Sporadic deficient mismatch repair in colorectal cancer increases the risk for non-colorectal malignancy: A European multicenter cohort study.

BACKGROUND AND OBJECTIVES: Disparities between tumors arising via different sporadic carcinogenetic pathways have not been studied systematically. This retrospective multicenter cohort study evaluated the differences in the risk for non-colorectal malignancy between sporadic colorectal cancer (CRC) patients from different DNA mismatch repair status. METHODS: A retrospective European multicenter cohort study including in total of 1706 CRC patients treated between 1996 and 2019 in three different countries. The proficiency (pMMR) or deficiency (dMMR) of mismatch repair was determined by immunohistochemistry. Cases were analyzed for tumor BRAFV600E mutation, and BRAF mutated tumors were further analyzed for hypermethylation status in the promoter region of MLH1 to distinguish between sporadic and hereditary cases. Swedish and Finish patients were matched with their respective National Cancer Registries. For the Czech cohort, thorough scrutiny of medical files was performed to identify any non-colorectal malignancy within 20 years before or after the diagnosis of CRC. Poisson regression analysis was performed to identify the incidence rates of non-colorectal malignancies. For validation purposes, standardized incidence ratios were calculated for the Swedish cases adjusted for age, year, and sex. RESULTS: Of the 1706 CRC patients included in the analysis, 819 were female [48%], median age at surgery was 67 years [interquartile range: 60-75], and sporadic dMMR was found in 188 patients (11%). Patients with sporadic dMMR CRC had a higher incidence rate ratio (IRR) for non-colorectal malignancy before and after diagnosis compared to patients with a pMMR tumor, in both uni- (IRR = 2.49, 95% confidence interval [CI] = 1.89-3.31, p = 0.003) and multivariable analysis (IRR = 2.24, 95% CI = 1.67-3.01, p = 0.004). This association applied whether or not the non-colorectal tumor developed before or after the diagnosis of CRC in both uni- (IRR = 1.91, 95% CI = 1.28-2.98, p = 0.004), (IRR = 2.45, 95% CI = 1.72-3.49, p = 0.004) and multivariable analysis (IRR = 1.67,95% CI = 1.05-2.65, p = 0.029), (IRR = 2.35, 95% CI = 1.63-3.42, p = 0.005), respectively. CONCLUSION: In this retrospective European multicenter cohort study, patients with sporadic dMMR CRC had a higher risk for non-colorectal malignancy than those with pMMR CRC. These findings indicate the need for further studies to establish the need for and design of surveillance strategies for patients with dMMR CRC.

PreCNet: Next-Frame Video Prediction Based on Predictive Coding.

Predictive coding, currently a highly influential theory in neuroscience, has not been widely adopted in machine learning yet. In this work, we transform the seminal model of Rao and Ballard (1999) into a modern deep learning framework while remaining maximally faithful to the original schema. The resulting network we propose (PreCNet) is tested on a widely used next-frame video prediction benchmark, which consists of images from an urban environment recorded from a car-mounted camera, and achieves state-of-the-art performance. Performance on all measures (MSE, PSNR, and SSIM) was further improved when a larger training set (2M images from BDD100k) pointed to the limitations of the KITTI training set. This work demonstrates that an architecture carefully based on a neuroscience model, without being explicitly tailored to the task at hand, can exhibit exceptional performance.

Human factors application for healthcare teams in low- and medium-income countries (LMIC) to help improve patient safety and performance.

Mistakes will always happen whether at work or in our personal lives. We can never completely eliminate error, but learning and disseminating lessons from these mistakes to others is essential. Human factors application for colleagues in healthcare, particularly in low- and medium-income countries (LMIC) can greatly improve patient safety and aid better team working and staff morale. Factors such as hunger, dehydration anger, and tiredness, all reduce personal performance and can raise the risk of personal error. It is vital that we understand and optimize interaction within the healthcare team members. As part of this, ineffective communication, steep hierarchy and loss of situational awareness can lead to compromised patient safety and potentially serious error. In this paper, we provide a brief overview of human factors for healthcare colleagues in LMIC. We highlight ways to reduce the chances of error and improve patient safety by recognizing and applying various human factors to our day to day practices.

