Ataxia telangiectasia: G2 checkpoint and chromosomal damage in proliferating lymphocytes.

There is a checkpoint pathway in eukaryotic cells that depends on ATM (ataxia telangiectasia mutated) kinase which activates the processes leading to the repair of DNA damage and also lengthens the G(2) stage of the cell cycle. In cells from ataxia telangiectasia patients, due to their lack of active ATM kinase, an increase in chromosomal aberrations and a failure to induce G(2) lengthening could be expected. However, the basal G(2) timing in ataxia telangiectasia cells was longer than in controls and was further extended after X-ray irradiation (0.4 Gy), although to a lesser extent than in controls. Moreover, in control cells caffeine shortened G(2) and increased chromosomal damage 7-fold, while in ataxia telangiectasia cells caffeine only trebled aberration yield without shortening G(2). As caffeine is an inhibitor of ATM kinase, these results suggest the existence of some redundant ATM-independent checkpoint in G(2) of ataxia telangiectasia cells. The differential response to caffeine of ataxia telangiectasia and control lymphocytes may be explained by the presence of two different subpathways in the G(2) checkpoint: one regulating the processing and repair of damaged DNA and the other controlling G(2) timing. While in controls both subpathways may be mediated by ATM kinase, in ataxia telangiectasia cells caffeine-sensitive ATR kinase and the caffeine-insensitive DNA-PK kinases might be responsible for DNA repair and the G(2) delay subpathways, respectively. Confirmation of this model in ataxia telangiectasia cells with another cell type in which both subpathways are mediated by DNA-PK should define whether a metylxanthine such as caffeine may also have an additional direct inhibitory effect on DNA repair.

T(11;18)(q21;q21) is associated with advanced mucosa-associated lymphoid tissue lymphoma that expresses nuclear BCL10.

The development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a multistep process and can be clinico-pathologically divided into Helicobacter pylori-associated gastritis, low-grade tumors, and high-grade tumors. The molecular events underlying this progression are largely unknown. However, identification of the genes involved in MALT lymphoma-specific t(11;18)(q21;q21) and t(1;14)(p22;q32) has provided fresh insights into the pathogenesis of this disease. T(11;18)(q21;q21) results in a chimeric transcript between the API2 and the MALT1 genes, whereas t(1;14) (p22;q32) causes aberrant nuclear BCL10 expression. Significantly, nuclear BCL10 expression also occurs frequently in MALT lymphomas without t(1;14)(p22;q32), suggesting an important role for BCL10 in lymphoma development. Thirty-three cases of H pylori gastritis, 72 MALT lymphomas, and 11 mucosal diffuse large B-cell lymphomas (DLBCL) were screened for t(11;18)(q21;q21) by reverse transcription-polymerase chain reaction followed by sequencing. BCL10 expression in lymphoma cases was examined by immunohistochemistry. The API2--MALT1 fusion transcript was not detected in H pylori gastritis and mucosal DLBCL but was found in 25 of 72 (35%) MALT lymphomas of various sites. Nuclear BCL10 expression was seen in 28 of 53 (53%) of MALT lymphomas. Of the gastric cases, the largest group studied, the frequency of both t(11;18)(q21;q21) and nuclear BCL10 expression was significantly higher in tumors that showed dissemination to local lymph nodes or distal sites (14 of 18 = 78% and 14 of 15 = 93%, respectively) than those confined to the stomach (3 of 29 = 10% and 10 of 26 = 38%). Furthermore, t(11;18)(q21;q21) closely correlated with BCL10 nuclear expression. These results indicate that both t(11;18)(q21;q21) and BCL10 nuclear expression are associated with advanced MALT lymphoma and that their oncogenic activities may be related to each other. (Blood. 2001;98:1182-1187)

Isochromosome (17)(q10) as the sole structural chromosomal rearrangement in a case of botryoid rhabdomyosarcoma.

