Second Malignant Neoplasms in Childhood Cancer Survivors Treated in a Tertiary Paediatric Oncology Centre

: One of the most feared complications of childhood cancer treatment is second malignant neoplasms (SMNs). This study evaluates the incidence, risk factors and outcomes of SMNs in a tertiary paediatric oncology centre in Singapore.: A retrospective review was conducted on patients diagnosed with childhood cancer under age 21 and treated at the National University Hospital, Singapore, from January 1990 to 15 April 2012. Case records of patients with SMNs were reviewed.: We identified 1124 cases of childhood cancers with a median follow-up of 3.49 (0 to 24.06) years. The most common primary malignancies were leukaemia (47.1%), central nervous system tumours (11.7%) and lymphoma (9.8%). Fifteen cases developed SMNs, most commonly acute myeloid leukaemia/myelodysplastic syndrome (n = 7). Median interval between the first and second malignancy was 3.41 (0.24 to 18.30) years. Overall 20-year cumulative incidence of SMNs was 5.3% (95% CI, 0.2% to 10.4%). The 15-year cumulative incidence of SMNs following acute lymphoblastic leukaemia was 4.4% (95% CI, 0% to 8.9%), significantly lower than the risk after osteosarcoma of 14.2% (95% CI, 0.7% to 27.7%) within 5 years (<0.0005). Overall 5-year survival for SMNs was lower than that of primary malignancies.: This study identified factors explaining the epidemiology of SMNs described, and found topoisomerase II inhibitor use to be a likely risk factor in our cohort. Modifications have already been made to our existing therapeutic protocols in osteosarcoma treatment. We also recognised the importance of other risk management strategies, including regular long-term surveillance and early intervention for detected SMNs, to improve outcomes of high risk patients.

Effect of folic acid in a modified experimental model of anorectal malformations adriamycin-induced in rats

PURPOSE: To determine the effect of a single dose of adriamycin (ADR) to induce anorectal malformations (ARMs) and determine the effect of folic acid (FA) in this model. METHODS: Ten female Wistar rats were divided randomly in two groups. Group A - ADR; Group B - FA+ADR. Dams from group B received daily, since two weeks before the pregnancy to the end of pregnancy, FA (50mg/kg) by gavage. Dams from both groups received ADR (6mk/kg) by intraperitoneal injection on gestational day (GD) 8. Their fetuses were harvested by cesarean section on GD21 and were examined looking for ARMs. The thickness of anal stratified squamous epithelium (ASSE) and intestinal epithelium (IE) were analyzed. p≤0.05*. RESULTS: 81 fetuses were harvested. The number of fetuses; number of ARMs; mean (∆%) (± SD) were determined to be, respectively: ADR - 41[29;65%(±37%)] versus FA+ADR - 40[04;16%(±36%)] (p=0.05). AMRs were significantly lower in FA+ADR group than in ADR group (p=0.05). The thickness (µm) of ASSE (± SD) and IE (± SD) were measured, respectively: ADR - [25.98(±0.74) and 19.48(±1.68)] versus FA+ADR - [24.74(±0.91) and 24.80(±0.81)] (p<0.005). The thickness of IE was significantly enlarged when FA was given (p<0.005). CONCLUSIONS: Single dose of adriamycin on D8 was able to induce anorectal malformations. Folic acid reduces the number and enlarged the IE of ARMs ADR-induced.

Evaluation of prognostic factors in patients with therapy-related acute myeloid leukemia

BACKGROUND: Therapy-related AML (t-AML) occurs as a late complication of chemotherapy administered to treat a prior disorder. Prognostic factors affecting the clinical outcome in t-AML have not yet been clearly defined; therefore, we evaluated these factors in this study. METHODS: Forty-eight patients diagnosed with t-AML within the past 10 years were enrolled, and their chemotherapy regimens categorized into 4 groups: alkylating agents (AK) only, topoisomerase II inhibitors (TI) and AK, TI only, and others. The prognostic factors affecting clinical outcome were evaluated. RESULTS: Five (10.4%), 21 (43.8%), 9 (18.8%), and 13 (27.0%) patients were treated with AK only, AK and TI, TI only, and others, respectively. Patients with an AML M3 phenotype showed significantly longer overall survival (OS; 55.1 vs. 14.3 months, P=0.040) and disease-free survival (DFS; 61.2 vs. 17.5 months, P=0.049) than other phenotypes. In contrast, patients with a complex karyotype showed significantly shorter OS (7.9 vs. 31.3 months, P=0.008) and DFS (9.5 vs. 38.6 months, P=0.046); additionally, patients with chromosome 5 or 7 abnormalities showed significantly shorter OS (9.1 vs. 30.7 months, P=0.011) than other phenotypes. Only the presence of a complex karyotype or AML M3 phenotype retained prognostic impact in a multivariate analysis. CONCLUSION: Only the AML M3 phenotype was identified as having a good prognosis, and this might suggest that it exhibits unique clinical features in t-AML patients. Moreover, our findings indicated that karyotype was the strongest prognostic indicator and predicted a poor prognosis for t-AML patients with a complex karyotype.

