MiR-16-5p is frequently down-regulated in astrocytic gliomas and modulates glioma cell proliferation, apoptosis and response to cytotoxic therapy.

AIMS: Aberrant expression of microRNAs (miRNAs) is frequent in various cancers including gliomas. We aimed to characterize the role of miR-16-5p as a candidate tumour suppressor miRNA in gliomas. METHODS: Real-time PCR-based approaches were used for miRNA and mRNA expression profiling of glioma and non-neoplastic brain tissues as well as glioma cell lines. Protein levels were determined by Western blotting. In vitro analyses were performed following overexpression of miR-16-5p, trichostatin A (TSA) treatment, and siRNA-mediated knock-down of HDAC3 in glioma cells. Effects of miR-16-5p on glioma cell viability, apoptosis and response to irradiation and temozolomide (TMZ) were assessed. RESULTS: Expression of miR-16-5p was reduced relative to control brain tissue in isocitrate dehydrogenase (IDH)-mutant astrocytomas of World Health Organization (WHO) grades II, III and IV, and a subset of IDH-wildtype glioblastomas WHO grade IV. MiR-16-5p expression was lower in IDH-mutant than in IDH-wildtype gliomas, and down-regulated in IDH-wildtype glioma lines. MiR-16-5p overexpression reduced expression of important cell cycle and apoptosis regulators in glioma cells, including CDK6, CDC25A, CCND3, CCNE1, WEE1, CHEK1, BCL2 and MCL1. In line, CDK6, WEE1, CHEK1, BCL2 and MCL1 transcript levels were increased in WHO grade III or IV gliomas. TSA treatment and HDAC3 knockdown in glioma cells induced miR-16-5p up-regulation and reduced expression of its targets. Moreover, miR-16-5p overexpression inhibited proliferation and induced apoptosis in various glioma cell lines and increased sensitivity of A172 glioma cells to irradiation and TMZ. CONCLUSION: Reduced expression of miR-16-5p contributes to glioma cell proliferation, survival and resistance to cytotoxic therapy.

Low incidence of heparin-induced skin lesions in orthopedic surgery patients with low-molecular-weight heparins.

BACKGROUND: Heparins are widely prescribed for prevention and therapy of arterial and venous thromboembolic diseases. Heparin-induced skin lesions are the most frequent adverse effect of subcutaneous heparin treatment in non-surgical patients (7.5%-39.8%); no data exist on surgical patients. Commonly, they are due to a delayed-type hypersensitivity reaction (DTH), but may also be a manifestation of life-threatening heparin-induced thrombocytopenia (HIT). Lesions of both entities resemble initially. The risk of HIT is highest among heparin-anticoagulated orthopedic surgery patients. OBJECTIVE: To determine incidence and causes of heparin-induced skin lesions in major orthopedic surgery patients. METHODS: In a prospective cohort study, consecutive patients with subcutaneous low-molecular-weight heparin (LMWH) treatment were examined for cutaneous adverse effects. Further diagnostics (skin biopsy, clinical/laboratory assessment for thrombosis, bleeding, HIT, cross-allergies) were performed. RESULTS: Six of 316 enrolled patients (1.9%; 95% CI: 0.4%-3.4%) developed heparin-induced skin lesions. All were caused by a DTH reaction, and none was due to HIT or other rare heparin-associated skin diseases. Therapeutic use (dosage) of LMWH was identified as only risk factor (odds ratio: 3.1, 95% CI: 1.4-4.9; P = .00141). In addition to DTH, 5 thromboembolic, 4 major bleeding complications but no cases of HIT or cross-allergies were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Orthopedic surgery patients have-unlike non-surgical patients-a low risk for heparin-induced skin lesions during LMWH treatment; all lesions were due to a DTH reaction. The risk for DTH differs considerably between individual patient cohorts. No association with HIT was observed. These data help to tailor anticoagulatory treatment individually and to increase patient safety.

Female, but not male, nematodes evolve under experimental sexual coevolution.

Coevolution between the sexes is often considered to be male-driven: the male genome is constantly scanned by selection for traits that increase relative male fertilization success. Whenever these traits are harmful to females, the female genome is scanned for resistance traits. The resulting antagonistic coevolution between the sexes is analogous to Red Queen dynamics, where adaptation and counteradaptation keep each other in check. However, the underlying assumption that male trait evolution precedes female trait counteradaptation has received few empirical tests. Using the gonochoristic nematode Caenorhabditis remanei, we now show that 20 generations of relaxed versus increased sexual selection pressure lead to female, but not to male, trait evolution, questioning the generality of a male-driven process.