Colon cancer patients with mismatch repair deficiency are more likely to present as acute surgical cases.

BACKGROUND: The effect of the genetic imprint on the emergency presentation of colon cancer remains unclear. The disparity between tumours evolving along different carcinogenetic pathways has not been studied systematically. This retrospective multicenter cohort study evaluates the association between mismatch repair status and the risk for acute surgery of colon cancer. PATIENTS AND METHODS: A retrospective multicenter cohort study including in total 870 patients from three different countries. Scandinavian cohort (Finland and Sweden), including a total of 412 patients operated between January 1, 1995 and December 31, 2010, was validated against a cohort from the Czech Republic, including a total of 458 patients, operated between January 1, 2018 and December 31, 2019. The proficiency or deficiency of mismatch repair was determined by immunohistochemistry. Primary outcome was the risk for acute colon cancer surgery given as the Odds Ratio (OR) in the univariable and multivariable analyses. Acute colon cancer surgery was defined as surgery performed during the same hospital admission as when the diagnosis of colon cancer was made. RESULTS: Of the 870 patients (399 females [46%]) included in the analyses, median age at surgery was 69 [interquartile range, 61-76] years, deficient Mismatch Repair (dMMR) status was found in 190 patients (22%), and 179 patients (21%) underwent acute surgery during the same hospital admission as when the diagnosis of colon cancer was made. In the Scandinavian cohort, a significant association between dMMR status and acute surgery was seen in both the univariable (OR 1.82, 95% CI 1.11-3.02, P = 0.017) and the multivariable (OR = 2.21, 95% CI 1.28-3.95, P = 0.005) analyses. This was confirmed in the Czech validation cohort in both the univariable (OR = 1.94, 95% CI 1.09-3.26, P = 0.022) and the multivariable (OR = 1.77, 95% CI 1.15-3.18, P = 0.021) analyses. CONCLUSION: This multicenter study reveals a strong association between acute colon cancer surgery and dMMR tumour status.

A deterministic approach for rapid identification of the critical links in networks.

We introduce a rapid deterministic algorithm for identification of the most critical links which are capable of causing network disruptions. The algorithm is based on searching for the shortest cycles in the network and provides a significant time improvement compared with a common brute-force algorithm which scans the entire network. We used a simple measure, based on standard deviation, as a vulnerability measure. It takes into account the importance of nodes in particular network components. We demonstrate this approach on a real network with 734 nodes and 990 links. We found the worst scenarios for the cases with and without people living in the nodes. The evaluation of all network breakups can provide transportation planners and administrators with plenty of data for further statistical analyses. The presented approach provides an alternative approach to the recent research assessing the impacts of simultaneous interruptions of multiple links.

Deficient mismatch repair as a prognostic marker in stage II colon cancer patients.

BACKGROUND: A number of reports have evaluated the relationship between deficient DNA mismatch repair (dMMR) and colorectal cancer prognosis. Unfortunately, the exact prognostic role of dMMR has not been clearly established due to contradictory results. This study aims to determine the prognostic impact of dMRR in stage II colon cancer patients only. The appropriate identification of high-risk stage II colon cancers is of paramount importance in the selection of patients who may benefit from adjuvant treatment after surgery. METHODS: Four hundred and fifty-two patients with curative resection of stage II colon cancer were included. Hospital records were used as data source, providing clinical, surgical, pathology, oncology and follow-up information for statistical analysis focusing on overall survival (OS) and time to progression (TTP). Mismatch repair status was determined by immunohistochemistry. Patient survival was followed-up for a mean of 77·35 months. RESULTS: dMMR was detected in 93 of 452 patients (20·6%). No impact on overall survival (Log-Rank, p = 0·583, 95% CI 0·76-1·67). However, the hazard ratio 0·50 for TTP was highly significant (Log-Rank, p = 0·012, 95% CI 0·28-0·87) in patients with dMMR compared with those with mismatch repair proficient tumours (pMMR). CONCLUSIONS: Patients with dMMR tumours have a lower risk for recurrence compared to those with pMMR tumours, but this finding did not correlate to better overall survival.

