Promoter hypomethylation of the LINE-1 retrotransposable elements activates sense/antisense transcription and marks the progression of chronic myeloid leukemia

Aberrant genome-wide hypomethylation is thought to be related to tumorigenesis by promoting genomic instability. Since DNA methylation is considered an important mechanism for the silencing of retroelements, hypomethylation in human tumors may lead to their reactivation. However, the role of DNA hypomethylation in chronic myeloid leukemia (CML) remains to be elucidated. In this study, the methylation status of the LINE-1 (L1) retrotransposon promoter was analysed in CML samples from the chronic-phase (CP, n=140) and the blast crisis (BC, n=47). L1 hypomethylation was significantly more frequent in BC (74.5%) than in CP (38%) (P<0.0001). Furthermore, L1 hypomethylation led to activation of both ORF1 sense transcription (P<0.0001) and c-MET gene antisense transcription (P<0.0001), and was significantly associated with high levels of BCR-ABL (P=0.02) and DNMT3b4 (P=0.001) transcripts. Interestingly, in CP-CML, extensive L1 hypomethylation was associated with poorer prognosis in terms of cytogenetic response to interferon (P=0.004) or imatinib (P=0.034) and progression-free survival (P=0.005). The above results strongly suggest that activation of both sense and antisense transcriptions by aberrant promoter hypomethylation of the L1 elements plays a role in the progression and clinical behavior of the CML.

Promoter hypermethylation of cancer-related genes: a strong independent prognostic factor in acute lymphoblastic leukemia

Promoter hypermethylation plays an important role in the inactivation of cancer-related genes. This abnormality occurs early in leukemogenesis and seems to be associated with poor prognosis in acute lymphoblastic leukemia (ALL). To determine the extent of hypermethylation in ALL, we analyzed the methylation status of the CDH1, p73, p16, p15, p57, NES-1, DKK-3, CDH13, p14, TMS-1, APAF-1, DAPK, PARKIN, LATS-1, and PTEN genes in 251 consecutive ALL patients. A total of 77.3% of samples had at least 1 gene methylated, whereas 35.9% of cases had 4 or more genes methylated. Clinical features and complete remission rate did not differ among patients without methylated genes, patients with 1 to 3 methylated genes (methylated group A), or patients with more than 3 methylated genes (methylated group B). Estimated disease-free survival (DFS) and overall survival (OS) at 11 years were 75.5% and 66.1%, respectively, for the nonmethylated group; 37.2% and 45.5% for methylated group A; and 9.4% and 7.8% for methylated group B (P &lt; .0001 and P = .0004, respectively). Multivariate analysis demonstrated that the methylation profile was an independent prognostic factor in predicting DFS (P &lt; .0001) and OS (P = .003). Our results suggest that the methylation profile may be a potential new biomarker of risk prediction in ALL.

Comparative study of propofol versus midazolam in the sedation of critically ill patients: results of a prospective, randomized, multicenter trial

OBJECTIVES

To compare the effectiveness, characteristics, duration of action, hemodynamic and biochemical effects, and side effects of propofol and midazolam used for continuous intravenous sedation of ventilated critically ill patients.

DESIGN

Multicenter, prospective, randomized, nonblinded study.

SETTING

Nine Spanish general intensive care units (ICUs).

PATIENTS

Ninety-eight patients admitted to the ICU who were mechanically ventilated and required sedation for a minimum of 48 hrs.

INTERVENTIONS

Propofol or midazolam was used for induction and maintenance of continuous intravenous sedation for a maximum of 5 days. The effectiveness of those two regimens was assessed according to their effects on ventilatory management and the presence of agitation.

