Geneviève Ameye

IL-TIF/IL-22: genomic organization and mapping of the human and mouse genes.

IL-TIF is a new cytokine originally identified as a gene induced by IL-9 in murine T lymphocytes, and showing 22% amino acid identity with IL-10. Here, we report the sequence and organization of the mouse and human IL-TIF genes, which both consist of 6 exons spreading over approximately 6 Kb. The IL-TIF gene is a single copy gene in humans, and is located on chromosome 12q15, at 90 Kb from the IFNγ gene, and at 27 Kb from the AK155 gene, which codes for another IL-10-related cytokine. In the mouse, the IL-TIF gene is located on chromosome 10, also in the same region as the IFNγ gene. Although it is a single copy gene in BALB/c and DBA/2 mice, the IL-TIF gene is duplicated in other strains such as C57Bl/6, FVB and 129. The two copies, which show 98% nucleotide identity in the coding region, were named IL-TIFα and IL-TIFβ. Beside single nucleotide variations, they differ by a 658 nucleotide deletion in IL-TIFβ, including the first non-coding exon and 603 nucleotides from the promoter. A DNA fragment corresponding to this deletion was sufficient to confer IL-9-regulated expression of a luciferase reporter plasmid, suggesting that the IL-TIFβ gene is either differentially regulated, or not expressed at all.

Improved detection of chromosomal abnormalities in chronic lymphocytic leukemia by conventional cytogenetics using CpG oligonucleotide and interleukin-2 stimulation: A Belgian multicentric study.

We performed a multicentric study to assess the impact of two different culture procedures on the detection of chromosomal abnormalities in 217 consecutive unselected cases with chronic lymphocytic leukemia (CLL) referred for routine analysis either at the time of diagnosis (n = 172) or during disease evolution (n = 45). Parallel cultures of peripheral blood or bone marrow were set up with the addition of either the conventional B‐cell mitogen 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) or a combination of CpG oligonucleotide (CpG) and interleukin‐2 (IL‐2). Cytogenetic analyses were performed on both cultures. Clonal abnormalities were identified in 116 cases (53%). In 78 cases (36%), the aberrant clone was detected in both cultures. Among these, the percentages of aberrant metaphases were similar in both conditions in 17 cases, higher in the CpG/IL‐2 culture in 43 cases, and higher in the TPA culture in 18 cases. Clonal aberrations were detected in only one culture, either in CpG/IL‐2 or TPA in 33 (15%) and 5 (2%) cases, respectively. Taken together, abnormal karyotypes were observed in 51% with CpG/IL‐2 and 38% with TPA (P < 0.0001). Application of FISH (n = 201) allowed the detection of abnormalities not visible by conventional cytogenetic analysis in 80 cases: del(13q) (n = 71), del(11q) (n = 5), +12 (n = 2), del(14q) (n = 1), and del(17p) (n = 1). In conclusion, our results confirm that CpG/IL‐2 stimulation increases the detection rate of chromosomal abnormalities in CLL compared with TPA and that further improvement can be obtained by FISH. However, neither conventional cytogenetics nor FISH detected all aberrations, demonstrating the complementary nature of these techniques.

KANK1, a candidate tumor suppressor gene, is fused to PDGFRB in an imatinib-responsive myeloid neoplasm with severe thrombocythemia

KANK1 , a candidate tumor suppressor gene, is fused to PDGFRB in an imatinib-responsive myeloid neoplasm with severe thrombocythemia

The value of interphase fluorescence in situ hybridization for the detection of translocation t(12;21) in childhood acute lymphoblastic leukemia

ETV6/CBFA2 fusion by means of FISH, using two cosmid probes mapped on ETV6 and on CBFA2, respectively. The cut-off value (mean + three standard deviations) for positivity established on control patients was 9.3%. A comparison between FISH and molecular methods [reverse-transcriptase polymerase chain reaction/Southern blot (RT-PCR/SB)] was possible in 52 patients: 34 of 52 (65.4%) showed negative results with both approaches, and 13 of 52 (25%) were positive; 5 of 52 (9.6%) showed discrepancies: four patients who were positive using RT-PCR/SB were negative using FISH. Conversely, one patient negative when using RT-PCR/SB was positive with FISH. Further investigations on this patient, cytogenetically characterized by add(12p), showed an atypical breakpoint on ETV6, located 5′ to the common breakpoint. Compared with RT-PCR and SB, dual-color interphase FISH with the cosmid probe set proved to be highly specific but showed limited sensitivity.