Mammary Analog Secretory Carcinoma of the Nasal Cavity: Characterization of 2 Cases and Their Distinction From Other Low-grade Sinonasal Adenocarcinomas.

Secretory carcinoma, originally described as mammary analog secretory carcinoma (MASC), is a low-grade salivary gland tumor characterized by a t(12;15)(p13;q25) translocation, resulting in an ETV6-NTRK3 gene fusion. Most MASCs are localized to the parotid gland and intraoral minor salivary glands. Moreover, ETV6-rearranged carcinomas with secretory features have been reported recently in the thyroid (with and without a history of radiation exposure), skin, and in very rare instances in the sinonasal tract. Here, we describe 2 cases of primary MASC in the sinonasal tract and provide a detailed clinical and histopathologic characterization of their morphology, immunohistochemical profile, and genetic background and highlight features allowing for its separation from its recently described molecular mimicker, ETV6-rearranged low-grade sinonasal adenocarcinoma.

Renal Cell Carcinoma With Leiomyomatous Stroma: A Group of Tumors With Indistinguishable Histopathologic Features, But 2 Distinct Genetic Profiles: Next-Generation Sequencing Analysis of 6 Cases Negative for Aberrations Related to the VHL gene.

We have studied a cohort of renal cell carcinomas (RCCs) with smooth-muscle stroma (N=6), which lacked any of following genetic aberrations: mutations in the VHL-gene-coding sequence, loss of heterozygosity of chromosome 3p, or hypermethylation of VHL. Using targeted next-generation sequencing, no intronic VHL mutations or mutations in selected genes involved in angiogenesis and genes frequently mutated in clear cell RCC were identified. Tumors were also tested for the presence of hotspot mutations in the TCEB1 gene with negative results in all cases. We conclude that there exists a group of RCCs with abundant leiomyomatous stroma, where the epithelial component is indistinguishable from conventional clear cell RCC and distinct from clear cell (tubulo-) papillary RCC and that these tumors lack aberrations related to the function of the VHL gene, mutations in genes involved in angiogenesis, and hotspot mutations in the TCEB1 gene.

Molecular Profiling of Mammary Analog Secretory Carcinoma Revealed a Subset of Tumors Harboring a Novel ETV6-RET Translocation: Report of 10 Cases.

ETV6 gene abnormalities are well described in tumor pathology. Many fusion partners of ETV6 have been reported in a variety of epithelial, mesenchymal, and hematological malignancies. In salivary gland tumor pathology, however, the ETV6-NTRK3 translocation is specific for (mammary analog) secretory carcinoma, and has not been documented in any other salivary tumor type. The present study comprised a clinical, histologic, and molecular analysis of 10 cases of secretory carcinoma, with typical morphology and immunoprofile harboring a novel ETV6-RET translocation.

The Role of Molecular Testing in the Differential Diagnosis of Salivary Gland Carcinomas.

