Chromosomal changes pattern and gene amplification in T cell non-Hodgkin's lymphomas

Pathogenetic and diagnostic significance of microRNA deregulation in peripheral T-cell lymphoma not otherwise specified

Peripheral T-cell lymphomas not otherwise specified (PTCLs/NOS) are rare and aggressive tumours whose molecular pathogenesis and diagnosis are still challenging. The microRNA (miRNA) profile of 23 PTCLs/NOS was generated and compared with that of normal T-lymphocytes (CD4+, CD8+, naive, activated). The differentially expressed miRNA signature was compared with the gene expression profile (GEP) of the same neoplasms. The obtained gene patterns were tested in an independent cohort of PTCLs/NOS. The miRNA profile of PTCLs/NOS then was compared with that of 10 angioimmunoblastic T-cell lymphomas (AITLs), 6 anaplastic large-cell lymphomas (ALCLs)/ALK+ and 6 ALCLs/ALK-. Differentially expressed miRNAs were validated in an independent set of 20 PTCLs/NOS, 20 AITLs, 19 ALCLs/ALK- and 15 ALCLs/ALK+. Two hundred and thirty-six miRNAs were found to differentiate PTCLs/NOS from activated T-lymphocytes. To assess which miRNAs impacted on GEP, a multistep analysis was performed, which identified all miRNAs inversely correlated to different potential target genes. One of the most discriminant miRNAs was selected and its expression was found to affect the global GEP of the tumours. Moreover, two sets of miRNAs were identified distinguishing PTCL/NOS from AITL and ALCL/ALK-, respectively. The diagnostic accuracy of this tool was very high (83.54%) and its prognostic value validated.

Genetic alterations in systemic nodal and extranodal non-cutaneous lymphomas derived from mature T cells and natural killer cells

Mature (peripheral) T-cell and natural killer (NK)-cell lymphomas comprise a series of rather different neoplasms. Based on morphologic, immunophenotypic, genetic, and clinical data, the World Health Organization classification recognizes more than 20 entities or provisional entities. The variable clinical presentations, the objective recognition and pathological stratification, the difficulties regarding treatment, and the hardly predictable response to therapy indicate that the management of these entities requires novel tools. In contrast to B-cell lymphomas or precursor T-cell neoplasms, few recurrent translocations have been identified so far in T-cell non-Hodgkin's and NK-cell lymphomas. Additionally, some of the entities recognized by the World Health Organization classification are very rare and very scarce molecular data are available for T-cell lymphomas. Here, we have reviewed published reports focusing on the genetic lesions and gene expression profiling underlying systemic nodal and extranodal non-cutaneous mature T-cell and NK-cell lymphomas. We also provide a summary of new agents in clinical development and outline some future directions.

MicroRNAs in mutagenesis, genomic instability, and DNA repair

MicroRNAs (miRNAs) are aiding our understanding of cancer biology, and are now coming close to therapeutic use as well. Here, we focus specifically on the interaction between miRNAs and genomic instability. MiRNA regulation is essential to many cellular processes, and escape from this regulatory network seems to be a common characteristic of malignant transformation. Genomic instability may preferentially target miRNAs either because of selective pressure or because of inherent vulnerability related to their location near fragile sites. Furthermore, disruption of miRNA processing elements affords a more global release from miRNA regulation. Finally, we review how miRNAs function as both effectors and modulators of the DNA damage response, intricately weaved with traditional elements such as ATM, P53, and MMR. Thus, miRNAs are important substrates for genomic instability and play a crucial role in cellular DNA sensing and repair mechanisms.

T-cell acute lymphoblastic leukemia in association with Börjeson-Forssman-Lehmann syndrome due to a mutation in PHF6

Börjeson-Forssman-Lehmann syndrome (BFLS) is a rare X-linked mental retardation syndrome that is caused by germline mutations in PHF6. We describe a 9-year-old male with BFLS, who developed T-cell acute lymphoblastic leukemia (T-ALL). The PHF6 gene is located on the X chromosome and encodes a protein with two PHD-type zinc finger domains and four nuclear localization sequences. Previously, overexpression of Phf6 was observed in murine T-cell lymphomas. Our observation indicates that BFLS may represent a cancer predisposition syndrome and that mutations of PHF6 contribute to T-ALL.

