Morphology combined with ancillary techniques: An algorithm approach for thyroid nodules.

INTRODUCTION: Several authors have underlined the limits of morphological analysis mostly in the diagnosis of follicular neoplasms (FN). The application of ancillary techniques, including immunocytochemistry (ICC) and molecular testing, contributes to a better definition of the risk of malignancy (ROM) and management of FN. According to literature, the application of models, including the evaluation of ICC, somatic mutations (ie, BRAFV600E ), micro RNA analysis is proposed for FNs. This study discusses the validation of a diagnostic algorithm in FN with a special focus on the role of morphology then followed by ancillary techniques. METHODS: From June 2014 to January 2016, we enrolled 37 FNs with histological follow-up. In the same reference period, 20 benign nodules and 20 positive for malignancy were selected as control. ICC, BRAFV600E mutation and miR-375 were carried out on LBC. RESULTS: The 37 FNs included 14 atypia of undetermined significance/follicular lesion of undetermined significance and 23 FN. Specifically, atypia of undetermined significance/follicular lesion of undetermined significance resulted in three goitres, 10 follicular adenomas and one NIFTP whereas FN/suspicious for FN by seven follicular adenomas and 16 malignancies (nine non-invasive follicular thyroid neoplasms with papillary-like nuclear features, two invasive follicular variant of papillary thyroid carcinoma [PTC] and five PTC). The 20 positive for malignancy samples included two invasive follicular variant of PTC, 16 PTCs and two medullary carcinomas. The morphological features of BRAFV600E mutation (nuclear features of PTC and moderate/abundant eosinophilic cytoplasms) were associated with 100% ROM. In the wild type cases, ROM was 83.3% in presence of a concordant positive ICC panel whilst significantly lower (10.5%) in a negative concordant ICC. High expression values of MirR-375 provided 100% ROM. CONCLUSIONS: The adoption of an algorithm might represent the best choice for the correct diagnosis of FNs. The morphological detection of BRAFV600E represents the first step for the identification of malignant FNs. A significant reduction of unnecessary thyroidectomies is the goal of this application.

A phase 2 study of temozolomide in pretreated metastatic colorectal cancer with MGMT promoter methylation.

BACKGROUND: Presently, few options are available for refractory colorectal cancer (CRC). O6-methyl-guanine-DNA-methyltransferase (MGMT) promoter methylation is a frequent and early event in CRC tumourigenesis. This epigenetic silencing is a predictor of response to the alkylating drug temozolomide in glioblastoma. Preclinical evidences and some case reports showed temozolomide activity in CRC with MGMT silencing, but the available data from clinical trials are inconsistent. METHODS: This was a multicentre, phase 2 trial, planned according to a two-stage Simon's optimal design to investigate activity and safety of temozolomide in refractory CRC harbouring MGMT promoter methylation. The primary end point was overall response rate (ORR). Patients who failed two or more prior treatments received temozolomide at a dose of 150-200 mg m-2 per day on days 1-5 every 28 days. RESULTS: From July 2012 to June 2016, 225 patients were screened, 80 showed MGMT promoter methylation and 41 were enrolled. Overall response rate was 10% and disease control rate was 32%. Median progression-free survival and overall survival were 1.9 and 5.1 months, respectively. CONCLUSIONS: Temozolomide showed a modest activity in this heavily pretreated population and the study did not meet its primary end point. The role of temozolomide in CRC remains still controversial and further research is warranted.

Morphological features that can predict BRAFV600E -mutated carcinoma in paediatric thyroid cytology.