Salivary gland neoplasms are a morphologically heterogenous group of lesions that are often diagnostically challenging. In recent years, considerable progress in salivary gland taxonomy has been reached by the discovery of tumor type-specific fusion oncogenes generated by chromosome translocations. This review describes the clinicopathologic features of a selected group of salivary gland carcinomas with a focus on their distinctive genomic characteristics. Mammary analog secretory carcinoma is a recently described entity characterized by a t(12;15)(p13;q25) translocation resulting in an ETV6-NTRK3 fusion. Hyalinizing clear cell carcinoma is a low-grade tumor with infrequent nodal and distant metastasis, recently shown to harbor an EWSR1-ATF1 gene fusion. The CRTC1-MAML2 fusion gene resulting from a t(11;19)(q21;p13) translocation, is now known to be a feature of both low-grade and high-grade mucoepidermoid carcinomas associated with improved survival. A t(6;9)(q22-23;p23-34) translocation resulting in a MYB-NFIB gene fusion has been identified in the majority of adenoid cystic carcinomas. Polymorphous (low-grade) adenocarcinoma and cribriform adenocarcinoma of (minor) salivary gland origin are related entities with partly differing clinicopathologic and genomic profiles; they are the subject of an ongoing taxonomic debate. Polymorphous (low-grade) adenocarcinomas are characterized by hot spot point E710D mutations in the PRKD1 gene, whereas cribriform adenocarcinoma of (minor) salivary glands origin are characterized by translocations involving the PRKD1-3 genes. Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma with morphologic and molecular features akin to invasive ductal carcinoma of the breast, including HER2 gene amplification, mutations of TP53, PIK3CA, and HRAS and loss or mutation of PTEN. Notably, a recurrent NCOA4-RET fusion has also been found in SDC. A subset of SDC with apocrine morphology is associated with overexpression of androgen receptors. As these genetic aberrations are recurrent they serve as powerful diagnostic tools in salivary gland tumor diagnosis, and therefore also in refinement of salivary gland cancer classification. Moreover, they are promising as prognostic biomarkers and targets of therapy.

Point cloud registration from local feature correspondences-Evaluation on challenging datasets.

Registration of laser scans, or point clouds in general, is a crucial step of localization and mapping with mobile robots or in object modeling pipelines. A coarse alignment of the point clouds is generally needed before applying local methods such as the Iterative Closest Point (ICP) algorithm. We propose a feature-based approach to point cloud registration and evaluate the proposed method and its individual components on challenging real-world datasets. For a moderate overlap between the laser scans, the method provides a superior registration accuracy compared to state-of-the-art methods including Generalized ICP, 3D Normal-Distribution Transform, Fast Point-Feature Histograms, and 4-Points Congruent Sets. Compared to the surface normals, the points as the underlying features yield higher performance in both keypoint detection and establishing local reference frames. Moreover, sign disambiguation of the basis vectors proves to be an important aspect in creating repeatable local reference frames. A novel method for sign disambiguation is proposed which yields highly repeatable reference frames.

[Diffuse tenosynovial giant cell tumor of the cervical spine destroying vertebra C6 - a case report]. / Difúzní obrovskobunecný tumor slachových pochev krcní pátere s destrukcí obratle C6 - kazuistika.

Presented is a case of 59-year-old woman with longstanding neck pain who has been promptly operated for spinal cord compression. Imaging studies disclosed ill-defined cervical paravertebral soft tissue mass at the level of vertebra C5/6 abutting left-sided intervertebral joint and destroying neighboring both vertebral arch and processus spinosus. Submitted specimen was interpreted as a possible metastatic skeletal process by clinicians and referring pathologist favored diagnosis of giant cell tumor/osteoclastoma of the bone. Microscopic features were consistent with giant cell lesion where uniform mononuclear mosaic stromal component dominated the unevenly distributed loose clusters of osteoclast-like giant cells frequently imparting appearance of peculiar pseudoalveolar spaces. Additionally, alternating geographic xanthomatous and densely hyalinized/ osteoid-like zones with speckled, coarsely granular haemosiderin pigment completed the variegated structural composition. The tumor infiltrated adjacent striated muscles; either original bone structures and/or extracellular matrix deposits were not identified. Immunohistochemical stains with p63, SATB2, desmin, EMA, clusterin and S100protein turned out to be completely negative. FISH analysis revealed no rearrangement of CSF1 gene. The diagnosis of the diffuse tenosynovial giant cell tumor was rendered.