We describe a case of botryoid rhabdomyosarcoma with the karyotype 53,XX,+2,+5,+8,+12,+13, i(17)(q10),+19,+20. Only two cytogenetically analyzed cases of this tumor were previously reported and structural chromosomal abnormalities in each tumor were different.

Karyotypic similarity identified by multiplex-FISH relates four prostate adenocarcinoma cell lines: PC-3, PPC-1, ALVA-31, and ALVA-41.

Recently developed molecular cytogenetic techniques for karyotyping are providing new and important insights regarding the chromosomal changes that occur in solid tumors. We used multiplex-FISH to analyze four adenocarcinoma cell lines, PC-3, PPC-1, ALVA-31, and ALVA-41, in which the characterization of a large number of rearranged chromosomes was partially or substantially inconclusive by G-banding. Although the original descriptions of these lines depict them as distinct entities established from different patients, this study demonstrates that these four lines share numerous, highly rearranged chromosomes, strongly supporting the conclusion that they are derived from the same patient material. Our analysis indicates that PPC-1, ALVA-31, and ALVA-41 were derived from PC-3 through mechanisms involving clonal progression represented by sequential changes and clonal diversion represented by differing patterns of changes. Extensive cellular heterogeneity was detected in all four lines, and most rearrangements included segments derived from multiple chromosomes. Each line also showed a set of unique derivative chromosomes. However, a limited number of metaphase cells (approximately 10) was analyzed for each line, and numerous single-cell abnormalities were detected in all of them. Therefore, it is plausible that the number of clonal, shared, and/or unique rearrangements has been underestimated. These cell lines have been utilized as models for understanding the biology of prostate cancer and reportedly differ in their cell physiology. Rather than detracting from their value, a complete understanding of the interrelationships of these lines to one another may provide the opportunity to define the molecular changes that have led to their individual malignant phenotypes.

Gains of chromosome 22 by fluorescence in situ hybridization in the context of an hyperdiploid karyotype are associated with aggressive clinical features in meningioma patients.

BACKGROUND: Meningiomas usually are considered to be benign tumors; however, 10-20% of cases recur. Few disease characteristics have proved to have prognostic impact for predicting disease free survival. The objective of the current study was to explore the prognostic value of numeric abnormalities of chromosome 22 for meningioma patients. METHODS: In this study, the authors prospectively analyzed the incidence of numeric chromosome abnormalities of chromosome 22 by interphase fluorescence in situ hybridization, using a specific probe for the bcr gene located in chromosome 22q11.2, on a total of 88 consecutive meningioma patients. The authors also analyzed its correlation with both the clinicobiologic characteristics at presentation and the patient's outcome. RESULTS: The authors' results show that monosomy 22 was present in 49% of the cases and that this numeric chromosomal abnormality is not associated with other prognostic features of the disease. In contrast, gains (trisomy/tetrasomy) of chromosome 22 were detected in 8 (9%) cases who simultaneously showed gains for other chromosomes and represent an adverse prognostic factor regarding disease free survival (P = 0.001); in addition, trisomy/tetrasomy 22 was more frequently related to younger patients (P = 0.001), aggressive histopathologic features (P < 0.000), a greater incidence of DNA aneuploidy (P =0.006), and a higher proportion of S-phase tumor cells (P = 0.02). CONCLUSIONS: In summary, the authors conclude that loss of a copy of chromosome 22 is a frequent finding in meningioma tumors, but it does not affect the clinical outcome of these patients. In contrast, gains (trisomy/tetrasomy) of chromosome 22, in the context of an hyperdiploid karyotype, although much less frequent, are associated with a more aggressive disease course.

Three cell line mosaicism involving structural and numerical abnormalities of chromosome 18 in a 3.5-year-old girl: 47,XX,+18/47,XX,+del(18)(q22)/46,XX.