Mechanisms of G2/M cycle arrest induced by topo IIalpha and II beta inhibitors in H460 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the mechanisms of G(2)/M cycle arrest induced by topo IIalpha and IIbeta inhibitors in H460 cells.</p><p><b>METHODS</b>The inhibitory effects of XK469, adriamycin and etoposide on H460 cell growth were analyzed by MTT assay. The changes in cell cycle and expressions of cdc2, phos-cdc2 and 14-3-3sigma proteins induced by these 3 topo II inhibitors were detected by flow cytometry and Western blotting, respectively.</p><p><b>RESULTS</b>Both of the two types of topo II inhibitor resulted in dose-dependent G(2)/M phase arrest and growth inhibition of H460 cells, but XK469 failed to induce 14-3-3sigma protein expression as adriamycin and etoposide did.</p><p><b>CONCLUSION</b>Topo IIalpha and topo IIbeta inhibitors induce growth inhibition of H460 cells possibly through two different mechanisms, namely the 14-3-3sigma-dependent pathway and the 14-3-3sigma-independent pathway, but further functional inhibition test of 14-3-3sigma is needed to confirm this hypothesis.</p>

hMRE11 plays an important role in U937 cellular response to DNA double-strand breaks following etoposide / 中国实验血液学杂志

MRE11 plays an important role in the signal transduction of DNA damage response, therefore this study was purposed to explore the relationship between hMRE11 focus formation and DNA double-strand breaks (DSBs) caused by etoposide (VP-16) in human promonocytic cells U937. After U937 cells were treated with VP-16, the drug-induced DSBs were assessed by pulsed-field gel electrophoresis (PFGE), the gene transcription levels of hMRE11 were evaluated by RT-PCR, the nuclear focus formation of hMRE11 protein was examined using immunofluorescence technique, the cell cycle in parallel was analyzed by flow cytometry. The results showed that the percentage of U937 cells with DSBs induced by VP-16 raised from 13.0 +/- 2.3% in VP-16 2 microg/ml to 32.0 +/- 4.3% in VP-16 20 microg/ml (P < 0.01) along with increase of VP-16 dose. No difference of the hMRE11 mRNA level in U937 cells following the treatment with 100 microg/ml VP-16 at different times was discovered (P > 0.05). The hMRE11 protein was abundantly and uniformly distributed in the nuclei of untreated U937 cells outside of nucleoli, however, it formed discrete nuclear foci following VP-16 treatment. The mean value of nuclear foci increased by 5 to 20 times following the drug dosing (P < 0.01). An average of 5 nuclear foci per positive nucleus were observed at a dose of 2 microg/ml, and it was increased to an average of over 14 nuclear foci per positive nucleus after treating with VP-16 20 microg/ml. The percentage of nuclei containing hMRE11 nuclear foci also increased from less than 10% after treatment wiht VP-16 2 microg/ml to over 50% after VP-16 20 microg/ml (P < 0.01) following treatment with VP-16. After U937 cells were treated with 100 microg/ml VP-16 for 2 hours and fixed at 4, 8, 12 and 24 hours, the percentage of nuclei with hMRE11 nuclear foci increased to 61.54 +/- 3.6% (the control U937 cells: 0.47 +/- 1.17%, P < 0.01) at 8 hours, with a subsequent decrease in the percentage of nuclear foci-positive cells by 24 hours. The ratio of S-phase U937 cells at 8 hours after being treated with 100 microg/ml VP-16 for 2 hours was 47.55 +/- 2.35%, and that without 100 microg/ml VP-16 was 21.95 +/- 2.91% (P < 0.05). It is concluded that the nuclear focus formation of hMRE11 protein may be a response to DNA damage induced by topoisomerase II inhibitor VP-16 in human promonocytic cell line U937.