"Mucin"-secreting papillary renal cell carcinoma: clinicopathological, immunohistochemical, and molecular genetic analysis of seven cases.

Mucin and mucin-like material are features of mucinous tubular and spindle renal cell carcinoma (MTS RCC) but are rarely seen in papillary renal cell carcinoma (PRCC). We reviewed 1311 PRCC and identified 7 tumors containing extracellular and/or intracellular mucinous/mucin-like material (labeled as PRCCM). We analyzed these using morphological, histochemical, immunohistochemical, and molecular genetic methods (arrayCGH, FISH). Clinical data were available for six of the seven patients (five males and one female, age range 61-78 years). Follow-up was available for four patients (2-4 years); one patient died of widespread metastases. Tumor size ranged from 3 to 5 cm (mean 3.8). Of all cases, histological architecture showed a predominantly papillary pattern. Mucin or mucin-like was extracellular in one, intracellular in three, and both intra/extracellular in three cases. All tumors were positive for AMACR, vimentin, and OSCAR, while CK7 was positive in four. Mucicarmine stain was positive in all cases, PAS in six and Alcian blue in three cases. Five tumors were positive for MUC 1, but none were positive for MUC 2, MUC 4, or MUC 6. In only four cases, genetic analysis could be performed. Gain of chromosomes 7 and 17 was found in two cases; gain of 17 only was found in one case. Loss of heterozygosity of 3p was found in one case together with polysomy of chromosomes 7 and 17. No abnormalities of VHL, fumarate dehydrogenase, and TFE3 genes were detected. We conclude that PRCCM is a rare but challenging subtype of RCC that deserves to be further studied. In all the tumors, the mucin-like material was found in those stained with mucicarmin, but other conventional and immunohistochemical stains did not reveal consistent features of a single mucin. The molecular-genetic profile of these tumors was most consistent with that of typical papillary RCC, although one case had mixed genetic features of papillary and clear RCC. PRCCM has metastatic potential, as evidenced by one case with widespread metastases. It remains to be determined whether PRCCM represents a unique tumor subtype, deserving to be distinguished from other subtypes of PRCC.

Ischemic Postconditioning and Nitric Oxide Administration Failed to Confer Protective Effects in a Porcine Model of Extracorporeal Cardiopulmonary Resuscitation.

The protective effects of ischemic postconditioning (IPC) and nitric oxide (NO) administration have been demonstrated in several ischemic scenarios. However, current evidence regarding the effect of IPC and NO in extracorporeal cardiopulmonary resuscitation remains lacking. Fifteen female swine (body weight 45 kg) underwent veno-arterial extracorporeal membrane oxygenation (ECMO) implantation; cardiac arrest-ventricular fibrillation was induced by rapid ventricular pacing. After 20 min of cardiac arrest, blood flow was restored by increasing the ECMO flow rate to 4.5 L/min. The animals (five per group) were then randomly assigned to receive IPC (three cycles of 3 min ischemia and reperfusion), NO (80 ppm via oxygenator), or mild hypothermia (HT; 33.0°C). Cerebral oximetry and aortic blood pressure were monitored continuously. After 90 min of reperfusion, blood samples were drawn for the measurement of troponin I, myoglobin, creatine-phosphokinase, alanine aminotransferase, neuron-specific enolase, cystatin C, and reactive oxygen metabolite (ROM) levels. Significantly higher blood pressure and cerebral oxygen saturation values were observed in the HT group compared with the IPC and NO groups (P < 0.05). The levels of troponin I, myoglobin, creatine phosphokinase, and alanine aminotransferase were significantly lower in the HT group (P < 0.05); levels of neuron-specific enolase, cystatin C, and ROM were not significantly different. IPC and NO were comparable in all monitored parameters. The results of the present study indicate that IPC and NO administration are not superior interventions to HT for the maintenance of blood pressure, cerebral oxygenation, organ protection, and suppression of oxidative stress following extracorporeal cardiopulmonary resuscitation.

