ABSTRACT
The COVID-19 outbreak is now one of the most critical crises to manage for most of national healthcare systems in the world. The situation is complicated by the absence of vaccines and authorized pharmacological treatments, except for remdesivir. In this context, many medicaments, including different Ebola and HIV antivirals, are used off-label in the hospital wards as life-treating medicines for COVID-19 patients. Authorized medicaments manipulation is sometimes necessary because they are not always formulated to be administered to non-cooperative patients or they are in shortage. It is this the case of the fixed combination of lopinavir/ritonavir, which was extensively used in the first phase of the outbreak inducing a shortage of the oral solution available in the EU market. This work provides data on size distribution, osmolarity other than drug chemical stability of a lopinavir/ritonavir extemporaneous preparation made by using the solid dosage form (i.e., tablet) available on the market as drug source. The reported data indicate that such preparation is suitable to be delivered through a nasogastric tube, and enough stable for two weeks from the preparation at room temperature.
ABSTRACT
Drift of floating debris is studied with a 2D Lagrangian model with stochastic beaching and sedimentation of plastics. An ensemble of >1010 virtual particles is tracked from anthropogenic sources (coastal human populations, rivers, shipping lanes) to environmental destinations (sea surface, coastlines, seabed). Daily analyses of ocean currents and waves provided by CMEMS at a horizontal resolution of 1/16° are used to force the plastics. High spatio-temporal variability in sea-surface plastic concentrations without any stable long-term accumulations is found. Substantial accumulation of plastics is detected on coastlines and the sea bottom. The most contaminated areas are in the Cilician subbasin, Catalan Sea, and near the Po River Delta. Also, highly polluted local patches in the vicinity of sources with limited circulation are identified. An inverse problem solution, used to quantify the origins of plastics, shows that plastic pollution of every Mediterranean country is caused primarily by its own terrestrial sources.
Subject(s)
Environmental Monitoring/methods , Models, Theoretical , Plastics/analysis , Seawater/chemistry , Waste Products/analysis , Human Activities , Humans , Mediterranean Sea , Monte Carlo Method , Spatio-Temporal AnalysisABSTRACT
We investigated in ninety Caucasian pediatric patients the impact of the main polymorphisms occurring in CYP3A, CYP2D6, ABCB1 and ABCG2 genes on second-generation antipsychotics plasma concentrations, and their association with the occurrence of adverse drug reactions. Patients with the CA/AA ABCG2 genotype had a statistically significant lower risperidone plasma concentration/dose ratio (Ct/ds) (P-value: 0.007) and an higher estimated marginal probability of developing metabolism and nutrition disorders as compared to the ABCG2 c.421 non-CA/AA genotypes (P-value: 0.008). Multivariate analysis revealed that the ABCG2 c.421 CA/AA genotype was found associated to a higher hazard (P-value: 0.004) of developing adverse drug reactions classified as metabolism and nutrition disorders. The ABCB1 2677TT/3435TT genotype had a statistically significant lower aripiprazole Ct/ds if compared with patients with others ABCB1 genotypes (P-value: 0.026). Information obtained on ABCB1 and ABCG2 gene variants may result useful to tailor treatments with these drugs in Caucasian pediatric patients.
Subject(s)
Aripiprazole/blood , Drug-Related Side Effects and Adverse Reactions/genetics , Risperidone/blood , Schizophrenia/blood , ATP Binding Cassette Transporter, Subfamily B/genetics , ATP Binding Cassette Transporter, Subfamily G, Member 2/genetics , Adolescent , Aripiprazole/administration & dosage , Child , Child, Preschool , Cytochrome P-450 CYP2D6/genetics , Cytochrome P-450 CYP3A/genetics , Drug-Related Side Effects and Adverse Reactions/blood , Drug-Related Side Effects and Adverse Reactions/pathology , Female , Genotype , Humans , Male , Neoplasm Proteins/genetics , Olanzapine/administration & dosage , Olanzapine/blood , Pediatrics/trends , Polymorphism, Genetic , Quetiapine Fumarate/administration & dosage , Quetiapine Fumarate/blood , Risperidone/administration & dosage , Schizophrenia/drug therapy , Schizophrenia/pathology , Young AdultABSTRACT
International guidelines consider quetiapine at medium doses (300-400 mg/day) as valid options for the treatment of bipolar depression for the supposed lower risk of a switch to hypomania/mania than antidepressants. Norquetiapine is an active metabolite with antidepressant action. We describe three cases of induced hypomania in bipolar type 2 subjects who received quetiapine extended-release monotherapy (300 mg/day) for a mild/moderate major depressive episode. Quetiapine and norquetiapine plasma concentrations were measured after 1 week of treatment. Hypomania appeared after 7-10 days of quetiapine extended-release monotherapy and all subjects had a quetiapine/norquetiapine plasma concentration ratio <1. We propose a ratio value <1 as a predictor of risk for a switch to hypomania in bipolar depressed subjects receiving quetiapine extended-release monotherapy. Future research should ascertain the validity of this laboratory parameter to assess the risk of quetiapine-induced hypomania in large samples of bipolar patients.
