Molecular characterisation defines clinically-actionable heterogeneity within Group 4 medulloblastoma and improves disease risk-stratification.

Group 4 tumours (MBGrp4) represent the majority of non-WNT/non-SHH medulloblastomas. Their clinical course is poorly predicted by current risk-factors. MBGrp4 molecular substructures have been identified (e.g. subgroups/cytogenetics/mutations), however their inter-relationships and potential to improve clinical sub-classification and risk-stratification remain undefined. We comprehensively characterised the paediatric MBGrp4 molecular landscape and determined its utility to improve clinical management. A clinically-annotated discovery cohort (n = 362 MBGrp4) was assembled from UK-CCLG institutions and SIOP-UKCCSG-PNET3, HIT-SIOP-PNET4 and PNET HR + 5 clinical trials. Molecular profiling was undertaken, integrating driver mutations, second-generation non-WNT/non-SHH subgroups (1-8) and whole-chromosome aberrations (WCAs). Survival models were derived for patients ≥ 3 years of age who received contemporary multi-modal therapies (n = 323). We first independently derived and validated a favourable-risk WCA group (WCA-FR) characterised by ≥ 2 features from chromosome 7 gain, 8 loss, and 11 loss. Remaining patients were high-risk (WCA-HR). Subgroups 6 and 7 were enriched for WCA-FR (p < 0·0001) and aneuploidy. Subgroup 8 was defined by predominantly balanced genomes with isolated isochromosome 17q (p < 0·0001). While no mutations were associated with outcome and overall mutational burden was low, WCA-HR harboured recurrent chromatin remodelling mutations (p = 0·007). Integration of methylation and WCA groups improved risk-stratification models and outperformed established prognostication schemes. Our MBGrp4 risk-stratification scheme defines: favourable-risk (non-metastatic disease and (i) subgroup 7 or (ii) WCA-FR (21% of patients, 5-year PFS 97%)), very-high-risk (metastatic disease with WCA-HR (36%, 5-year PFS 49%)) and high-risk (remaining patients; 43%, 5-year PFS 67%). These findings validated in an independent MBGrp4 cohort (n = 668). Importantly, our findings demonstrate that previously established disease-wide risk-features (i.e. LCA histology and MYC(N) amplification) have little prognostic relevance in MBGrp4 disease. Novel validated survival models, integrating clinical features, methylation and WCA groups, improve outcome prediction and re-define risk-status for ~ 80% of MBGrp4. Our MBGrp4 favourable-risk group has MBWNT-like excellent outcomes, thereby doubling the proportion of medulloblastoma patients who could benefit from therapy de-escalation approaches, aimed at reducing treatment induced late-effects while sustaining survival outcomes. Novel approaches are urgently required for the very-high-risk patients.

Variants in vincristine pharmacodynamic genes involved in neurotoxicity at induction phase in the therapy of pediatric acute lymphoblastic leukemia.

Vincristine is an important drug of acute lymphoblastic leukemia (ALL) treatment protocols that can cause neurotoxicity. Patients treated with LAL/SHOP protocols often suffer from vincristine-related neurotoxicity in early phases of treatment. A genetic variant in CEP72, a gene involved in vincristine pharmacodynamics, was recently associated with neurotoxicity after prolonged vincristine treatment. This association was not replicated in our Spanish population during induction phase. To test the possibility that other variants in genes involved in vincristine pharmacodynamics were associated with vincristine neuropathy in early phases of the treatment, we evaluated the correlation with toxicity of 24 polymorphisms in 9 key genes in a large cohort of 152 Spanish children with B-ALL homogeneously treated. Results showed no association between any genetic variant in the TUBB1, TUBB2A, TUBB2B, TUBB3, TUBB4, MAPT, MIR146a, MIR202, and MIR411 genes and vincristine-related neurotoxicity. These results are in line with the hypothesis that there are different mechanisms causing pheripheral neurotoxicity after prolonged and short-term vincristine treatments.

Mir-pharmacogenetics of Vincristine and peripheral neurotoxicity in childhood B-cell acute lymphoblastic leukemia.