The Cortisol to Cortisone Ratio during Cardiac Catheterisation in Sows.

A possible effect of mini-invasive heart intervention on a response of hypothalamo-pituitary-adrenal stress axis and conversion of cortisone to cortisol were studied. We have analysed two stress markers levels (cortisol, cortisone) and cortisol/cortisone ratio in 25 sows using minimally invasive heart catheterisation as the stress factor. The values of studied parameters were assessed in four periods of the experiment: (1) the baseline level on the day before intervention, (2) after the introduction of anaesthesia, (3) after conducting tissue stimulation or ablation, and (4) after the end of the catheterisation. For statistical analyses we used the non-parametric Friedman test for four dependent samples (including all four stages of the operation) or three dependent samples (influence of operation only, baseline level was excluded). Statistically significant differences in both Friedman tests were found for cortisol and for cortisone. We have found the highest level of cortisol/cortisone ratio in unstressed conditions, then it decreased to the minimal level at the end of the intervention. We have concluded that cortisol levels are blunted by the influence of anaesthesia after its administration, and therefore decrease back to the baseline at the end of the operation.

Increasing venoarterial extracorporeal membrane oxygenation flow negatively affects left ventricular performance in a porcine model of cardiogenic shock.

BACKGROUND: The aim of this study was to assess the relationship between extracorporeal blood flow (EBF) and left ventricular (LV) performance during venoarterial extracorporeal membrane oxygenation (VA ECMO) therapy. METHODS: Five swine (body weight 45 kg) underwent VA ECMO implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock with signs of tissue hypoxia was induced. Hemodynamic and cardiac performance parameters were then measured at different levels of EBF (ranging from 1 to 5 L/min) using arterial and venous catheters, a pulmonary artery catheter and a pressure-volume loop catheter introduced into the left ventricle. RESULTS: Myocardial hypoxia resulted in a decline in mean (±SEM) cardiac output to 2.8 ± 0.3 L/min and systolic blood pressure (SBP) to 60 ± 7 mmHg. With an increase in EBF from 1 to 5 L/min, SBP increased to 97 ± 8 mmHg (P < 0.001); however, increasing EBF from 1 to 5 L/min significantly negatively influences several cardiac performance parameters: cardiac output decreased form 2.8 ± 0.3 L/min to 1.86 ± 0.53 L/min (P < 0.001), LV end-systolic volume increased from 64 ± 11 mL to 83 ± 14 mL (P < 0.001), LV stroke volume decreased from 48 ± 9 mL to 40 ± 8 mL (P = 0.045), LV ejection fraction decreased from 43 ± 3 % to 32 ± 3 % (P < 0.001) and stroke work increased from 2096 ± 342 mmHg mL to 3031 ± 404 mmHg mL (P < 0.001). LV end-diastolic pressure and volume were not significantly affected. CONCLUSIONS: The results of the present study indicate that higher levels of VA ECMO blood flow in cardiogenic shock may negatively affect LV function. Therefore, it appears that to mitigate negative effects on LV function, optimal VA ECMO blood flow should be set as low as possible to allow adequate tissue perfusion.

Lewis-acid induced disaggregation of dimeric arylantimony oxides.

The previously known dimeric arylantimony oxides (Ph3SbO)2 and [2,6-(Me2NCH2)2C6H3SbO]2 were disaggregated by the Lewis acid B(C6F5)3 giving rise to the formation of the Lewis pair complexes Ph3SbOB(C6F5)3 and 2,6-(Me2NCH2)2C6H3SbOB(C6F5)3 having short bipolar single Sb-O bonds.

Median frequencies of prolonged ventricular fibrillation treated by V-A ECMO correspond to a return of spontaneous circulation rate.

