RUNX3 is oncogenic in natural killer/T-cell lymphoma and is transcriptionally regulated by MYC.

RUNX3, runt-domain transcription factor, is a master regulator of gene expression in major developmental pathways. It acts as a tumor suppressor in many cancers but is oncogenic in certain tumors. We observed upregulation of RUNX3 mRNA and protein expression in nasal-type extranodal natural killer (NK)/T-cell lymphoma (NKTL) patient samples and NKTL cell lines compared to normal NK cells. RUNX3 silenced NKTL cells showed increased apoptosis and reduced cell proliferation. Potential binding sites for MYC were identified in the RUNX3 enhancer region. Chromatin immunoprecipitation-quantitative PCR revealed binding activity between MYC and RUNX3. Co-transfection of the MYC expression vector with RUNX3 enhancer reporter plasmid resulted in activation of RUNX3 enhancer indicating that MYC positively regulates RUNX3 transcription in NKTL cell lines. Treatment with a small-molecule MYC inhibitor (JQ1) caused significant downregulation of MYC and RUNX3, leading to apoptosis in NKTL cells. The growth inhibition resulting from depletion of MYC by JQ1 was rescued by ectopic MYC expression. In summary, our study identified RUNX3 overexpression in NKTL with functional oncogenic properties. We further delineate that MYC may be an important upstream driver of RUNX3 upregulation and since MYC is upregulated in NKTL, further study on the employment of MYC inhibition as a therapeutic strategy is warranted.

JAK-STAT and G-protein-coupled receptor signaling pathways are frequently altered in epitheliotropic intestinal T-cell lymphoma.

Epitheliotropic intestinal T-cell lymphoma (EITL, also known as type II enteropathy-associated T-cell lymphoma) is an aggressive intestinal disease with poor prognosis and its molecular alterations have not been comprehensively characterized. We aimed to identify actionable easy-to-screen alterations that would allow better diagnostics and/or treatment of this deadly disease. By performing whole-exome sequencing of four EITL tumor-normal pairs, followed by amplicon deep sequencing of 42 tumor samples, frequent alterations of the JAK-STAT and G-protein-coupled receptor (GPCR) signaling pathways were discovered in a large portion of samples. Specifically, STAT5B was mutated in a remarkable 63% of cases, JAK3 in 35% and GNAI2 in 24%, with the majority occurring at known activating hotspots in key functional domains. Moreover, STAT5B locus carried copy-neutral loss of heterozygosity resulting in the duplication of the mutant copy, suggesting the importance of mutant STAT5B dosage for the development of EITL. Dysregulation of the JAK-STAT and GPCR pathways was also supported by gene expression profiling and further verified in patient tumor samples. In vitro overexpression of GNAI2 mutants led to the upregulation of pERK1/2, a member of MEK-ERK pathway. Notably, inhibitors of both JAK-STAT and MEK-ERK pathways effectively reduced viability of patient-derived primary EITL cells, indicating potential therapeutic strategies for this neoplasm with no effective treatment currently available.

p53 haploinsufficiency and functional abnormalities in multiple myeloma.

Hemizygous deletion of 17p13, which harbors the TP53 gene, has been identified in >10% of newly diagnosed multiple myeloma (MM) patients and is associated with poor prognosis. To date, there is no conclusive evidence that TP53 is the critical gene. Furthermore, the functional effect of TP53 haploinsufficiency is not well characterized. By utilizing human myeloma cell lines, we showed that TP53 hemizygous loss was associated with decreased basal expression level with a partially or severely inactivated p53 response upon genotoxic and non-genotoxic stress. The pathway deficiency was manifested as defective p53 transcriptional activities, together with significant resistance to apoptosis. In some cases with p53 WT/- and no p53 protein expression, the remaining allele was silenced by promoter hypermethylation. We also developed a p53 target gene signature to summarize the complexity of the p53 pathway abnormalities in MM and showed that it is strongly associated with genomic complexity and patient survival. In conclusion, this study identified TP53 as the critical gene located in 17p13, and revealed its haploinsufficiency properties in MM. Furthermore, we have elucidated that multiple mechanisms can deregulate the p53 functions and that this has important prognostic impact in MM.

Type II EATL (epitheliotropic intestinal T-cell lymphoma): a neoplasm of intra-epithelial T-cells with predominant CD8αα phenotype.

