Detection of malignant effusions: comparison of a telomerase assay and cytologic examination

Construction and analysis of expression profile of exosomal lncRNAs in pleural effusion in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is a highly malignant tumor with a very low five-year survival rate. In this study, we aimed to identify differentially expressed long-chain non-coding RNA (lncRNAs) and mRNAs from benign and malignant pleural effusion exosomes.

METHODS

We used gene microassay and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) to detect and verify differentially expressed mRNAs and lncRNAs in benign and malignant pleural effusion exosomes. Gene Ontology (GO) functional significance and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway significance enrichment analyses were performed to identify the difference in biological processes and functions between different mRNAs. We selected the lncRNA ZBED5-AS1 with an upregulated differential fold of 3.003 and conducted a preliminary study on its cellular function.

RESULTS

Gene microassay results revealed that 177 differentially expressed lncRNAs were upregulated, and 215 were downregulated. The top 10 upregulated were FMN1, AL118505.1, LINC00452, AL109811.2, CATG00000040683.1, AC137932.1, AC008619.1, AL450344.1, AC092718.6, and ZBED5-AS1. The top 10 downregulated were TEX41, G067726, JAZF1-AS1, AC027328.1, AL445645.1, AL022345.4, AC008572.1, AC123777.1, AC093714.1, and PHKG1. For the mRNAs, 79 were upregulated, and 123 were notably downregulated. GO analysis revealed that the upregulated differential mRNAs were mainly involved in "cellular response to acidic pH" (biological processes), "endoplasmic reticulum part" (cellular components), and "at DNA binding, cyclase activity" (molecular functions). KEGG pathways were found to be related to V. cholerae infection, Parkinson's disease, and cell adhesion molecules. RT-qPCR showed that ZBED5-AS1 was highly expressed in LUAD tissues, cells, and benign and malignant pleural fluid exosomes. Overexpression of ZBED5-AS1 could significantly promote the proliferation, migration, invasion, and colony formation of LUAD cells, and knockdown had the opposite consequence.

CONCLUSION

The pleural effusion exosomes from patients with LUAD include several improperly expressed genes, and lncRNA-ZBED5-AS1 is a new biomarker that aids in our understanding of the occurrence and progression of LUAD.

Exploring the value of pleural fluid biomarkers for complementary pleural effusion disease examination

OBJECTIVE

Pleural fluid biomarkers are beneficial for the complementary diagnosis of pleural effusion etiologies. This study focuses on the multidimensional evaluation of deep learning to investigate the pleural effusion biomarkers value and the diagnostic utility of combining these markers, in distinguishing pleural effusion etiologies.

METHODS

Pleural effusion were divided into three groups according to the diagnosis and treatment guidelines: malignant pleural effusion (MPE), parapneumonic effusion (PPE), and congestive heart failure (CHF). First, the value of the biomarker was analyzed by a receiver operating characteristic (ROC) curve. Then by utilizing deep learning and entropy weight method (EWM), the clinical value of biomarkers was computed multidimensionally for complementary diagnosis of pleural effusion diseases.

RESULTS

There were significant differences in the six biomarkers, TP, ADA, CEA, CYFRA211, NSE, MNC% (p < 0.05) and no significant differences in three physical characteristics including color, transparency, specific gravity and six other biomarkers such as WBC, PNC%, MTC%, pH level, GLU, LDH (p > 0.05) among the three pleural effusion groups. The comprehensive test of pleural fluid biomarkers based on deep learning is of high accuracy. The clinical value of cytomorphology biomarkers WBC, MNC %, PNC %, MTC % was higher among pleural fluid biomarkers.

CONCLUSION

The clinical value of multi-dimensional analysis of biomarkers by deep learning and entropy weight method is different from the ROC curve analysis. It is suggested that during the clinical examination process, more attention should be paid to the cell morphology biomarkers, but the physical properties of the pleural fluid are less clinical significance.

