Whole-genome sequencing identifies recurrent mutations in chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia (CLL), the most frequent leukaemia in adults in Western countries, is a heterogeneous disease with variable clinical presentation and evolution. Two major molecular subtypes can be distinguished, characterized respectively by a high or low number of somatic hypermutations in the variable region of immunoglobulin genes. The molecular changes leading to the pathogenesis of the disease are still poorly understood. Here we performed whole-genome sequencing of four cases of CLL and identified 46 somatic mutations that potentially affect gene function. Further analysis of these mutations in 363 patients with CLL identified four genes that are recurrently mutated: notch 1 (NOTCH1), exportin 1 (XPO1), myeloid differentiation primary response gene 88 (MYD88) and kelch-like 6 (KLHL6). Mutations in MYD88 and KLHL6 are predominant in cases of CLL with mutated immunoglobulin genes, whereas NOTCH1 and XPO1 mutations are mainly detected in patients with unmutated immunoglobulins. The patterns of somatic mutation, supported by functional and clinical analyses, strongly indicate that the recurrent NOTCH1, MYD88 and XPO1 mutations are oncogenic changes that contribute to the clinical evolution of the disease. To our knowledge, this is the first comprehensive analysis of CLL combining whole-genome sequencing with clinical characteristics and clinical outcomes. It highlights the usefulness of this approach for the identification of clinically relevant mutations in cancer.

Landscape of somatic mutations and clonal evolution in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is an aggressive tumor, but a subset of patients may follow an indolent clinical course. To understand the mechanisms underlying this biological heterogeneity, we performed whole-genome and/or whole-exome sequencing on 29 MCL cases and their respective matched normal DNA, as well as 6 MCL cell lines. Recurrently mutated genes were investigated by targeted sequencing in an independent cohort of 172 MCL patients. We identified 25 significantly mutated genes, including known drivers such as ataxia-telangectasia mutated (ATM), cyclin D1 (CCND1), and the tumor suppressor TP53; mutated genes encoding the anti-apoptotic protein BIRC3 and Toll-like receptor 2 (TLR2); and the chromatin modifiers WHSC1, MLL2, and MEF2B. We also found NOTCH2 mutations as an alternative phenomenon to NOTCH1 mutations in aggressive tumors with a dismal prognosis. Analysis of two simultaneous or subsequent MCL samples by whole-genome/whole-exome (n = 8) or targeted (n = 19) sequencing revealed subclonal heterogeneity at diagnosis in samples from different topographic sites and modulation of the initial mutational profile at the progression of the disease. Some mutations were predominantly clonal or subclonal, indicating an early or late event in tumor evolution, respectively. Our study identifies molecular mechanisms contributing to MCL pathogenesis and offers potential targets for therapeutic intervention.

Clinical impact of remote heart failure management using the multiparameter ICD HeartLogic alert.

INTRODUCTION AND OBJECTIVES: The multiparametric implantable cardioverter-defibrillator HeartLogic index has proven to be a sensitive and timely predictor of impending heart failure (HF) decompensation. We evaluated the impact of a standardized follow-up protocol implemented by nursing staff and based on remote management of alerts. METHODS: The algorithm was activated in HF patients at 19 Spanish centers. Transmitted data were analyzed remotely, and patients were contacted by telephone if alerts were issued. Clinical actions were implemented remotely or through outpatient visits. The primary endpoint consisted of HF hospitalizations or death. Secondary endpoints were HF outpatient visits. We compared the 12-month periods before and after the adoption of the protocol. RESULTS: We analyzed 392 patients (aged 69±10 years, 76% male, 50% ischemic cardiomyopathy) with implantable cardioverter-defibrillators (20%) or cardiac resynchronization therapy defibrillators (80%). The primary endpoint occurred 151 times in 86 (22%) patients during the 12 months before the adoption of the protocol, and 69 times in 45 (11%) patients (P<.001) during the 12 months after its adoption. The mean number of hospitalizations per patient was 0.39±0.89 pre- and 0.18±0.57 postadoption (P<.001). There were 185 outpatient visits for HF in 96 (24%) patients before adoption and 64 in 48 (12%) patients after adoption (P<.001). The mean number of visits per patient was 0.47±1.11 pre- and 0.16±0.51 postadoption (P<.001). CONCLUSIONS: A standardized follow-up protocol based on remote management of HeartLogic alerts enabled effective remote management of HF patients. After its adoption, we observed a significant reduction in HF hospitalizations and outpatient visits.