Unusual acute and delayed skin reactions during and after whole-brain radiotherapy in combination with the BRAF inhibitor vemurafenib. Two case reports.

BACKGROUND: Besides radiotherapy (RT) and surgery, the introduction of BRAF inhibitors like vemurafenib has provided new opportunities for treatment of patients with metastasized malignant melanomas. RT and vemurafenib are being increasingly used concurrently, although little is known about the potential side effects of this combination. Vemurafenib is known to cause severe cutaneous skin reactions such as phototoxicity and evidence is accumulating that RT may further enhance these side effects. PATIENTS AND METHODS: We report two cases of unusual skin reactions occurring during and after treatment with a combination of vemurafenib and whole-brain irradiation in patients with cerebral metastases arising from malignant melanomas. RESULTS: One case report describes excessive acute radiodermatitis which arose during whole-brain irradiation in combination with vemurafenib. The second describes a late skin reaction occurring approximately 30 days after completion of RT. CONCLUSION: These two case reports show that combination of both treatment modalities is possible, but requires close monitoring of patients and good interdisciplinary collaboration.

Substance use and sexual risk behaviour among HIV-positive men who have sex with men in specialized out-patient clinics.

OBJECTIVES: Unprotected sexual intercourse between men who have sex with men (MSM) is the most common route of HIV infection in Germany. Approximately 70% of newly infected people are MSM. Substance use is a determinant of sexual risk behaviour in the general population, but also in the MSM subpopulation. There are only a few studies, from the USA, on the correlation between substance use and sexual risk behaviour in HIV-infected MSM in specialized care. METHODS: In a German sample of 445 HIV-infected MSM treated in specialized out-patient clinics, the influence of substance use on sexual risk behaviour was investigated. Information was obtained from subjects using self-report questionnaires and a structured interview. RESULTS: Recreational drug use was common. The prevalences of cannabis addiction (4.5%), harmful use of cannabis (4.3%) and harmful use of dissociative anaesthetics (0.4%) were higher than in the general German male population. A substantial proportion of patients reported unprotected insertive (32.9%) and receptive (34.6%) anal intercourse during the last 12 months. Use of cannabis, amyl nitrite, dissociative anaesthetics, cocaine, amphetamines and erectile dysfunction medication was significantly correlated with unprotected sexual contacts. Substance use in the context of sexual activity significantly increased sexual risk behaviour. CONCLUSIONS: Substance use, especially in the context of sexual activity, should be taken into account when developing new prevention and intervention programmes aimed at reducing sexual risk behaviour in HIV-infected MSM currently in specialized care.

[Bitemporal scalp necrosis : a very rare manifestation of giant cell arteritis]. / Bitemporale Skalpnekrose : Eine sehr seltene Manifestation der Riesenzellarteriitis.

A 71-year-old woman developed progressive spreading of bitemporal scalp necrosis within 4 weeks accompanied by headaches, myalgia of the shoulder girdle and muscle weakness that had started a few months previously. No additional diseases were reported. The suspected temporal giant cell arteritis could be confirmed by temporal artery biopsy. Therapy with glucocorticoids led to a rapid resolution of clinical symptoms and was tapered over 18 months. Recovery of the scalp necrosis emerged following second intention healing and split-skin transplantation of necrotic areas after successful wound conditioning. The case study demonstrates a rare and serious complication of temporal arteritis which is often accompanied by a poor prognosis.

Microparticles in a collisional Rf plasma sheath under hypergravity conditions as probes for the electric field strength and the particle charge.

We used microparticles under hypergravity conditions, induced by a centrifuge, in order to measure nonintrusively and spatially resolved the electric field strength as well as the particle charge in the collisional rf plasma sheath. The measured electric field strengths demonstrate good agreement with the literature, while the particle charge shows decreasing values towards the electrode. We demonstrate that it is indeed possible to measure these important quantities without changing or disturbing the plasma.

Longitudinal stability of molecular alterations and drug response profiles in tumor spheroid cell lines enables reproducible analyses.