ABSTRACT
BACKGROUND: Tenofovir (TDF) is one of the most widely used antiretroviral drug. Despite the high degree of tolerability a small percentage of patients experienced alteration in tubular function during TDF use. Intracellular TDF disposition is regulated by ATP-binding cassette (ABC) drug efflux transporters and, a reduced transport activity may be implicated in accumulation of TDF into the cells. The aim of our study was to assess the major determinants of TDF associated tubular dysfunction (KTD) in a real-life setting including the usefulness of single-nucleotide polymorphisms (SNPs) mapping into ABCC2, ABCC4 and ABCC10 genes. METHODS: We retrospectively analyzed all HIV positive patients who were followed at the Infectious Diseases Unit, DIBIC Luigi Sacco, University of Milan from April 2013 to June 2016. All patients treated with TDF who underwent a genotypization for the functional variants mapping in ABCC2 rs717620 (-24 C > T), ABCC4 rs1751034 (3463 A > G) and ABCC10 rs2125739 (T > C) were evaluated. KTD was defined as the presence of urine phosphate wasting and/or proteinuria at 24 h urine analysis. RESULTS: One hundred fifty-eight patients were genotyped, of which 42 (26.6%) experienced signs of KTD. No statistical significant differences were observed among patients with or without KTD regarding age, gender, ethnicity and comorbidities (hypertension and diabetes). The percentage of patients with KTD was higher among those with "GG" genotype at rs1751034 of ABCC4 compared to patients without KTD [6 (14.3%) vs 4 (3.5%), p = 0.01]. No statistical significant differences were observed regarding the distribution of ABCC2 and ABCC10 SNPs. Carriers of "G" allele in homozygous status at rs1751034 of ABCC4 showed a significant association with KTD (Odds Ratio 4.67, 95% CI 1.25-17.46, p = 0.02) in bivariate analysis, but this association was lost in multivariable analysis. A significant association between bone diseases and KTD was observed (Odds Ratio 3.178, 95%CI 1.529-6.603, p = 0.002). CONCLUSIONS: According to our results ABCC4 rs1751034 could be a genetic determinant of KTD; however validation studies are needed for therapy personalization. Noteworthy, a strong association between bone disease and KTD was also observed.
Subject(s)
Anti-HIV Agents/adverse effects , Kidney Diseases/chemically induced , Kidney Diseases/genetics , Polymorphism, Single Nucleotide , Tenofovir/adverse effects , Adult , Alleles , Cohort Studies , Female , HIV Infections/drug therapy , Humans , Kidney Diseases/physiopathology , Male , Middle Aged , Multidrug Resistance-Associated Protein 2 , Multidrug Resistance-Associated Proteins/genetics , Proteinuria/chemically inducedABSTRACT
Single-nucleotide polymorphisms (SNPs) related to hereditary thrombophilia were investigated as risk factors for thromboembolism in cancer patients. Their effect in metastatic colorectal cancer (mCRC) has never been explored so far. Our aim was to analyse the effect of coagulation factor V (FVL G1691A), prothrombin (PT G20210A), methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and plasminogen activator inhibitor type 1 (PAI-1 5G/4G) allelic variants in this setting. Fifty-two patients treated with first-line chemotherapy plus bevacizumab who developed a thromboembolic event in their lifetime were initially genotyped. A contemporary cohort of 127 patients who did not experience any thromboembolic event was also analysed. DNA was extracted from peripheral blood and genotypes were determined by real-time PCR, using LightSNiP (TIB MOLBIOL) on LightCcler 480 (Roche). The association between thromboembolism and SNPs was investigated by univariable and multivariable analyses. All SNPs were in Hardy-Weinberg equilibrium (χ2 test P>0.20). FVL G1691A and PT G20210A were present only in heterozygosis in 4 (2.2%) and 7 (3.9%) patients, respectively; MTHFR C677T in homozygosis in 29 (16.2%), MTHFR A1298C in homozygosis in 13 (7.3%); PAI-1 5G/4G in 98 (54.7%) and 4G/4G in 41 (23%) patients. At univariable analysis, treatment duration was significantly associated with thromboembolism (P<0.001), whereas gender, age, obesity, platelets count and chemotherapy backbone were not. Similarly, FVL G1691A and PT G20210A as well as MTHFR C677T and PAI-1 4G allele were significantly associated, whereas MTHFR A1298C was not. At multivariable model including PT G20210A, MTHFR C677T and PAI-1 4G (age, obesity, treatment duration and chemotherapy backbone were included as adjustment factors), the three SNPs were significantlty associated with higher risk of thromboembolism (P=0.025, <0.0001 and P=0.033, respectively). Further validation studies are warranted in order to design a prospective trial of thromboprophylaxis in mCRC patients with high-risk genotypes.