OBJECTIVE: BRAFV600E represents the most common diagnostic marker in papillary thyroid carcinoma (PTC). A few papers have demonstrated the correlation between BRAFV600E and specific morphological findings on PTCs in the adult population. This is the first reported series investigating cytological morphological parameters in paediatric thyroid carcinoma. METHODS: One hundred and nineteen paediatric samples (56 male and 63 female patients), diagnosed in the period between April 2013 and July 2015, were enrolled in the study. Fifteen patients with inadequate results were excluded. Cytological cases were processed with liquid-based cytology (LBC). BRAFV600E and immunocytochemistry for the VE1 antibody were performed on LBC. RESULTS: The diagnostic series included 10 mutated and 94 wild-type (WT) cases. Twenty two percent surgical samples showed 96% cytohistological concordance. The morphological analysis revealed plump cells (abundant eosinophilic cytoplasm and PTC nuclei) in all 10 mutated cases with only four cases showing a focal (less than 20% of the cells) plump component. None of the WT showed plump cells. A sickle nuclear shape was seen only in the mutated cases. VE1 yielded 100% positivity on mutated cases with three cytohistological discrepancies. CONCLUSIONS: The BRAFV600E mutation is also seen in paediatric cytology and the morphological features showed a high accuracy as both predictive mutational parameters and a helpful aid in management mainly of the aggressive BRAFV600E mutated carcinomas.

The potential of liquid-based cytology in lymph node cytological evaluation: the role of morphology and the aid of ancillary techniques.

OBJECTIVES: Our aim was to evaluate the feasibility and diagnostic accuracy of liquid-based cytology (LBC) on lymph node fine needle aspiration (FNA). FNA may fulfil a challenging role in the evaluation of the majority of primary (benign and malignant) diagnoses as well as metastatic lymph node lesions. Although the morphological features may be quite easily recognized, cytological samples with a scant cellular component may raise some issues. METHODS: We appraised 263 cytological lymph nodes from different body regions analysed between January and December 2013, including 137 male and 126 female patients, and processed with LBC. RESULTS: The cytological diagnoses included 160 benign and 103 malignant lesions. We reported 35 benign and 73 malignant lesions from 108 with surgical follow-up. The latter malignant series included 68 metastatic lesions, four suspicious for malignancy and one inadequate sample. The cytological diagnoses were supported by 62 conclusive immunocytochemical and 28 molecular analyses. Of the 108 cases, we documented 35 true negatives, 72 true positives, one false negative and no false positives, resulting in 98.6% sensitivity, 100% specificity, 99% diagnostic accuracy, 97.2% negative predictive value and 100% positive predictive value. CONCLUSIONS: FNA represents the first diagnostic tool in lymph node management and a reliable approach in order to avoid an excision biopsy. Furthermore, LBC is a feasible method for ancillary tests for which methanol-fixed samples are suitable, such as immunocytochemistry and molecular analysis.

Pituitary-tumour-transforming-gene 1 expression in testicular cancer.

Genomic instability is a feature of germ cell tumours. The pituitary-tumour-transforming-gene 1 (PTTG1) is the major effector of chromosome segregation during mitosis, protecting the cell from aneuploidy. The protein expression of this gene has been evaluated in testicular tumours by immunohistochemistry. Formalin-fixed and paraffin-embedded specimens of testicular tissues from 83 patients undergoing therapeutic orchidectomy for seminomas (n = 53), embryonal carcinoma (n = 10), yolk sac tumour (n = 10) and teratoma (n = 10) were examined. Seminoma was associated with in situ carcinoma (CIS) in 23 samples. PTTG1 immunostaining was performed using rabbit anti-PTTG1 as a primary antibody. In CIS, only isolated cells showed nuclear staining for PTTG1. In the peripheral area of seminoma, PTTG1 was mostly detected as localised in the nucleus; in the central area of seminoma, PTTG1 staining was more intense in cytoplasm. PTTG1-positive cells were also present in the areas of seminoma infiltration. On the other hand, in embryonal carcinoma, cells had a diffuse positive immunostaining, mainly cytoplasmatic, while we did not observe an expression of PTTG1 in yolk sac tumour and mature teratoma. We firstly identified the PTTG1 expression pattern in normal testis, CIS and testicular cancer. Further investigation is needed to clarify the functional activity of PTTG1 in testicular oncogenesis.