Different distribution of NOTCH1 mutations in chronic lymphocytic leukemia with isolated trisomy 12 or associated with other chromosomal alterations.

Chronic lymphocytic leukemia (CLL) is the most common leukemia among adults in Western countries. Chromosomal abnormalities commonly found using conventional cytogenetics and FISH are del(11)(q22-23), trisomy 12, del(13)(q14), and del(17)(p13). Trisomy 12 is the most frequent numerical abnormality in CLL. It can appear isolated or associated with other chromosomal aberrations, including t(14;18)(q32;q21) and trisomy 18. The aim of this study was to determine whether CLL patients with isolated trisomy 12 or associated with other chromosomal alterations have different clinico-pathological features, including a different distribution NOTCH1 mutation. Patients were classified into four groups: Group 1, isolated trisomy 12 (n=14); Group 2, trisomy 12 plus trisomy 18 (n=4); Group 3, trisomy 12 plus t(14;18) (n=8); and Group 4: patients with trisomy 12 plus other abnormalities not involving BCL2 (n=28). The Binet stage and expression of ZAP70 were significantly different among cytogenetic groups. NOTCH1 mutations were detected in 6/12 (50%) patients from Group 1, 4/25 (16%) patients from Group 4, and in no patient from groups 2 and 3 (P=0.020). Patients in Group 2 had a more rapid disease progression (median Treatment-free Survival 2 months) as against patients from Groups 1 (50 months), 3 (69 months), or 4 (68 months; P=0.001). These findings indicate that the distribution of NOTCH1 mutations in CLL with trisomy 12 is heterogeneous and that the presence of additional chromosomal abnormalities such as trisomy 18 could change the prognosis of these patients.

The NDDG criteria versus the IADPSG or the ADA criteria for diagnosing early-onset gestational diabetes mellitus or abnormal glucose tolerance.

OBJECTIVE: To analyze the effects of substituting the National Diabetes Data Group (NDDG) criteria with the International Association of Diabetes and Pregnancy Study Groups (IADPSG) or American Diabetes Association (ADA) criteria for the diagnosis of early-onset gestational diabetes mellitus (Early-GDM) or first trimester abnormal glucose tolerance (1 t-AGT). METHODS: A retrospective cohort study was conducted of 3200 women: 400 with Early-GDM, 800 with GDM, and 2000 with Non-GDM, according to the NDDG criteria. Rates of women with missed and new Early-GDM according to the IADPSG or ADA criteria were calculated. Multivariate logistic regression analysis was used to compare perinatal outcomes between groups. RESULTS: Using the IADPSG criteria, 61.6% of women with Early-GDM according to the NDDG were undiagnosed (Missed-Early-GDM group), and 25.9% of women with GDM and 15.7% of women with Non-GDM were diagnosed with Early-GDM (New-Early-GDM groups). Perinatal outcomes were worse in Missed-Early-GDM than in Non-GDM and better in New-Early-GDM groups than in the Early-GDM group. According to the ADA recommendations, only 11.8% of women with Early-GDM according to the NDDG criteria were diagnosed. CONCLUSION: Replacing the NDDG recommendations for the diagnosis of Early-GDM with the IADPSG or ADA criteria would mean depriving a large number of women with AGT and higher risk of adverse perinatal outcomes from early treatment and treating others with lower risk.