BACKGROUND: The aim of our study was to analyze, in a pig model of prolonged ventricular fibrillation (VF) treated by veno-arterial extracorporeal membrane oxygenation (ECMO), the time dependent changes of VF wavelet frequency obtained from intracardial signals and its relations to return of spontaneous circulation (ROSC). METHODS: 11 female pigs (50.3 ± 3.4 kg) under general anesthesia had undergone 15 min of VF with ECMO flow of 5 to 10 ml/kg per min simulating "untreated" VF followed by continued VF with full ECMO flow of 100 ml/kg per min. The median frequency (MF) of VF from right ventricular apex, coronary perfusion pressure, myocardial oxygen metabolism and resuscitability were determined. RESULTS: Median (interquartile range) of MF of fibrillatory wavelets in minute 15 of low ECMO flow [9.7 Hz (8.3; 10.1)] was not significantly changed in comparison to minute 1 [10.5 Hz (9.8; 12.4)], p = 0.12. Five minutes after full ECMO initiation MF increased [11.6 Hz (10.6; 13.5)], p = 0.04 (compared to minute 15 of VF) and did not deteriorate during the rest of ECMO treatment. Out of all subjects, three animals did not reach ROSC. Those subjects demonstrated deeper decrease of MF at the VF minute 15 as compared to others [-2.4 Hz (-2.5; -2.3) vs. -0.6 Hz (-1.6; -0.1)] and continuously significantly higher increase in MF on full ECMO support [4.3 Hz (2.9; 5.6) vs. 1.1 Hz (0.6; 1.6)] with p = 0.05 for both observations, respectively. CONCLUSIONS: The veno-arterial ECMO reperfusion influences MF of VF wavelet obtained from right ventricular apex. The course of changes in wavelet frequency corresponds to a presence of later ROSC.

The availability of HEPA-filtered rooms and the incidence of pneumonia in patients after haematopoietic stem cell transplantation (HSCT): results from a prospective, multicentre, eastern European study.

AIMS AND OBJECTIVES: To establish the availability of High Efficiency Particulate Air (HEPA)- and nonHEPA-filtered rooms in eastern European transplant centres and to investigate the impact on incidence of pneumonia and mortality after haematopoietic stem cell transplantation (HSCT). BACKGROUND: Barrier nursing in HEPA-filtered rooms is generally recommended for patients undergoing HSCT. There are only limited data on the availability of HEPA-filtered rooms and the impact on incidence of pneumonia and mortality. DESIGN: A prospective, observational, international study. METHODS: Monitoring cards were distributed within the East Forum EBMT-Nurses Group cooperating centres, and 689 consecutive patients were registered in 1/2010-6/2012. Patients were monitored for 100 days post-transplant. RESULTS: In patients undergoing autologous HSCT, pneumonia developed in 14/400 (3·5%) and was the cause of death in 2/14 (14%) of patients. There was no significant difference in mortality between HEPA-filtered and nonHEPA-filtered groups (4·5% vs. 4·9%, respectively). 239/400 (59%) transplantations were performed in single-bed rooms [190/239 (79%) HEPA-filtered] and 161 (41%) in two-bed rooms [28/161 (17%) HEPA-filtered]. In allogeneic transplantation, pneumonia developed in 24/289 (8·3%) and was the cause of death in 11/24 (45%) of patients. There was no significant difference in mortality between HEPA-filtered and non-HEPA-filtered groups (14% vs. 17%, respectively). 281/289 (97%) of allogeneic transplantations were performed in single-bed rooms [254/281 (90%) HEPA-filtered], and pneumonia was more frequent in patients on corticosteroids and in rooms without HEPA. CONCLUSION: The incidence of pneumonia in the autologous transplantation setting is low. More pneumonia was observed in the allogeneic HSCT group, especially in patients on corticosteroids. There was a trend towards a lower incidence of pneumonia in allogeneic HSCT patients treated in HEPA-filtered rooms. RELEVANCE TO CLINICAL PRACTICE: Autologous HSCT transplantation may safely be performed without HEPA filtration. HEPA filtration might be preferable in patients undergoing allogeneic transplantation.