KRAS mutational status affects oxaliplatin-based chemotherapy independently from basal mRNA ERCC-1 expression in metastatic colorectal cancer patients.

BACKGROUND: In this study, we evaluated the possibility that KRAS mutational status might be predictive of oxaliplatin (OXA) efficacy. We also explored the role of excision repair cross complementing group-1 (ERCC-1). METHODS: Ninety anti-epidermal growth factor receptor-naive advanced colorectal cancer patients were retrospectively analysed. In all patients KRAS mutational status was assessed. In 60 patients mRNA ERCC-1 expression was also investigated. Response rate (RR) and progression-free survival (PFS) after FOLFOX-6±bevacizumab were evaluated according to KRAS status and mRNA ERCC-1 expression. RESULTS: Among 90 patients 47% wild-type (wt) and 53% mutated (mt) KRAS tumours were found. Response rate was 26% in the wt KRAS group, whereas it was 56% in the mt KRAS group; the difference is statistically significant in the total sample (P=0.008) and when only patients receiving FOLFOX-6±bevacizumab as first-line are considered (P=0.01). Progression-free survival was longer in mt than in wt KRAS patients over all patients (10 vs 8 months, respectively, P=0.001) and in those treated as first-line (10 vs 8 months, respectively, P=0.0069). Mt KRAS patients experienced a longer survival (24 vs 18 months; P=0.01). ERCC-1 mRNA expression was not found to correlate with FOLFOX activity in our analysis. CONCLUSION: Our results suggest that activating mutation of KRAS oncogene may predict response to OXA. Basal expression of ERCC-1 mRNA does not explain the high efficacy of FOLFOX-6 in mt KRAS patients.

Methylation Analysis of Urinary Sample in Non-Muscle-Invasive Bladder Carcinoma: Frequency and Management of Invalid Result.

BACKGROUND: Numerous studies showed that methylation analysis represents a newly developed urinary marker based on DNA methylation changes in a panel of genomic biomarkers and it could represent a valid tool in terms of the diagnosis and prediction of high-grade urothelial carcinoma recurrences. One of the limits of the use of this new molecular method during a follow-up is represented by the number of invalid tests in routine practice. METHOD: A total of 782 patients with a diagnosis of non-muscle-invasive high-grade carcinoma (NMIBC) was studied. The Bladder EpiCheck test (BE) was performed together with cytology in all cases within 1 year after the end of treatment. In 402 patients, the urinary samples were voided urine (UV), while, in 380 cases, the samples were collected after bladder washing (IU). For all the patients with invalid BE results, a second BE test was performed following the instructions for use that indicated the test should be repeated with a new urinary sample in the case of an invalid result. RESULTS: Analyzing the two different groups (UV and IU), we found the invalid BE results seemed to be not related to urinary samples (p = 0.13 Fisher's exact test), suggesting that the collection method was not relevant in order to reduce the number of invalid tests. CONCLUSIONS: In the follow-up for NMIBC, for patients for whom a BE test is planned, a combined approach of cytology and a methylation test is recommended in order to repeat the BE test with an invalid result only in those cases with a cytological diagnosis of atypical urothelial cells (AUC) suspicious for high-grade urothelial carcinoma (SHGUC) and high-grade urothelial carcinoma (HGUC).

Mesenchymal differentiation of glioblastoma stem cells.

Glioblastoma multiforme is a severe form of cancer most likely arising from the transformation of stem or progenitor cells resident in the brain. Although the tumorigenic population in glioblastoma is defined as composed by cancer stem cells (CSCs), the cellular target of the transformation hit remains to be identified. Glioma stem cells (SCs) are thought to have a differentiation potential restricted to the neural lineage. However, using orthotopic versus heterotopic xenograft models and in vitro differentiation assays, we found that a subset of glioblastomas contained CSCs with both neural and mesenchymal potential. Subcutaneous injection of CSCs or single CSC clones from two of seven patients produced tumor xenografts containing osteo-chondrogenic areas in the context of glioblastoma-like tumor lesions. Moreover, CSC clones from four of seven cases generated both neural and chondrogenic cells in vitro. Interestingly, mesenchymal differentiation of the tumor xenografts was associated with reduction of both growth rate and mitotic index. These findings suggest that in a subclass of glioblastomas the tumorigenic hit occurs on a multipotent stem cell, which may reveal its plasticity under specific environmental stimuli. The discovery of such biological properties might provide considerable information to the development of new therapeutic strategies aimed at forcing glioblastoma stem cell differentiation.

