Comprehensive mutational analysis of primary and relapse acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is a subtype of myeloid leukemia characterized by differentiation block at the promyelocyte stage. Besides the presence of chromosomal rearrangement t(15;17), leading to the formation of PML-RARA (promyelocytic leukemia-retinoic acid receptor alpha) fusion, other genetic alterations have also been implicated in APL. Here, we performed comprehensive mutational analysis of primary and relapse APL to identify somatic alterations, which cooperate with PML-RARA in the pathogenesis of APL. We explored the mutational landscape using whole-exome (n=12) and subsequent targeted sequencing of 398 genes in 153 primary and 69 relapse APL. Both primary and relapse APL harbored an average of eight non-silent somatic mutations per exome. We observed recurrent alterations of FLT3, WT1, NRAS and KRAS in the newly diagnosed APL, whereas mutations in other genes commonly mutated in myeloid leukemia were rarely detected. The molecular signature of APL relapse was characterized by emergence of frequent mutations in PML and RARA genes. Our sequencing data also demonstrates incidence of loss-of-function mutations in previously unidentified genes, ARID1B and ARID1A, both of which encode for key components of the SWI/SNF complex. We show that knockdown of ARID1B in APL cell line, NB4, results in large-scale activation of gene expression and reduced in vitro differentiation potential.

NUDT15 gene polymorphism related to mercaptopurine intolerance in Taiwan Chinese children with acute lymphoblastic leukemia.

A recent study identified a variant of the NUDT15 gene (rs116855232 C>T) associated with intolerance to thiopurine in Korean patients with Crohn's disease. This study prompted us to substantiate the finding in a Taiwanese population. Four hundred and four children with acute lymphoblastic leukemia (ALL), and 100 adults with chronic immune thrombocytopenic purpura or localized lymphoma having normal bone marrow were examined. Two candidate gene approaches, pyrosequencing for NUDT15 and TaqMan assay for thiopurine methyltransferase (TPMT) genotyping (rs1142345 A>G), were performed. We showed a risk allele frequency of NUDT15 of 11.6% in children with ALL and 15.5% in adults. By contrast, the risk allele frequency of TPMT was only 1.6% in children with ALL and 0.5% in adults. The high frequency of risk variant for NUDT15, but not the very low frequency of risk variant for TPMT, was closely associated with the intolerance to mercaptopurine in children with ALL in Taiwan, contrast to that of European descent. In regard to NUDT15 polymorphism, the maximal tolerable daily doses of mercaptopurine in homozygotes, heterozygotes and wild-type groups were 9.4 mg m-2, 30.7 mg m-2 and 44.1 mg m-2, respectively. The outcomes did not differ significantly among the different genotypes.

Collision in the colon: concurrent adenocarcinoma and diffuse large B-cell lymphoma in the same tumour.

Double malignancies in the gastrointestinal tract are unusual. Concurrent lymphoma and adenocarcinoma is a rare clinical condition. We herein report a collision tumour which first presented with a diffuse large B-cell lymphoma in the skull base and ileocecal junction area. After rituximab and chemotherapy the skull base tumour disappeared, but the ileocecal lesion remained. A biopsy revealed the presence of adenocarcinoma in the same lesion. The tumour was surgically removed. Further microscopic examination of the tumour showed it was an adenocarcinoma but residual lymphoma cell infiltration could still be observed. Serum Epstein-Barr virus (EBV) was detected at diagnosis of lymphoma and the concentration further elevated at diagnosis of adenocarcinoma. Therefore, both lymphoma and carcinoma may be EBV related. Our experience illustrated that such collision tumours are rare and difficult in diagnosis. Clinicians and pathologists should be aware of such an association in order to make a correct diagnosis and initiate proper treatment.

Concurrence of multiple myeloma and idiopathic erythrocytosis.

The association of erythrocytosis and multiple myeloma is rare. We encountered a 76-year-old male patient with erythrocytosis followed by the diagnosis of multiple myeloma 8 months later. Related laboratory examinations revealed absolute erythrocytosis, normal oxygen saturation and erythropoietin (EPO) levels, the absence of endogenous erythroid colony (EEC) and JAK2-V617F mutations. The diagnosis of idiopathic erythrocytosis (IE), instead of polycythemic vera (PV), was made. In the literature, about 20 cases of erythrocytosis associated with myeloma can be found. Based on elevated EPO levels, 2 of such cases should be considered secondary erythrocytosis while others are reported as PV. None of them is considered to be have idiopathic erythrocytosis. Our present case is the first one with multiple myeloma developing in a patient with the diagnosis well established by extensive laboratory workup. The pathogenic role of these two entities remains to be established.