Vincristine (VCR), an important component of childhood acute lymphoblastic leukemia (ALL) therapy, can cause sensory and motor neurotoxicity. This neurotoxicity could lead to dose reduction or treatment discontinuation, which could in turn reduce survival. In this line, several studies associated peripheral neurotoxicity and polymorphisms in genes involved in pharmacokinetics (PK) and pharmacodynamics (PD) of VCR. Nowadays, it is well known that these genes are regulated by microRNAs (miRNAs) and SNPs in miRNAs could modify their levels or function. Therefore, the aim of this study was to determine whether SNPs in miRNAs could be associated with VCR-induced neurotoxicity. To achieve this aim, we analyzed all the SNPs in miRNAs (minor allele frequency (MAF) ≥ 0.01) which could regulate VCR-related genes in a large cohort of Spanish children with B-cell precursor ALL (B-ALL) homogeneously treated with LAL/SHOP protocols. We identified the A allele of rs12402181 in the seed region of miR-3117-3p, that could affect the binding with ABCC1 and RALBP1 gene, and C allele of rs7896283 in pre-mature sequence of miR-4481, which could be involved in peripheral nerve regeneration, significantly associated with VCR-induced neurotoxicity. These findings point out the possible involvement of two SNPs in miRNA associated with VCR-related neurotoxicity.

MiR-pharmacogenetics of methotrexate in childhood B-cell acute lymphoblastic leukemia.

OBJECTIVES: Methotrexate (MTX), the key drug in childhood B-cell acute lymphoblastic leukemia (B-ALL) therapy, often causes toxicity. An association between genetic variants in MTX transport genes and toxicity has been found. It is known that these transporters are regulated by microRNAs (miRNAs), and miRNA single nucleotide polymorphisms (SNPs) interfere with miRNA levels or function. With regard to B-cell ALL, we have previously found rs56103835 in miR-323b that targets ABCC4 associated with MTX plasma levels. Despite these evidences and that nowadays a large amount of new miRNAs have been annotated, studies of miRNA polymorphisms and MTX toxicity are almost absent. Therefore, the aim of this study was to determine whether there are other variants in miRNAs associated with MTX levels. PATIENTS AND METHODS: Blood samples of 167 Spanish patients with pediatric B-cell ALL treated with the LAL-SHOP protocol were analyzed. We selected all the SNPs described in pre-miRNAs with a minor allele frequency more than 1% (213 SNPs in 206 miRNAs) that could regulate MTX transporters because the miRNAs that target MTX transporter genes are not completely defined. Genotyping was performed with VeraCode GoldenGate platform. RESULTS: Among the most significant results, we found rs56292801 in miR-5189, rs4909237 in miR-595, and rs78790512 in miR-6083 to be associated with MTX plasma levels. These miRNAs were predicted, in silico, to regulate genes involved in MTX uptake: SLC46A1, SLC19A1, and SLCO1A2. CONCLUSION: In this study, we detected three SNPs in miR-5189, miR-595, and miR-6083 that might affect SLC46A1, SLC19A1, and SLCO1A2 MTX transport gene regulation and could affect MTX levels in patients with pediatric B-cell ALL.

Relapse patterns and outcome after relapse in standard risk medulloblastoma: a report from the HIT-SIOP-PNET4 study.

The HIT-SIOP-PNET4 randomised trial for standard risk medulloblastoma (MB) (2001-2006) included 338 patients and compared hyperfractionated and conventional radiotherapy. We here report the long-term outcome after a median follow up of 7.8 years, including detailed information on relapse and the treatment of relapse. Data were extracted from the HIT Group Relapsed MB database and by way of a specific case report form. The event-free and overall (OS) survival at 10 years were 76 ± 2 % and 78 ± 2 % respectively with no significant difference between the treatment arms. Seventy-two relapses and three second malignant neoplasms were reported. Thirteen relapses (18 %) were isolated local relapses in the posterior fossa (PF) and 59 (82 %) were craniospinal, metastatic relapses (isolated or multiple) with or without concurrent PF disease. Isolated PF relapse vs all other relapses occurred at mean/median of 38/35 and 28/26 months respectively (p = 0.24). Late relapse, i.e. >5 years from diagnosis, occurred in six patients (8 %). Relapse treatment consisted of combinations of surgery (25 %), focal radiotherapy (RT 22 %), high dose chemotherapy with stem cell rescue (HDSCR 21 %) and conventional chemotherapy (90 %). OS at 5 years after relapse was 6.0 ± 4 %. In multivariate analysis; isolated relapse in PF, and surgery were significantly associated with prolonged survival whereas RT and HDSCR were not. Survival after relapse was not related to biological factors and was very poor despite several patients receiving intensive treatments. Exploration of new drugs is warranted, preferably based on tumour biology from biopsy of the relapsed tumour.