Cell-free circulating DNA in Hodgkin's and non-Hodgkin's lymphomas.

BACKGROUND: Levels of cell-free circulating DNA have been correlated to clinical characteristics and prognosis in patients with cancers of epithelial origin, while there are no data on patients with B-lymphoproliferative diseases. PATIENTS AND METHODS: Cell-free DNA levels in the plasma samples of 142 patients with lymphomas [45 with Hodgkin's lymphoma (HL), 63 with diffuse large B-cell non-Hodgkin's lymphoma (DLBCL), 24 with follicular, and 10 with mantle cell non-Hodgkin's lymphoma (NHL)] at diagnosis and of 41 healthy individuals were determined using a quantitative PCR for the beta-globin gene. RESULTS: Levels of circulating DNA in patients with HL, DLBCL, and mantle cell NHL were significantly higher than in controls (P < 0.01 for all). Increased levels of plasma DNA were associated with advanced stage disease, presence of B-symptoms, elevated lactate dehydrogenase levels, and age >60 years (P = 0.009; <0.0001; <0.0001; 0.04, respectively). In HL, histological signs of necrosis and grade 2 type of nodular sclerosis were associated with increased plasma DNA. Elevated plasma DNA levels were associated with an inferior failure-free survival in patients with HL (P = 0.01) and DLBCL (P = 0.03). CONCLUSION: Quantification of circulating DNA by real-time PCR at diagnosis can identify patients with elevated levels that are associated with disease characteristics indicating aggressive disease and poor prognosis.

Hydrogen peroxide-related colitis (previously known as "pseudolipomatosis"): a series of cases occurring in an epidemic pattern.

We report several cases of hydrogen peroxide-related colitis that occurred in an epidemic pattern in our gastrointestinal endoscopy center during a 2-month period in early 2007. During colonoscopy using sterilized endoscopes that had been flushed with hydrogen peroxide after the peracetic acid cycle, instantaneous effervescence and blanching (the "snow white sign") were observed on the intestinal mucosa when the water button was depressed. Biopsy specimens revealed features resembling a clinical condition which used to be known as "pseudolipomatosis." At follow-up, no patient was found to have suffered morbidity associated with this peroxide colitis. Endoscopists should consider hydrogen peroxide colitis when they see a snow white sign during colonoscopy which cannot be attributed to active inflammation or organic disease of the digestive tract.

Posttransplant lymphoproliferative disorders after liver transplantation: analysis of early and late cases in a 255 patient series.

We reviewed the incidence and the impact of posttransplant lymphoproliferative disorders (PTLDs) on patient survival among a consecutive series of 255 patients. Five cases of PTLD were observed in adults: two cases were early (less than 1 year) and three cases, late lymphomas. The EBV positivity and the degree of immunosuppression were the main risk factors. We labeled cases as early or late according to whether the time elapsed from the transplant to the first clinical evidence of PTLD was less than 12 months. The median time from transplant to diagnosis of PTLD was 8 (early) and 108 (late) months. All cases were treated by reduction in immunosuppressive therapy with conventional chemotherapy and rituximab. The early cases with lymphoma located at the hepatic hilum died due to local complications (biliary sepsis and hemobilia), after an initial partial response to chemotherapy. The three patients with late cases are in remission after a mean follow-up of 23 months.

High accuracy and cost-effectiveness of a biopsy-avoiding endoscopic approach in diagnosing coeliac disease.