The utility of patient-derived tumor cell lines as experimental models for glioblastoma has been challenged by limited representation of the in vivo tumor biology and low clinical translatability. Here, we report on longitudinal epigenetic and transcriptional profiling of seven glioblastoma spheroid cell line models cultured over an extended period. Molecular profiles were associated with drug response data obtained for 231 clinically used drugs. We show that the glioblastoma spheroid models remained molecularly stable and displayed reproducible drug responses over prolonged culture times of 30 in vitro passages. Integration of gene expression and drug response data identified predictive gene signatures linked to sensitivity to specific drugs, indicating the potential of gene expression-based prediction of glioblastoma therapy response. Our data thus empowers glioblastoma spheroid disease modeling as a useful preclinical assay that may uncover novel therapeutic vulnerabilities and associated molecular alterations.

Depth perception in virtual reality: distance estimations in peri- and extrapersonal space.

The present study investigated depth perception in virtual environments. Twenty-three participants verbally estimated ten distances between 40 cm and 500 cm in three different virtual environments in two conditions: (1) only one target was presented or (2) ten targets were presented at the same time. Additionally, the presence of a metric aid was varied. A questionnaire assessed subjective ratings about physical complaints (e.g., headache), the experience in the virtual world (e.g., presence), and the experiment itself (self-evaluation of the estimations). Results show that participants underestimate the virtual distances but are able to perceive the distances in the right metric order even when only very simple virtual environments are presented. Furthermore, interindividual differences and intraindividual stabilities can be found among participants, and neither the three different virtual environments nor the metric aid improved depth estimations. Estimation performance is better in peripersonal than in extrapersonal space. In contrast, subjective ratings provide a preferred space: a closed room with visible floor, ceiling, and walls.

Mutations in the human homologue of the Drosophila segment polarity gene patched (PTCH) in sporadic basal cell carcinomas of the skin and primitive neuroectodermal tumors of the central nervous system.

The human homologue of the Drosophila segment polarity gene patched (PTCH) has recently been identified as the tumor suppressor gene responsible for the nevoid basal cell carcinoma (BCC) syndrome (H. Hahn et al., Cell, 85: 841-851, 1996; R. L. Johnson et al., Science (Washington DC), 272: 1668-1671, 1996). In addition to multiple BCCs, patients with nevoid BCC syndrome have a predisposition for the development of primitive neuroectodermal tumors (PNETs) of the central nervous system. We have analyzed 9 sporadic BCCs and 37 PNETs for mutation and expression of the PTCH gene. PTCH mutations were found in 3 BCCs (33.3%) and in 5 PNETs (14%), including 1 of 5 cerebral PNETs, 2 of 15 medulloblastomas, and 2 of 17 desmoplastic medulloblastomas. The sequence changes in six of these tumors (four PNETs, two BCCs) were mutations predicted to result in truncated proteins. Missense mutations were detected in one PNET and one BCC each. In addition, novel sequence polymorphisms were found in exon 2, intron 5, intron 10, and intron 14 of PTCH. Reverse transcription-PCR analysis revealed increased PTCH expression levels compared to nonneoplastic brain tissue and normal skin in the majority of PNETs and BCCs investigated. Our data suggest that genetic alterations of PTCH are not only of significance in hereditary and sporadic BCCs but are also involved in the molecular pathogenesis of a subset of sporadic central nervous system PNETs.

Missense mutations in SMOH in sporadic basal cell carcinomas of the skin and primitive neuroectodermal tumors of the central nervous system.

About one-third of sporadic basal cell carcinomas (BCCs) of the skin and 10-15% of primitive neuroectodermal tumors (PNETs) of the central nervous system show mutations in the PTCH tumor suppressor gene. The PTCH gene product (Ptch) functions as a transmembrane receptor for the Sonic hedgehog protein (Shh) and interacts with another transmembrane protein called Smoh. To further elucidate the significance of alterations in the Shh signaling pathway, we investigated 31 sporadic BCCs and 15 PNETs for the mutation and/or expression of SMOH, PTCH, SHH, and GL11. In addition, we fine-mapped the SMOH gene locus by fluorescence in situ hybridization to chromosomal band 7q32. Mutational analysis identified four BCCs with somatic missense mutations in SMOH affecting codon 535 (TGG==>TTG: Trp==>Leu) in three tumors and codon 199 (CGG==>TGG: Arg==>Trp) in one tumor. A missense mutation at codon 533 (AGC==>AAC: Ser==>Asn) was found in one PNET. PTCH mutations were detected in eight BCCs and one PNET. Two BCCs demonstrated mutations in both SMOH and PTCH. The majority of tumors showed an increased expression of SMOH, PTCH, and GL11 transcripts as compared with that of normal skin and nonneoplastic brain tissue, respectively. In contrast, only one BCC and one PNET expressed SHH mRNA at levels detectable by reverse transcription-PCR, and no SHH gene mutations were found. In summary, our results indicate that both PTCH and SMOH represent important targets for genetic alterations in sporadic BCCs and PNETs.