Methylthioadenosine phosphorylase inactivation depends on gene deletion in laryngeal squamous cell carcinoma.

AIMS: Methylthioadenosine phosphorylase (MTAP) is an essential enzyme for the methionine and adenosine salvage pathway in normal cells, frequently inactivated in many different human cancers. MTAP status could be important for tumour cell sensitivity to adjuvant chemotherapy. To our knowledge, there have been no reports to date on MTAP status in laryngeal carcinoma. METHODS AND RESULTS: A series of 31 laryngeal squamous cell carcinomas was investigated for MTAP mRNA expression using reverse transcription and quantitative polymerase chain reaction (qPCR), as well as for MTAP gene deletion and/or promoter hypermethylation using qPCR and methylation-specific PCR, respectively. Low MTAP mRNA expression was found in 32% of cases, and was associated with MTAP gene deletion (in 70%; P<0.001) but not with MTAP promoter hypermethylation, indicating that, in this tumour, gene deletion is the main mechanism for MTAP inactivation. Neither low mRNA expression nor gene deletion was associated with any of the clinicopathological parameters investigated. CONCLUSION: Given the significance of MTAP status for cell sensitivity to different chemotherapeutic regimens, our results suggest that determination of MTAP inactivation should be taken into consideration in managing laryngeal squamous cell carcinomas.

Remote heart failure management using the HeartLogic algorithm. RE-HEART registry.

INTRODUCTION AND OBJECTIVES: HeartLogic is a multiparametric algorithm incorporated into implantable cardioverter-defibrillators (ICD). The associated alerts predict impending heart failure (HF) decompensations. Our objective was to analyze the association between alerts and clinical events and to describe the implementation of a protocol for remote management in a multicenter registry. METHODS: We evaluated study phase 1 (the investigators were blinded to the alert state) and phases 2 and 3 (after HeartLogic activation, managed as per local practice and with a standardized protocol, respectively). RESULTS: We included 288 patients from 15 centers. In phase 1, the median observation period was 10 months and there were 73 alerts (0.72 alerts/patient-y), with 8 hospitalizations and 2 emergency room admissions for HF (0.10 events/patient-y). There were no HF hospitalizations outside the alert period. In the active phases, the median follow-up was 16 (95%CI, 15-22) months and there were 277 alerts (0.89 alerts/patient-y); 33 were associated with HF hospitalizations or HF death (n=6), 46 with minor decompensations, and 78 with other events. The unexplained alert rate was 0.39 alerts/patient-y. Outside the alert state, there was only 1 HF hospitalization and 1 minor HF decompensation. Most alerts (82% in phase 2 and 81% in phase 3; P=.861) were remotely managed. The median NT-proBNP value was higher within than outside the alert state (7378 vs 1210 pg/mL; P <.001). CONCLUSIONS: The HeartLogic index was frequently associated with HF-related events and other clinically relevant situations, with a low rate of unexplained events. A standardized protocol allowed alerts to be safely and remotely detected and appropriate action to be taken on them.

Ghrelin attenuates hepatocellular injury and liver fibrogenesis in rodents and influences fibrosis progression in humans.