MEASUREMENTS AND MAIN RESULTS

In 93% of the patients studied, there was a medical cause necessitating mechanical ventilation. The mean (+/-SD) duration of sedation was 81 +/- 25 hrs and 88 +/- 27 hrs for the propofol and midazolam groups, respectively. The induction dose was 2.24 +/- 0.43 mg/kg over 318 +/- 363 secs for propofol, and 0.22 +/-0.07 mg/kg over 33 +/-29 secs for midazolam. The maintenance dose was 2.8 +/-1.1 mg/kg/hr for propofol and 0.14 +/- 0.10 mg/kg/hr for midazolam. There was no difference regarding the opiate and muscle relaxant requirements between the two groups. Sedation with propofol was more effective in achieving patient-ventilator synchrony than that with midazolam after the first hour of treatment (p < .01). Patients sedated with propofol awoke more rapidly and with less variability that those patients sedated with midazolam (23 +/- 16 mins vs. 137 +/- 185 mins, respectively, p < .05), particularly in those patients requiring deep sedation (27 +/- 16 mins vs. 237 +/- 222 mins, respectively, p < .01). No hemodynamic or biochemical changes were detected in any of the treatment groups. During induction, five patients in the propofol group and two patients in the midazolam group had hypotension.

CONCLUSIONS

In this population of critically ill patients, propofol is an effective and safe alternative for sedation, with some advantages, such as short duration of action and high effectiveness over the conventional regimen with benzodiazepines and opiates.

GLIM Criteria Using Hand Grip Strength Adequately Predict Six-Month Mortality in Cancer Inpatients

Protein-calorie malnutrition is very frequent in cancer patients and is associated with an increase in morbidity and mortality. Recently, the Global Leadership Initiative on Malnutrition (GLIM) criteria were proposed to standardize the diagnosis of malnutrition. Nevertheless, these criteria were not validated in prospective studies. Our objective is to determine the prevalence of malnutrition in cancer inpatients using different diagnostic classifications, including GLIM criteria, and to establish their association with length of stay and mortality. Hence, we designed a prospective study. Within the first 24 hours of admission to the Inpatient Oncology Unit, subjective global assessment (SGA) was carried out, and anthropometric data (body mass index (BMI), mid-arm circumference (MAC), arm muscle circumference (AMC), fat-free mass index (FFMI)) and hand grip strength (HGS) were obtained to assess the reduction of muscle mass according to GLIM criteria. Length of stay, biomarkers (albumin, prealbumin, C-reactive protein (CRP)), and in-hospital and six-month mortality were evaluated. Regarding the 282 patients evaluated, their mean age was 60.4 ± 12.6 years, 55.7% of them were male, and 92.9% had an advanced-stage tumor (17.7% stage III, 75.2% stage IV). According to SGA, 81.6% of the patients suffered from malnutrition (25.5% moderate malnutrition, and 56.1% severe malnutrition), and, based on GLIM criteria, malnutrition rate was between 72.2 and 80.0% depending on the used tool. Malnourished patients (regardless of the tool used) showed significantly worse values concerning BMI, length of stay, and levels of CRP/albumin, albumin, and prealbumin than normally nourished patients. In logistic regression, adjusted for confounding variables, the odds ratio of death at six months was significantly associated with malnutrition by SGA (odds ratio 2.73, confidence interval (CI) 1.35-5.52, p = 0.002), and by GLIM criteria calculating muscle mass with HGS (odds ratio 2.72, CI 1.37-5.40, p = 0.004) and FFMI (odds ratio 1.87, CI 1.01-3.48, p = 0.047), but not by MAC or AMC. The prevalence of malnutrition in advanced-stage cancer inpatients is very high. SGA and GLIM criteria, especially with HGS, are useful tools to diagnose malnutrition and have a similar predictive value regarding six-month mortality in cancer inpatients.