Negative regulation of tumor suppressor p53 by microRNA miR-504

Tumor suppressor p53 plays a central role in tumor prevention. p53 protein levels and activity are under a tight and complex regulation in cells to maintain the proper function of p53. MicroRNAs play a key role in the regulation of gene expression. Here we report the regulation of p53 through miR-504. miR-504 acts as a negative regulator of human p53 through its direct binding to two sites in the p53 3' untranslated region. Overexpression of miR-504 decreases p53 protein levels and functions in cells, including p53 transcriptional activity, p53-mediated apoptosis, and cell-cycle arrest in response to stress, and furthermore promotes tumorigenecity of cells in vivo. These results demonstrate the direct negative regulation of p53 by miR-504 as a mechanism for p53 regulation in cells, which highlights the importance of microRNAs in tumorigenesis.

High resolution SNP array genomic profiling of peripheral T cell lymphomas, not otherwise specified, identifies a subgroup with chromosomal aberrations affecting the REL locus

Little is known about genomic aberrations in peripheral T cell lymphoma, not otherwise specified (PTCL NOS). We studied 47 PTCL NOS by 250k GeneChip single nucleotide polymorphism arrays and detected genomic imbalances in 22 of the cases. Recurrent gains and losses were identified, including gains of chromosome regions 1q32-43, 2p15-16, 7, 8q24, 11q14-25, 17q11-21 and 21q11-21 (> or = 5 cases each) as well as losses of chromosome regions 1p35-36, 5q33, 6p22, 6q16, 6q21-22, 8p21-23, 9p21, 10p11-12, 10q11-22, 10q25-26, 13q14, 15q24, 16q22, 16q24, 17p11, 17p13 and Xp22 (> or = 4 cases each). Genomic imbalances affected several regions containing members of nuclear factor-kappaB signalling and genes involved in cell cycle control. Gains of 2p15-16 were confirmed in each of three cases analysed by fluorescence in situ hybridization (FISH) and were associated with breakpoints at the REL locus in two of these cases. Three additional cases with gains of the REL locus were detected by FISH among 18 further PTCL NOS. Five of 27 PTCL NOS investigated showed nuclear expression of the REL protein by immunohistochemistry, partly associated with genomic gains of the REL locus. Therefore, in a subgroup of PTCL NOS gains/rearrangements of REL and expression of REL protein may be of pathogenetic relevance.

Array comparative genomic hybridization analysis of PTCL-U reveals a distinct subgroup with genetic alterations similar to lymphoma-type adult T-cell leukemia/lymphoma

PURPOSE

Peripheral T-cell lymphoma, unspecified (PTCL-U) comprises histopathologically and clinically heterogeneous groups. The purpose of this study was to identify subgroups with distinct genetic, histopathologic, and prognostic features.

EXPERIMENTAL DESIGN

We used array comparative genomic hybridization (CGH) for high-resolution analysis of 51 PTCL-U patients and the array data for examining possible correlations of histopathologic and clinical features. Moreover, we compared the genetic, histopathologic, and prognostic features of the PTCL-U cases with those of 59 cases of lymphoma-type adult T-cell leukemia/lymphoma (ATLL).

RESULTS

We identified 32 regions with frequent genomic imbalance, 1 region with high copy number gain at 14q32.2, and 1 region with homozygous loss at 9p21.3. Gains of 7p and 7q and loss of 9p21.3 showed a significant association with poor prognosis. PTCL-U cases with genomic imbalance showed distinct histopathologic and prognostic features compared with such cases without alteration and a marked genetic, histopathologic, and prognostic resemblance to lymphoma-type ATLL.

CONCLUSIONS

The array CGH enabled us to identify the frequently altered genomic regions with strong prognostic power among PTCL-U cases. A correlative analysis using the array CGH data disclosed a subgroup in PTCL-U with genomic alterations and with histopathologic and clinical relevance. In addition to histopathologic similarity, the strong genetic and prognostic resemblance between PTCL-U cases with genomic imbalance detected by array CGH and lymphoma-type ATLL seems to support the notion that the former may constitute a distinct PTCL-U subgroup.