Effectiveness of national cervical cancer screening programme in Taiwan: 12-year experiences.

BACKGROUND: We examined cervical cancer incidence before and after nationwide cervical cancer screening was initiated in Taiwan in mid-1995. RESULTS: The invasive cancer incidence decreased by 47.8% during 1995-2006. The carcinoma in situ incidence increased 1.7-fold during 1995-2000, and decreased by 19.6% during 2000-2006. CONCLUSION: The Taiwan national programme has significantly decreased invasive cervical cancer.

RUNX1 mutations are frequent in chronic myelomonocytic leukemia and mutations at the C-terminal region might predict acute myeloid leukemia transformation.

Runt-related transcription factor 1 (RUNX1) is essential for normal hematopoiesis. RUNX1 mutations have rarely been reported in chronic myelomonocytic leukemia (CMML). We examined RUNX1 mutations in 81 patients with CMML at initial diagnosis. Mutational analysis was performed on bone marrow samples by direct sequencing of all reverse transcription PCR products amplified with three primer pairs that cover the entire coding sequences of RUNX1b. Thirty-two RUNX1 mutations were detected in 30 patients (37%); 23 mutants were located in the N-terminal part and 9 in the C-terminal region. The mutations consisted of 9 missense, 1 silent, 7 nonsense and 15 frameshift mutations. Two patients had biallelic heterozygous mutations. There was no difference in overall survival between patients with and without RUNX1 mutations, but a trend of higher risk of acute myeloid leukemia (AML) progression was observed in mutation-positive patients (16/30 vs 17/51, P=0.102), especially in patients with C-terminal mutations (P=0.023). The median time to AML progression was 6.8 months in patients with C-terminal mutations compared with 28.3 months in those without mutations (P=0.022). This study showed for the first time a high frequency of RUNX1 mutations in CMML. C-terminal mutations might be associated with a more frequent and rapid AML transformation.

Cooperating mutations of receptor tyrosine kinases and Ras genes in childhood core-binding factor acute myeloid leukemia and a comparative analysis on paired diagnosis and relapse samples.

c-KIT mutations have been described in core-binding factor (CBF) acute myeloid leukemia (AML) at diagnosis. The role of c-KIT mutations in the relapse of CBF-AML is not clear. The role of CSF1R mutation in the pathogenesis of AML remains to be determined. We analyzed receptor tyrosine kinases (RTKs) and Ras mutations on 154 children with AML. Also, we examined the paired diagnosis and relapse samples in CBF-AML. CBF-AML accounted for 27% (41/154). c-KIT mutations were detected in 41.5% of CBF-AML at diagnosis (6 in exon 8, 10 in exon 17 and 1 in both exons 8 and 17) , FLT3-TKD 2.7%, N-Ras mutations 7.3% and K-Ras mutations 4.9%. FLT3-LM and CSF1R mutations were not found in CBF-AML. The mutations of RTKs and Ras were mutually exclusive except for one patient who had both c-KIT and N-Ras mutations. Eight of the 41 CBF-AML patients relapsed; four patients retained the identical c-KIT mutation patterns as those at diagnosis, the remaining four without c-KIT mutations at diagnosis did not acquire c-KIT mutations at relapse. Our study showed that 54% of childhood CBF-AML had RTKs and/or Ras mutations; c-KIT but not CSF1R mutations play a role in the leukemogenesis of childhood CBF-AML.

AML patients with CEBPalpha mutations mostly retain identical mutant patterns but frequently change in allelic distribution at relapse: a comparative analysis on paired diagnosis and relapse samples.

The roles of CEBPalpha mutations and its cooperating mutations in the relapse of acute myeloid leukemia (AML) are not clear. CEBPalpha mutations were analyzed on 149 patients with de novo AML at both diagnosis and relapse. Twenty-two patients (14.8%) had the mutations at diagnosis, two patients had N-terminal nonsense mutations alone, one had homozygous inframe duplication at the bZIP domain, and 19 patients had both N-terminal and bZIP mutations. Twenty patients relapsed with identical mutant patterns, two lost CEBPalpha mutations and none acquired the mutations at relapse. Cloning analysis showed that the N-terminal and C-terminal mutations occurred on separate cloned alleles and also on the same alleles in most of the diagnosis and relapse samples. Losing one of the two or more mutations on the same allele or acquiring the other mutation on the allele original carrying single mutation were observed not infrequently in the paired samples analyzed. Seven patients with CEBPalpha mutations had cooperating mutations with FLT3/ITD, FLT3/TKD or N-ras but not K-ras mutations. Our study showed that 91% of de novo AML harboring CEBPalpha mutations at diagnosis retained the identical mutant patterns but frequently changed in the allelic distribution at relapse.