We report on a 3.5-year-old girl with a mosaic karyotype including full trisomy 18, normal cells and a majority of cells with partial trisomy involving an extra chromosome 18 deleted at band q22. She had cardiac and CNS anomalies, dysmorphic facial features failure to thrive and developmental delay. A gastrostomy tube was placed at 2 years of age. The combination of improved nutrition and optimal developmental therapy has led to her sitting supported, attempting to stand and enhancement of her cognitive and non-verbal communication abilities. Molecular investigation of the patient and her parents using microsatellite analysis has led to the conclusion that, as expected, the additional copy of chromosome 18 constituting the full trisomic cell line is maternal meiosis I in origin. The data, however, indicate that in the trisomic cell line containing the deleted chromosome 18q, the structurally abnormal 18 was of paternal origin. We think this case is the first described with both structural and numerical trisomic mosaicism involving chromosome 18 in a liveborn infant. We propose a mechanism of origin and review the literature, comparing the clinical presentation of this case with individuals having full or partial trisomy 18.

Chromosomal abnormalities and developmental kinetics in in vivo-developed cattle embryos at days 2 to 5 after ovulation.

The frequency of chromosome abnormalities was investigated in cattle embryos (n = 256) derived from superovulated heifers (n = 35) on Days 2, 3, 4, and 5 postovulation (PO). Interphase nuclei (n = 4358) were analyzed for chromosome abnormalities using fluorescent in situ hybridization with chromosome 6- and chromosome 7-specific probes and the developmental rate was described by scoring cell numbers. We found that 93%, 85%, 84%, and 69% of the embryos from Days 2, 3, 4, and 5 PO, respectively, displayed a normal diploid chromosome number in all cells. Of the embryos containing abnormal cells, mixoploidy was significantly more frequent than polyploidy. The percentage of mixoploidy at Days 2, 3, 4, and 5 PO was 5%, 13%, 16%, and 31%, respectively, whereas the percentages of polyploidy were 2%, 2%, 0%, and 0%, respectively. The mean number of cells per embryo was 4.7, 8, 11.5, and 48.3, respectively, at Days 2, 3, 4, and 5 PO. Thus, in vivo-developed embryos were significantly more advanced than the in vitro-produced (IVP) embryos except for Day 2. In conclusion, a significantly lower frequency of chromosomally abnormal embryos, in particular displaying polyploidy early after fertilization, was seen in in vivo versus IVP embryos, and these chromosomal abnormalities may be inherent to the process of IVP in cattle.

Ductal invasive G2 and G3 carcinomas of the breast are the end stages of at least two different lines of genetic evolution.

Ductal invasive grade (G) 2 and G3 carcinomas represent the majority of invasive breast cancers. Previous morphological and cytogenetic studies have provided evidence that ductal invasive G2 carcinoma may originate from at least two different genetic pathways. The aim of this study was to evaluate further the heterogeneity of G2 breast cancer in comparison with G3 cancers by cytogenetic and quantitative analysis. To this end, 35 cases of ductal invasive G2 and 42 cases of ductal invasive G3 carcinomas were investigated by means of comparative genomic hybridization (CGH) and these findings were correlated with DNA ploidy status, mitotic activity index (MAI), mean nuclear area (MNA), volume per lumen (VPL), and clinico-pathological parameters. The findings of this study demonstrate that ductal invasive G2 carcinomas, in contrast to ductal invasive G3 carcinomas, have to be interpreted as the morphological end stage resulting from two different cytogenetic and morphological pathways; the loss of 16q material is the cytogenetic key event in the evolution of a subgroup of this entity. By correlating genetic alterations with DNA ploidy status, an extended morphology-based cytogenetic progression model is presented, with early and late genetic alterations in the pathogenesis of breast cancer. The correlation with MAI gives rise to the hypothesis that these different genetic pathways significantly differ in their proliferation rate. Further studies will be required to elucidate which genes contribute to an altered proliferation rate in these subgroups and to the associated prognosis.

Chromosomal instability detected by fluorescence in situ hybridization in Japanese breast cancer patients.