High-resolution analysis of chromosome copy number alterations in angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, unspecified, with single nucleotide polymorphism-typing microarrays

Angioimmunoblastic T-cell lymphoma (AILT) and peripheral T-cell lymphoma, unspecified (PTCL-u) are relatively frequent subtypes of T- or natural killer cell lymphoma. To characterize the structural anomalies of chromosomes associated with these disorders, we here determined chromosome copy number alterations (CNAs) and loss of heterozygosity (LOH) at >55,000 single nucleotide polymorphism loci for clinical specimens of AILT (n=40) or PTCL-u (n=33). Recurrent copy number gain common to both conditions was detected on chromosomes 8, 9 and 19, whereas common LOH was most frequent for a region of chromosome 2. AILT- or PTCL-u-specific CNAs or LOH were also identified at 21 regions, some spanning only a few hundred base pairs. We also identified prognosis-related CNAs or LOH by several approaches, including Cox's proportional hazard analysis. Among the genes that mapped to such loci, a poor prognosis was linked to overexpression of CARMA1 at 7p22 and of MYCBP2 at 13q22, with both genes being localized within regions of frequent copy number gain. For a frequent LOH region at 2q34, we also identified IKAROS family zinc-finger 2 cDNAs encoding truncated proteins. Our data indicate that AILT and PTCL-u consist of heterogeneous subgroups with distinct transforming genetic alterations.

Genomic profiling reveals different genetic aberrations in systemic ALK-positive and ALK-negative anaplastic large cell lymphomas

Anaplastic large cell lymphoma (ALCL) is a T/null-cell neoplasm characterized by chromosomal translocations involving the anaplastic lymphoma kinase (ALK) gene (ALK). Tumours with similar morphology and phenotype but negative for ALK have been also recognized. The secondary chromosomal imbalances of these lymphomas are not well known. We have examined 74 ALCL, 43 ALK-positive and 31 ALK-negative, cases by comparative genomic hybridization (CGH), and locus-specific alterations for TP53 and ATM were examined by fluorescence in situ hybridization and real-time quantitative polymerase chain reaction. Chromosomal imbalances were detected in 25 (58%) ALK-positive and 20 (65%) ALK-negative ALCL. ALK-positive ALCL with NPM-ALK or other ALK variant translocations showed a similar profile of secondary genetic alterations. Gains of 17p and 17q24-qter and losses of 4q13-q21, and 11q14 were associated with ALK-positive cases (P = 0.05), whereas gains of 1q and 6p21 were more frequent in ALK-negative tumours (P = 0.03). Gains of chromosome 7 and 6q and 13q losses were seen in both types of tumours. ALCL-negative tumours had a significantly worse prognosis than ALK-positive. However no specific chromosomal alterations were associated with survival. In conclusion, ALK-positive and negative ALCL have different secondary genomic aberrations, suggesting they correspond to different genetic entities.

Alteration of cyclin D1 in Chinese patients with breast carcinoma and its correlation with Ki-67, pRb, and p53

BACKGROUND

For the female population in Asia, systematic investigation on alterations of cyclin D1 in breast carcinoma is rare, and correlation between cyclin D1 expression with clinicopathological parameters, survival rate, and other prognostic marker associated with cell cycle is unclear.

METHODS

Expression of cyclin D1 protein, Ki-67, pRb, and p53 was determined by immunohistochemistry in 18 cases of early breast carcinomas and 80 cases of invasive ductal carcinomas. Genetic alteration of cyclin D1 gene and overexpression of cyclin D1 mRNA were detected by Southern blot and RT-PCR, respectively.

RESULTS

Expression of cyclin D1 is negative in usual ductal hyperplasia (UDH) and atypical ductal hyperplasia (ADH). However, in 52.0% (51/98) of all breast carcinomas, positive expression of cyclin D1 was observed. Five-year survival rate of the patients with positive expression of cyclin D1 (52.7%) is significantly lower than the cases with negative expression of cyclin D1 (72.1%). Positive rate of cyclin D1 protein in invasive ductal carcinoma (52.5%) is slightly higher than overexpression rate (40.8%) of cyclin D1 mRNA but significantly higher than amplification rate of cyclin D1 gene (18.4%). Expression of cyclin D1 is correlated with Ki-67 expression, but not correlated with pRb and p53 expression.

CONCLUSIONS

Positive expression of cyclin D1 could serve as a poor prognostic marker for Chinese patients with breast carcinoma independent of nodal metastasis and clinical stage. Expression of cyclin D1 protein is affected more directly by overexpression of cyclin D1 mRNA rather than cyclin D1 gene amplification. The cooperation between pRb and p53 with cyclin D1 protein in the carcinogenesis of breast carcinoma is not supported by the results.

