two tumors, which were both histologically classified as tall-cell PTC variants, suggests that gain of 2q may be important in the development of this morphological variant.