[In vitro cytotoxicity evaluation of sixteen new n-piperazinyl quinolone derivatives against a panel of tumor cell lines]

Fluoroquinolones are potent inhibitors of bacterial topoisomerase II. They can also inhibit eukaryotic topoisomerase, and may confer antitumoral properties. In this study the antitumoral activity of a new series of N-substituted piperazinyl- fluoroquinolones against a panel of human tumor cell lines was determined by MTT assays. Among the tested compounds N-[2- [5-bromo-2-thienyl]-2-oxoethyl] [C1,N1,E1], N-[2- [5-bromo-2-thienyl]-2-[hydroxyimino] ethyl][C2,N2,E2] and N-[2-[5-bromo-2-thienyl]-2-[phenylmethoxyimino] ethyl] [C3,N3,E3] piperazinyl quinolones exhibited the most cytotoxic activities [mean IC50s = 2.5 to 3 microg/ml], comparable to that of the Etoposide [mean IC50= 1.7micro g/ml]. Replacement of the 5- bromo-2-thienyl with 4- fluorophenyl or 2, 6- difluorophenyl rings leads to variable inhibition activity. The quinolone activity was enhanced by the presence of a chlorine and two fluorine atoms at the benzyl and phenyl groups, especially against ACHN renal adenocarcinoma cell line. These data suggest that these series of quinolones provide good models for the further design of potent antitumor compounds

Topoisomerase II inhibitors etoposide and doxorubicin induced rearrangement and fusion of AML1 gene / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between topoisomerase II inhibitors and t(8;21) chromosomal translocation.</p><p><b>METHODS</b>The rearrangements of AML1 and ETO genes were detected by Southern Blot and the AML1-ETO fusion gene by nested RT-PCR combined with sequencing in K562 cells treated with etoposide (Vp16) and doxorubicin (DOX).</p><p><b>RESULTS</b>The rearrangements of AML1 gene were detectable after DOX treatment at concentrations of 10, 50 and 100 micro mol/L for 16 h, AML1-ETO fusion gene appeared after 50 micro mol/L DOX treatment for 48 h.</p><p><b>CONCLUSION</b>Induction of AML1 gene rearrangement and fusion by topoisomerase II inhibitors, represents one of the molecular mechanisms of t(8;21) chromosomal translocation.</p>

Chromosomal Abnormalities at 11q23 after Topoisomerase II Inhibitor Treatment: A Report of Three Cases / 대한임상병리학회지

It has become apparent that the MLL (myeloid-lymphoid leukemia or mixed-lineage leukemia) gene is frequently rearranged in patients with secondary leukemias or myelodysplasias associated with chemotherapeutic regimens including topoisomerase II inhibitors (topo II inhibitors). Few studies have been reported on hematological or chromosomal abnormalities associated with topo II inhibitor therapy in Korea. We report three cases with 11q23 abnormalities associated with topo II inhibitor therapy. The first case was a 10-year-old female patient with t(11;16)(q23;p13.3) but without abnor-mal bone marrow findings. The second patient was a 67-year old male with therapy-related myelodys-plastic syndrome (MDS) with add(11)(q23), which evolved into acute myeloid leukemia with t(2;11) (p23;q23) after one year. The other patient was a 42-year-old male with a therapy-related acute myeloid leukemia with rearranged 11q23 demonstrated by fluorescence in situ hybridization (FISH) analysis using an MLL gene probe, which subsequently proved to be t(9;11)(p22;q23) by cytoge-netic analysis. The chemotherapeutic agents for the primary malignancies in the three patients (ovarian primitive neuroectodermal tumor, PNET; lung squamous cell carcinoma; and Ewing's sar-coma/ PNET, respectively) included topo II inhibitiors as well as alkylating agents. The periods from the primary therapy to the identification of 11q23 abnormalities were relatively short; 9 months, 35 months, and 22 months, respectively. Patients treated with topo II inhibitors are at risk for develop-ing secondary MDS and leukemia that have distinct features from those associated with alkylating agents. Although the genetic basis and optimal treatment for the clonal changes induced by topo II inhibitor therapy remain to be determined, a close follow-up with cytogenetic and/or MLL FISH study in patients with a history of topo II inhibitor treatment would be very useful for diagnosis and prediction of secondary hematologic malignancies.