Noncoding RNA-related polymorphisms in pediatric acute lymphoblastic leukemia susceptibility.

BACKGROUND: Evidence for an inherited genetic risk for pediatric acute lymphoblastic leukemia has been provided in several studies. Most of them focused on coding regions. However, those regions represent only 1.5% of the entire genome. In acute lymphoblastic leukemia (ALL), it has been suggested that the expression of microRNAs (miRNAs) is dysregulated, which suggests that they may have a role in ALL risk. Changes in miRNA function may occur through single-nucleotide polymorphisms (SNPs). Therefore, the aim of this study was to evaluate whether polymorphisms in pre-miRNAs, and/or miRNA-processing genes, contribute to a predisposition for childhood ALL. METHODS: In this study, we analyzed 118 SNPs in pre-miRNAs and miRNA-processing genes in 213 B-cell ALL patients and 387 controls. RESULTS: We found 11 SNPs significantly associated with ALL susceptibility. These included three SNPs present in miRNA genes (miR-612, miR-499, and miR-449b) and eight SNPs present in six miRNA biogenesis pathway genes (TNRC6B, DROSHA, DGCR8, EIF2C1, CNOT1, and CNOT6). Among the 118 SNPs analyzed, rs12803915 in mir-612 and rs3746444 in mir-499 exhibited a more significant association, with a P value <0.01. CONCLUSION: The results of this study indicate that SNP rs12803915 located in pre-mir-612, and SNP rs3746444 located in pre-mir-499, may represent novel markers of B-cell ALL susceptibility.

Polymorphisms in the methotrexate transport pathway: a new tool for MTX plasma level prediction in pediatric acute lymphoblastic leukemia.

OBJECTIVES: Methotrexate (MTX) is an important component of therapy for pediatric acute lymphoblastic leukemia (ALL). Treatment with MTX often causes toxicity, which can necessitate dose reduction or treatment cessation. Interindividual differences in adverse reactions can be due to different factors, including polymorphisms in key genes. Recently, we confirmed the association between SLCO1B1 rs11045879 polymorphism and toxicity previously proposed by Treviño and colleagues. As SLCO1B1 is a transporter involved in MTX elimination, other polymorphisms in genes from this pathway could also have a role in MTX toxicity. The aim of the present study was to analyze in depth the role of polymorphisms in the genes of the MTX transport pathway as putative toxicity predictors in pediatric ALL. METHODS: We analyzed 384 single nucleotide polymorphisms in 12 transporter genes (SLCO1B1, SLCO1B3, SLCO1A2, ABCB1, ABCG2, ABCC1, ABCC2, ABCC3, ABCC4, SLC19A1, SLC22A6 and SLC22A8) and their correlation with different toxicity parameters in 151 pediatric ALL patients treated using the LAL/SHOP protocol. RESULTS: A significant association with MTX plasma levels was found for 21 polymorphisms from seven genes and 15 haplotypes. After correction, rs9516519 in ABCC4, rs3740065 in ABCC2, and haplotype GCGGG in ABCC2 remained significantly associated. CONCLUSION: Our results suggest that polymorphisms in ABCC4 and ABCC2 could be novel markers for MTX toxicity in pediatric ALL.

Polymorphisms of the SLCO1B1 gene predict methotrexate-related toxicity in childhood acute lymphoblastic leukemia.