UNLABELLED: There are no effective antifibrotic therapies for patients with liver diseases. We performed an experimental and translational study to investigate whether ghrelin, an orexigenic hormone with pleiotropic properties, modulates liver fibrogenesis. Recombinant ghrelin was administered to rats with chronic (bile duct ligation) and acute (carbon tetrachloride) liver injury. Hepatic gene expression was analyzed by way of microarray analysis and quantitative polymerase chain reaction. The hepatic response to chronic injury was also evaluated in wild-type and ghrelin-deficient mice. Primary human hepatic stellate cells were used to study the effects of ghrelin in vitro. Ghrelin hepatic gene expression and serum levels were assessed in patients with chronic liver diseases. Ghrelin gene polymorphisms were analyzed in patients with chronic hepatitis C. Recombinant ghrelin treatment reduced the fibrogenic response, decreased liver injury and myofibroblast accumulation, and attenuated the altered gene expression profile in bile duct-ligated rats. Moreover, ghrelin reduced the fibrogenic properties of hepatic stellate cells. Ghrelin also protected rats from acute liver injury and reduced the extent of oxidative stress and inflammation. Ghrelin-deficient mice developed exacerbated hepatic fibrosis and liver damage after chronic injury. In patients with chronic liver diseases, ghrelin serum levels decreased in those with advanced fibrosis, and ghrelin gene hepatic expression correlated with expression of fibrogenic genes. In patients with chronic hepatitis C, polymorphisms of the ghrelin gene (-994CT and -604GA) influenced the progression of liver fibrosis. CONCLUSION: Ghrelin exerts antifibrotic effects in the liver and may represent a novel antifibrotic therapy.

Long term clinical outcomes in survivors after out-of-hospital cardiac arrest.

INTRODUCTION AND OBJECTIVES: Information regarding long-term outcomes in patients surviving out-of-hospital cardiac arrest (OHCA) is scarce. Our aim was to study the long-term clinical outcomes of a large cohort of OHCA patients surviving until hospital discharge and to identify predictors of mortality and cardiovascular events. METHODS: Consecutive OHCA patients admitted in the Acute Cardiac Care Unit who survived at least until hospital discharge between 2007 and 2019 were included. All received therapeutic hypothermia according to the local protocol. Pre- and intra-hospital clinical and analytical variables were analyzed, as well as the clinically relevant events during follow-up. RESULTS: A total of 201 patients were included, with a mean age of 57.6 ± 14.2 years, 168 (83.6%) were male. Thirty-six (17.9%) died during a median follow-up of 40.3 months (18.9-69.1), the most frequent causes of death being cardiovascular and neurological, followed by cancer. We calculated a predictive model for mortality during follow-up using Cox regression that included the following variables: poor neurological outcome [HR 3.503 (1.578-7.777)], non-shockable rhythm [HR 2.926 (1.390-6.163)], time to onset of CPR [HR 1.063 (0.997-1.134)], older age [1.036 (1.008-1.064)) and worse ejection fraction at discharge [1.033 (1.009-1.058)]. CONCLUSIONS: Even though few patients experience recurrent cardiac arrest events, survivors after OHCA face high morbidity and mortality during long-term follow-up. Therefore, they may benefit from multidisciplinary teams providing an integral management and ensuring continuity of care.

Rupture of a thoracic aorta pseudoaneurysm: rare presentation and role of real-time 3D transoesophageal echocardiography.

A 59-year-old man presented with cardiogenic shock caused by acute right ventricular failure due to extrinsic compression of the right coronary artery by a thoracic aorta pseudoaneurysm. Angiography and real-time 3D transoesophageal echocardiography (TEE) were performed and enough diagnostic accuracy was achieved to operate on the patient without further image techniques and consequent delay. Three-dimensional TEE is a new technology that combines high-quality anatomic and colour Doppler information with bedside performance, essential in emergent clinical scenarios.

Association of CDK4 and CCND1 mRNA overexpression in laryngeal squamous cell carcinomas occurs without CDK4 amplification.