Identification of a Proliferation Signature Related to Survival in Nodal Peripheral T-Cell Lymphomas

Purpose

Nodal peripheral T-cell lymphomas (PTCLs) constitute a heterogeneous group of neoplasms, suggesting the existence of molecular differences contributing to their histologic and clinical variability. Initial expression profiling studies of T-cell lymphomas have been inconclusive in yielding clinically relevant insights. We applied DNA microarrays to gain insight into the molecular signatures associated with prognosis.

Materials and Methods

We analyzed the expression profiles of 35 nodal PTCLs (23 PTCLs unspecified and 12 angioimmunoblastic) using two different microarray platforms, the cDNA microarray developed at the Spanish National Cancer Centre and an oligonucleotide microarray.

Results

We identified five clusters of genes, the expression of which varied significantly among the samples. Genes in these clusters seemed to be functionally related to different cellular processes such as proliferation, inflammatory response, and T-cell or B-cell lineages. Regardless of the microarray platform used, overexpression of genes in the proliferation signature was associated significantly with shorter survival of patients. This proliferation signature included genes commonly associated with the cell cycle, such as CCNA, CCNB, TOP2A, and PCNA. Moreover the PTCL proliferation signature showed a statistically significant inverse correlation with clusters of the inflammatory response (P < .0001), as well as with the percentage of CD68+ cells.

Conclusion

Our findings indicate that proliferation could be an important factor in evaluating nodal PTCL outcome and may help to define a more aggressive phenotype.

Extra copies of chromosomes 16 and X in invasive breast carcinomas are related to aggressive phenotype and poor prognosis

BACKGROUND

Breast cancer is a genetically complex disease, which involves the accumulation of various structural and numerical chromosomal aberrations.

AIM

To assess the numerical status of chromosomes 16 and X by interphase cytogenetics, in 114 women with primary invasive breast carcinomas, in relation to clinicopathological parameters, patients' overall survival and indices of cell growth (c-erbB-2, topoisomerase IIalpha (topoIIalpha)) and cell survival (caspase-3, bcl-2).

EXPERIMENTAL DESIGN

Chromogenic in situ hybridisation with pericentromeric probes was performed for molecular analysis, while oestrogen and progesterone receptors, cerbB-2, topoIIalpha, caspase-3 and bcl-2 expression was immunohistochemically detected (ABC/HRP). The results were statistically assessed by univariate and multivariate analyses.

RESULTS

Polysomy of chromosomes 16 and X was detected as the predominant aberration (73.7% and 57.9%, respectively). Gain of chromosome 16 copies was associated with high nuclear grade (p = 0.009), increased tumour size (p = 0.041), advanced stage (p = 0.002), the expression of topoIIalpha (p = 0.005) and worse overall survival by multivariate analysis (p = 0.032). Chromosome X polysomy was increased in ductal carcinomas of high histological grade (p = 0.008), in high nuclear grade tumours (p = 0.001), and was associated with the expression of topoIIalpha (p = 0.005), loss of caspase-3 (p = 0.036) and impaired prognosis of ductal carcinomas (p = 0.041).

CONCLUSIONS

Polysomy of chromosomes 16 and X was reported as the predominant alteration in phenotypically aggressive breast tumours, characterised by poor differentiation, increased growth potential and impaired prognosis, whereas gain of chromosome X in particular is probably implicated in cell survival.

Detection of NOTCH1 mutations in adult T-cell leukemia/lymphoma and peripheral T-cell lymphoma

We analyzed NOTCH1 gene mutation in 53 adults with mature T-cell leukemia/lymphoma: 21 patients with adult T-cell leukemia (ATL), 25 with T-cell non-Hodgkin's lymphoma (T-NHL), and 7 with T-cell prolymphocytic leukemia. We detected a nonsense mutation, C7249T (resulting in Q2417X, where X is a termination codon) in the PEST domain of NOTCH1 in an ATL patient and detected a 3-bp deletion (positions 7234-7236) that resulted in deletion of a proline codon at codon 2412 in the PEST domain of NOTCH1 in a patient with a T-NHL, peripheral T-cell lymphoma-unspecified (PTCL-u). We also analyzed the expression of NOTCH1 target genes (HES1, CCND1, and MYC), all of which were expressed in the sample of the PTCL-u patient with the NOTCH1 mutation, but found only MYC to be expressed in the sample from the ATL patient. These findings suggest that nonsense mutation in the PEST domain in the ATL case was associated with NOTCH1 signaling through a pathway different from that for T-cell acute lymphoblastic leukemia (T-ALL). Although NOTCH1 mutation occurs infrequently in mature T-cell leukemia/lymphoma, NOTCH1 may be involved in leukemogenesis associated with various forms of T-cell leukemia/lymphoma rather than only with T-ALL.