BACKGROUND: Methotrexate (MTX) is an important component of the therapy for childhood acute lymphoblastic leukemia. Treatment with high-dose MTX often causes toxicity, recommending a dose reduction and/or cessation of treatment. Polymorphisms in genes involved in the MTX metabolism have been associated with toxicity with controversial results. The discrepancies could be due to differences in treatment protocols among studies, small, or non-homogeneous populations or the use of different toxicity criteria. The aim of the present study was to analyze the possible correlation of polymorphisms of genes involved in the MTX metabolism with the toxicity during therapy with the well-established LAL/SHOP protocol. PROCEDURE: We analyzed 10 polymorphisms in seven genes (MTHFR, TS, SHMT1, RFC1, ABCB1, ABCG2, and SLCO1B1) from the MTX metabolism in 115 Spanish pediatric B-ALL patients, using MTX plasma concentration as an objective and quantifiable marker of toxicity. RESULTS: We confirmed the suitability of MTX plasma levels as a toxicity marker. We found a statistically significant association between MTX plasma concentration and the SLCO1B1 rs11045879 CC genotype (P = 0.030). The rs4149081 AA genotype, in the same gene, could also be an indicator for high-MTX plasma concentrations. We did not find any significant association in the other genetic polymorphisms analyzed. CONCLUSIONS: Identification of the rs4149081 and rs11045879 SLCO1B1 polymorphisms in children with ALL could be a useful tool for monitoring patients at risk of low-MTX clearance in order to avoid MTX-related toxicity.

Effects of the growth pattern of medulloblastoma on short-term neurological impairments after surgery: results from the prospective multicenter HIT-SIOP PNET 4 study.

OBJECTIVE: Extensive resection of a tumor in the posterior fossa in children is associated with the risk of neurological deficits. The objective of this study was to prospectively evaluate the short-term neurological morbidity in children after medulloblastoma surgery and relate this to the tumor's growth pattern and to the extent of resection. METHODS: In 160 patients taking part in the HIT-SIOP PNET 4 (Hyperfractionated Versus Conventionally Fractionated Radiotherapy in Standard Risk Medulloblastoma) trial, neurosurgeons prospectively responded to questions concerning the growth pattern of the tumor they had resected. The extent of resection (gross, near, or subtotal) was evaluated using MRI. The patients' neurological status before resection and around 30 days after resection was recorded. RESULTS: Invasive tumor growth, defined as local invasion in the brain or meninges, cranial nerve, or major vessel, was reported in 58% of the patients. After surgery almost 70% of all patients were affected by one or several neurological impairments (e.g., impaired vision, impaired extraocular movements, and ataxia). However, this figure was very similar to the preoperative findings. Invasive tumor growth implied a significantly higher number of impairments after surgery (p = 0.03) and greater deterioration regarding extraocular movements (p = 0.012), facial weakness (p = 0.048), and ataxia in the arms (p = 0.014) and trunk (p = 0.025) compared with noninvasive tumor growth. This deterioration was not dependent on the extent of resection performed. Progression-free survival (PFS) at 5 years was 80% ± 4% and 76% ± 5% for patients with invasive and noninvasive tumor growth, respectively, with no difference in the 5-year PFS for extent of resection. CONCLUSIONS: Preoperative neurological impairments and invasive tumor growth were strong predictors of deterioration in short-term neurological outcome after medulloblastoma neurosurgery, whereas the extent of resection was not. Neither tumor invasiveness nor extent of resection influenced PFS. These findings support the continuation of maximal safe resection in medulloblastoma surgery where functional risks are not taken in areas with tumor invasion.

Involvement of miRNA polymorphism in mucositis development in childhood acute lymphoblastic leukemia treatment.

AIM: Mucositis, linked to methotrexate, daunorubicin or cyclophosphamide, is a frequent childhood acute lymphoblastic leukemia (ALL) therapy side effect. miRNAs regulate the expression of pharmacokinetic/pharmacodynamic pathway genes. SNPs in miRNAs could affect their levels or function, and affect their pharmacokinetic/pharmacodynamic pathway target genes. Our aim was to determine the association between miRNA genetic variants targeting mucositis-related genes and mucositis-developing risk. PATIENTS & METHODS: We analyzed 160 SNPs in 179 Spanish children with B-cell precursor ALL homogeneously treated with LAL/SHOP protocols. RESULTS: We identified three SNPs in miR-4268, miR-4751 and miR-3117 associated with mucositis, diarrhea and vomiting, respectively. CONCLUSION: The effect of these SNPs on genes related to drug pharmacokinetics/pharmacodynamics could explain mucositis, diarrhea and vomiting development during ALL therapy.