CDK4 is involved in the control of G1-S phase transition as a part of the CCND1/CDK4 complexes. CCNDI and CDK4 gene alterations have been implicated in the development of different tumors. CCND1 has been associated with progression in laryngeal carcinomas. CDK4 protein overexpression was described associated to CCND 1 overexpression in these tumors. However, the mechanisms implicated were not known. We analyzed CDK4 gene alterations and mRNA expression in a series of carcinomas of the larynx, and the results were compared to CCND1 expression and clinicopathological characteristics of the patients. CDK4 mRNA was overexpressed in 42 out of 60 tumors (70%) associated with CCND1 mRNA overexpression because 15 out of 16 cases with high CCND1 levels showed simultaneous increased levels of CDK4 mRNA (p = 0.023) and 12 (87%) of the tumors overexpressing both genes were in stage 4. No CDK4 gene amplifications, rearrangements, or mutations were detected in any of the tumors, including 24 overexpressed cases. These findings confirm that CDK4 overexpression is a frequent phenomenon in laryngeal carcinomas, which occurs at the transcriptional level but is related neither to gene amplification nor to gene mutation, and suggest that cooperation with CCND1 may be involved in the progression of laryngeal tumors.

Síndrome de activación macrofágica como desenlace de enfermedades reumatológicas: reporte de 4 casos / Macrophage activation syndrome as a result of rheumatological diseases: Report of 4 cases

RESUMEN El síndrome de activación macrofágica (SAM) es una grave complicación de varias entidades reumáticas entre las que se encuentran la artritis idiopática juvenil sistémica, enfermedad de Still y lupus eritematoso sistémico. Este síndrome forma parte de las linfohistiocitosis hemofagocíticas adquiridas y constituye una enfermedad potencialmente mortal, con difi cultad en su identificación y carencia de consensos en cuanto a su manejo. Describimos una serie de casos de pacientes con SAM, exponiendo su proceso diagnóstico, su relación con las enfermedades reumáticas de base, su seguimiento y tratamiento, así como los resultados de diferentes esquemas de manejo.

ABSTRACT Macrophage activation syndrome (MAS) is a serious complication of several rheumatic disor ders, among which are the systemic juvenile idiopathic arthritis, Still's disease and systemic lupus erythematosus. This syndrome is part of the Acquired Haemophagocytic Lymphohistiocytoses, and is a potentially fatal disease, with difficulty in its identification and a lack of consensus regarding its management. A series of cases are describe of patients with macrophage activation syndrome, explaining their diagnostic process, their relationship with rheumatic diseases, their monitoring, and treatment, as well as the results of different management schemes.

Cross-sectional study about primary health care professionals views on the inclusion of the vaccine against human papillomavirus in the vaccine schedules.

BACKGROUND: Although the inclusion of the HPV vaccine has been registered in Spain since 2007, vaccination rates are lower than expected. The patients wish to be vaccinated is heavily influenced by information they have received from many source. The Knowledge of primary health care professionals affects the information provided to patients and is fundamental in the decision making. The aim of this study is to assess the opinions of primary health care professionals on the vaccine against HPV and their knowledge about HPV infection and its links to with gynecological and oropharyngeal cancer. METHODS: Cross-sectional study. A 19-item survey was drawn up. It included questions on basic aspects of HPV infection and marketed vaccines, personal opinion about the inclusion in the immunization schedules and their level of prescription and recommendation to patients in their clinical practice. From October 2013 to December 2013, 607 surveys were distributed among 20 primary health centers affiliated to the University Hospital 12 de Octubre. The results were analyzed using SPSS statistical package. RESULTS: One hundred sixty four successfully completed surveys were obtained for analysis. 89 % of the professionals knew about the relationship between HPV infection and cervical cancer, 57.3 % did not know any of the serotypes against which vaccines are targeted; 40.4 % believed that there is insufficient data to support the commercialization of the vaccines. Of these, 65.7 % argue that there is no data of its long-term effectiveness, 13.4 % that there is no data as to its side effects, 13.4 % believed that the cost effectiveness is not worthwhile. CONCLUSIONS: There is a strong controversy among health professionals regarding the marketing and inclusion of HPV vaccine in immunization schedules. However, the knowledge of the primary care health professionals on key aspects of infection and vaccine protection are insufficient. The training of professionals in vaccination, cervical pathology and HPV infection should be improved to provide objective information on the use as this vaccine for patients.