Dicentric (1;15) in myeloid disorders

We report three cases of myeloid disorders with a dic(1;15)(p11;p11), resulting in trisomy of the long arm of chromosome 1. A review of the literature showed six cases, reported as t(1;15). We suggest that these cases have the same anomaly and should be reappraised as dic(1;15).

Chronic Myeloid Leukemia with a Rare Variant Philadelphia Translocation: t(9;22;21)(q34;q11;q22)

A case of chronic myeloid leukemia displaying an uncommon t(21;22)(q22;q11) is reported. For the first time, this translocation has been characterized by fluorescence in situ hybridization (FISH) and the reverse transcriptase polymerase chain reaction (RT-PCR). FISH, with the use of whole-chromosome painting probes and probes specific for the BCR and ABL genes, showed a three-way variant Philadelphia translocation (9;22;21)(q34;q11;q22) with a BCR/ABL fusion residing on the der(22). In addition, RT-PCR demonstrated a b2a3 BCR/ABL fusion transcript. Underlying mechanisms and prognostic implications are discussed.

Neonatal acute myeloid leukemia in an infant whose mother was exposed to diethylstilboestrol in utero.

We report on an acute myeloid leukemia in a neonate whose mother was exposed to diethylstilboestrol in utero. The newborn presented with leukemia cutis, hemorrhagic skin lesions, hyperleucocytosis and disseminated intravascular coagulation. A bone marrow examination confirmed the diagnosis of acute monocytic leukemia with a t(11;19) MLL‐ELL fusion transcript. Chemotherapy was initiated but the child developed a bilateral pulmonary infection that led to fatal respiratory distress. This case shows acute myeloid leukemia and the third pediatric leukemia reported after maternal diethylstilboestrol exposure. Pediatr Blood Cancer 2009;53:220–222.

Trisomy 16 as the sole anomaly in hematological malignancies: three new cases and a short review

We report on three cases, two with myelodysplastic syndrome (MDS) and one with acute lymphoblastic leukemia (ALL), displaying trisomy 16 as the sole cytogenetic anomaly. In none of these cases was a concomitant inv(16)(p13q22) detected by fluorescence in situ hybridization (FISH) or reverse transcription polymerase chain reaction (RT-PCR). Summarizing the literature, only six other cases cytogenetically characterized by an isolated trisomy 16 have been reported in hematological malignancies. These patients had either MDS, acute myeloblastic leukemia (AML), myelofibrosis, or ALL. All but one of these cases were aged less than 50.

The peculiar 11q-gain/loss aberration reported in a subset of MYC-negative high-grade B-cell lymphomas can also occur in a MYC-rearranged lymphoma