Subject(s)
Colorectal Neoplasms/genetics , Factor V/genetics , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Plasminogen Activator Inhibitor 1/genetics , Polymorphism, Single Nucleotide/genetics , Prothrombin/genetics , Thromboembolism/genetics , Adult , Aged , Alleles , Bevacizumab/therapeutic use , Colorectal Neoplasms/drug therapy , Female , Genetic Predisposition to Disease/genetics , Genotype , Humans , Male , Middle Aged , Prospective Studies , RiskABSTRACT
WHAT IS KNOWN AND OBJECTIVES: The occurrence of dysgraphia after sertraline intake has never been reported. The objective was to describe a case of this adverse drug reaction and present a review of similar cases held in international databases with a discussion of the possible pharmacological mechanisms. CASE SUMMARY: We observed a 60-year-old man who experienced resting tremors, dyskinesia and dysgraphia 2 months after a stepwise increase in sertraline dosing from 50 to 200 mg/day. WHAT IS NEW AND CONCLUSION: Dysgraphia is a possible adverse drug reaction to sertraline, and we suggest that inhibition of extrapyramidal dopaminergic activity might be the pharmacological mechanism.
Subject(s)
Agraphia/chemically induced , Selective Serotonin Reuptake Inhibitors/adverse effects , Sertraline/adverse effects , Adverse Drug Reaction Reporting Systems , Databases, Factual , Dopamine/metabolism , Dose-Response Relationship, Drug , Humans , Male , Middle Aged , Selective Serotonin Reuptake Inhibitors/administration & dosage , Sertraline/administration & dosageABSTRACT
Toll-like receptors (TLRs) are a class of pattern recognition receptors that are deputed to recognise a range of molecular structures in pathogens. One of the most studied members of this family is the TLR4, which is essential for the signalling of lipopolysaccharide. The gene encoding for TLR4 is highly polymorphic and this genetic variability may explain in part the interindividual variability observed in several clinical setting, including the response to vaccination. Herein, we review and systematise the available scientific evidence about the effect of TLR4 polymorphisms on vaccine response, including approved prophylactic, new therapeutic cancer vaccines and recently approved vaccine adjuvants. Data reviewed in this analysis indicate that TLR4 polymorphisms significantly affect vaccine response. If these results are confirmed by further analyses, the use of these genetic biomarkers may become a useful tool to tailor vaccination in specific subsets of patients.