5' CpG island hypermethylation is associated with transcriptional silencing of the p21(CIP1/WAF1/SDI1) gene and confers poor prognosis in acute lymphoblastic leukemia

The p21 is a downstream effector of p53/p73 and belongs to the CIP/KIP family of cyclin-dependent kinase inhibitors (CDKIs). It is, therefore, a potential tumor suppressor gene and probably plays an important role in tumor development. Moreover, reduced expression of p21 has been reported to have prognostic value in several human malignancies. In contrast with other CDKIs, mutational inactivation of p21 is infrequent, but gene inactivation by an alternative mechanism seems to be the general pathway. In this study, we analyzed the methylation status of the p21 promoter region using semiquantitative polymerase chain reaction in 124 patients with acute lymphoblastic leukemia (ALL). We observed p21 hypermethylation in bone marrow cells from 41% (51 of 124) of ALL patients. Hypermethylation within promoter strongly correlated with decreased p21 messenger RNA expression in tumoral cells. Clinical, molecular, and laboratory features and complete remission rate did not differ significantly between hypermethylated and normally methylated patients. Estimated disease-free survival (DFS) and overall survival at 7 and 9 years, respectively, were 59% and 65% for healthy patients and 6% and 8% for hypermethylated patients (P =.00001 and P =.006). Multivariate analysis of potential prognostic factors demonstrated that p21 methylation status was an independent prognostic factor in predicting DFS (P =.0001). Our results indicate that the p21 gene is subject to methylation regulation at the transcription level in ALL and seems to be an important factor in predicting the clinical outcome of these patients.

Transcriptional silencing of the Dickkopfs-3 (Dkk-3) gene by CpG hypermethylation in acute lymphoblastic leukaemia

Dkk-3 is a newly characterised mortalisation-related gene and an antagonist of the Wnt oncogenic signalling pathway whose expression is decreased in a variety of cancer cell lines, suggesting that the Dkk-3 gene, located at chromosome 11p15.1, functions as a tumour suppressor gene. Although 11p15 is a ‘hot spot’ for methylation in acute lymphoblastic leukaemia (ALL), the role of Dkk-3 abnormalities has never been evaluated in this disease. We analysed CpG island methylation of the Dkk-3 promoter in six ALL cell lines and 183 ALL patients. We observed Dkk-3 hypermethylation in all cell lines and in cells from 33% (60/183) of ALL patients. Moreover, Dkk-3 methylation was associated with decreased Dkk-3 mRNA expression and this expression was restored after exposure to the demethylating agent 5-AzaC. Clinical features did not differ between hypermethylated and unmethylated patients. Estimated disease-free survival (DFS) and overall survival at 10 and 11 years, respectively, were 49.8 and 45.6% for normal patients and 10.5 and 15.1% for hypermethylated patients (P=0.001 and 0.09). Multivariate analysis demonstrated that Dkk-3 methylation was an independent prognostic factor predicting DFS (P=0.0009). Our data suggest that Dkk-3 methylation occurs at an early stage in ALL pathogenesis and probably influences the clinical behaviour of the disease.

The Role of Copper Suppression as an Antiangiogenic Strategy in Head and Neck Squamous Cell Carcinoma

OBJECTIVE

To determine whether tetrathiomolybdate (TM), a powerful chelator of copper, is capable of lowering the body stores of copper and suppressing the growth of head and neck squamous cell carcinoma in an orthotopic murine model.

STUDY DESIGN

In vivo, murine model.

METHODS

Twelve 8-week-old male C3H/HeJ mice were assigned to either a TM treatment group (n = 7) or a control group (n = 5). Serum samples were obtained from a single mouse in each group to measure the level of ceruloplasmin as a surrogate marker of total body copper on days 0, 4, and 7. Mice in both groups received a floor-of-mouth injection of 1.5 x 105 SCC VII/SF cells. After 7 to 10 days of tumor growth the treatment group received fresh water daily, to which TM was added to achieve an oral intake of 50 mg per mouse. The control group received only fresh drinking water daily. Tumor volume measurements were obtained every other day. Microvessel density counts were assessed in the tumors by Factor VIII analysis.

RESULTS

Measurable tumor growth was achieved in 100% of the mice by the tenth day. Total body copper was reduced by 28% from baseline levels in mice in the treatment group. The difference in mean tumor volume in the control group was 4.7 times greater than the TM-treated group at the completion of treatment (3004 mm3 and 633mm3, respectively). This accounted for an overall suppression rate of 79% (P =.008; two-tailed Student t test). In addition, microvessel density was reduced by 50% in the TM-treated group.