Mutation of the PTEN (MMAC1) tumor suppressor gene in a subset of glioblastomas but not in meningiomas with loss of chromosome arm 10q.

The PTEN (MMAC1) gene, which has been identified as a tumor suppressor gene at 10q23.3, is mutated in multiple malignant tumors, including glioblastomas [J. Li et al., Science (Washington DC), 275: 1943-1947, 1997; P. A. Steck et al., Nat. Genet., 15: 356-362, 1997]. Among tumors of the central nervous system, loss of 10q is not restricted to glioblastomas but is also common in atypical and anaplastic meningiomas. Therefore, we have investigated 36 glioblastomas and 34 meningiomas (2 benign, 17 atypical, and 15 anaplastic meningiomas) for loss on 10q, as well as deletion, mutation, and expression of PTEN. Analysis of eight microsatellites from 10q revealed loss of heterozygosity (LOH) in 25 of 36 glioblastomas (69%). Twenty-three of these tumors demonstrated LOH at all informative loci. Two glioblastomas showed LOH restricted to markers located distally to PTEN, with breakpoints mapping telomeric to D10S541 and D10S185. One glioblastoma demonstrated evidence of homozygous deletion of PTEN by differential PCR analysis. PTEN mutations were detected in 9 of 36 glioblastomas (25%). Seven of these tumors showed LOH at all informative loci from 10q, indicating complete loss of wild-type PTEN. Although loss of 10q was detected by comparative genomic hybridization and/or LOH analysis in 14 of the 34 meningiomas investigated (41%), none of these tumors showed evidence of PTEN mutations or homozygous gene deletions. Our findings corroborate that PTEN is inactivated in a subset of glioblastomas. However, the lack of detectable PTEN alterations in a considerable fraction of glioblastomas and all meningiomas with 10q loss strongly supports the hypothesis that at least one additional tumor suppressor gene is located on 10q.

Amplification and overexpression of the MDM4 (MDMX) gene from 1q32 in a subset of malignant gliomas without TP53 mutation or MDM2 amplification.

We have previously reported on the amplification and overexpression of the MDM2 proto-oncogene in a subset of malignant gliomas without TP53 mutation (G. Reifenberger et al, Cancer Res., 53: 2736-2739, 1993). Here, we show that the MDM4 (MDMX) gene located on 1q32 is a further target for amplification in malignant gliomas. MDM4 codes for a Mdm2-related protein that can bind to p53 and inhibits p53-mediated transcriptional transactivation. We investigated a series of 208 gliomas (106 glioblastomas, 46 anaplastic gliomas, and 56 low-grade gliomas) and identified 5 tumors (4 glioblastomas and 1 anaplastic oligodendroglioma) with MDM4 amplification and overexpression. Several other genes from 1q32 were found to be coamplified with MDM4, such as GAC1 in five tumors, REN in four tumors, and RBBP5 in three tumors. Additional analyses revealed that the malignant gliomas with MDM4 amplification and overexpression carried neither mutations in conserved regions of the TP53 gene nor amplification of the MDM2 gene. Taken together, our data indicate that amplification and overexpression of MDM4 is a novel molecular mechanism by which a small fraction of human malignant gliomas escapes p53-dependent growth control.

Proteoform profiling of peripheral blood serum proteins from pregnant women provides a molecular IUGR signature.