Subject(s)
Toll-Like Receptor 4/genetics , Vaccines/immunology , Adjuvants, Immunologic/physiology , Animals , Cancer Vaccines/immunology , Humans , Measles Vaccine/immunology , Meningococcal Vaccines/immunology , Pertussis Vaccine/immunology , Polymorphism, Single NucleotideSubject(s)
Benzoates/adverse effects , Glucuronosyltransferase/genetics , Iron Chelating Agents/adverse effects , Multidrug Resistance-Associated Proteins/genetics , Thalassemia/genetics , Triazoles/adverse effects , ATP Binding Cassette Transporter, Subfamily G, Member 2 , ATP-Binding Cassette Transporters/genetics , Benzoates/blood , Benzoates/therapeutic use , Child, Preschool , Deferasirox , Female , Humans , Iron Chelating Agents/therapeutic use , Multidrug Resistance-Associated Protein 2 , Neoplasm Proteins/genetics , Polymorphism, Single Nucleotide , Thalassemia/blood , Thalassemia/drug therapy , Triazoles/blood , Triazoles/therapeutic useABSTRACT
WHAT IS KNOWN AND OBJECTIVES: To date, no case of headache has been reported with enoxaparin. We present the case of a 60-years-old man, who developed enoxaparin-induced throbbing headache and discuss the possible pharmacological mechanisms. We provide an analysis of enoxaparin-induced headache in three international databases. CASE SUMMARY: A few hours after the subcutaneous administration of this drug at therapeutic dose, the patient experienced throbbing headache. Rechallenge on two other separate occasions separated by several days produced the same effect although with reduced intensity when the dose was lowered. The Naranjo Algorithm indicated a 'certain' relationship. WHAT IS NEW AND CONCLUSION: We report a case of throbbing headache associated with the use of enoxaparin; with the increasing use of enoxaparin, physicians who prescribe this drug should be aware of this potential ADR. We suggest that it is a heparin class-effect, and therefore, a more general caution is also appropriate.
Subject(s)
Anticoagulants/adverse effects , Enoxaparin/adverse effects , Headache/chemically induced , Anticoagulants/administration & dosage , Databases, Factual , Dose-Response Relationship, Drug , Enoxaparin/administration & dosage , Humans , Male , Middle Aged , PharmacovigilanceABSTRACT
Mitochondrial fission and fusion are essential processes in the maintenance of the skeletal muscle function. The contribution of these processes to muscle development has not been properly investigated in vivo because of the early lethality of the models generated so far. To define the role of mitochondrial fission in muscle development and repair, we have generated a transgenic mouse line that overexpresses the fission-inducing protein Drp1 specifically in skeletal muscle. These mice displayed a drastic impairment in postnatal muscle growth, with reorganisation of the mitochondrial network and reduction of mtDNA quantity, without the deficiency of mitochondrial bioenergetics. Importantly we found that Drp1 overexpression activates the stress-induced PKR/eIF2α/Fgf21 pathway thus leading to an attenuated protein synthesis and downregulation of the growth hormone pathway. These results reveal for the first time how mitochondrial network dynamics influence muscle growth and shed light on aspects of muscle physiology relevant in human muscle pathologies.
Subject(s)
Dynamins/metabolism , Muscle, Skeletal/metabolism , Animals , Blotting, Western , DNA, Mitochondrial/metabolism , Dynamins/genetics , Immunoprecipitation , Membrane Potential, Mitochondrial/genetics , Membrane Potential, Mitochondrial/physiology , Mice , Mice, Transgenic , Oxygen Consumption/physiologyABSTRACT
Until now, the occurrence of adverse reactions among individuals inoculated with identical vaccines has been ascribed to unpredictable stochastic processes. Recent advances in pharmacogenomics indicate that some features of host response to immunisation are influenced by genetic traits, henceforth predictable. The ability to predict the adverse reaction to vaccination would represent an important step towards the development of personalised vaccinology and could enhance public confidence in the safety of vaccines. Herein, we have reviewed all the available information on the association between genetic variants and the risk for healthy subjects to develop adverse reactions.
