Molecular Diagnostic Modalities Research Articles

DNA Methylation Profiling Confirms a Challenging Glioblastoma, Atypical Mesenchymal Type Which Mimics Intracranial Mesenchymal Tumor

Abstract Introduction/Objective Brain tumors exhibit distinct DNA methylation patterns that reflect their cellular origin, molecular subtype, and clinical behavior. DNA methylation signatures provide valuable insights into tumor heterogeneity, evolution, and treatment response, guiding personalized therapeutic strategies. Our case, glioblastoma, atypical mesenchymal type confirmed by DNA methylation profile and it reflects the clonal evolution of the glioblastoma metaplasia with minimal glial component which was histologically challenging. Methods/Case Report A 56-year-old gentleman presented with headaches. MRI brain demonstrated a heterogeneous enhancing mass with areas of central necrosis in the left temporal lobe, measuring approximately 49 x 34 mm, with surrounding T2 FLAIR hyperintensity extending into the left basal ganglia, causing compression of the left lateral ventricle and uncal herniation. He underwent left-sided craniotomy for tumor resection. Microscopic examination revealed hypercellular spindle cell neoplasm, forming fascicles. Brisk mitotic activity and geographic necrosis were evident. GFAP highlighted narrow margins of the tumor which could represent the entrapped glial tissue. CD99 stained the tumor cells, Other immunohistochemical stains for spindle cell work up, like S100, EMA, PR STAT6 and desmin were all negative. A diagnosis of intracranial mesenchymal tumor /sarcoma was considered. Methylation profiling results showed class calibrated scores of 0.9741, compatible with Glioblastoma, IDH-wildtype, atypical mesenchymal type with a cytogenetic profile including gain of chromosome 7 (including EGFR) and loss of chromosome 10 (including PTEN), and loss of CDKN2A/B. Results (if a Case Study enter NA) NA Conclusion Although histopathological examination and immunohistochemical study are fundamental in diagnosing brain tumors, the rapid development of cytogenetic and molecular diagnostic modalities has significantly contributed to diagnostic accuracy and the potential for targeted treatment. Particularly, DNA methylation profiling has proven valuable in diagnosing morphologically challenging cases with prognostic value. Eventually, DNA methylation profiling will be adopted as a major cancer diagnostic criterion and will become a standard procedure performed at major academic centers.

A cross-sectional pilot study to estimate the frequency of minor blood group alleles and phenotypes in RhD-negative North Indian blood donors by DNA microarray analysis

Abstract: INTRODUCTION: There are scarce data on Indian blood donors with respect to blood group phenotypes using molecular diagnostic modalities. Hence, we planned to estimate frequencies of blood group alleles/phenotypes using DNA microarray analysis in the north Indian RhD-negative blood donor population. With this initial pilot study, we plan to expand it to our entire donor population. METHODOLOGY: The cross-sectional prospective study was conducted on 50 Indian blood donors (O RhD negative), to study the blood group genotype frequency. Genotyping for the most relevant red blood cell antigens (Rh, Kell, Duffy, Kidd, MNS, Lutheran, and Dombrock) was done using Bioarray Precise TypeHM Human Erythrocyte Antigen BeadChip kit containing probes directed to polymorphic sites. RESULTS: In the Rh system, the most common alleles were RHCE*e/RHCE*e (98%) and RHCE*c/RHCE*c (80%). Phenotype K-k+ (genotype- KEL*02/KEL*02) was seen in 98% of samples, Js(a-b+) (KEL*02.07/KEL*02.07) was detected in 98% (49/50) of the samples tested. Jk(a + b+) (JK*01/JK*02) was the most common phenotype (48%) in the Kidd blood group system. In MNSs system, M+N+ (GYPA*01/GYPA*02) 44% and S+s+U+ (GYPB*03/GYPB*04) 34% were the most common phenotypes detected. CONCLUSION: This pilot study shows the feasibility of genotyping a Northern Indian donor population. To the best of our knowledge, it is the first study on molecular blood grouping in Indian blood donors using the Bioarray platform.