Intrauterine growth restriction (IUGR) is an important cause of perinatal morbidity and mortality and contributes substantially to medically indicated preterm birth; preventing fetal death. Molecular profiling of the mothers' peripheral blood was desired to monitor the health conditions of the fetuses. To develop such a minimally invasive assay, we applied a protein affinity fractionation method to peripheral blood serum samples from pregnant women belonging to either the IUGR or to the control group. Proof-of-principle was shown by relative quantitation analysis of mixtures of intact proteoforms using MALDI-ToF mass spectrometry. The two best differentiating proteins and proteoforms, respectively, were apolipoprotein C-II and apolipoprotein C-III0. Together with three robustly expressed protein proteoforms proapolipoprotein C-II, apolipoprotein C-III1, and apolipoprotein C-III2, which served as landmarks for relative quantitation analysis, they constituted the maternal IUGR proteome signature. Separation confidence of our IUGR proteoform signature reached a sensitivity of 0.73 and a specificity of 0.87 with an area under curve of 0.86 in receiver operator characteristics. SIGNIFICANCE: Identification of IUGR newborns in the case room is required as children are severely diseased and need specialized care during infancy. Yet, at time of birth there is no readily applicable clinical test available. Hence, a molecular profiling assay is highly desired. It needs to be mentioned that current clinical definitions and recommendations for IUGR are unfortunately misleading and are not universally applicable. The most commonly adopted definition is an abdominal circumference (AC) or estimated fetal weight measurement <10th percentile. Although both, the American College of Obstetricians and Gynecologists (ACOG) and the Royal College of Obstetricians and Gynecologists (RCOG) agree that at this cut-off the risk of perinatal morbidity and mortality increases, this definition does not take into account the individualized growth potential of each fetus. In particular its sole use fails to identify larger fetuses that have not achieved their growth potential and may be at risk of adverse outcomes. Also, this definition, when solely applied, will result in the misdiagnosis of IUGR for some constitutionally small fetuses. It needs to be pointed out that the above mentioned criteria can only be determined during pregnancy in case mothers report from early on during pregnancy. We have developed a test that relies on mass spectrometric analysis of the mother's serum protein composition (IUGR signature) which can be determined just ahead of delivery and at date of delivery, respectively using a minimal invasive blood sampling approach. With this manuscript we describe the use of a mass spectrometric profiling method of 30 peripheral blood samples from pregnant women prior to giving birth of either unsuspicious newborns or IUGR-affected infants. We report for the first time that maternal blood sample analysis via affinity mass spectrometry differentiates IUGR infants from controls with high confidence.

Dissociable roles for histone acetyltransferases p300 and PCAF in hippocampus and perirhinal cortex-mediated object memory.

The importance of histone acetylation for certain types of memory is now well established. However, the specific contributions of the various histone acetyltransferases to distinct memory functions remain to be determined; therefore, we employed selective histone acetyltransferase protein inhibitors and short-interference RNAs to evaluate the roles of CREB-binding protein (CBP), E1A-binding protein (p300) and p300/CBP-associated factor (PCAF) in hippocampus and perirhinal cortex (PRh)-mediated object memory. Rats were tested for short- (STM) and long-term memory (LTM) in the object-in-place task, which relies on the hippocampus and PRh for spatial memory and object identity processing, respectively. Selective inhibition of these histone acetyltransferases by small-interfering RNA and pharmacological inhibitors targeting the HAT domain produced dissociable effects. In the hippocampus, CBP or p300 inhibition impaired long-term but not short-term object memory, while inhibition of PCAF impaired memory at both delays. In PRh, HAT inhibition did not impair STM, and only CBP and PCAF inhibition disrupted LTM; p300 inhibition had no effects. Messenger RNA analyses revealed findings consistent with the pattern of behavioral effects, as all three enzymes were upregulated in the hippocampus (dentate gyrus) following learning, whereas only CBP and PCAF were upregulated in PRh. These results demonstrate, for the first time, the necessity of histone acetyltransferase activity for PRh-mediated object memory and indicate that the specific mnemonic roles of distinctive histone acetyltransferases can be dissociated according to specific brain regions and memory timeframe.

[Silica-containing urinary stones--clinical issues to keep in mind]. / Silikathaltige Harnsteine im Klinikalltag. Was gibt es zu beachten?

Formation of calculi in efferent urinary passages is always due to supersaturation of urinary calculi substances and associated increased crystallization. Apart from the typical calculi, consisting of calcium oxalate, inorganic phosphates, uric acid or cystine, there are occasional signs of rare substance classes. Although more than 50 silicate stones have already been reported internationally, this stone entity remains relatively unknown. In particular, the occurrence of silicate stones in the absence of magnesium trisilicate abuse is extremely rare. A medium-sized left-sided ureterolith was removed from a 54-year-old male patient using a ureteroscope. X-ray diffraction showed it to be a compound stone consisting of 40% silicate. The patient, who in 1986 was living close to the nuclear reactor accident in Chernobyl, showed no signs of a constant uptake of magnesium trisilicate. However, he had undergone partial (2/3) gastrectomy 4 months before for a drug-refractory gastric ulcer, which had been diagnosed at the end of the 1980s and treated with excessive dosages of a magnesium trisilicate antacid preparation until the time of the operation. The patient had also been suffering from unstable angina pectoris since 1986 and treated with Pentalong (pentaerythrityltetranitrate) for 17 years. We were also able to detect silicium dioxide in components of this drug using X-ray diffraction. Silicate uroliths are extremely rare but they can be clearly identified by X-ray diffraction or infrared spectroscopy and distinguished from artifacts or quartz pebbles. Formation of calculi can be prevented by increasing diuresis as well as switching to a different drug and reducing the dosage.