P16(INK4a) overexpression is associated with CDKN2A mutation and worse prognosis in HPV-negative laryngeal squamous cell carcinomas.

We studied the expression of p16(INK4a) in a series of HPV-negative laryngeal squamous cell carcinomas and assessed its association with prognosis. Forty-five patients with laryngeal carcinoma were included in the study. Clinicopathological features and prognosis were reviewed. p16(INK4a) protein expression was analysed through immunohistochemistry. We analysed messenger RNA (mRNA) in 25 cases through quantitative reverse transcription polymerase chain reaction. HPV status was assessed by PCR using three different protocols based on MY09/11 and GP5/6 primers. Four out of 45 (9 %) cases overexpressed p16(INK4a) protein and showed a tendency to worse survival that was significant for stages I-III (log-rank p value = 0.001). Expression of p16(INK4a) mRNA was high in 12 out of 25 (48 %) cases using an arbitrary cut-off level. All tumours were HPV negative with all three detection methods. A CDKN2A mutation was found in eight cases. One case with a missense and one with a frameshift mutation showed p16(INK4a) protein expression by immunohistochemistry. Six out of seven (86 %) mutated but only 6 out of 18 (33 %) non-mutated cases presented p16(INK4a) mRNA overexpression (p = 0.03). Our findings suggest that p16(INK4a) overexpression, both at protein and mRNA levels, may reflect CDKN2A genetic alterations in HPV-negative laryngeal squamous cell carcinomas.

Electrocardiographic changes during induced therapeutic hypothermia in comatose survivors after cardiac arrest.

AIM: To assess the safety of therapeutic hypothermia (TH) concerning arrhythmias we analyzed serial electrocardiograms (ECG) during TH. METHODS: All patients recovered from a cardiac arrest with Glasgow < 9 at admission were treated with induced mild TH to 32-34 °C. TH was obtained with cool fluid infusion or a specific intravascular device. Twelve-lead ECG before, during, and after TH, as well as ECG telemetry data was recorded in all patients. From a total of 54 patients admitted with cardiac arrest during the study period, 47 patients had the 3 ECG and telemetry data available. ECG analysis was blinded and performed with manual caliper by two independent cardiologists from blinded copies of original ECG, recorded at 25 mm/s and 10 mm/mV. Coronary care unit staff analyzed ECG telemetry for rhythm disturbances. Variables measured in ECG were rhythm, RR, PR, QT and corrected QT (QTc by Bazett formula, measured in lead v2) intervals, QRS duration, presence of Osborn's J wave and U wave, as well as ST segment displacement and T wave amplitude in leads II, v2 and v5. RESULTS: Heart rate went down an average of 19 bpm during hypothermia and increased again 16 bpm with rewarming (P < 0.0005, both). There was a non-significant prolongation of the PR interval during TH and a significant decrease with rewarming (P = 0.041). QRS duration significantly prolonged (P = 0.041) with TH and shortened back (P < 0.005) with rewarming. QTc interval presented a mean prolongation of 58 ms (P < 0.005) during TH and a significant shortening with rewarming of 22.2 ms (P = 0.017). Osborn or J wave was found in 21.3% of the patients. New arrhythmias occurred in 38.3% of the patients. Most frequent arrhythmia was non-sustained ventricular tachycardia (19.1%), followed by severe bradycardia or paced rhythm (10.6%), accelerated nodal rhythm (8.5%) and atrial fibrillation (6.4%). No life threatening arrhythmias (sustained ventricular tachycardia, polymorphic ventricular tachycardia or ventricular fibrillation) occurred during TH. CONCLUSION: A 38.3% of patients had cardiac arrhythmias during TH but without life-threatening arrhythmias. A concern may rise when inducing TH to patients with long QT syndrome.

Circulating progenitor cells during exercise, muscle electro-stimulation and intermittent hypobaric hypoxia in patients with traumatic brain injury: a pilot study.