BACKGROUND: The 'immersion' technique during upper endoscopy allows the visualization of duodenal villi and the detection of total villous atrophy. AIM: To evaluate the accuracy of the immersion technique in detecting total villous atrophy in suspected coeliac patients. The accuracy in diagnosing coeliac disease and the potential cost-sparing of a biopsy-avoiding approach, based on selection of individuals with coeliac disease-related antibodies and on endoscopic detection of absence of villi, were also analysed. METHODS: The immersion technique was performed in 79 patients with positive antibodies and in 105 controls. Duodenal villi were evaluated as present or absent. As reference, results were compared with histology. Diagnostic approaches, including endoscopy with or without biopsy, were designed to investigate patients with coeliac disease-related antibodies and total villous atrophy. A cost-minimization analysis was performed. RESULTS: All patients with positive antibodies had coeliac disease. The sensitivity, specificity, positive and negative predictive values of endoscopy to detect total villous atrophy was always 100%. The sensitivity, specificity, positive and negative predictive values of biopsy-avoiding or biopsy-including strategies in diagnosing coeliac disease when villi were absent was always 100%. The biopsy-avoiding strategy was cost-sparing. CONCLUSIONS: Upper endoscopy is highly accurate in detecting total villous atrophy coeliac patients. A biopsy-avoiding approach is both accurate and cost-sparing to diagnose coeliac disease in subjects with marked duodenal villous atrophy.

Delayed allergy to aminopenicillins: clinical and immunological findings.

Aminopenicillins are the most used beta-lactam antibiotics. Morbilliform or maculopapular rashes are rather frequent during therapy with aminopenicillins. The pathogenesis of these reactions is often due to a cell-mediated allergy. The aim of this work is to characterize patients with cell-mediated allergy to aminopenicillins and to identify alternative beta-lactam drugs that can be safely administered to these patients. We studied 27 subjects affected by cell-mediated allergy to aminopenicillins. The diagnosis was made on the basis of positivity of patch tests with aminopenicillins. These patients then underwent an allergological evaluation (skin and patch tests, oral and/or intramuscular challenge tests) with a wide spectrum of beta-lactam antibiotics. Our work highlights the following main characteristics of cell-mediated allergy to aminopenicillins: time elapsing between drug administration and onset of symptoms of about 2 days; the maculopapular rash and delayed appearance of urticaria/angioedema were the most typical symptoms (82.8 percent of cases); a cross-reactivity with aminocephalosporins is usually absent, or it is limited to cephalexin (in our study, in fact, just 3 out of 20 patients challenged with cephalexin showed a positive oral challenge test); all the beta-lactams, other than aminopenicillins, are well tolerated. Patch tests represent a specific diagnostic tool with a good predictive value of identifying alternative drugs that can be safely administered to patients with beta-lactam allergy. Our patients could tolerate other beta-lactam drugs after a complete allergological evaluation. On the basis of our study, cell-mediated allergy to aminopenicillins should be considered a well-defined nosologic entity.

Ischaemic jejunal vasculitis during treatment with pegylated interferon-alpha 2b and ribavirin for hepatitis C virus related cirrhosis.

A 53-year-old male with compensated cirrhosis (Child-Pugh class A5) and mixed cryoglobulinaemia (cryocrit: 2.0%), both hepatitis C virus-related, was treated with pegylated interferon-alpha 2b and ribavirin. After three months of therapy, he developed segmental jejunal vasculitis requiring emergency resection of an ischaemic intestinal loop 60cm long. Pathological examination of the surgical specimen revealed signs of ischaemic injury with haemorrhagic infarction due to arteritis and arterial occlusion. The postoperative course was complicated by progressive liver and renal failure that led to the patient's death six months after surgery. To our knowledge, ischaemic jejunal vasculitis has never been reported during interferon therapy, but the latter treatment may have played causative roles.

Minimally invasive diagnosis of acquired immunodeficiency syndrome-related primary central nervous system lymphoma.