Identification of Novel/Rare EWSR1 Fusion Partners in Undifferentiated Mesenchymal Neoplasms.

Recurrent gene fusions (GFs) in translocated sarcomas are recognized as major oncogenic drivers of the disease, as well as diagnostic markers whose identification is necessary for differential diagnosis. EWSR1 is a 'promiscuous' gene that can fuse with many different partner genes, defining different entities among a broad range of mesenchymal neoplasms. Molecular testing of EWSR1 translocation traditionally relies on FISH assays with break-apart probes, which are unable to identify the fusion partner. Therefore, other ancillary molecular diagnostic modalities are being increasingly adopted for accurate classification of these neoplasms. Herein, we report three cases with rare GFs involving EWSR1 in undifferentiated mesenchymal neoplasms with uncertain differential diagnoses, using targeted RNA-seq and confirming with RT-PCR and Sanger sequencing. Two GFs involved hormone nuclear receptors as 3' partners, NR4A2 and RORB, which have not been previously reported. NR4A2 may functionally replace NR4A3, the usual 3' partner in extraskeletal myxoid chondrosarcoma. The third GF, EWSR1::BEND2, has previously been reported in a subtype of astroblastoma and other rare entities, including a single case of a soft-tissue tumor that we discuss in this work. In conclusion, our findings indicate that the catalogue of mesenchymal neoplasm-bearing EWSR1 fusions continues to grow, underscoring the value of using molecular ancillary techniques with higher diagnostic abilities in the routine clinical setting.

Challenges in Characterization of Coagulase Negative Staphylococcus by Conventional Methods and Comparison with Molecular Diagnostic Modalities

Coagulase-negative Staphylococcus (CoNS) has emerged as a significant primary pathogen, frequently determined in hospitalized individuals with immune deficiencies, and regularly with indwelling or implantable clinical devices. Most infections are nosocomial, and conservative infections can lead to a variety of chronic diseases, such as urinary tract infections (S. saprophyticus), infections brought on by medical devices, endocarditis, mediastinitis, meningitis, and bloodstream infections. Although many new species have been revealed in recent years, there is still a defect in clinical details for most of that genus. Additionally, interspecies variations that must be considered make certain species more pathogenic than others. Blood cultures and other samples are commonly contaminated because CoNS has the ability to colonize human skin. Determining cases where CoNS are causal agents rather than contaminants is hence the key diagnostic challenge. However, neither phenotypic nor genetic approaches have been successful in offering a satisfactory answer to this issue. MALDI-TOF MS (99.3% of strains properly identified) was the most effective method for speedy and precise CoNS differentiation. Vitek2 paired with partial tuf gene sequencing might be an alternative that yields 100% accurate strain identification when both techniques are used together. All of the staphylococcal subspecies under investigation, include S.capitis subspecies capitis as well as subspecies urealyticus, S.cohnii subspecies urealyticus, S.saprophyticus subspecies saprophyticus, and Staphylococcus hominis subspecies novobiosepticus and subspecies. As a result, staphylococci can be routinely identified by MALDI-TOF MS without incurring significant consumable expenses or requiring time-consuming DNA sequence analysis. The revolutionary high-quality RIDOM is superior to phenotypic techniques and the NCBI database. Staphylococci are easily identified using sequencing databases, even seldom isolated species and phenotypic differences. Another challenge facing CoNS is their comprehensive antimicrobial resistance profile is relevant to clinical practice, notably in medical facilities. Consequently, genuine infections brought on by CoNS require the usage of second-line antimicrobial medications the majority of the time.

Real-world performance analysis of a novel computational method in the precision oncology of pediatric tumors.