Up-regulation of MYC through chromosomal translocation is the genetic hallmark of Burkitt lymphoma/leukemia (BL) but can occur in other aggressive B-cell lymphomas, such as DLBCL and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL (DLBCL/BL) (1). Gene expression profiling identified a molecular signature, which distinguishes BL from DLBCL, but gray-zone lymphomas remain a problem (2,3). MYC dysregulation needs other cooperating events for BL development. Recent studies, which used high-throughput sequencing to decrypt the mutational landscape of BL, identified frequent inactivating mutations of ID3 inducing constitutive activation of TCF3 (4–6). A new subset of MYC-negative, high grade B-cell lymphoma with features of BL was recently identified in immunocompetent patients (7) and in post-transplant immunocompromised patients (8). These lymphomas are characterized by a recurrent chromosome 11q aberration combining 11q23 interstitial gain/amplification with 11q24q25 telomeric loss. Despite the lack of MYC rearrangement, these cases display morphological and immunophenotypic features resembling BL rather than DLBCL. Moreover, they are usually classified as BL or intermediate BL/DLBCL by gene expression profiling. Yet, they differ from BL by a significantly higher chromosomal complexity and by the absence of ID3 mutation. They are associated with an excellent survival rate, which is similar to typical BL (7). Salaverria and co-workers raised the question whether these lymphomas may be considered as genetic variants of BL lacking a MYC translocation. They identified candidate genes potentially deregulated in both gained (PAFAH1B2) and deleted (FLI1, ETS1) 11q regions (7). We analyzed patterns of genetic aberrations by molecular karyotyping (100K-XbaI SNP-array, Affymetrix) and by sequencing hot-spot mutations of ID3, TCF3 and CCND3 in a series of 34 MYC-rearranged aggressive B-cell lymphomas reviewed by two hematopathologists (MR and IT) and classified according to the latest WHO classification (1). We detected 11q23 interstitial gain/amplification and/or 11q24-q25 telomeric loss in 4 male cases: a classical BL (B32 – 5 year-old) and 3 other cases sharing similarities with BL but classified as DLBCL (B16 – 9 year-old) or DLBCL/BL (B33 – 71 year-old and B43 – 43 year-old). B16 had the characteristic 11q-gain/loss aberration. A sole 11q23 amplification was detected in B32 and B33 including the known minimal amplified region. B43 had a sole terminal 11q24-q25 deletion without 11q23 gain, which appears similar to the case 3 described by Salaverria and coworkers (7). Although harboring an incomplete 11q-gain/loss, we chose to group B32, B33 and B43 with the case having the typical pattern because these 4 cases shared several similarities. First, they all had complex genomic anomalies. Second, despite complex karyotypes, known to be associated with a worse prognosis in BL (9–11), the 3 patients with available clinical data were alive at the last follow-up (B16: 3.5 yr; B32: 9 yr; B43: 8 yr). Third, the most frequent additional aberrations to 11q gain and/or loss were 6q24 deletions and 18q21 changes (in 3 and 2 cases, respectively), but no ID3 mutation was identified, similar to Salaverria and co-workers (7). The classical BL displayed a CCND3 mutation. Finally, as previously observed in 5/17 MYC-negative lymphomas (7), we detected the same peculiar pattern of genomic aberration, consisting of alternating gain and loss on several chromosomal arms other than 11q: on chromosomes 13 (B16, B32 & B43), 18q (B16 & B43), 2p (B43), 9p (B43) and 17q (B16). This alternation was repeated along chromosomes 2 and 13 in B43, similar to what was previously seen on chromosomes 2 and 3 in 2 MYC-negative lymphomas (7), suggesting a mechanism of complex and clustered segmental rearrangements reminiscent of chromothripsis (12). The amplified and deleted regions potentially deregulate candidate genes involved in lymphomagenesis, such as overexpressing the oncogenic miR-17-92 cluster at 13q31 (13) (demonstrated for B43), the low-fidelity DNA polymerase iota (POLI) at 18q21 (which may shift the balance of DNA repair to more error-prone repairs) (14), the BCL11A and REL oncogenes at 2p14-16 or inactivating the CDKN2A tumor suppressor gene at 9p21. In summary, we provided evidence that this specific 11qgain/loss aberration can occur in a MYC-rearranged aggressive B-cell lymphoma. Moreover, we showed that this peculiar genomic aberration consisting of alternating copy number profiles that are clustered on the same chromosomal arm can simultaneously affect other chromosomes, especially chromosomes 13 and 18. The question raised by these chromosomal aberrations is whether they are oncogenic per se and/or reflect a peculiar mechanism of genomic instability (gain and loss together or separately). Confirmation in the setting of clinical trials of the excellent survival rate despite complex genomic rearrangements will be an additional argument to individualize this subset of aggressive B-cell lymphoma.

Solitary extramedullary plasmocytoma of the thyroid: a case report and histological approach to plasma cells infiltrate in the thyroid gland.

Abstract Background: Solitary extramedullary plasmacytoma (SEP) is a rare malignant neoplasm arising from plasma cells. SEP mostly occurs in the upper respiratory tract. Thyroid gland is rarely affected (<78 cases). Methods/results: We describe the case of a 78-year-old woman presenting a rapidly enlarging palpable thyroid mass. Neck computed tomography scan showed enlargement of both thyroid lobes. Laboratory tests were normal, including serum protein level with no monoclonal gamma globulin peak. Cytology was suspicious for lymphoma. Biopsy showed an infiltrating neoplasm composed of atypical tumor cells with abundant cytoplasm and eccentric nuclei. These revealed diffuse immunoreactivity for CD138 and predominant staining for immunoglobulin kappa light chains. Clinical workup for multiple myeloma was negative. Conclusions: SEP should be considered in the differential diagnosis of a rapidly enlarging thyroid nodule and be distinguished from involvement of thyroid in multiple myeloma, mucosa-associated lymphoid tissue lymphoma, plasma cell granuloma and medullary carcinoma. Clinical correlation and immunohistochemistry are crucial in avoiding pitfalls.