BACKGROUND: The detection of Epstein-Barr virus (EBV)-DNA in cerebrospinal fluid (CSF) by means of the polymerase chain reaction (PCR) has been revealed, in retrospective studies, to be a good marker of primary central nervous system lymphoma (PCNSL) related to acquired immunodeficiency syndrome (AIDS); however, the technique's usefulness in the management of AIDS patients with focal brain lesions is still unknown. We studied the clinical usefulness of testing CSF obtained by lumbar puncture for the presence of EBV-DNA as a minimally invasive approach to the diagnosis of AIDS-PCNSL in patients with focal brain lesions. METHODS: Human immunodeficiency virus (HIV)-infected patients with focal brain lesions, observed prospectively during a 30-month period, underwent lumbar puncture if not contraindicated; otherwise, ventricular CSF was obtained at brain biopsy. The presence of EBV-DNA was determined by means of PCR. RESULTS: We evaluated 122 patients: 42 diagnosed with brain lymphoma and the remaining 80 diagnosed with other brain disorders. Cerebrospinal fluid was collected from 101 patients--by lumbar puncture in 95, including 40 patients with AIDS-PCNSL. The sensitivity and specificity of PCR for EBV-DNA detection in lumbar CSF were 80% (95% confidence interval [CI] = 60.9%-91.6%) and 100% (95% CI = 92.6%-100%), respectively. Lumbar puncture and subsequent assessment of EBV-DNA would have allowed a correct diagnosis in 63.2% (95% CI = 46.0%-77.7%) of patients with AIDS-PCNSL and excluded this diagnosis in 76.3% (95% CI = 65.2%-84.8%) of patients without lymphoma (because EBV-DNA was not detected). CONCLUSIONS: The presence of EBV-DNA in lumbar CSF is a sensitive and highly specific diagnostic marker of AIDS-PCNSL, and EBV-DNA detection in this fluid may allow a minimally invasive diagnosis in a large percentage of patients with brain lymphomas.

Gadolinium in human glioblastoma cells for gadolinium neutron capture therapy.

157Gd is a potential agent for neutron capture cancer therapy (GdNCT). We directly observed the microdistribution of Gd in cultured human glioblastoma cells exposed to Gd-diethylenetriaminepentaacetic acid (Gd-DTPA). We demonstrated, with three independent techniques, that Gd-DTPA penetrates the plasma membrane, and we observed no deleterious effect on cell survival. A systematic microchemical analysis revealed a higher Gd accumulation in cell nuclei compared with cytoplasm. This is significant for prospective GdNCT because the proximity of Gd to DNA increases the cell-killing potential of the short-range, high-energy electrons emitted during the neutron capture reaction. We also exposed Gd-containing cells to thermal neutrons and demonstrated the GdNC reaction effectiveness in inducing cell death. These results in vitro stimulated in vivo Gd-DTPA uptake studies, currently underway, in human glioblastoma patients.

Gemcitabine versus FOLFIRINOX in patients with advanced pancreatic adenocarcinoma hENT1-positive: everything was not too bad back when everything seemed worse.

PURPOSE: hENT1 is a transmembrane protein which acts as a nucleoside transporter and is the main mediator of Gemcitabine (GEM) uptake into human cells. In this retrospective study we compared GEM versus FOLFIRINOX in patients with metastatic pancreatic cancer in which hENT1 evaluation was available. METHODS: 149 patients affected by unresectable metastatic pancreatic cancer, treated in our institution from 2009 to 2013, have been screened for inclusion in this retrospective study. Seventy patients, treated with GEM or FOLFIRINOX in first-line therapy, fulfilled clinical inclusion criteria for survival analysis. Thirty-one patients were available and contained sufficient quality/quantity RNA for evaluation of hENT1 expression by RT-PCR. The primary endpoint was OS and the secondary endpoint was PFS. RESULTS: The survival analysis, carried out on 70 patients regardless of hENT1 expression, showed a statistically longer OS and PFS in the group treated with FOLFIRINOX compared to GEM. Within the exploratory analysis, which included 31 patients, no differences were found in hENT1 positive patients treated with FOLFIRINOX compared to GEM in terms of OS (8.5 vs 7 months, HR: 0.89; 95 % CI 0.3-2.5; p = 0.8) and PFS (5.5 vs 5 months, HR: 0.8, 95 % CI 0.2-2.2; p = 0.61). GEM-treated hENT1 positive patients showed a statistically significant improvement both of OS (8 vs 2 months; p = 0.0012) and PFS (5 vs 1 months; p = 0.0004) in comparison to GEM-treated hENT1 negative patients. CONCLUSIONS: In our exploratory analysis GEM seems as effective as FOLFIRINOX in terms of survival with a better safety profile in hENT1 positive metastatic pancreatic cancer.