Involvement of SNPs in miR-3117 and miR-3689d2 in childhood acute lymphoblastic leukemia risk.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Numerous studies have shown that microRNAs (miRNAs) could play a role in this disease. Nowadays, more than 2500 miRNAs have been described, that regulate more than 50% of genes, including those involved in B-cell maturation, differentiation and proliferation. Genetic variants in miRNAs can alter their own levels or function, affecting their target gene expression, and then, may affect ALL risk. Therefore, the aim of this study was to determine the role of miRNA genetic variants in B-ALL susceptibility. We analyzed all variants in pre-miRNAs (MAF > 1%) in two independent cohorts from Spain and Slovenia and inferred their functional effect by in silico analysis. SNPs rs12402181 in miR-3117 and rs62571442 in miR-3689d2 were associated with ALL risk in both cohorts, possibly through their effect on MAPK signalling pathway. These SNPs could be novel markers for ALL susceptibility.

Pharmacoepigenetics in childhood acute lymphoblastic leukemia: involvement of miRNA polymorphisms in hepatotoxicity.

AIM: Hepatotoxicity is one of the most common drug-related toxicities during the treatment of childhood acute lymphoblastic leukemia (ALL). Many genes involved in liver-specific signaling pathways are tightly controlled by miRNAs, and miRNA function could be modulated by SNPs. As a consequence, we hypothesized that variants in miRNAs could be associated with drug-induced hepatotoxicity. METHODS: We analyzed 213 SNPs in 206 miRNAs in a cohort of 179 children with ALL homogeneously treated. RESULTS: rs2648841 in miR-1208 was the most significant SNP during consolidation phase after false discovery rate correction, probably through an effect on its target genes DHFR, MTR and MTHFR. CONCLUSION: These results point out the possible involvement of SNPs in miRNAs in toxicity to chemotherapy in children with ALL.

[Results of the SHOP LNHB98 (LMB89) trial in pediatric patients with B-cell non-Hodgkin's lymphoma]. / Resultados del protocolo SHOP LNHB98 (LMB89) en pacientes de edad pediátrica afectados de linfoma no hodgkiniano de células B.

BACKGROUND AND OBJECTIVE: After the good results obtained by the Société Française d'Oncologie Pédiatrique (SFOP) regarding the pediatric B-type non-Hodgkin's (Burkitt and large B-cell) lymphoma and L3 leukemia, the Sociedad Española de Hematología y Oncología Pediátricas (SHOP) decided to use the same treatment protocol. PATIENTS AND METHOD: Pediatric patients diagnosed with B-type non-Hodgkin's lymphoma without a previous history of malignant diseases were eligible for this study. They were classified in 3 groups of risk: group A (resected stage I and abdominal stage II), group B (not eligible for groups A or C), and group C (with central nervous system involvement and L3 leukemia). All received treatment according to the SFOP's LMB89 protocol. RESULTS: A total of 153 patients were considered in this multicenter, prospective and non-randomized trial (1997-2005). The global and event-free survival (EFS) were found to be of 88% (0.88; 95% confidence interval [CI], 0.83-0.93) and 85% (0.85; 95% CI, 0.79-0.90), respectively. The EFS was 100% for the group A (n = 16), 86% (0.86; 95% CI, 0.79-0.92) for the group B (n = 113), and 68% (0.68; 95% CI, 0.49-0.86) for the group C (n = 24). CONCLUSIONS: The results confirm the good efficiency of the LMB89 protocol for treating B-cell lymphoma and L3 leukemia, despite having diminished the treatment intensity in the less risk groups. The worst prognostic factor was found to be a central nervous system involvement, whereas being younger than 10 years was confirmed to be a favorable prognostic factor. In addition, no differences were evidenced between Burkitt and large B-cell lymphoma.

Confirmation of involvement of new variants at CDKN2A/B in pediatric acute lymphoblastic leukemia susceptibility in the Spanish population.