The relationship between chromosomal instability (CIN) and prognostic factors was investigated in 31 breast cancers and 5 benign breast lesions (three fibroadenomas and two papillomas). Using fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes of chromosomes 1, 2, 6, 7, 10, 11, 17 and 18, CIN for each case was determined. CIN varied from 8.1% to 59.3% among the breast cancer patients tested, and was significantly higher than that observed in the benign breast lesions (p<0.01). Moreover, CIN showed a significant correlation with lymph node metastases (p<0.05) and estrogen receptor negativity (p<0.01). These findings suggest that CIN might be useful in the prediction of the biological aggressiveness of breast cancers.

Ossifying fibromyxoid tumor of soft parts: report of a case with novel cytogenetic findings.

A slowly growing tumor of the left thenar region in a 40-year-old man had the classic features of an ossifying fibromyxoid tumor of soft parts, including an incomplete shell of lamellar bone; a center composed of nodular aggregates of small spindled, oval, and stellate cells in abundant myxoid stroma; and strong expression of vimentin, S-100, and neuron-specific enolase by the tumor cells. Clonal chromosomal abnormalities included loss of a chromosome 6, extra material of unknown origin attached to the long arm of chromosome 12, and an unbalanced translocation involving the short arm of a chromosome 6 and the long arm of a chromosome 14. The karyotype was interpreted as 45,XY, der(6;14)(p10;q10),add(12)(q24.3). The chromosomal abnormalities suggest osteochondroblastic rather than neuronal or schwannian lineage.

Clinical importance of cytogenetics in acute myeloid leukaemia.

Acquired chromosome aberrations are present in the marrow of most patients with acute myeloid leukaemia (AML) at diagnosis. Cytogenetically, AML is a very heterogeneous disease with over 160 structural chromosome abnormalities observed recurrently to date. Molecular dissection of many reciprocal translocations and inversions has resulted in cloning of the genes involved in leukaemogenesis. Some recurrent aberrations and the resulting gene rearrangements, namely inv(16)/t(16;16) and CBFbeta- MYH11, t(8;21) and CBFA2-CBFA2T1, t(15;17) and PML-RARalpha, and rearrangements of band 11q23 and the MLL gene, are now used to help define distinct disease entities within AML in the new World Health Organization classification of haematological malignancies. Moreover, cytogenetic abnormalities, whether molecularly characterized or not, are among the most important, independent prognostic factors in AML, and are being used in the management of AML patients. This review presents current information on chromosome abnormalities in AML, and on associations between karyotype and clinical characteristics and outcome of AML patients.

Integration of amplified BCR/ABL fusion genes into the short arm of chromosome 17 as a novel mechanism of disease progression in chronic myeloid leukemia.

We describe the cases of two patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML), in whom the extramedullary blastic phase developed during disease progression. The similar clinical presentations of these patients was accompanied by gain of identical secondary chromosome abnormalities, that is, monosomies 9, 14, and 22, and by a clustered amplification of the BCR/ABL fusion gene. The additional copies of the BCR/ABL fusion gene were integrated into the short arm of structurally abnormal chromosomes 17 in both patients. The conformity of these genetic features in two patients with a rare disease manifestation leads us to the assumption that either the clustered amplification of the BCR/ABL fusion gene or the integration of this cluster into the short arm of chromosome 17 or both are associated with extramedullar disease progression in CML. Furthermore, the insertion of amplified BCR/ABL fusion genes into structurally abnormal chromosomes provides a novel mechanism of disease progression in BCR/ABL-positive CML.

Cross-species color banding in ten cases of myeloid malignancies with complex karyotypes.

Cross-species color banding is a multiple-color fluorescence in situ hybridization (FISH) technique using probes developed from other animal species. Hybridization to human metaphases produces color banding patterns specific for each homologous chromosome pair. The technique has been evaluated in a complementary manner with G-banding and chromosome painting in a series of 10 myeloid malignancies with complex or unresolved karyotypes. Color banding detected the majority of chromosomal abnormalities, which had been identified by G-banding and in each case revealed chromosomal changes that G-banding had not identified. Painting was necessary to confirm these abnormalities due to the limitation of only seven colors in the color-banded karyotype. At the same time, painting fortuitously uncovered cryptic abnormalities in 6 of 10 cases that had not been detected by color banding. Insertions were visible by painting only. This study has demonstrated that in the analysis of complex karyotypes, the application of color banding revealed the involvement of the long arm of chromosome 3, indicating a poor risk, in two cases not identified by G-banding. Therefore, these techniques applied together have revealed cryptic chromosomal abnormalities with prognostic significance, which in some cases may have implications for patient management.