BACKGROUND: Circulating progenitor cells (CPC) treatments may have great potential for the recovery of neurons and brain function. OBJECTIVE: To increase and maintain CPC with a program of exercise, muscle electro-stimulation (ME) and/or intermittent-hypobaric-hypoxia (IHH), and also to study the possible improvement in physical or psychological functioning of participants with Traumatic Brain Injury (TBI). METHODS: Twenty-one participants. Four groups: exercise and ME group (EEG), cycling group (CyG), IHH and ME group (HEG) and control group (CG). Psychological and physical stress tests were carried out. CPC were measured in blood several times during the protocol. RESULTS: Psychological tests did not change. In the physical stress tests the VO2 uptake increased in the EEG and the CyG, and the maximal tolerated workload increased in the HEG. CPC levels increased in the last three weeks in EEG, but not in CyG, CG and HEG. CONCLUSIONS: CPC levels increased in the last three weeks of the EEG program, but not in the other groups and we did not detect performed psychological test changes in any group. The detected aerobic capacity or workload improvement must be beneficial for the patients who have suffered TBI, but exercise type and the mechanisms involved are not clear.

POT1 mutations cause telomere dysfunction in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is the most frequent leukemia in adults. We have analyzed exome sequencing data from 127 individuals with CLL and Sanger sequencing data from 214 additional affected individuals, identifying recurrent somatic mutations in POT1 (encoding protection of telomeres 1) in 3.5% of the cases, with the frequency reaching 9% when only individuals without IGHV@ mutations were considered. POT1 encodes a component of the shelterin complex and is the first member of this telomeric structure found to be mutated in human cancer. Somatic mutation of POT1 primarily occurs in gene regions encoding the two oligonucleotide-/oligosaccharide-binding (OB) folds and affects key residues required to bind telomeric DNA. POT1-mutated CLL cells have numerous telomeric and chromosomal abnormalities that suggest that POT1 mutations favor the acquisition of the malignant features of CLL cells. The identification of POT1 as a new frequently mutated gene in CLL may facilitate novel approaches for the clinical management of this disease.

Epigenomic analysis detects widespread gene-body DNA hypomethylation in chronic lymphocytic leukemia.

We have extensively characterized the DNA methylomes of 139 patients with chronic lymphocytic leukemia (CLL) with mutated or unmutated IGHV and of several mature B-cell subpopulations through the use of whole-genome bisulfite sequencing and high-density microarrays. The two molecular subtypes of CLL have differing DNA methylomes that seem to represent epigenetic imprints from distinct normal B-cell subpopulations. DNA hypomethylation in the gene body, targeting mostly enhancer sites, was the most frequent difference between naive and memory B cells and between the two molecular subtypes of CLL and normal B cells. Although DNA methylation and gene expression were poorly correlated, we identified gene-body CpG dinucleotides whose methylation was positively or negatively associated with expression. We have also recognized a DNA methylation signature that distinguishes new clinico-biological subtypes of CLL. We propose an epigenomic scenario in which differential methylation in the gene body may have functional and clinical implications in leukemogenesis.

Role of microsatellite instability in young patients with laryngeal carcinoma.

OBJECTIVE: To determine whether early development of carcinoma in young patients could be explained by an alternative pathway such as microsatellite instability or whether it follows the classical tumor suppressor pathway characterized by loss of heterozygosity. STUDY DESIGN: Microsatellite instability, loss of heterozygosity, and multiple mismatch repair, p16, p53, and p63 protein expression were analyzed in a series of 18 young patients with laryngeal cancer. RESULTS: Only 2 of the 18 cases showed low microsatellite instability, whereas 9 of 17 presented loss of heterozygosity in at least one of the markers tested. All cases retained multiple mismatch repair protein expression. The p53, p16, and p63 expression profiles were consistent with the classical tumor suppressor pathway. CONCLUSION: Laryngeal carcinoma in young patients develops through the classical tumor suppressor pathway.