Novel t(5;9)(q33;q22) fuses ITK to SYK in unspecified peripheral T-cell lymphoma

Among peripheral T-cell lymphomas (PTCL), the heterogeneous category of unspecified PTCL represents the most common subtype. Nevertheless, recurrent chromosomal translocations are unknown in this aggressive type of lymphoma. Here we describe a novel t(5;9)(q33;q22) in unspecified PTCL. Molecular analyses delineated the breakpoints to ITK and SYK resulting in a previously undescribed expression of the Syk tyrosine kinase by Itk. ITK-SYK transcripts were detected in five of 30 (17%) unspecified PTCL, but not in cases of angioimmunoblastic T-cell lymphoma (n=9) and anaplastic lymphoma kinase-negative anaplastic large-cell lymphoma (n=7). In all five translocation-positive cases, the breakpoints were identical fusing the N-terminal pleckstrin homology domain and proline-rich region of ITK to the tyrosine kinase domain of SYK. Three of the five t(5;9)(q33;q22)+ unspecified PTCL shared a very similar histological pattern with predominant involvement of lymphoid follicles and the same CD3+CD5+CD4+bcl-6+CD10+ immunophenotype. These results demonstrate the presence of a recurrent t(5;9)(q33;q22) in a subset of unspecified PTCL, which may represent a novel distinct subgroup of PTCL.

Chromosomal aberrations in angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma unspecified: A matrix-based CGH approach

Angioimmunoblastic T-cell lymphoma (AILT) is a histopathologically well-defined entity. However, despite a number of cytogenetic studies, the genetic basis of this lymphoma entity is not clear. Moreover, there is an overlap to some cases of peripheral T-cell lymphoma unspecified (PTCL-u) in respect to morphological and genetic features. We used array-based comparative genomic hybridization (CGH) to study genetic imbalances in 39 AILT and 20 PTCL-u. Array-based CGH revealed complex genetic imbalances in both AILT and PTCL-u. Chromosomal imbalances were more frequent in PTCL-u than in AILT and gains exceeded the losses. The most recurrent changes in AILT were gains of 22q, 19, and 11p11-q14 (11q13) and losses of 13q. The most frequent changes in PTCL-u were gains of 17 (17q11-q25), 8 (involving the MYC locus at 8q24), and 22q and losses of 13q and 9 (9p21-q33). Interestingly, gains of 4q (4q28-q31 and 4q34-qtel), 8q24, and 17 were significantly more frequent in PTCL-u than in AILT. The regions 6q (6q16-q22) and 11p11 were predominantly lost in PTCL-u. Moreover, we could identify a recurrent gain of 11q13 in both AILT and PTCL-u, which has previously not been described in AILT. Trisomies 3 and 5, which have been described as typical aberrations in AILT, were identified only in a small number of cases. In conclusion, CGH revealed common genetic events in peripheral T-cell lymphomas as well as peculiar differences between AILT and PTCL-u.

Comparative genomic hybridization analysis of thymic neuroendocrine tumors

Thymic neuroendocrine (carcinoid) tumors are a rare neoplasm of the anterior mediastinum. The tumors frequently exhibit a wide spectrum of histology and appear to follow a more aggressive behavior than their nonthymic counterparts. Given the differing clinicopathologic manifestations, thymic neuroendocrine tumors may also possess different cytogenetic abnormalities from those that occur in foregut carcinoid tumors. In this study, we employed comparative genomic hybridization to detect genomic instability in 10 sporadic thymic neuroendocrine tumors and one multiple endocrine neoplasia type 1 (MEN1)-associated case. Gross chromosomal imbalances were found in nine cases, including gains of chromosomal material on regions X, 8, 18 and 20p and losses on 3, 6, 9q, 13q and 11q. We did not observe deletion at locus 11q13 where the MEN1 gene is located. These findings were essentially dissimilar to those reported in sporadic and MEN1-associated foregut carcinoid tumors. Consequently, we consider that a distinctive cytogenetic mechanism is at work in the development of thymic neuroendocrine tumors, which is different from that of foregut carcinoid tumors.