The utility of routine extensive molecular profiling of pediatric tumors is a matter of debate due to the high number of genetic alterations of unknown significance or low evidence and the lack of standardized and personalized decision support methods. Digital drug assignment (DDA) is a novel computational method to prioritize treatment options by aggregating numerous evidence-based associations between multiple drivers, targets, and targeted agents. DDA has been validated to improve personalized treatment decisions based on the outcome data of adult patients treated in the SHIVA01 clinical trial. The aim of this study was to evaluate the utility of DDA in pediatric oncology. Between 2017 and 2020, 103 high-risk pediatric cancer patients (< 21years) were involved in our precision oncology program, and samples from 100 patients were eligible for further analysis. Tissue or blood samples were analyzed by whole-exome (WES) or targeted panel sequencing and other molecular diagnostic modalities and processed by a software system using the DDA algorithm for therapeutic decision support. Finally, a molecular tumor board (MTB) evaluated the results to provide therapy recommendations. Of the 100 cases with comprehensive molecular diagnostic data, 88 yielded WES and 12 panel sequencing results. DDA identified matching off-label targeted treatment options (actionability) in 72/100 cases (72%), while 57/100 (57%) showed potential drug resistance. Actionability reached 88% (29/33) by 2020 due to the continuous updates of the evidence database. MTB approved the clinical use of a DDA-top-listed treatment in 56 of 72 actionable cases (78%). The approved therapies had significantly higher aggregated evidence levels (AELs) than dismissed therapies. Filtering of WES results for targeted panels missed important mutations affecting therapy selection. DDA is a promising approach to overcome challenges associated with the interpretation of extensive molecular profiling in the routine care of high-risk pediatric cancers. Knowledgebase updates enable automatic interpretation of a continuously expanding gene set, a "virtual" panel, filtered out from genome-wide analysis to always maximize the performance of precision treatment planning.

Pythium insidiosum keratitis - A review.

Pythium insidiosum is an oomycete and is also called “parafungus” as it closely mimics fungal keratitis. The last decade saw an unprecedented surge in Pythium keratitis cases, especially from Asia and India, probably due to growing research on the microorganism and improved diagnostic and treatment modalities. The clinical features such as subepithelial infiltrate, cotton wool-like fluffy stromal infiltrate, satellite lesions, corneal perforation, endoexudates, and anterior chamber hypopyon closely resemble fungus. The classical clinical features of Pythium that distinguish it from other microorganisms are reticular dots, tentacular projections, peripheral furrowing, and early limbal spread, which require a high index of clinical suspicion. Pythium also exhibits morphological and microbiological resemblance to fungus on routine smearing, revealing perpendicular or obtuse septate or aseptate branching hyphae. Culture on blood agar or any other nutritional agar is the gold standard for diagnosis. It grows as cream-colored white colonies with zoospores formation, further confirmed using the leaf incarnation method. Due to limited laboratory diagnostic modalities and delayed growth on culture, there was a recent shift toward various molecular diagnostic modalities such as polymerase chain reaction, confocal microscopy, ELISA, and immunodiffusion. As corneal scraping (10% KOH, Gram) reveals fungal hyphae, antifungals are started before the culture results are available. Recent in vitro molecular studies have suggested antibacterials as the first-line drugs in the form of 0.2% linezolid and 1% azithromycin. Early therapeutic keratoplasty is warranted in nonresolving cases. This review aims to describe the epidemiology, clinical features, laboratory and molecular diagnosis, and treatment of Pythium insidiosum keratitis.

