Gary Lu

Molecular characterization of de novo Philadelphia chromosome-positive acute myeloid leukemia

Philadelphia chromosome-positive (Ph+) AML is a controversial diagnosis, as others propose it represents CML in blast phase (CML-BP). NPM1 mutations occur in 25-35% of AML but are absent in CML patients. Conversely, ABL1 mutations occur in 25% of Imatinib-naive CML-BP but are not described in AML patients. We analyzed for NPM1 and ABL1 mutations in 9 Ph+ AML and 5 CML-BP patients initially presented in BP. In 6 Ph+ AML cases, we screened for a panel of gene mutations using Sequenome®-based methods including AKT1, AKT2, AKT3, BRAF, EGFR, GNAQ, GNAS, IDH1, IDH2, KRAS, MET, NRAS, PIK3CA, and RET. Two of 9 (22%) Ph+ AML patients had NPM1 mutations and were alive 36 and 71 months after diagnosis. All Ph+ AML were negative for ABL1 and other gene mutations. One (20%) CML-BP patients had ABL1 mutation; no patients had NPM1 mutations. These data suggest that Ph+ AML is distinct from CML-BP.Philadelphia chromosome-positive (Ph+) acute myeloid leukemia (AML) is a controversial diagnosis, as others propose that it represents chronic myelogenous leukemia in blast phase (CML-BP). NPM1 mutations occur in 25–35% of patients with AML but are absent in patients with CML. Conversely, ABL1 mutations occur in 25% of imatinib-naive patients with CML-BP but are not described in patients with AML. We analyzed for NPM1 and ABL1 mutations in nine Ph+ patients with AML and five patients with CML-BP initially presenting in BP. In six cases of Ph+ AML, we screened for a panel of gene mutations using Sequenome®-based methods including AKT1, AKT2, AKT3, BRAF, EGFR, GNAQ, GNAS, IDH1, IDH2, KRAS, MET, NRAS, PIK3CA and RET. Two of nine (22%) patients with Ph+ AML had NPM1 mutations and were alive 36 and 71 months after diagnosis. All cases of Ph+ AML were negative for ABL1 and other gene mutations. One (20%) patient with CML-BP had ABL1 mutation; no patients had NPM1 mutations. These data suggest that Ph+ AML is distinct from CML-BP.

Myeloid neoplasms with isolated isochromosome 17q represent a clinicopathologic entity associated with myelodysplastic/myeloproliferative features, a high risk of leukemic transformation, and wild-type TP53.

Isolated isochromosome (17q) is a rare cytogenetic abnormality in Philadelphia chromosome‐negative myeloid neoplasms, usually myelodysplastic and/or myeloproliferative neoplasms (MDS/MPN). De novo acute myeloid leukemia (AML) with isochromosome 17q has rarely been reported. The frequency of genetic mutations is unknown.

Advances in the molecular pathobiology of B-lymphoblastic leukemia

B-lymphoblastic leukemia/lymphoma, also known as B-acute lymphoblastic leukemia, is derived from B-cell progenitors. B-acute lymphoblastic leukemia occurs predominantly in children, but can occur at any age. Risk-adapted intensive chemotherapy is effective in treating most children with B-acute lymphoblastic leukemia, but this approach is less successful in adults. Recent developments in genome-wide genetic analysis in B-acute lymphoblastic leukemia have provided insights into disease pathogenesis and prognosis. B-acute lymphoblastic leukemia cases usually carry a primary genetic event, often a chromosome translocation, and a constellation of secondary genetic alterations that are acquired and selected dynamically in a nonlinear fashion. These genetic changes commonly affect cellular mechanisms that control B-cell differentiation and proliferation. The cooperative interaction between inactivation of hematopoietic transcription factors involved in differentiation (class II mutation) and activating mutations involved in cell proliferation (class I mutation) is reminiscent of the pathogenic model of acute myeloid leukemia. The resulting improved molecular understanding of B-acute lymphoblastic leukemia is helping to refine disease risk stratification and discover new therapeutic approaches for patients with refractory disease. In this review, we first summarize the clinicopathologic and immunophenotypic features of B-acute lymphoblastic leukemia and introduce current understanding of B-cell development and B-acute lymphoblastic leukemia leukemogenesis. We then focus on recent advances in genetic analysis and gene expression profiling of B-acute lymphoblastic leukemia and discuss the implications of these findings for disease evolution, risk prediction, and possible novel therapeutic approaches.