Identification of amplified and highly expressed genes in amplicons of the T-cell line huT78 detected by cDNA microarray CGH

Background

Conventional Comparative Genomic Hybridization (CGH) has been widely used for detecting copy number alterations in cancer and for identifying regions containing candidate tumor responsible genes. Recently, several studies have shown the utility of cDNA microarray CGH for studing gene copy changes in various types of tumors. However, no such studies on T-cell lymphomas have been performed. To date T-cell lymphomas analyzed by the use of chromosome CGH have revealed only slight copy number alterations and not gene amplifications.

Results

In the present study, we describe the characterization of three amplicons of the T-cell line huT78 located at 2q34-q37, 8q23-q24 and 20p, where new amplified and overexpressed genes are found. The use of a cDNA microarray containing 7.657 transcripts allowed the identification of certain genes, such as BCLX, PCNA, FKBP1A, IGFBP2 and cMYC, that are amplified, highly expressed, and also contained in the amplicons on 20p and 2q. The expresion of these genes was analyzed in 39 T-cell lymphomas and 3 other T-cell lines.

Conclusion

By the use of conventional CGH and CGH and expression cDNA microarrays we defined three amplicons in the T-cell line huT78 and identified several novel gene amplifications (BCLX, PCNA, FKBP1A, IGFBP2 and cMYC). We showed that overexpression of the amplified genes could be attributable to gene dosage. We speculate that deregulation of those genes could be important in the development of T-cell lymphomas and/or in the maintenance of T-cell lines.

Gene expression analysis of chromosomal regions with gain or loss of genetic material detected by comparative genomic hybridization

Comparative genomic hybridization (CGH) has been widely used to detect copy number alterations in cancer and to identify regions containing candidate tumor-responsible genes; however, gene expression changes have been described only in highly amplified regions (amplicons). To study the overall impact of slight copy number changes on gene expression, we analyzed 16 T-cell lymphomas by using CGH and a custom-designed cDNA microarray containing 7,657 genes and expressed sequence tags related to tumorigenesis. We evaluated mean gene expression and variability within CGH-altered regions and explored the relationship between the effects of the gene and its position within these regions. Minimally overlapping CGH candidate areas (6q25, 13q21-q22, and 19q13.1) revealed a weak relationship between altered genomic content and gene expression. However, some candidate genes showed modified expression within these regions in the majority of tumors; these candidate genes were evaluated and confirmed in another independent series of 23 T-cell lymphomas by use of the same cDNA microarray and by FISH on a tissue microarray. When all the CGH regions detected for each tumor were considered, we found a significant increase or decrease in the mean expression of the genes contained in gained or lost regions, respectively. In addition, we found that the expression of a gene was dependent not only on its position within an altered region but also on its own mechanism of regulation: genes in the same altered region responded very differently to the gain or loss of genetic material. Supplementary material for this article can be found on the Genes, Chromosomes, and Cancer website at http://www.interscience.wiley.com/jpages/1045-2257/suppmat/index.html.

Alteration of cyclin D1 in gastric carcinoma and its clinicopathologic significance

AIM: To detect the genetic alteration and abnormal expression of cyclin D1 in gastric carcinoma and investigate its clinicopathologic significance in advanced gastric carcinoma.

METHODS: Proteins of cyclin D1 were detected by immunohistochemistry in 42 cases of advanced gastric carcinoma with their follow-up data available, 27 cases of early stage carcinoma, 21 cases of gastric adenoma, 22 cases of hyperplastic polyp and 20 cases of normal mucosa adjacent to adenocarcinomas. Genetic alteration of cyclin D1 was detected by Southern blot and expression of cyclin D1 mRNA was detected by PT-PCR in 42 cases of advanced gastric carcinoma.