A Review of Recent Advances in Cytopathology for Diagnosis of Hepato-Biliary Lesions

Cytology has emerged as an important diagnostic modality for hepato-biliary lesions because of its minimally invasive, rapid turnaround time and cost-effective nature. This is especially important in diagnosis of neoplastic pathology of liver, gall bladder or bile duct where biopsy is difficult and delayed diagnosis may lead to complications or even mortality. The advent of newer molecular diagnostic modalities like polymerase chain reaction (PCR), fluorescent in situ hybridization (FISH), immunochemistry or more recently circulating tumour cells and next generation sequencing (NGS) have not only led to precise diagnosis but are also helpful in targeted therapy and prognostication of tumour. Cytology which is a minimally invasive technique can be judiciously used for advanced molecular analysis for diagnosis and management of hepato-biliary lesions. Awareness regarding the use of cytological samples for molecular analysis in hepato- biliary lesions is essential so that mutational changes may be easily determined without undergoing any invasive technique in these deep-seated lesions. It is also necessary that guidelines on molecular cytology should be chalked out so that uniform reporting is followed with maintenance of high-quality standards.

Shifting Gears in Precision Oncology-Challenges and Opportunities of Integrative Data Analysis.

For decades, research relating to modification of host immunity towards antitumor response activation has been ongoing, with the breakthrough discovery of immune-checkpoint blockers. Several biomarkers with potential predictive value have been reported in recent studies for these novel therapies. However, with the plethora of therapeutic options existing for a given cancer entity, modern oncology is now being confronted with multifactorial interpretation to devise “the best therapy” for the individual patient. Into the bargain come the multiverse guidelines for established and emerging diagnostic biomarkers, as well as the complex interplay between cancer cells and tumor microenvironment, provoking immense challenges in the therapy decision-making process. Through this review, we present various molecular diagnostic modalities and techniques, such as genomics, immunohistochemistry and quantitative image analysis, which have the potential of becoming powerful tools in the development of an optimal treatment regime when analogized with patient characteristics. We will summarize the underlying complexities of these methods and shed light upon the necessary considerations and requirements for data integration. It is our hope to provide compelling evidence to emphasize on the need for inclusion of integrative data analysis in modern cancer therapy, and thereupon paving a path towards precision medicine and better patient outcomes.

An Update on Molecular Biology of Cutaneous T Cell Lymphoma.

Cutaneous T cell lymphomas represent a heterogenous group of lymphoproliferative disorders defined by clonal proliferation of T cells present in the skin. The latest WHO classification in 2016 and WHO-EORTC classification in 2018 has updated the classification of these entities based on the molecular profile. Research in the field of molecular genetics of CTCL has allowed a better understanding of the biology of these tumors and has helped to identify potential targets for therapy that can be tailored to individual patients. In this review, we discuss the latest developments in the molecular profile of CTCLs including biomarkers for diagnosis, prognosis, and potential therapeutic targets. We have also touched upon the utility of various molecular diagnostic modalities. For the purpose of this review, we researched papers in PubMed indexed journals in English literature published in the past 20 years using keywords CTCL, mycosis fungoides, molecular profile, molecular diagnosis, whole genome profile, genomic landscape, TCR clonality.

Oral candida prevalence and species specificity in leprosy

BackgroundLeprosy represents a chronic progressive debilitating disease. The severe morbidity associated with leprosy predisposes the patients to opportunistic infections. To assess the oral candida prevalence and species specificity in lepromatous leprosy patients. MethodsThe cross-sectional study included 70 lepromatous leprosy patients under a multi-drug regimen for less than 1 year (group 1) and 70 healthy volunteers (group 2). Both group 1 and 2 were matched for potential confounding factors including age, gender, ethnicity, absence of HIV co-infection. Oral swab samples obtained from both groups were subjected to a series of conventional and molecular diagnostic modalities. ResultsYeast growth was statistically higher (0.0006) in group 1 (45.7%) than in group 2 (18.5%). 28 of the 32 yeast growth in group 1 and all 13 yeast growth in group 2 were identified as candida. Among the 28 candida species in group 1, 23 (71.88%) were Candida albicans, 3 (9.37%) were Candida parapsilosis, 1 (3.13%) was Candida lusitaniae and 1 (3.13%) was Candida nivariensis. Among group 2, 11 (84.6%) were Candida albicans, 1 (7.7%) was Candida parapsilosis and 1 was Candida tropicalis. ConclusionOral candida prevalence is higher in leprosy patients than in healthy individuals, indicating a predisposition towards opportunistic infections. The increasing prevalence of the non-candida albicans species in leprosy is a major concern as they have shown to possess inherent resistant towards common anti-fungal agents.