Subject(s)
Drug-Related Side Effects and Adverse Reactions/genetics , Genetic Variation/genetics , Vaccination/adverse effects , Vaccines/adverse effects , Humans , Pharmacogenetics/methods , RiskABSTRACT
Patients with brain injury are prone to bacterial colonisations because of mechanical ventilation during intensive care and the long-term retention of tracheostomical tubes during rehabilitation. Reduced levels of isolation, typical of rehabilitation, could also contribute to propagate colonisations. We evaluated the presence of bacteria through different stages of healthcare, their antibiotic resistances and their clinical impact in a rehabilitation setting. This retrospective study included all tracheostomised patients referred to the paediatric brain injury unit of the Scientific Institute IRCCS E. Medea (Italy) over a six-year period. Data were collected from antibiograms regarding the presence of bacterial species and antibiotic resistances; clinical data were collected from medical records. Antibiograms revealed bacteria and antibiotic resistances typical of intensive care, while prevalence patterns were characteristic for each species (P. aeruginosa and S. aureus prevailing in the acute setting, K. pneumoniae, A. baumannii and others in rehabilitation). Despite very frequent antibiotic resistances, consistent with Italian averages, we observed a limited clinical impact for these colonisations. We analysed risk factors correlating to the development of respiratory symptoms and found a role for the acute clinical course after brain injury (having undergone neurosurgery; duration of intensive care stay) as well as for rehabilitation (duration of coma). Our data suggest that, in a long-term perspective, an appropriate balance is yet to be found between patient isolation and social interactions, to control respiratory colonisations and antibiotic resistances without compromising rehabilitation. They also suggest that regular containment measures should be complemented by thorough training to non-medic personnel and parents alike.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Bacterial Infections/epidemiology , Carrier State/epidemiology , Drug Resistance, Bacterial , Tracheostomy/adverse effects , Adolescent , Bacteria/isolation & purification , Bacterial Infections/microbiology , Carrier State/microbiology , Child , Child, Preschool , Cohort Studies , Female , Humans , Infant , Italy/epidemiology , Male , Microbial Sensitivity Tests , Prevalence , Rehabilitation Centers , Retrospective Studies , Risk Factors , Young AdultABSTRACT
The invertebrate model Galleria mellonella is a widely used factitious host to study the microbial pathogenesis in vivo. However, a specific procedure for the recovery and the processing of the infected tissues, important for a better understanding of the host-pathogen interactions, has not been reported to our knowledge. In the present study we describe a new procedure of fixation and processing of larval tissue that allows studying the larval topographic anatomy and assessing the morphological changes due to the fungal infection. Lepidopteran larvae were infected with Candida albicans strains displaying various biofilm-forming abilities. The whole larvae were then examined for tissue changes by histological techniques. We show that comparing cutting planes, serial transversal sections of paraffin-embedded larva result in better accuracy and information recovering. Using this technique, it was possible to preserve the integrity of G. mellonella internal structures allowing the detailed analysis of morphological differences in different experimental groups (i.e., healthy vs infected larvae). We were also able to study strain-related differences in the pathogenesis of C. albicans by observing the immune response elicited and the invasiveness of two isolates within the larval tissues. In general, by processing the whole larva and optimizing routinely histochemical stainings, it is possible to visualize and analyse infected tissues. Various degrees of pathogenicity (strain- or inoculum-related), and the infection time course can be described in details. Moreover, the host immune response events can be followed throughout the infectious process leading to a comprehensive picture of the studied phenomenon.
Subject(s)
Candida albicans/physiology , Moths/microbiology , Tissue Fixation/methods , Animals , Disease Models, Animal , Host-Pathogen Interactions , LarvaABSTRACT
Bacterial meningitis is an important source of mortality and morbidity worldwide. Data exist on specific vaccines against Streptococcus pneumoniae and Neisseria meningitidis indicating that they reduce the incidence of meningitis, yet comprehensive information on the trend of bacterial meningitis is still lacking. We analysed the Kids' Inpatient Database and the National Inpatient Database considering all bacterial meningitides in the United States, excluding cases of tuberculosis and sexually transmitted diseases. We analysed the trend of meningitis incidence from 1993 to 2011 and in specific age groups before and after the introduction of the pneumococcal conjugate vaccine 7 (PCV-7) and the meningococcal conjugate vaccine 4 (MCV-4). Moreover, we analysed the prevalence of aetiological agents to assess their changes. We estimated 295,706 cases of meningitis having occurred in the United States and a reduction of the discharge rate of 21 %. We observed a significant reduction in cases of meningitis in children and elderly patients following the introduction of the PCV-7. We also found a reduction in subjects aged 10-14 years, an age span consistent with the introduction of MCV-4, although further analyses based on serotypes data are required to confirm this observation. By contrast, we observed an increased prevalence of cases of staphylococcal and streptococcal meningitides. The introduction of PCV-7 has reduced the incidence and changed significantly the aetiology of bacterial meningitis in the United States during the last two decades.
Subject(s)
Hospitalization , Meningitis, Bacterial/epidemiology , Adolescent , Adult , Aged , Bacteria/classification , Bacteria/isolation & purification , Child , Child, Preschool , Female , Heptavalent Pneumococcal Conjugate Vaccine , Humans , Incidence , Infant , Infant, Newborn , Male , Meningitis, Bacterial/etiology , Meningococcal Vaccines/administration & dosage , Middle Aged , Pneumococcal Vaccines/administration & dosage , Prevalence , United States/epidemiology , Young AdultABSTRACT
WHAT IS KNOWN AND OBJECTIVE: Dantrolene can be combined with baclofen to better treat spasticity, but may cause muscular weakness and dysphagia. We instead describe a pharyngeal spasm due to dantrolene. CASE SUMMARY: A 12-year-old male received dantrolene 3 mg/kg/day in adjunct to baclofen 2 mg/kg/day, to improve spasticity. After 5 days of full-dose dantrolene, his dysphagia worsened and he developed pharyngeal spasm. Dantrolene was suspected for an adverse reaction and removed. The patient subsequently improved. WHAT IS NEW AND CONCLUSION: Causality analysis determined a probable relationship between dantrolene and pharyngeal spasm. This may be due to direct muscle contraction by dantrolene, an effect seen previously in vitro.