CONCLUSION

In this initial study, the first of its kind in head and neck squamous cell carcinoma, we have demonstrated the ability of TM to significantly suppress both the growth of squamous cell carcinoma and tumor vascularity in this orthotopic murine model, suggesting its potential for efficacy in the treatment of this disease in humans.

Neuropsychological functioning in a subclinical obsessive-compulsive sample

BACKGROUND

Previous neuropsychological research has suggested that the study of psychometrically defined subclinical samples might be a valid approach to understand the underlying pathophysiology of obsessive-compulsive disorder (OCD). This approach has the potential benefit of overcoming some of the methodological problems linked to the use of clinical samples.

METHODS

A group of subclinical obsessive-compulsive (OC) subjects (n = 35), selected on the basis of their scores on the Padua Inventory, and a control group were assessed on executive functioning tasks and other neuropsychological tests which have been demonstrated to be impaired in clinical OCD patients and/or in those with several basal ganglia disorders.

RESULTS

Subclinical OC subjects needed significantly more moves than controls to reach the solution criteria on the Tower of Hanoi puzzle, and performance on this test was positively correlated with total score and the Checking factor of the Padua Inventory. There were no between-group differences on the other frontal lobe tests.

CONCLUSIONS

The results suggest that deficits in manipulating spatial information might be basic in OCD, and are congruent with the involvement of the frontostriatal circuits in the disorder.

Subgroups among mu-opioid receptor agonists distinguished by ATP-sensitive K+ channel-acting drugs

1. We evaluated the effects of the i.c.v. administration of different K+ channel blockers (gliquidone, 4-aminopyridine and tetraethylammonium) and an opener of K+ channels (cromakalim) on the antinociception induced by several mu-opioid receptor agonists in a tail flick test in mice. 2. The s.c. administration of all agonists of mu-opioid receptors tested (morphine, 1-16 mg kg-1; metadone, 1-6 mg kg-1; buprenorphine, 0.04-0.64 mg kg-1; fentanyl, 0.02-0.32 mg kg-1 and levorphanol, 0.2-3.2 mg kg-1) elicited a dose-dependent antinociceptive effect. 3. The ATP-sensitive K+ channel blocker, gliquidone (0.06-16 micrograms per mouse, i.c.v.) antagonized the antinociception induced by buprenorphine, morphine and metadone. In contrast, gliquidone (0.25-160 micrograms per mouse) did not modify the antinociceptive effects of fentanyl and levorphanol. 4. Cromakalim (4-64 micrograms per mouse, i.c.v.), an opener of ATP-sensitive K+ channels, enhanced the antinociception produced by buprenorphine, morphine, and methadone, and did not significantly modify the antinociceptive effects of fentanyl and levorphanol. 5. The i.c.v. administration of the K+ channel blockers tetraethylammonium (10 micrograms per mouse) or 4-aminopyridine (25 ng per mouse) did not significantly modify the antinociception induced by any mu-opioid receptor agonist tested. 6. These results suggest that the opening of ATP-sensitive K+ channels is involved in the antinociceptive effect of morphine, buprenorphine and methadone, but not in that of fentanyl or levorphanol. Consequently, we suggest that at least two subgroups can be distinguished among mu-opioid receptor agonists, each inducing antinociception through different effector mechanisms.