In this multicentre study, we examined 60 cases of Type II enteropathy-associated T-cell lymphoma (EATL) from the Asia-Pacific region by histological review, immunohistochemistry and molecular techniques. Patients were mostly adult males (median age: 58 years, male:female 2.6:1), presenting with abdominal pain (60%), intestinal perforation (40%) and weight loss (28%). None had a history of coeliac disease and the median survival was only 7 months. Histologically, these tumours could be divided into (i) central tumour zone comprising a monotonous population of neoplastic lymphocytes, (ii) peripheral zone featuring stunted villi and morphologically atypical lymphocytes showing epitheliotropism, and (iii) distant mucosa with normal villous architecture and cytologically normal intra-epithelial lymphocytes (IELs). Characterized by extensive nuclear expression of Megakaryocyte-associated tyrosine kinase (MATK) (87%) and usually a CD8(+)CD56(+) (88%) cytotoxic phenotype, there was frequent aberrant expression of CD20 (24%). T-cell receptor (TCR) expression was silent or not evaluable in 40% but of the remainder, there was predominant expression of TCRαß over TCRγδ (1.6:1). In keeping with the normal ratio of IEL subsets, CD8(+) cases showed predominant CD8αα homodimer expression (77%), regardless of TCR lineage. These tumours constitute a distinct entity from classical EATL, and the pathology may reflect tumour progression from IEL precursors, remnants of which are often seen in the distant mucosa.

Single-breath vital capacity high concentration sevoflurane induction in children: with or without nitrous oxide?

BACKGROUND: Single-breath vital capacity inhalation induction with high concentration sevoflurane (SBVC-HC) is a rapid and 'needleless' technique, preferred and well tolerated in the cooperative child. The addition of nitrous oxide may speed up induction by its second gas effects. Previous studies done in children looking at the effect of N(2)O on this technique lacked power and showed conflicting results. This study aims to investigate the effect of N(2)O on induction time for SBVC-HC sevoflurane induction in children. METHODS: Eighty unpremedicated, ASA I and II children, aged 5-15 yr having elective surgical procedures under general anaesthesia, were recruited and randomized to: Group A: 8% sevoflurane in O(2) 6 litre min(-1), and Group B: 8% sevoflurane in N(2)O 4 litre min(-1) and O(2) 2 litre min(-1). The primary outcome was the time to 'loss of eyelash reflex'. The time to return of 'regular respiration' and 'conjugate gaze' were also noted. RESULTS: The difference in the 'time to loss of eyelash reflex' was small but statistically significant. Group B: mean duration 53.6 s, standard deviation (SD) 16.1, compared with Group A: 63.5 s, SD 16.1 (mean difference 9.9, 95% confidence interval 2.5-17.3, P=0.01). Differences in the time to return of 'regular breathing' and 'conjugate gaze' were not statistically significant. Patients receiving N(2)O had less excitatory movements (P=0.007), but incidence of other adverse events was low and did not differ significantly between both groups. More than 94% of children would choose this method of induction again in both groups. CONCLUSIONS: We conclude that for SBVC-HC sevoflurane induction in children, the addition of N(2)O resulted in faster loss of consciousness and reduced excitatory movements.

T-cell death following immune activation is mediated by mitochondria-localized SARM.

Following acute-phase infection, activated T cells are terminated to achieve immune homeostasis, failure of which results in lymphoproliferative and autoimmune diseases. We report that sterile α- and heat armadillo-motif-containing protein (SARM), the most conserved Toll-like receptors adaptor, is proapoptotic during T-cell immune response. SARM expression is significantly reduced in natural killer (NK)/T lymphoma patients compared with healthy individuals, suggesting that decreased SARM supports NK/T-cell proliferation. T cells knocked down of SARM survived and proliferated more significantly compared with wild-type T cells following influenza infection in vivo. During activation of cytotoxic T cells, the SARM level fell before rising, correlating inversely with cell proliferation and subsequent T-cell clearance. SARM knockdown rescued T cells from both activation- and neglect-induced cell deaths. The mitochondria-localized SARM triggers intrinsic apoptosis by generating reactive oxygen species and depolarizing the mitochondrial potential. The proapoptotic function is attributable to the C-terminal sterile alpha motif and Toll/interleukin-1 receptor domains. Mechanistically, SARM mediates intrinsic apoptosis via B cell lymphoma-2 (Bcl-2) family members. SARM suppresses B cell lymphoma-extra large (Bcl-xL) and downregulates extracellular signal-regulated kinase phosphorylation, which are cell survival effectors. Overexpression of Bcl-xL and double knockout of Bcl-2 associated X protein and Bcl-2 homologous antagonist killer substantially reduced SARM-induced apoptosis. Collectively, we have shown how T-cell death following infection is mediated by SARM-induced intrinsic apoptosis, which is crucial for T-cell homeostasis.

Retrospective review of tracheoplasty for congenital tracheal stenosis.