Correlation of prenatal clinical findings with those observed in fetal autopsies: pathological approach.

Our objective was to present a comprehensive description of the clinicopathological findings of 173 abortions, including 121 therapeutic and 52 spontaneous ones in the period between 1992 and 1998. In all of these fetuses pathological examination was carried out. It was complemented when indicated by immunohistochemistry, in situ hybridization, flow cytometry, and X-ray examination. In the 121 therapeutic abortions the distribution of malformations was: 45 central nervous system anomalies (37%), 12 genitourinary anomalies (10%), 25 gastrointestinal anomalies (21%), two respiratory system anomalies (1.65%), eight cardiac anomalies (6.6%) and 28 other anomalies (17.2%) as revealed by autopsy. From the clinically selected 52 spontaneous abortions, major malformations were seen in 15/52 cases. With the comparison of the pathological and clinical findings in 121 therapeutic abortions, the percentage of cases with correct clinical designation and no missed anomalies amounted for 49%. However in 51% additional or different lethal, severe, or major malformations were revealed or excluded by fetopathological examinations. In 4% the clinical observation and diagnosis were modified, but without implications for the therapeutic termination of pregnancy. The clinical indication could not be supported in another 3% of the cases.

A correlative study of prenatal ultrasound and post-mortem findings in fetuses and infants with an abnormal karyotype.

OBJECTIVE: To compare ultrasound and post-mortem findings in 98 fetuses and infants with an abnormal karyotype. DESIGN: Criteria for inclusion were an ultrasound examination at the National Center for Fetal Medicine (NCFM), an abnormal karyotype, and an autopsy performed during the period 1985-94. RESULTS: Trisomy 18 and 21 were the two most common abnormal karyotypes. The highest number of congenital anomalies was observed in cases with trisomy 13 and 18; congenital heart defects (CHD) were most prevalent among fetuses with trisomy 18. In 80% of cases there was full agreement between the ultrasound and autopsy findings; in another 8% of cases there was nearly complete concordance. Thus, in 88% of cases, the main prenatal sonographic diagnosis was correct. In 6% major autopsy findings were not detected by ultrasound examination, in 1% none of the autopsy findings were detected by routine ultrasound and in 5% ultrasound findings were not verified at autopsy. Where the correlation was related to individual autosomal trisomies, structural anomalies were most often correctly diagnosed in fetuses with trisomy 13, with the main diagnosis correct in all cases; second in accuracy were the ultrasound diagnoses in fetuses with trisomy 21 with the main diagnosis correct in 96%; for trisomy 18 the concordance was less good, with the main diagnosis correct in 71%. CONCLUSION: The present comparison of sonographic diagnoses with post-mortem findings demonstrates good accordance between the two methods. It also demonstrates the importance of awareness of the anomalies known to occur with different aneuploidies.

Correlation between cytogenetic abnormalities and disease characteristics in multiple myeloma: monosomy of chromosome 13 and structural abnormalities of 11q are associated with a high percentage of S-phase plasma cells.