Reliable quantification of hematopoietic chimerism after allogeneic transplantation for acute leukemia using amplification by real-time PCR of null alleles and insertion/deletion polymorphisms

Increasing mixed chimerism (MC) after allogeneic stem cell transplantation (SCT) has been associated with a high risk of relapse in acute leukemia. We evaluated a new method for chimerism detection, based on the quantitative real-time PCR (qrt-PCR) amplification of null alleles or insertion/deletion polymorphisms (indels). All qrt-PCR assays with null alleles and indels attained a sensitivity of at least 10(-4), as well as good intra- and interassay concordance, and a high accuracy in experiments with cell mixtures. Informativeness was found in 80.3% of the 61 donor/recipient pairs tested. Nonrelapsed patients showed a progressive decrease in peripheral blood chimerism to values below 0.01% (complete chimerism (CC)). Bone marrow chimerism failed to reach CC more than 4 years after SCT. Increasing MC was observed prior to relapse in 88.2% of patients. Compared with conventional PCR amplification of variable number of tandem repeats, qrt-PCR predicted a significantly higher number of relapses (88.2 vs 44.4%) with a median anticipation period of 58 days. In conclusion, chimerism determination by qrt-PCR amplification of null alleles and indels constitutes a useful tool for the follow-up of patients with acute leukemia after SCT, showing better results than those obtained with conventional PCR.

Correlation of atrophy measures on MRI with neuropsychological sequelae in children and adolescents with traumatic brain injury

To examine the relationship between neuropsychological sequelae and atrophy parameters from magnetic resonance imaging (MRI) following paediatric moderate-to-severe traumatic brain injury (TBI), 19 head injured children and adolescents were studied at least 6 years after injury. Three-dimensional MRI scans were obtained. A semi-automatic computerized method was used to estimate ventricular volumes and the corpus callosum area. Tests of intellectual, memory, visuospatial, frontal lobe, and motor speed functioning were administered to all patients and to 19 matched normal control subjects. Patients' performance significantly differed from controls in general intellectual function, visual memory, visuospatial and frontal lobe tests. The corpus callosum area correlated strongly with several measures involving processing speed and visuospatial function. Ventricular enlargement was less related to neuropsychological outcome. In conclusion, quantitative measurement of the corpus callosum on MRI reflects neuropsychological outcome better than ventricular dilation in paediatric patients.

The NMDA receptor antagonist dizocilpine (MK-801) stereoselectively inhibits morphine-induced place preference conditioning in mice

The effect of the non-competitive NMDA receptor antagonist dizocilpine (MK-801) on conditioned place preference induced by morphine was studied in mice. As expected, morphine (1-8 mg/kg, i.p.) elicited a significant preference for the drug-paired compartment. Pretreatment of mice with (+)-dizocilpine (0.1 and 0.2 mg/kg, i.p.), the more active dizocilpine enantiomer, dose-dependently reversed the conditioned place preference produced by morphine (4 mg/kg, i.p.), whereas (-)-dizocilpine (0.2 mg/kg, i.p.) did not modify morphine-induced effects. In contrast, both enantiomers of dizocilpine (at a dose of 0.2 mg/kg, i.p.) elicited a conditioned place preference. These data suggest that (1) NMDA receptors play a role in morphine-induced place preference, and (2) dizocilpine-reinforcing properties in the place preference paradigm do not seem to be dependent on NMDA receptor blockade.

Prognostic value of changes in resting-state functional connectivity patterns in cognitive recovery after stroke: A 3T fMRI pilot study

Resting‐state studies conducted with stroke patients are scarce. First objective was to explore whether patients with good cognitive recovery showed differences in resting‐state functional patterns of brain activity when compared to patients with poor cognitive recovery. Second objective was to determine whether such patterns were correlated with cognitive performance. Third objective was to assess the existence of prognostic factors for cognitive recovery. Eighteen right‐handed stroke patients and eighteen healthy controls were included in the study. Stroke patients were divided into two groups according to their cognitive improvement observed at three months after stroke. Probabilistic independent component analysis was used to identify resting‐state brain activity patterns. The analysis identified six networks: frontal, fronto‐temporal, default mode network, secondary visual, parietal, and basal ganglia. Stroke patients showed significant decrease in brain activity in parietal and basal ganglia networks and a widespread increase in brain activity in the remaining ones when compared with healthy controls. When analyzed separately, patients with poor cognitive recovery (n = 10) showed the same pattern as the whole stroke patient group, while patients with good cognitive recovery (n = 8) showed increased activity only in the default mode network and fronto‐temporal network, and decreased activity in the basal ganglia. We observe negative correlations between basal ganglia network activity and performance in Semantic Fluency test and Part A of the Trail Making Test for patients with poor cognitive recovery. A reverse pattern was observed between frontal network activity and the abovementioned tests for the same group. Hum Brain Mapp 35:3819–3831, 2014. © 2014 The Authors. Human Brain Mapping published by Wiley Periodicals, Inc.