The locus CDKN2A/B (9p21.3), which comprises the tumor suppressors genes CDKN2A and CDKN2B and the long noncoding RNA (lncRNA) known as ANRIL (or CDKN2B-AS), was associated with childhood acute lymphoblastic leukemia (ALL) susceptibility in several genome wide association studies (GWAS). However, the variants associated in the diverse studies were different. Recently, new and independent SNPs deregulating the locus function were also identified in association with ALL risk. This diversity in the results may be explained because different variants in each population could alter CDKN2A/B locus function through diverse mechanisms. Therefore, the aim of this study was to determine whether the annotated risk variants in the CDKN2A/B locus affect the susceptibility of B cell precursor ALL (B-ALL) in our Spanish population and explore if other SNPs altering additional regulatory mechanisms could be also involved. We analyzed the four SNPs proposed by GWAs and two additional SNPs in miRNA binding sites in 217 pediatric patients with B-ALL and 330 healthy controls. The SNPs rs2811712, rs3731249, rs3217992 and rs2811709 were associated with B-ALL susceptibility in our Spanish population. ALL subtypes analyses showed that rs2811712 was associated with B-hyperdiploid ALL. These results provide evidence for the influence of genetic variants at CDKN2A/B locus with the risk of developing B-ALL.

Childhood central nervous system tumours--incidence and survival in Europe (1978-1997): report from Automated Childhood Cancer Information System project.

This paper describes the incidence and survival of childhood central nervous system (CNS) tumours in Europe for the period 1978-1997. A total of 19,531 cases, aged 0-14 years, from the ACCIS database were analysed by five regions: the British Isles, East, North, South, and West. Overall age-standardised incidence rate (ASR) of CNS tumours in Europe (1988-1997) was 29.9 per million, with the highest rates in the North. Astrocytoma (ASR=11.8), primitive neuroectodermal tumours (PNET) (ASR=6.5) and ependymoma (ASR=3.4) were the most frequent types. Incidence increased significantly during 1978-1997, on average by 1.7% per year. Diagnostic methods may partially explain incidence rates and trends, although a role of variations in risk factors cannot be excluded. Overall 5-year survival was 64% and varied between 72% in the North and 53% in the East. PNET had the poorest prognosis (49%) and astrocytoma the best (75%). Survival has improved by 29% since late 1970s. The positive trends were seen in all regions, although the interregional differences persisted, as a reflection of the different healthcare systems.

[Molecular diagnosis of retinoblastoma: molecular epidemiology and genetic counseling]. / Diagnóstico molecular del retinoblastoma: epidemiología molecular y consejo genético.

BACKGROUND AND OBJECTIVE: Retinoblastoma, a prototype of hereditary cancer, is the most common intraocular tumor in children and a potential cause of blindness from therapeutic eye ablation, second tumors in germ line mutation carriers, and even death when untreated. The molecular scanning of RB1 in search of germ line mutations in 213 retinoblastoma patients from Spain, Cuba, Colombia and Serbia, has led to the detection of 106 mutations whose knowledge is important for genetic counselling and characterization of phenotypic-genotypic relations. PATIENTS AND METHOD: Mutational study (PCR-sequentiation and microsatellites analysis) in patients with retinoblastoma, from Spain, Cuba, Colombia and Serbia. RESULTS: 45% of mutations, including most of the frame shift (FS), missense (MS) and splicing (SP), were new, while all nonsense mutations (NS) corresponded to hypermutable sites in RB1. Germ line mutations were found in 22% of unilateral sporadic patients. The incidence of SP plus MS mutations in this group of patients was greater (p = 0.018) than in bilateral patients. The frequency of SP mutations was higher (p = 0.0003) in Spain and France than in Germany and United Kingdom, while the incidence of NS mutations was lower (p = 0.0006). SP mutations were associated with the low penetrance phenotype and were also overrepresented (p = 0.018) in patients with delayed retinoblastoma onset. CONCLUSIONS: Mutational scanning of unilateral patients is important for genetic counselling and may help decipher the molecular mechanisms leading to low penetrance or expressivity. The functional characterization of mutations associated with low-penetrance or expressivity phenotypes and the molecular classification of tumors using multiple expression profiling is important for a better understanding of the retinoblastoma pathogenesis.

Vincristine pharmacokinetics pathway and neurotoxicity during early phases of treatment in pediatric acute lymphoblastic leukemia.