INTRODUCTION: Congenital tracheal stenosis is a rare but life-threatening obstructive airway disease. It usually presents in early infancy and requires surgical intervention. This study is a review of our experience in the management of congenital tracheal stenosis in children at KK Women's and Children's Hospital, Singapore. METHODS: All children who had undergone tracheoplasty for congenital tracheal stenosis between January 1999 and December 2008 were included. The patients' medical records were retrieved from our database, and the demographic data, comorbidities, clinical presentation and management, surgery performed, postoperative complications, final outcomes and follow-up were reviewed. RESULTS: A total of 11 children aged 12 days to six years underwent surgery for congenital long-segment tracheal stenosis, of which ten (90.9 percent) had associated cardiac and vascular anomalies and nine (81.8 percent) had left pulmonary artery sling predominance. Five (45.4 percent) children had associated bronchopulmonary abnormalities. All the patients underwent slide tracheoplasty with concomitant repair of congenital heart defects. Overall mortality was 45.4 percent (n is 5), including one late mortality due to an unrelated cause. With the exception of one, the follow-up of all patients was complete at this writing. One patient had mild residual tracheal stenosis and another had bilateral bronchomalacia. CONCLUSION: This is the largest case series of congenital long-segment tracheal stenosis reported in Southeast Asia to date. Slide tracheoplasty with concomitant repair of cardiac lesions is currently the preferred management for long-segment stenosis. Management of such patients remains a challenge for clinicians and the patients' families, and requires a multidisciplinary approach.

Clinical and biological implications of MYC activation: a common difference between MGUS and newly diagnosed multiple myeloma.

Events mediating transformation from the pre-malignant monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM) are unknown. We analyzed gene expression data sets generated on the Affymetrix U133 platform from 22 MGUS and 101 MM patients using gene-set enrichment analysis. Genes overexpressed in MM were enriched for cell cycle, proliferation and MYC activation gene sets. Upon dissecting the relationship between MYC and cell-cycle gene sets, we identified and validated an MYC activation signature dissociated from proliferation. Applying this signature, MYC is activated in 67% of myeloma, but not in MGUS. This was further confirmed by immunohistochemistry (IHC) using membrane CD138 and nuclear MYC double staining. We also showed that almost all tumors with RAS mutations expressed the MYC activation signature, and multiple mechanisms may be involved in activating MYC. MYC activation, whether assessed by gene-expression signature or IHC, is associated with hyperdiploid MM and shorter survival even in tumors that are not proliferative. Bortezomib treatment is able to overcome the survival disadvantage in patients with MYC activation.

Aggressive osteoblastoma of the proximal humerus.

A nine-year-old boy presented with increasingly worsening right shoulder pain of 18 months' duration. On physical examination, there was a tender firm swelling over the right upper arm. Radiographs showed a large osteolytic lesion in the proximal humeral diaphysis, with prominent mixed acute-on-chronic periosteal reaction in a lamellar fashion. There was a pathological fracture. The lesion appeared to be radiographically aggressive in nature. Bone scintiscan showed solitary marked uptake. On-table frozen section histopathological examination of the lesion showed an osteoblastic lesion with aggressive features. Completion curettage and high speed burring of the cavity was performed. In view of the patient's young age, which required a biological solution, and potential for local recurrence, that necessitated a radiopaque filler, the lesion was packed with a calcium phosphate cement paste. The final diagnosis was osteoblastoma with aggressive features. The patient remained well on follow-up to date. The filler continues to be remodelled to native tissue and there is no evidence of local recurrence. Osteoblastoma is a relatively rare benign tumour that typically occurs in the posterior elements of the vertebral column. The humerus is a very rare site of disease in the appendicular skeleton, and poses a diagnostic dilemma which implicates the possibility of osteogenic sarcoma.

Dorsal penile nerve block.

BACKGROUND: The dorsal penile nerve block (DPNB) is a common form of regional anaesthesia for circumcisions in children. The safety of this block has been questioned following several case reports of potentially serious complications. METHODS: We performed a retrospective review of all the incidents related to the conduct of this block in our institution over a period of 53 months. RESULTS: A total of 3909 circumcisions were performed under DPNB and nine incidents were recorded. This included two cases of bleeding from the prepuce, two urethral injuries, three haematomas and two drug errors. Two cases required further surgical intervention but all of the patients recovered with no apparent long-term sequelae. CONCLUSIONS: We feel that the DPNB is a safe technique for circumcisions in infants and children.

Critical incidents in paediatric anaesthesia: an audit of 10 000 anaesthetics in Singapore.