Emotional state of patients with relapsing-remitting MS treated with interferon beta-1b

BACKGROUND

Depression has been cited as a possible side effect of interferon beta-1b (IFNbeta-1b) therapy in patients with MS. This association remains unproven because of a lack of longitudinal studies.

OBJECTIVE

To determine the changes in emotional state in relapsing-remitting (RR) MS patients during the first 2 years of treatment with IFNbeta-1b.

METHODS

Emotional state was evaluated in a sample of 90 patients at the onset of IFNbeta-1b treatment during an inclusion period of 2.5 years. Seventy-five patients were evaluated at their 12th month of treatment and 56 patients at their 24th month. We assessed their emotional state with the following psychological tests: Hamilton Depression Rating Scale, Beck Depression Inventory, and State-Trait Anxiety Inventory.

RESULTS

We found significant improvement in emotional state after the first and second years of treatment.

CONCLUSIONS

Our findings show that IFNbeta-1b does not increase depression or anxiety in RR MS patients during the first and second years of IFNbeta-1b treatment. In fact, slight but significant improvement in depression and anxiety symptoms was observed during this period.

Panton-Valentine leukocidin-positive Staphylococcus aureus skin and soft tissue infections among children in an emergency department in Madrid, Spain

Fifty-three children who attended the emergency department with community-associated (CA) Staphylococcus aureus skin and soft tissue infections (SSTIs) were enrolled in the study. Seven cases of infection (13.2%) were due to methicillin-resistant S. aureus (MRSA). Twelve of 46 available isolates (26.1%) were Panton-Valentine leukocidin (PVL)-positive. PVL-positive S. aureus SSTIs were more frequently associated with abscesses and cellulitis (75% vs. 38%, p 0.028), and more commonly required incision and drainage (75% vs. 21%, p 0.001). Most PVL-positive CA-MRSA isolates belonged to a single multilocus sequence type (ST8). In contrast, PVL-positive methicillin-susceptible S. aureus isolates belonged to four different sequence types (ST8, ST30, ST80, ST120).

Treatment of young patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia using increased dose of imatinib and deintensified chemotherapy before allogeneic stem cell transplantation

The main outcomes of the Programa Español para Tratamiento de Hemopatías (PETHEMA)-acute lymphoblastic leukaemia (ALL)-Ph-08 trial were described and compared with those of the historical PETHEMA-CSTIBES02 trial. The trials differed in imatinib dose (600 vs. 400 mg/d) and amount of chemotherapy (one vs. two consolidation cycles) before stem cell transplantation (SCT). All patients (n = 29) enrolled in the ALL-Ph-08 trial achieved complete remission (CR) (vs. 90% in CSTIBES02), and SCT was performed in CR in 90% (vs. 78%). The reduction in early death, relapse before SCT and transplant-related mortality observed in the ALL-Ph-08 trial resulted in an improved 2-year event-free survival (63% vs. 37%, P = 0·009).