Metabolic/Proteomic Signature Defines Two Glioblastoma Subtypes With Different Clinical Outcome.

Glioblastoma (GBM) is one of the deadliest human cancers. Because of the extremely unfavorable prognosis of GBM, it is important to develop more effective diagnostic and therapeutic strategies based on biologically and clinically relevant subclassification systems. Analyzing a collection of seventeen patient-derived glioblastoma stem-like cells (GSCs) by gene expression profiling, NMR spectroscopy and signal transduction pathway activation, we identified two GSC clusters, one characterized by a pro-neural-like phenotype and the other showing a mesenchymal-like phenotype. Evaluating the levels of proteins differentially expressed by the two GSC clusters in the TCGA GBM sample collection, we found that SRC activation is associated with a GBM subgroup showing better prognosis whereas activation of RPS6, an effector of mTOR pathway, identifies a subgroup with a worse prognosis. The two clusters are also differentiated by NMR spectroscopy profiles suggesting a potential prognostic stratification based on metabolic evaluation. Our data show that the metabolic/proteomic profile of GSCs is informative of the genomic/proteomic GBM landscape, which differs among tumor subtypes and is associated with clinical outcome.

Epstein-Barr virus infection is predictive of CNS involvement in systemic AIDS-related non-Hodgkin's lymphomas.

PURPOSE: This study aimed at correlating Epstein-Barr virus (EBV) infection of systemic AIDS-related non-Hodgkin lymphomas (AIDS-NHL) with the development of a CNS localization of the tumor. PATIENTS AND METHODS: Demographic, epidemiologic, clinical, histologic, and virologic features were collected for all systemic AIDS-NHL patients included in the study (n = 50). Pathologic specimens were classified according to the working formulation for NHL and the Revised European-American Lymphoma classification. EBV infection in tumor tissue samples was studied by EBV small encoded RNA in situ hybridization; EBV-DNA detection in CSF was carried out by nested polymerase chain reaction using Epstein-Barr nuclear antigen-1-specific primers. In addition, selected EBV-positive lymphomas were subjected to a detailed characterization of EBV molecular heterogeneity. RESULTS: Eleven patients had a CNS involvement at some point during their clinical history (four at diagnosis and seven at relapse). Thirty patients (11 with CNS involvement and 19 without) harbored EBV infection of the tumor. Sensitivity, specificity, and positive and negative predictive values of EBV-DNA detection in CSF for CNS involvement by lymphoma were 90%, 100%, 100%, and 97.6%, respectively. Factors significantly predictive of CNS involvement were EBV infection of the tumor (P=.003), an extranodal disease at diagnosis other than CNS (P=.006), and a non-CNS relapse (P=.01). In four cases of CNS involvement, EBV-DNA in CSF preceded any other sign of disease by a mean of 35 days. CONCLUSION: These results show that EBV infection of the tumor clone significantly increases the risk of CNS involvement by systemic AIDS-NHL, without regard of specific molecular features. The detection of EBV-DNA in the CSF of AIDS-NHL patients may select cases with higher risk of CNS involvement and, therefore, may prove useful in the therapeutic stratification of these tumors.