Genetic and immunophenotypic profile of IGH@ rearrangement detected by fluorescence in situ hybridization in 149 cases of B-cell chronic lymphocytic leukemia

Recent studies have shown a higher frequency of immunoglobulin heavy (IGH@) locus rearrangement in B-cell chronic lymphocytic leukemia (B-CLL) than previously reported. However, association of the IGH@ rearrangement with specific chromosomal abnormalities and immunophenotypic markers in B-CLL is still under further investigation. In this study, we analyzed 149 bone marrow aspirate or peripheral blood specimens from patients diagnosed with B-CLL, evaluated by four different laboratory studies: morphology examination, three- or four-color flow cytometry analysis, conventional cytogenetics, and fluorescence in situ hybridization (FISH) with a dual-color, break-apart IGH@ probe in addition to a B-CLL FISH probe panel for del(11)(q22) ATM, del(13)(q14.3), del(17)(p13) TP53, and +12. An IGH@ rearrangement was found by FISH in 24 cases (16.0%). Of these 24 cases, 16 (67%) contained chromosomal abnormalities, including t(14;19)(q32;q13.2), t(8;14)(q24;q32), and t(14;18)(q32;q21). In addition, a cryptic deletion of the immunoglobulin heavy variable region (IGHV) was revealed. Using 30% as the cutoff for positive CD38 expression, 22 of the 24 cases (92%) were positive for CD38. The present results further confirm that IGH@ rearrangement is not a rare genomic abnormality in B-CLL, and also show both that t(14;19)(q32;q13.2) is the most common cytogenetic change involving IGH@ rearrangement detected by FISH in B-CLL and that IGH@ rearrangement is correlated with CD38 expression. It is appropriate to include an IGH@ probe in the FISH panel for B-CLL diagnosis.

High‐grade B cell lymphoma, unclassifiable, with blastoid features: an unusual morphological subgroup associated frequently with BCL2 and/or MYC gene rearrangements and a poor prognosis

Kanagal‐Shamanna R, Medeiros L J, Lu G, Wang S A, Manning J T, Lin P, Penn G M, Young K H, You M J, Vega F, Bassett R & Miranda R N 
(2012) Histopathology 61, 945–954

Chromosome 20q deletion: A recurrent cytogenetic abnormality in patients with chronic myelogenous leukemia in remission

del(20q) can be observed in hematologic neoplasms, including chronic myelogenous leukemia (CML), and has been reported in patients undergoing blast transformation. We describe 10 patients with CML in hematologic and cytogenetic remission with del(20q) detected by conventional cytogenetics. There were 6 men and 4 women with a median age of 56 years. All patients initially had BCR-ABL1 and t(9;22) (q34;q11.2) and achieved morphologic and cytogenetic remission after therapy. del(20q) was identified before (2/10 [20%]), at the time of (3/10 [30%]), or after (5/10 [50%]) cytogenetic remission and was not associated with morphologic evidence of dysplasia. At last follow-up, no patients had a myelodysplastic syndrome (MDS). Leukocyte and platelet counts were normal; 4 of 10 patients had mild anemia. Nine patients have remained in morphologic and cytogenetic remission with stable del(20q). BCR-ABL1 fusion transcript levels were absent or low (median, 0.01%). Recently, in 1 patient, recurrent CML developed and del(20q) was lost. We conclude that del(20q) in the setting of CML in remission is not predictive of MDS or blast transformation.