BACKGROUND AND OBJECTIVES: Cytogenetic studies in multiple myleoma (MM) are limited by the difficulties in obtaining metaphases that can be investigated and few studies have analyzed the relationship between cytogenetics and clinical disease characteristics. The aim of our study was to analyze the recurrent cytogenetic changes in MM and to correlate them with clinical and biological characteristics including the percentage of S-phase plasma cells (PCs). DESIGN AND METHODS: Chromosomal abnormalities were analyzed in 86 patients with MM. In all patients, two types of cultures (5 d culture with interleukin-4 and unstimulated 72 h culture) were used for cytogenetic analysis. DNA content analysis (ploidy and cell cycle analysis) together with the most relevant clinical and biological disease features were studied. RESULTS: Cytogenetic analysis was successful in 72 of the 86 patients (84%). Forty-seven patients (65%) had an abnormal karyotype. The most frequent trisomies involved chromosomes 3, 5, 9, 11, 15, 19, 22, 1, 7, 17, 18, and 21, and monosomies affected chromosomes 13 and 8, while structural changes involved chromosomes 1, 11, 14q32, 4p16 and 16q22-23. Patients with abnormal karyotype displayed a poor performance status, advanced stage, anemia and a high percentage of bone marrow plasma cells. In addition, MM patients with -13/13q- and 11q abnormalities showed a significantly higher proportion of S-phase PCs (p=0.02). INTERPRETATION AND CONCLUSIONS: In summary, our study shows a relationship between unfavorable cytogenetics (-13/13q-/11q abnormalities) and a high percentage of S-phase PCs, a well-known adverse prognostic factor.

Severe gingival recession in trisomy 18 primary dentition. A clinicopathologic case report of self-inflicted injury associated with mental retardation.

This clinicopathologic case report documents severe gingival recession in the primary dentition of a trisomy 18 patient. Primary molar and canine teeth exhibited recession extending beyond the midpoint of the buccal aspect of the root, occasionally reaching the root apex. Radiographic examination revealed taurodontism in both primary and permanent teeth. Clinical and histopathologic findings, along with case history, eliminated the possibility of prepubertal periodontitis and suggested a diagnosis of self-inflicted injury associated with mental retardation. Histologic examination of the primary teeth revealed normal cementum and dentin structure. Taurodontism, histologic structure of the dentition, and severe attachment loss in the primary dentition have not been described previously in trisomy 18.

Relevance of presenting white blood cell count and kinetics of molecular remission in the prognosis of acute myeloid leukemia with CBFbeta/MYH11 rearrangement.

BACKGROUND AND OBJECTIVES: The detection of CBFbeta/MYH11 transcripts by RT-PCR has became a valuable and widely used technique in the accurate cytogenetic and molecular classification of acute myeloid leukemia (AML), but the clinical value of RT-PCR for monitoring minimal residual disease (MRD) during follow-up remains unclear. DESIGN AND METHODS: We analyzed the factors predicting relapse and the value of MRD monitoring by RT-PCR in a series of 16 patients with CBFb/MYH11-positive AML (15 M4Eo; 1 M4). Fifteen were newly diagnosed cases (CR1) and one was studied after first relapse (CR2). Eight patients had clinical relapse at 6 to 19 months from the achievement of CR. RESULTS: Presenting WBC count had a significant prognostic influence on disease-free survival (p=0.001). All four patients with a WBC count >100x10(9)/L relapsed, while only four additional relapses occurred among the eleven patients who had an initial WBC count below 100x10(9)/L. With regards to molecular monitoring, all relapses but one occurred in patients who showed persistent RT-PCR positivity during hematologic remission. By contrast, conversion to a repeatedly PCR-negative status was observed in the seven patients who remained in CR1 after a median follow-up of 48 months (range 31-79 months), as well as in the transplanted patient who was monitored in CR2. In these patients a PCR-positivity could be detected up to 24 months after diagnosis (median time to conversion to PCR-negative: 8 months). INTERPRETATION AND CONCLUSIONS: In conclusion, marked hyperleukocytosis (>100x10(9)/L) confers poor prognosis to the patient with CBFbeta/MYH11-positive AML. In addition, slow kinetics of molecular remission was observed in this subset of AML, but the CBFb/MYH11 fusion transcript is no longer detectable in long-term survivors, indicating that molecular remission is an important therapeutic goal.

Patología molecular de las neoplasias de pulmón / Molecular pathology of lung neoplasia

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