[Herpetic neonatal hepatitis]. / Les hépatites herpétiques néonatales.

Herpes simplex virus (HSV) infection can affect various organs-systems in the neonatal period. Herpetic hepatitis was seldom reported in the literature. We report on 2 cases. Firstly, a 16 day-old newborn infant was admitted because of haemorrhagic syndrome and shock. Biological assessment showed a severe hepatic insufficiency. Antibiotic and aciclovir therapy was started as HSV infection was suspected. Five days later, the herpetic attack was confirmed by polymerase chain reaction (PCR) in blood and cerebrospinal fluid (CSF). The genotye of the virus in the CSF was HSV1. Treatment included aciclovir for 21 days intravenously and 2 months orally. At 10 months, the clinical and biological examinations were normal. Secondly, a 4 day-old newborn was hospitalised because of fever and polypnea. Pulmonary X rays showed heterogeneous opacities of the right base. Serum C reactive protein was 30 mg/l. Antibiotic therapy was started. Two days later, the fever persisted while a severe hepatic insufficiency developed. The diagnosis of herpetic hepatitis was evoked and the child was given aciclovir. Forty-eight hours later, the PCR confirmed a HSV in blood, while viral culture of a mouth swab found HSV 2. Evolution was favourable after 21 days of specific and symptomatic treatment. Aciclovir treatment was continued orally for six months. Herpetic hepatitis is rare in the neonatal period. Diagnosis must be evoked early when facing severe neonatal hepatic insufficiency. Provided specific treatment, prognosis is good.

[Obstetrical risk factors of 365 primiparous adolescent pregnancies in Reunion Island]. / Etude des facteurs de risques obstétricaux dans le suivi de 365 grossesses primipares adolescentes à l'île de la Réunion.

OBJECTIVES: Analysis of obstetrical risk factors in teenage primiparous pregnancies in Reunion Island (4% of total births). MATERIALS AND METHODS: Retrospective study, between 2001 and 2002, comparing primiparous adolescents (13-17 years, n = 365), with primiparous controls (18-29 years, n = 2050). The analysis included demographical factors, maternal medical histories, prenatal follow-up, obstetrical risk factors, delivery modes and neonatal characteristics. RESULTS: Adolescents attended on average 8 prenatal consultations, however 4% had poor prenatal care (less than 3 visits, OR 4.2, P < 0.001 vs controls). They presented less gestational diabetes, but there were no differences concerning pre-existing hypertension, hypertensive disorders of pregnancy, medical reasons of hospitalisation between the two groups. Mode of delivery was more favorable in adolescents (half rate of caesarean sections, shorter duration of membrane ruptures). Nevertheless, adolescents presented a higher risk of severe prematurity (<32 Weeks gestation, incidence 3.6% vs 1.6%, OR 2.3, p = 0.008). CONCLUSION: With optimal prenatal care (more than 90% of our cohort), primiparous adolescents present globally a favorable course of their pregnancies and have better deliveries than their young (18-29 years) counterparts. However, there is a significant risk of severe prematurity requiring special care for these pregnancies.

Activation of a cryptic splice site of PTEN and loss of heterozygosity in benign skin lesions in Cowden disease.

Cowden disease is an autosomal dominant syndrome characterized by facial trichilemmomas, acral keratoses, papillomatous papules, mucosal lesions, and an increased risk for breast and nonmedullary thyroid cancer. Here, we describe a novel PTEN splicing site mutation in a family with classical Cowden disease and we studied benign skin lesions typical for Cowden disease for loss of heterozygosity. We found a PTEN IVS2 + 1G > Alpha 5'-splicing acceptor mutation resulting in activation of a cryptic splice site. Activation of this cryptic splice site is predicted to result in a frameshift with a premature stop codon, thus disrupting the phosphatase core motif of PTEN. Loss of heterozygosity analysis of two trichilemmomas, one fibroma, and three acanthomas of the index patient demonstrated loss of heterozygosity at the PTEN locus in four of these lesions. In conclusion, our data demonstrate that a PTEN splicing site mutation causes activation of a cryptic splice site, which results in aberrant transcripts.