High-grade B cell lymphoma, unclassifiable, with blastoid features

Kanagal‐Shamanna R, Medeiros L J, Lu G, Wang S A, Manning J T, Lin P, Penn G M, Young K H, You M J, Vega F, Bassett R & Miranda R N 
(2012) Histopathology 61, 945–954

Evidence of a role for the novel zinc-finger transcription factor ZKSCAN3 in modulating Cyclin D2 expression in multiple myeloma

Dysregulation of cyclin D2 contributes to the pathogenesis of multiple myeloma, and can occur through translocations that activate MAF/MAFB or MMSET/FGFR3. However, cyclin D2 induction can also be seen in the absence of such translocations, such as in patients with hyperdiploid disease, through unknown mechanisms. In UniGene cluster data-mining and ECgene analysis, we found that zinc-finger with KRAB and SCAN domains 3 (ZKSCAN3), a novel transcription factor, is overrepresented in this malignancy, and three consensus ZKSCAN3 binding sites were found in the cyclin D2 promoter. Analysis of a panel of myeloma cell lines, primary patient samples and datasets from Oncomine and the Multiple Myeloma Genomics Portal (MMGP) revealed expression of ZKSCAN3 messenger RNA (mRNA) in a majority of samples. Studies of cell lines by western blotting, and of primary tissue microarrays by immunohistochemistry, showed ZKSCAN3 protein expression in a majority, and in a manner that paralleled messenger levels in cell lines. ZKSCAN3 overexpression was associated with increased gene copy number or genomic DNA gain/amplification in a subset based on analysis of data from the MMGP, and from fluorescence in situ hybridization studies of cell lines and primary samples. Overexpression of ZKSCAN3 induced cyclin D2 promoter activity in a MAF/MAFB-independent manner, and to an extent that was influenced by the number of consensus ZKSCAN3 binding sites. Moreover, ZKSCAN3 protein expression correlated with cyclin D2 levels in cell lines and primary samples, and its overexpression induced cyclin D2. Conversely, ZKSCAN3 suppression using small hairpin RNAs (shRNAs) reduced cyclin D2 levels, and, importantly, inhibited myeloma cell line proliferation. Finally, ZKSCAN3 was noted to specifically bind to oligonucleotides representing sequences from the cyclin D2 promoter, and to the endogenous promoter itself in myeloma cells. Taken together, the data support the conclusion that ZKSCAN3 induction represents a mechanism by which myeloma cells can induce cyclin D2 dysregulation, and contribute to disease pathogenesis.

Chromosome 8q24.1/c-MYC abnormality: a marker for high-risk myeloma

Abstract The proto-oncogene c-MYC is rearranged in about 15% of patients with multiple myeloma (MM). We identified 23 patients with MM and c-MYC. Primary objectives were to describe the clinical characteristics, response to therapy, progression-free survival and overall survival (OS). Twelve out of twenty-three patients presented with or progressed to either plasma cell leukemia (PCL) and/or extramedullary disease (EMD). Induction therapy consisted of an immunomodulatory, proteasome inhibitor-based or conventional chemotherapy regimen. Fifteen patients achieved a partial response and three achieved a very good partial response. Sixteen patients received an autologous and one patient an allogeneic hematopoietic stem cell transplant. Median OS from diagnosis was 20.2 months. Patients with PCL or EMD had significantly shorter OS (15.5 vs. 40.4 months, p = 0.0005). This is the first report describing the clinical characteristics of patients with MM and c-MYC. These abnormalities are associated with an aggressive form of MM, high incidence of PCL/EMD and short OS.

Plasmablastic lymphoma involving the penis: a previously unreported location of a case with aberrant CD3 expression

Lymphomas of the penis are rare and can either arise at this site or be a manifestation of systemic disease. We report the case of an elderly man with a plasmablastic lymphoma (PBL) involving the uncircumcised penile prepuce. The neoplasm was composed of plasmablasts positive for monotypic immunoglobulin lambda light chain, CD3, CD79a, CD138 and Epstein-Barr virus encoded RNA (EBER), and was negative for CD2, CD5, CD7, CD20, and PAX5. This case is highly unusual for at least two reasons. The penile foreskin is a rare location for lymphoma and PBL at this site has not been reported. Secondly, the tumour was shown by immunohistochemistry to be positive for the T-cell marker CD3. Lineage ambiguity in terminally differentiated B-cell lymphomas has been reported to be closely related with immune compromise and is associated with Epstein-Barr virus infection. The literature on penile lymphomas is also reviewed.