RESULTS: Cyclin D1 protein was not expressed in normal mucosa, hyperplastic polyp and gastric adenoma, while it was only positively expressed in gastric carcinoma. The expression rate of cyclin D1 protein in early stage gastric carcinoma, advanced gastric carcinoma and lymph node metastasis was 48.1%, 47.4% and 50.0%, respectively. The amplification of cyclin D1 gene was detected in 16.6% of advanced gastric carcinomas. The overexpression of cyclin D1 mRNA was detected in 40.5% of the samples. There was no significant correlation between cyclin D1 protein expression and age, lymph-node metastasis and histological grading in patients with advanced gastric carcinoma (χ² = 0.038,0.059,0.241, P > 0.05). Significant correlation was observed between the expression of cyclin D1 protein and the 5-year survival rate (χ² = 3.92, P < 0.05).

CONCLUSION: Detection of cyclin D1 protein by immunohistochemistry may be useful in the diagnosis of early gastric carcinomas. Patients with positive expression of cyclin D1 protein tend to have a worse prognosis.

Genomic profiling of peripheral T-cell lymphoma, unspecified, and anaplastic large T-cell lymphoma delineates novel recurrent chromosomal alterations

To characterize genetic alterations in peripheral T-cell lymphoma, not otherwise specified (PTCL NOS), and anaplastic large T-cell lymphoma (ALCL), 42 PTCL NOS and 37 ALCL [17 anaplastic large cell kinase (ALK)-negative ALCL, 9 ALK-positive ALCL, 11 cutaneous ALCL] were analyzed by comparative genomic hybridization. Among 36 de novo PTCL NOS, recurrent chromosomal losses were found on chromosomes 13q (minimally overlapping region 13q21, 36% of cases), 6q and 9p (6q21 and 9p21-pter, in 31% of cases each), 10q and 12q (10q23-24 and 12q21-q22, in 28% of cases each), and 5q (5q21, 25% of cases). Recurrent gains were found on chromosome 7q22-qter (31% of cases). In 11 PTCL NOS, high-level amplifications were observed, among them 3 cases with amplification of 12p13 that was restricted to cytotoxic PTCL NOS. Whereas cutaneous ALCL and ALK-positive ALCL showed few recurrent chromosomal imbalances, ALK-negative ALCL displayed recurrent chromosomal gains of 1q (1q41-qter, 46%), and losses of 6q (6q21, 31%) and 13q (13q21-q22, 23%). Losses of chromosomes 5q, 10q, and 12q characterized a group of noncytotoxic nodal CD5+ peripheral T-cell lymphomas. The genetics of PTCL NOS and ALK-negative ALCL differ from other T-NHLs characterized genetically so far, among them enteropathy-type T-cell lymphoma, T-cell prolymphocytic leukemia, and adult T-cell lymphoma/leukemia.

Identification of recurrent regions of chromosome loss and gain in vestibular schwannomas using comparative genomic hybridisation

BACKGROUND

Schwannomas are benign tumours of the nervous system that are usually sporadic but also occur in the inherited disorder neurofibromatosis type 2 (NF2). The NF2 gene is a tumour suppressor on chromosome 22. Loss of expression of the NF2 protein product, merlin, is universal in both sporadic and NF2 related schwannomas. The GTPase signalling molecules RhoA and Rac1 regulate merlin function, but to date only mutation in the NF2 gene has been identified as a causal event in schwannoma formation.

METHODS

Comparative genomic hybridisation (CGH) was used to screen 76 vestibular schwannomas from 76 patients (66 sporadic and 10 NF2 related) to identify other chromosome regions that may harbour genes involved in the tumorigenesis.

RESULTS

The most common change was loss on chromosome 22, which was more frequent in sporadic than in NF2 related tumours. Importantly, eight tumours (10%) showed gain of copy number on chromosome 9q34. Each of the two NF2 patients who had received stereotactic radiotherapy had non-chromosome 22 changes, whereas only one of eight non-irradiated NF2 patients had any chromosome changes. Three tumours had gain on 17q, which has also been reported in malignant peripheral nerve sheath tumours that are associated with neurofibromatosis type 1. Other sites that were identified in three or fewer tumours were regions on chromosomes 10, 11, 13, 16, 19, 20, X, and Y.

CONCLUSIONS

These findings should be verified using techniques that can detect smaller genetic changes, such as microarray-CGH.