Characterization of fusion partner genes in 114 patients with de novo acute myeloid leukemia and MLL rearrangement.

The fusion transcripts of MLL rearrangement [MLL(+)] in acute myeloid leukemia (AML) and their clinicohematologic correlation have not be well characterized in the previous studies. We used Southern blot analysis to screen MLL(+) in de novo AML. Reverse transcriptase-polymerase chain reaction was used to detect the common MLL fusion transcripts. cDNA panhandle PCR was used to identify infrequent or unknown MLL partner genes. MLL(+) was identified in 114 (98 adults) of 988 AML patients. MLL fusion transcripts comprised of 63 partial tandem duplication of MLL (MLL-PTD), 14 MLL-AF9, 9 MLL-AF10, 9 MLL-ELL, 8 MLL-AF6, 4 MLL-ENL and one each of MLL-AF1, MLL-AF4, MLL-MSF, MLL-LCX, MLL-LARG, MLL-SEPT6 and MLL-CBL. The frequency of MLL-PTD was 7.1% in adults and 0.9% in children (P<0.001). 11q23 abnormalities were detected in 64% of MLL/t11q23 and in none of MLL-PTD by conventional cytogenetics. There were no differences in remission rate, event-free survival and overall survival between adult MLL-PTD and MLL/t11q23 groups. Adult patients had a significantly poorer outcome than children. The present study showed that cDNA panhandle PCR can identify all rare or novel MLL partner genes. MLL-PTD was rare in childhood AML. MLL(+) adults had a poor outcome with no difference in survival between MLL-PTD and MLL/t11q23 groups.

Dlk1 in normal and abnormal hematopoiesis.

Dlk1 (Pref-1) is a transmembrane and secreted protein, which is a member of the epidermal growth factor-like family, homologous to Notch/Delta/Serrate. We have found by real-time RT-PCR that Dlk1 mRNA levels were high in CD34(+) cells in 10 of 12 MDS samples compared with CD34(+) cells from 11 normals. Also, Dlk1 mRNA was elevated in mononuclear, low density bone marrow cells from 11/38 MDS patients, 5/11 AML M6 and 2/4 AML M7 samples. Furthermore, 5/6 erythroleukemia and 2/2 megakaryocytic leukemia cell lines highly expressed Dlk1 mRNA. Levels of Dlk1 mRNA markedly increased during megakaryocytic differentiation of both CMK megakaryoblasts as well as normal CD34(+) hematopoietic stem cells. High serum levels of Dlk1 occurred in RA (4/10) and essential thrombocythemia (2/10) patients. Functional studies showed that forced expression of Dlk1 enhanced proliferation of K562 cells growing in 1% fetal bovine serum. Analysis of hematopoiesis of Dlk1 knockout mice suggested that Dlk1 contributed to granulocyte, megakaryocyte and B-cell clonogenic growth and was needed for generation of splenic B-cells. In summary, Dlk1 is overexpressed in selected samples of MDS (especially RA and RAEB) and AML (particularly M6, M7), and it appears to be associated with normal development of megakaryocytes and B cells.

CEBPalpha mutations in childhood acute myeloid leukemia.

CEBPalpha: mutations have been described in adult acute myeloid leukemia (AML) and conferred a favorable prognosis. However, CEBPalpha mutation has not been reported in children. We investigated 117 children with de novo AML using DNA PCR assay followed by sequencing for each PCR product. CEBPalpha mutations were detected in seven patients, four had FAB M2, two M1 and one M4. CEBPalpha mutations only occurred in patients with intermediate cytogenetics and not in 56 children with AML1-ETO, CBFbeta-MYH11, PML-RARalpha or MLL rearrangements. Five patients had mutations occurred in both N-terminal part and basic-leucine zipper (bZIP) domain, one had an N-terminal frameshift mutation and the remaining one had an inframe insertion in the bZIP domain. Cloning analysis on five samples carrying more than one mutations demonstrated one homozygous combined mutations and four heterozygous biallelic mutations. Four of seven CEBPalpha mutation(+) patients had cooperating mutations with FLT3-ITD or N-ras mutations compared to 27 in 109 CEBPalpha mutation(-) patients. Our results showed that CEBPalpha mutations occurred in 6% of childhood AML and most exhibited combined mutations in both N-terminal part and bZIP domain.