BACKGROUND: We undertook an audit of paediatric perioperative incidents in the first 10000 anaesthetics administered in KK Women's and Children's Hospital in Singapore between May 1997 and April 1999. The spectrum of surgery performed ranged from simple ambulatory surgery to open heart surgery for complicated congenital heart diseases. METHODS: An audit form is completed for every anaesthetic delivered and critical incidents are reported on the reverse blank page of the audit form. An anaesthetic incident was defined as 'any incident which affected, or could have affected, the safety of the patient under anaesthetic care'. RESULTS: Two hundred and ninety-seven critical incidents were reported. The majority of them happened in healthy patients (80.1% ASA I and II) scheduled for elective surgery (73.3%). Critical incidents in infants less than 1 year of age were four times as common as in older children (8.6% versus 2.1%). Incidents occurred mainly during maintenance (80.6%). There was no anaesthetic mortality. Respiratory events were the most common (77.4%) with laryngospasm accounting for 35.7%. Cardiovascular incidents (10.8%) included hypotension from haemorrhage and sepsis, and dysrhythmias. The incidence of equipment and pharmacologically related problems was low. CONCLUSIONS: Future reviews of a larger patient population may be helpful to determine trends of perioperative events and whether quality assurance programs have made a difference.

A case of pulmonary tumour embolism mimicking miliary tuberculosis.

Pulmonary metastases from choriocarcinoma can very rarely give rise to a 'miliary' pattern on the chest X-ray. A 23-year-old woman with a diffuse nodular pattern on chest X-ray died due to acute respiratory failure and cor pulmonale. At autopsy, choriocarcinoma of the uterus was found. In the lungs, multiple macrovascular tumour emboli within branches of pulmonary muscular arteries in the region of segmental/subsegmental bronchi were detected. There was no evidence of pulmonary parenchymal metastases, pneumonia or tuberculosis. The 'miliary' pattern of pulmonary metastases described in cases of choriocarcinoma may be due to large vessel intra-arterial tumour emboli rather than disseminated parenchymal metastases.

Rosai-Dorfman disease of the breast: a mimic of breast malignancy.

Rosai-Dorfman disease (RDD) or sinus histiocytosis with massive lymphadenopathy (SHML) is primarily a nodal-based, idiopathic, benign proliferative disorder of histiocytes with 43% of these cases also involving extranodal sites. The breast is an unusual site of occurrence of RDD. We report two cases of this exceptional event. The first represents an intramammary nodal Rosai-Dorfman disease, while the second is an extranodal disease with sole involvement of the breast. In both, the possibility of malignancy was raised. Histological examination of the two breast lesions revealed sheets of characteristic large histiocytes displaying emperipolesis, a microscopic hallmark of this disease. Immunohistochemical and ultrastructural studies were also performed; the former showed cytoplasmic staining of histiocytes for S-100 protein, while histiocytes that engulfed lymphocytes and plasma cells were identified on electron microscopy.

Primitive neuroectodermal tumour of the chest wall--a report of two cases and review of literature.

INTRODUCTION: Primitive neuroectodermal tumours (PNETs) of the chest wall are rare entities and little is known regarding its biological activity and prognostic factors. Two cases are reported and the available literature reviewed to highlight the presentation and management of these tumours. CLINICAL FEATURES: We report 2 patients who were diagnosed with PNET of the chest wall in our centre. As there are no clinical features or basic diagnostic measures which are characteristic of these tumours, diagnosis is based on special tests. With the advent of newer immunohistochemical methods, it is now diagnosed more confidently. TREATMENT: Both patients received multidisciplinary modalities of treatment, comprising extensive surgical resection, chemotherapy and radiotherapy. OUTCOME: One patient succumbed to the disease one year after diagnosis and the other is currently disease-free, both clinically and radiologically at 24 months. CONCLUSION: Despite multidisciplinary modalities of treatment, the prognosis of PNET is still generally poor. Early diagnosis and treatment are important to improve the chances of survival.

Peak expiratory flow rate guided protocol did not improve outcome in emergency room asthma.

UNLABELLED: BACKGROUND AND AIMS OF STUDY: All current international practice guidelines recommend that treatment of acute asthma in the emergency room (ER) should be guided by the peak expiratory flow rate (PEFR). The aim of this study was to assess the efficacy of a PEFR guided protocol in treating ER asthma. METHODS: We compared two different management protocols in adult asthmatics who presented to the ER with acute exacerbations. The routine protocol (RP) assessed and dispensed patients according to overall subjective and clinical response without predetermined criteria. The peak protocol (PP) used serial measurements of PEFR to guide intensity of bronchodilator treatment and fitness for hospital discharge. On the PP, a threshold PEFR of > or = 60% predicted had to be achieved before the patient could be discharged from the ER. RESULTS: There were 79 patients in the RP group and 70 in the PP group. There was no significant difference between the two groups in baseline PEFR, PEFR after treatment and percentage increase in PEFR with treatment. The PP resulted in a higher hospital admission rate than RP. CONCLUSION: We conclude that in the management of acute asthma in the ER, a PEFR guided protocol neither improved overall PEFR response to treatment nor reduced admission rates when compared with current management as it is practised in Singapore.