High frequency of genetic aberrations in enteropathy-type T-cell lymphoma

To define genetic aberrations playing a role in the development of enteropathy-type T-cell lymphoma (ETL), we examined 26 such tumors using a battery of 47 microsatellite markers. The most frequent aberration (seen in 40% of informative genotypes) was amplification of genomic material in region 9q34 encompassing c-abl and Notch-1 gene loci. Other frequent amplifications were detected in regions 5q33.3-34 and 7q31 (both in more than 30%). Multiple losses of heterozygosity were detected in 6p24, 7p21, 17q23-25, regions containing putative tumor suppressor genes, and in the p53 locus in 17p13.1. Analysis of the pattern of occurrence of these aberrations revealed existence of two ETL subgroups: one of them characterized by the 9q34 aberration and another smaller one showing allelic imbalances in 3q27. These two aberrations were mutually exclusive. Microsatellite instability (MSI) was detected in 69% of the examined lymphomas; the percentage of MSI-positive genotypes per tumor ranged from 2% to 12%. The spectrum of genetic alterations detected showed patterns dependent on morphology. Monomorpic ETLs displayed frequently biallelic TCR-gamma gene rearrangement (p = 0078, chi(2) test). They showed a different pattern and fewer allelic imbalances (no 3q27, 4q28, 13q14, fewer 5q21, or 5q33.3-34 aberrations) and a lower frequency of MSI than pleomorphic ETLs.

Recurrent partial trisomy 1q22-q44 in clonal intraepithelial lymphocytes in refractory celiac sprue

BACKGROUND & AIMS

Refractory celiac sprue, a low-grade intraepithelial lymphoma characterized by expansion of clonal intraepithelial lymphocytes with intracellular CD3 epsilon but no surface CD3-T-cell receptor complexes, can be an intermediary step between celiac disease and overt T-cell lymphoma. To gain insight into the mechanisms of lymphomagenesis in celiac disease, we have performed the first cytogenetic study in refractory celiac sprue.

METHODS

Karyotypes were performed on: (1) 7 cell lines derived from clonal intraepithelial lymphocytes of patients with refractory celiac sprue; (2) 14 control T-cell lines, either from 4 of 7 patients with refractory celiac sprue or from 10 patients with uncomplicated celiac disease; and (3) bone marrow and peripheral blood lymphocytes in 1 of 7 patients with refractory celiac sprue. Rearrangements were confirmed by in situ hybridization using whole-chromosome painting probes and by comparative genomic hybridization in one patient.

RESULTS

A recurrent structural chromosomal aberration leading to partial trisomy of the long arm of chromosome 1 was found in 6 of 7 cell lines from patients with refractory celiac sprue but in none of the control T-cell lines. In one patient with circulating abnormal intraepithelial lymphocytes, the partial trisomy 1q was confirmed on cells freshly isolated from bone marrow and blood.

CONCLUSIONS

Refractory celiac sprue is strongly associated with partial trisomy of the 1q region. Gain of chromosome 1q, recently found in 16% of enteropathy-type T-cell lymphoma, may be an early event in lymphomagenesis related to celiac disease and provides a key to investigating molecular mechanisms of lymphoid transformation in this disease.

Chromosomal gains at 9q characterize enteropathy-type T-cell lymphoma

Genetic alterations in enteropathy-type T-cell lymphoma (ETL) are unknown so far. In this series, 38 cases of ETL were analyzed by comparative genomic hybridization (CGH). CGH revealed chromosomal imbalances in 87% of cases analyzed, with recurrent gains of genetic material involving chromosomes 9q (in 58% of cases), 7q (24%), 5q (18%), and 1q (16%). Recurrent losses of genetic material occurred on chromosomes 8p and 13q (24% each), and 9p (18%). In this first systematic genetic study on ETL, chromosomal gains on 9q (minimal overlapping region 9q33-q34) were found to be highly characteristic of ETL. Fluorescence in situ hybridization analysis on four cases of ETL, using a probe for 9q34, indicated frequent and multiple gains of chromosomal material at 9q34 (up to nine signals per case). Among 16 patients with ETL who survived initial disease presentation, patients with more than three chromosomal gains or losses (n = 11) followed a worse clinical course than those with three or less imbalances (n = 5). The observation of similar genetic alterations in ETL and in primary gastric (n = 4) and colonic (n = 1) T-cell lymphoma, not otherwise specified, is suggestive of a genetic relationship of gastrointestinal T-cell lymphomas at either localization.