Somatostatin release is enhanced in the hippocampus of partially and fully kindled rats

The release of somatostatin (somatostatin-like immunoreactivity) from hippocampal slices during the development of hippocampal kindling in rats was measured under resting and depolarizing conditions. Preliminary experiments in naive rats showed that the spontaneous efflux of somatostatin (4.0 +/- 0.3 fmol/ml every 10 min) was independent of external Ca2+ but was reduced to 71.5 +/- 6% of baseline (P < 0.05) during 20 min incubation with 5 microM tetrodotoxin. Neuronal depolarization with 25, 50 and 100 mM KCl induced a Ca(2+)-dependent somatostatin release, respectively 4.3 +/- 0.4, 16.7 +/- 1.6 and 22.0 +/- 1.3 times baseline (P < 0.01). Veratridine caused a dose-dependent Ca2+ and tetrodotoxin (5 microM) sensitive release ranging from 6.5 +/- 0.1 to 13.0 +/- 1.4 times baseline at 1.4 microM and 50 microM respectively (P < 0.01). One week after the last of three consecutive stage 5 seizures (full seizure expression) or 48 h after the last stage 2 stimulation (preconvulsive stage), 50 mM KCl-induced somatostatin release was significantly higher (1.8 +/- 0.1, P < 0.01) than in shams (animals implanted with electrodes but not stimulated) in the stimulated and contralateral hippocampus. Somatostatin release measured under resting conditions was increased by 1.5 times in the stimulated hippocampus at stage 2 (P < 0.05) and by 2.2 and 1.7 times in both hippocampi at stage 5 (P < 0.01). Forty-eight hours after the induction of a single afterdischarge no significant changes were found in either spontaneous or 50 mM KCl-induced release of somatostatin.(ABSTRACT TRUNCATED AT 250 WORDS)

Poor prognosis in acute lymphoblastic leukemia may relate to promoter hypermethylation of cancer-related genes

The hallmark of acute lymphoblastic leukemia (ALL) is a progressive appearance of malignant cell behavior that is triggered by the evolution of altered gene function. ALL has traditionally been viewed as a genetic disease; however, epigenetic defects also play an important role. DNA promoter methylation has gained increasing recognition as an important mechanism for transcriptional silencing of tumor-suppressor genes. Hypermethylation may contribute to the pathogenesis of leukemias providing an alternative route to gene mutation. We have reported that gene methylation in ALL cells is the most important way to inactivate cancer-related genes in this disease. In fact, this epigenetic event can help to inactivate tumor-suppressive apoptotic or growth-arresting responses and has prognostic impact in B- and T-ALL. The presence in individual tumors of multiple genes simultaneously methylated is an independent factor of poor prognosis in both childhood and adult ALL in terms of disease-free survival and overall survival. Moreover, methylation status is able to redefine the prognosis of selected ALL groups with well-established prognostic features.

Hypermethylation of the calcitonin gene in acute lymphoblastic leukaemia is associated with unfavourable clinical outcome

We analysed calcitonin (CALC1) gene hypermethylation using semiquantitative differential polymerase chain reaction in 105 patients with adult (n = 49) and childhood (n = 56) acute lymphoblastic leukaemia (ALL), and studied the association of CALC1 hypermethylation with clinical presentation features and disease outcome. We also investigated the possible relationship between CALC1 methylation status and expression of the cell cycle inhibitor gene p57KIP2. We observed CALC1 hypermethylation in bone marrow cells from 43% (45 out of 105) of ALL patients. Clinical, molecular and laboratory features did not differ significantly between hypermethylated and hypomethylated patients, only T-cell lineage was associated with hypermethylation (14% vs. 47%, P = 0025). Complete remission rate was similar in both groups although hypermethylated patients had a higher relapse rate (68% vs. 19%, P < 0.00001) and mortality rate (55% vs. 36%, P = 0.06) than hypomethylated patients. Estimated disease-free survival (DFS) at 6 years was 66.1% for hypomethylated patients and 5.3% for hypermethylated patients (P < 0,00001). Multivariate analysis from potential prognostic factors demonstrated that CALC1 methylation status was an independent prognostic factor in predicting DFS (P = 0.0001). Separate analysis of adult and childhood ALL patients showed similar results to the whole series. In addition, hypermethylated patients showed downregulation of p57KIP2 expression. Our results suggest that CALC1 gene hypermethylation is associated with an enhanced risk of relapse independently of known poor-prognostic factors and we describe, for the first time, a possible implication of the p57KIP2 gene in the genesis and prognosis of ALL.