English

Bloodstream infections are a challenge to clinicians due to high rates of morbidity and mortality. Moreover, rational antimicrobial therapy, if promptly started, can improve the prognosis of sepsis. The gold-standard blood culture has some limitations and it takes time to complete (about 2-5 days). This leaves the clinicians to start immediately broad-range antimicrobial therapy until microbiology culture’s results available that may lead to complicate situation of patient further. Therefore, there is an urgent need for the development of more advanced diagnostic approaches that can overcome limitations of culture-based methods. This review gives an overview of the BSIs and its epidemiology over several cities and hospitals in Saudi Arabia. It also encompasses the diverse molecular diagnostic modalities developed for the rapid detection and identification of BSIs. Furthermore, the growing understanding of the host’s inflammatory responses to infections has led to the discovery of immunological biomarkers as diagnostic tools for sepsis-related BSI. The rational use of immunological and molecular diagnostic markers in clinical settings may speed up diagnosis and prognosis of septic patients. This review shows that the percentage of BSIs in Saudi Arabia, from 1983 to 2015, ranges from 1% to 11% among patients with confirmed infection. It also indicated that Staphylococcus aureus and coagulase negative staphylococci (CoNS) were the most common Gram-positive pathogens; while Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were the most Gram-negative ones from patients with BSI. The recommendation of this review is to initiate new surveillance systems of BSI in different regions and hospitals in Saudi Arabia and determining the antibiotic susceptibility profile to design antibiograms that may improve the antibiotic stewardship program for treating BSIs. A comparative study should be conducted for patients suspected to have sepsis, using the standard blood cultures, immunological markers and rapid molecular assays to set up a panel to help diagnose BSIs rapidly. This will allow early and optimal patient management and treatment in Saudi Arabia and therefore decrease overall healthcare costs. Key words: Bloodstream infections, sepsis, molecular diagnosis, inflammatory markers, BSI in Saudi Arabia.

The spectrum of EWSR1-rearranged neoplasms at a tertiary sarcoma centre; assessing 772 tumour specimens and the value of current ancillary molecular diagnostic modalities

Background:EWSR1 rearrangements were first identified in Ewing sarcoma, but the spectrum of EWSR1-rearranged neoplasms now includes many soft tissue tumour subtypes including desmoplastic small round cell tumour (DSRCT), myxoid liposarcoma (MLPS), extraskeletal myxoid chondrosarcoma (EMC), angiomatoid fibrous histiocytoma (AFH), clear cell sarcoma (CCS) and myoepithelial neoplasms. We analysed the spectrum of EWSR1-rearranged soft tissue neoplasms at our tertiary sarcoma centre, by assessing ancillary molecular diagnostic modalities identifying EWSR1-rearranged tumours and reviewing the results in light of our current knowledge of these and other Ewing sarcoma-like neoplasms.Methods:We retrospectively analysed all specimens tested for EWSR1 rearrangements by fluorescence in situ hybridisation (FISH) and/or reverse transcription–PCR (RT–PCR) over a 7-year period.Results:There was a total of 772 specimens. FISH was performed more often than RT–PCR (n=753, 97.5% vs n=445, 57.6%). In total, 210 (27.9%) specimens were FISH-positive for EWSR1 rearrangement compared to 111 (14.4%) that showed EWSR1 fusion transcripts with RT–PCR. Failure rates for FISH and RT–PCR were 2.5% and 18.0%. Of 109 round cell tumours with pathology consistent with Ewing sarcoma, 15 (13.8 %) cases were FISH-positive without an identifiable EWSR1 fusion transcript, 4 (3.7%) were FISH-negative but RT–PCR positive and 4 (3.7%) were negative for both. FISH positivity for DSRCT, MLPS, EMC, AFH and CCS was 86.3%, 4.3%, 58.5%, 60.0% and 87.9%, respectively. A positive FISH result led to diagnostic change in 40 (19.0%) EWSR1-rearranged cases. 13 FISH-positive cases remained unclassifiable.Conclusions:FISH is more sensitive for identifying EWSR1 rearrangements than RT–PCR. However, there can be significant morphologic and immunohistochemical overlap between groups of EWSR1-rearranged neoplasms, with important prognostic and therapeutic implications. FISH and RT–PCR should be used as complementary modalities in diagnosing EWSR1-rearranged neoplasms, but as tumour groups harbouring EWSR1 rearrangements are increasingly characterised and because given translocations involving EWSR1 and its partner genes are not always specific for tumour types, it is critical that these are evaluated by specialist soft tissue surgical pathologists noting the morphologic and immunohistochemical context. As RT–PCR using commercial primers is limited to only the most prevalent EWSR1 fusion transcripts, the incorporation of high-throughput sequencing technologies into the standard diagnostic repertoire to assess for multiple molecular abnormalities of soft tissue tumours in parallel (including detection of newly characterised Ewing sarcoma-like tumours) might be the most effective and efficient means of ancillary diagnosis in future.