Subject(s)
Dantrolene/adverse effects , Muscle Relaxants, Central/adverse effects , Muscle Spasticity/chemically induced , Pharyngeal Diseases/chemically induced , Baclofen/administration & dosage , Child , Dantrolene/administration & dosage , Deglutition Disorders/chemically induced , Drug Therapy, Combination , Humans , Male , Muscle Contraction/drug effects , Muscle Relaxants, Central/administration & dosage , Muscle Spasticity/physiopathology , Pharyngeal Diseases/physiopathologyABSTRACT
Intrauterine growth restriction (IUGR) and pregnancy hypertensive disorders such as preeclampsia (PE) associated with IUGR share a common placental phenotype called "placental insufficiency", originating in early gestation when high availability of energy is required. Here, we assess mitochondrial content and the expression and activity of respiratory chain complexes (RCC) in placental cells of these pathologies. We measured mitochondrial (mt)DNA and nuclear respiratory factor 1 (NRF1) expression in placental tissue and cytotrophoblast cells, gene and protein expressions of RCC (real-time PCR and Western blotting) and their oxygen consumption, using the innovative technique of high-resolution respirometry. We analyzed eight IUGR, six PE, and eight uncomplicated human pregnancies delivered by elective cesarean section. We found lower mRNA levels of complex II, III, and IV in IUGR cytotrophoblast cells but no differences at the protein level, suggesting a posttranscriptional compensatory regulation. mtDNA was increased in IUGR placentas. Both mtDNA and NRF1 expression were instead significantly lower in their isolated cytotrophoblast cells. Finally, cytotrophoblast RCC activity was significantly increased in placentas of IUGR fetuses. No significant differences were found in PE placentas. This study provides genuine new data into the complex physiology of placental oxygenation in IUGR fetuses. The higher mitochondrial content in IUGR placental tissue is reversed in cytotrophoblast cells, which instead present higher mitochondrial functionality. This suggests different mitochondrial content and activity depending on the placental cell lineage. Increased placental oxygen consumption might represent a limiting step in fetal growth restriction, preventing adequate oxygen delivery to the fetus.
Subject(s)
Fetal Growth Retardation/metabolism , Mitochondria/metabolism , Placenta/metabolism , Pre-Eclampsia/metabolism , Adult , DNA, Mitochondrial/metabolism , Female , Fetal Growth Retardation/pathology , Fetal Growth Retardation/physiopathology , Humans , Infant, Newborn , Mitochondria/pathology , Nuclear Respiratory Factor 1/metabolism , Oxygen Consumption , Placenta/pathology , Placenta/physiopathology , Pre-Eclampsia/pathology , Pre-Eclampsia/physiopathology , Pregnancy , Trophoblasts/metabolism , Trophoblasts/pathologyABSTRACT
Melanoma is a rapidly growing and highly metastatic cancer with high mortality rates, for which a resolutive treatment is lacking. Identification of novel therapeutic strategies and biomarkers of tumour stage is thus of particular relevance. We report here on a novel biomarker and possible candidate therapeutic target, the sphingolipid metabolising enzyme acid sphingomyelinase (A-SMase). A-SMase expression correlates inversely with tumour stage in human melanoma biopsies. Studies in a mouse model of melanoma and on cell lines derived from mouse and human melanomas demonstrated that A-SMase levels of expression actually determine the malignant phenotype of melanoma cells in terms of pigmentation, tumour progression, invasiveness and metastatic ability. The action of A-SMase is mediated by the activation of the extracellular signal-regulated kinase, the subsequent proteasomal degradation of the Microphtalmia-associated transcription factor (Mitf) and inhibition of cyclin-dependent kinase 2, Bcl-2 and c-Met, downstream targets of Mitf involved in tumour cell proliferation, survival and metastatisation.