AIM: Vincristine is an important component of acute lymphoblastic leukemia (ALL) treatment protocols that can cause neurotoxicity. Patients treated with LAL/SHOP protocols often suffer from vincristine-related neurotoxicity in early phases of treatment. Recently, a genome-wide association study connected a SNP in CEP72, involved in vincristine pharmacodynamics, with neurotoxicity during later phases of therapy, which was not replicated during induction phase. These results, together with previous studies indicating that polymorphisms in pharmacokinetic genes are associated with drug toxicity, suggest that changes in the activity or levels of vincristine transporters or metabolizers could work as predictors of vincristine-related neurotoxicity in early phases of treatment in pediatric ALL. PATIENTS & METHODS: We analyzed 150 SNPs in eight key genes involved in vincristine pharmacokinetics and in 13 miRNAs that regulate them. We studied their correlation with neurotoxicity during induction phase in 152 ALL patients treated with LAL/SHOP protocols. RESULTS: The strongest associations with neurotoxicity were observed for two SNPs in ABCC2. The genotypes rs3740066 GG and rs12826 GG were associated with increased neurotoxicity. CONCLUSION: Polymorphisms in ABCC2 could be novel markers for vincristine-related neurotoxicity in pediatric ALL in early phases.

Identification of 26 new constitutional RB1 gene mutations in Spanish, Colombian, and Cuban retinoblastoma patients.

Constitutional mutations in the RB1 gene predispose to retinoblastoma development. Hence genetic screening of retinoblastoma patients and relatives is important for genetic counseling purposes. In addition, RB1 gene mutation studies may help decipher the molecular mechanisms leading to tumors with different degrees of penetrance or expressivity. In the course of genetically screening of 107 hereditary and non-hereditary retinoblastoma patients (11 familiar bilateral, 4 familiar unilateral, 49 sporadic bilateral and 43 sporadic unilateral) and kindred from Spain, Colombia and Cuba, using direct PCR sequencing, we observed 45 distinct mutations and four RB1 deletions in 53 patients (9 familiar bilateral, 2 familiar unilateral, 31 sporadic bilateral and 11 sporadic unilateral). Most of these mutations (26/45, 57%) have not been reported before. In 32 patients, the predisposing mutations correspond to nonsense (mainly CpG transitions) and small insertions or deletions whose expected outcome is a truncated Rb protein that lacks the functional pockets and tail. Five single aminoacid replacements and seventeen mutations affecting splicing sites were also observed in retinoblastoma patients. Two of these sixteen mutations are of unclear pathogenic nature.

Disseminated fusariosis and hematologic malignancies, a still devastating association. Report of three new cases.

BACKGROUND: Fungi of the genus Fusarium are primarily plant pathogens and saprobes that produce disseminated infections in immunologically deficient humans. After aspergillosis, disseminated fusariosis is the second most common cause of invasive infection by filamentous fungi in patients with hematologic malignancies or those undergoing transplants of hematopoietic progenitors. AIMS: Disseminated fusariosis (DF) is considered an extremely rare infection and has reached a stable incidence rate, but its high mortality rate and the lack of an optimal management protocol have raised increasing interest in this mycosis. METHODS: We present three cases of DF produced by Fusarium oxysporum species complex, Fusarium solani species complex and the highly unusual Fusarium dimerum in patients with advanced hematological malignancies diagnosed in our hospital between 2007 and 2011. The species level identification of the Fusarium isolates was established by sequencing their TEF1 gene. RESULTS: The isolates showed low susceptibility to most of the antifungal agents analyzed, except that observed for F. dimerum to amphotericin B (AmB) and terbinafine, and F. oxysporum species complex to AmB. Interestingly, the strain of F. solani species complex exhibited high MIC values for AmB and voriconazole, notwithstanding these drugs were used for treatment with good results. Other relevant aspects to be considered in the treatment of DF are surgically cleaning foci of infection, withdrawing presumably contaminated catheters and recovery from neutropenia. CONCLUSIONS: The prevention of infection in colonized patients, the maintenance of a high level of diagnostic suspicion for early diagnosis, and the combined, vigorous and prolonged use of L-AmB and voriconazole are essential to decrease the mortality rate of this devastating infection.