Acute leukaemia in chronic hepatitis B patients with lamivudine therapy.

Extensive clinical data have shown that lamivudine is an effective and safe drug for patients with chronic hepatitis B virus infection. No significant serious side effect has been reported. Four hundred and forty-eight patients with chronic hepatitis B, treated with lamivudine for more than 6 months, were closely monitored. Two patients developed acute myeloid leukaemia during or after lamivudine therapy. The first case developed acute myeloid leukaemia, 1 year after stopping lamivudine therapy, when A529T mutant HBV-DNA was still detectable. The second case achieved complete virological response but suffered from acute myeloid leukaemia during the ninth month of lamivudine treatment. D553N mutant hepatitis B virus was detected in granulocytes of her peripheral blood. Based on our lamivudine therapy data, the calculated incidence of acute myeloid leukaemia in patients during or after lamivudine therapy was higher in males and females than that of the general population. Whether lamivudine-selected viral mutations have enhanced activity/production of transcriptional transactivator and thereby increased the chance of leukaemic transformation of haematopoietic progenitor cells deserves further investigation.

Posttransplant Kaposi's sarcoma: report from a single center.

UNLABELLED: Posttransplant Kaposi's sarcoma (KS) is not uncommon. This study investigated the clinical manifestations, impact of immunosuppression, and presence of HHV-8 antigen in our patients. METHODS: Among 568 renal transplant recipients, four developed KS. The physical findings, radiologic studies, immunosuppressive regimens, and the clinical outcomes were reviewed. In two patients, the expression of human herpes virus-8 was examined with polymerase chain reaction and in situ hybridization. RESULTS: The incidence of KS was 0.7% in our recipients. The intervals between the transplantation and the development of KS ranged from 2 months to 8.4 years. All KS patients had calcineurin inhibitor-based antirejection therapies. Peripheral lymphadenopathy was the initial manifestation in three of four patients; the fourth presented with violaceous papules over his lower legs. Besides lymphadenopathy, KS in one patient also involved internal visceral organs. One patient died at the time of diagnosis because of Salmonellosis; the other three experienced tumor regression after discontinuation of calcineurin inhibitors. HHV-8 expression was detected in two examined specimens. CONCLUSION: Lymph node involvement is the most common clinical presentation in our posttransplant KS patients. HHV-8 infection is associated with the development of KS. Early withdrawal of calcineurin inhibitors produces a favorable outcome in posttransplant KS.

Acquisition of FLT3 or N-ras mutations is frequently associated with progression of myelodysplastic syndrome to acute myeloid leukemia.

The role of internal tandem duplication of fms-like tyrosine kinase 3 (FLT3/ITD), mutations at tyrosine kinase domain (FLT3/TKD) and N-ras mutations in the transformation of myelodysplastic syndrome (MDS) to AML was investigated in 82 MDS patients who later progressed to AML; 70 of them had paired marrow samples at diagnosis of MDS and AML available for comparative analysis. Five of the 82 patients had FLT3/ITD at presentation. Of the 70 paired samples, seven patients acquired FLT3/ITD during AML evolution. The incidence of FLT3/ITD at diagnosis of MDS was significantly lower than that at AML transformation (3/70 vs 10/70, P<0.001). FLT3/ITD(+) patients progressed to AML more rapidly than FLT3/ITD(-) patients (2.5+/-0.5 vs 11.9+/-1.5 months, P=0.114). FLT3/ITD(+) patients had a significantly shorter survival than FLT3/ITD(-) patients (5.6+/-1.3 vs 18.0+/-1.7 months, P=0.0008). After AML transformation, FLT3/ITD was also associated with an adverse prognosis. One patient had FLT3/TKD mutation (D835Y) at both MDS and AML stages. Additional three acquired FLT3/TKD (one each with D835 H, D835F and I836S) at AML transformation. Five of the 70 matched samples had N-ras mutation at diagnosis of MDS compared to 15 at AML transformation (P<0.001), one lost and 11 gained N-ras mutations at AML progression. Coexistence of FLT3/TKD and N-ras mutations was found in two AML samples. N-ras mutations had no prognostic impact either at the MDS or AML stage. Our results show that one-third of MDS patients acquire activating mutations of FLT3 or N-ras gene during AML evolution and FLT3/ITD predicts a poor outcome in MDS.