Comparative Study of Autoantibody Responses between Lung Adenocarcinoma and Benign Pulmonary Nodules

IntroductionThe reduction in lung cancer mortality associated with computed tomography (CT) screening has led to its increased use and a concomitant increase in the detection of benign pulmonary nodules. Many individuals found to have benign nodules undergo unnecessary, costly, and invasive procedures. Therefore, there is a need for companion diagnostics that stratify individuals with pulmonary nodules into high-risk or low-risk groups. Lung cancers can trigger host immune responses and elicit antibodies against tumor antigens. The identification of these autoantibodies (AAbs) and their corresponding antigens may expand our knowledge of cancer immunity, leading to early diagnosis or even benefiting immunotherapy. Previous studies were performed mostly in the context of comparing cancers and healthy (smoker) controls. We have performed one of the first studies to understand humoral immune response in patients with cancer, patients with benign nodules, and healthy smokers. MethodsWe first profiled seroreactivity to 10,000 full-length human proteins in 40 patients with early-stage lung cancer and 40 smoker controls by using nucleic acid programmable protein arrays to identify candidate cancer-specific AAbs. Enzyme-linked immunosorbent assays of promising candidates were performed on 137 patients with lung cancer and 127 smoker controls, as well as on 170 subjects with benign pulmonary nodules. ResultsFrom protein microarray screening experiments using a discovery set of 40 patients and 40 smoker controls, 17 antigens showing higher reactivity in lung cancer cases relative to the controls were subsequently selected for evaluation in a large sample set (n = 264) by using enzyme-linked immunosorbent assay. A five-AAb classifier (tetratricopeptide repeat domain 14 [TTC14], B-Raf proto-oncogene, serine/threonine kinase [BRAF], actin like 6B [ACTL6B], MORC family CW-type zinc finger 2 [MORC2], and cancer/testis antigen 1B [CTAG1B]) that can differentiate lung cancers from smoker controls with a sensitivity of 30% at 89% specificity was developed. We further tested AAb responses in subjects with CT-positive benign nodules (n = 170), and developed a five-AAb panel (keratin 8, type II, TTC14, Kruppel-like factor 8, BRAF, and tousled like kinase 1) with a sensitivity of 30% at 88% specificity. Interestingly, messenger RNA levels of six AAb targets (TTC14, BRAF, MORC family CW-type zinc finger 2, cancer/testis antigen 1B, keratin 8, type II, and tousled like kinase 1) were also found to increase in lung adenocarcinoma tissues based on The Cancer Genome Atlas data set. ConclusionWe discovered AAbs associated with lung adenocaricnoma that have the potential to differentiate cancer from CT-positive benign diseases. We believe that these antibodies warrant future validation using a larger sample set and/or longitudinal samples individually or as a panel. They could potentially be part of companion molecular diagnostic modalities that will benefit subjects undergoing CT screening for lung cancer.

Expression of Alpha Crystallin Protein in Osteoarticular Tuberculosis in Latent Phase: A Review of Evidences

Due to scarcity of bacilli, an accurate diagnosis of osteoarticular tuberculosis is always being a challenge. Though conventional methods lack sensitivity and are time consuming, molecular diagnostic modalities are very effective for early diagnosis with high sensitivity and specificity. Timely diagnosis even in latent period will improve the efficacy of the treatment of osteoarticular tuberculosis. Under some stress conditions like hypoxia, nitric oxide stress, long term viability of M. tuberculosis is favoured by alpha crystallin protein (acr), which is a dominant protein of latent phase. In this article we focuses on protein that shows significant expression in the latent phase of M. tuberculosis. It may be further used as a prognostic biomarker for differentiating latent and active tuberculosis.

Invasive fungal infections in acute leukemia

Invasive fungal infection (IFI) is among the leading causes for morbidity, mortality, and economic burden for patients with acute leukemia. In the past few decades, the incidence of IFI has increased dramatically. The certainty of diagnosis of IFI is based on host factors, clinical evidence, and microbiological examination. Advancement in molecular diagnostic modalities (e.g. non-culture-based serum biomarkers such as β-glucan or galactomannan assays) and high-resolution radiological imaging has improved our diagnostic approach. The early use of these diagnostic tests assists in the early initiation of preemptive therapy. Nonetheless, the complexity of IFI in patients with leukemia and the limitations of these diagnostic tools still mandate astute clinical acumen. Its management has been further complicated by the increasing frequency of infection by non-Aspergillus molds (e.g. zygomycosis) and the emergence of drug-resistant fungal pathogens. In addition, even though the antifungal armamentarium has expanded rapidly in the past few decades, the associated mortality remains high. The decision to initiate antifungal treatment and the choice of anti-fungal therapy requires careful consideration of several factors (e.g. risk stratification, local fungal epidemiologic patterns, concomitant comorbidities, drug-drug interactions, prior history of antifungal use, overall cost, and the pharmacologic profile of the antifungal agents). In order to optimize our diagnostic and therapeutic management of IFI in patients with acute leukemia, further basic research and clinical trials are desperately needed.

Cancer screening test

SCreening lest is Iimited to asymptomatic individuals and its purpose is to decrease mortality. Beyond the technical issues involved in study design, other requirements addressing implementation，analysis，and interpretation including biases, must be met to demonstrate that a screening test is useful. A positive screening test may lead to early intervention that could allow "cure'' of the disease but not be efficacious for a person's general health. There are effective screening modalities for breast cancer ‘colorectal cancers , and cervical cancers，whereas no compelling evidence exists for the value to screening for lung cancer. Over the past few years ‘there have been rapid developments applying new imaging and molecular diagnostic modalities for the purpose of cancer screenings. Appropriate methods for incorporating these new techniques into screening trials must be considered.

Retinal Perivasculitis in an Immunocompetent Patient With Systemic Herpes Simplex Infection

To describe a case of retinal perivasculitis in an immunocompetent patient with systemic herpes simplex infection. Polymerase chain reaction amplifications were performed for aqueous and blood samples using primers specific for the following members of the herpesvirus family: cytomegalovirus, Epstein-Barr virus, herpes simplex virus (types 1 and 2), and varicella-zoster virus. The patient was placed on intravenous acyclovir and systemic corticosteroids. A positive polymerase chain reaction signal was found only for herpes simplex virus type 1. Vision in the left eye improved from light perception to 20/25, and signs of retinal perivasculitis resolved. The use of molecular diagnostic modalities in clinical practice may aid in determining infectious etiologies in patients with atypical clinical manifestations.