Clinical value of combined detection of reactive oxygen species modulator 1 and adenosine deaminase in pleural effusion in the identification of NSCLC associated malignant pleural effusion

Background

Reactive oxygen species modulator 1 (ROMO1) is recognized to be involved in cell proliferation and is elevated in serum of various cancer patients. However, ROMO1 had little research in distinguishing between malignant pleural effusions (MPEs) and benign pleural effusions (BPEs).

Methods

Malignant pleural effusion samples from patients with non–small‐cell lung cancer (NSCLC) and benign pleural effusion (BPE) samples containing tuberculous and inflammatory pleural effusions were collected. The samples were tested for ROMO1, pleural effusion adenosine deaminase (pADA), pleural effusion carbohydrate antigen (pCA125, pCA153, pCA199), pleural effusion ferritin (pFER), and pleural effusion lactate dehydrogenase (pLDH) levels, and the other relevant partial clinical data that were gathered were used to conduct statistical analysis.

Results

The ROMO1, pCA125, pCA199, pCA153, pADA + ROMO1, pCA153 + ROMO1, pCA125 + ROMO1, and pCA199 + ROMO1 levels in MPE were appreciably higher in comparison with BPE group (all P = .000). The concentration of pADA in MPE was markedly lower than BPE (P = .000). When the cutoff = 0.38, the sensitivity of combined detection of ROMO1 + pADA is 98.67% and the specificity is 70.73%, respectively, and the AUC (0.941) is the highest among other parameters.

Conclusion

The combined detection of ROMO1 + ADA in pleural effusion is an effective biomarker for identifying MPE caused by NSCLC.

Identification and diagnostic value of pleural fluid periostin and serum periostin of malignant pleural effusions in patients with non-small-cell lung cancer

Background

Limited data are available for the diagnostic value, and the diagnostic sensitivity and specificity of pleural fluid periostin (pPOSTN) and serum periostin (sPOSTN) in malignant pleural effusion (MPE) caused by non–small‐cell lung cancer (NSCLC).

Methods

We collected 84 pleural effusion samples, including 44 cases of MPE caused by NSCLC and 40 cases of benign pleural effusions (BPEs) from August 2018 to January 2019. The pPOSTN, sPOSTN, pleural fluid lactate dehydrogenase (pLDH), pleural effusion adenosine deaminase (pADA), pleural effusion total protein (pTP), pleural fluid glucose (pGLU), pleural effusion leukocyte count (pWBC), pleural effusion red cell count (pRBC), pleural effusion carbohydrate antigen 199 (pCA199), pleural fluid carbohydrate antigen 125 (pCA125), pleural effusion ferritin (pFer), serum total protein (sTP), and serum C‐reactive protein (sCRP) were tested, and the obtained data were analyzed by statistical software.

Results

Compared to the BPE group, the pPOSTN level in the MPE group was observably lower, while the levels of sPOSTN, sPOSTN/pADA, pCA199/pADA, and pCA199/pPOSTN increased. The receiver operating characteristic (ROC) curve showed that the area under the ROC curve (AUC) (=0.844, 0.847, 0.841) of sPOSTN/pADA, pCA199/pADA, and pCA199/pPOSTN (cutoff = 11.86, 0.244, 0.015) was observably higher than other indicators for the diagnosis of MPE caused by NSCLC. Thus, the combined detection of pPOSTN, pCA125/pPOSTN, and pCA125/sCRP suggested that the AUC, sensitivity, and specificity was 0.912%, 95.45%, and 77.50% at the cutoff 0.317 and diagnostic performance was higher than sPOSTN/pADA or pCA199/pADA or pCA199/pPOSTN.

Conclusion

Combined detection of sPOSTN/pADA, pCA199/pADA, and pCA199/pPOSTN can be used as a good indicator for MPE caused by NSCLC.

Clinical value of jointly detection pleural fluid Midkine, pleural fluid adenosine deaminase, and pleural fluid carbohydrate antigen 125 in the identification of nonsmall cell lung cancer-associated malignant pleural effusion

BACKGROUND

Midkine (MK) level has been shown to be elevated in serum of patients with nonsmall cell lung cancer (NSCLC). However, the diagnostic value of MK in pleural effusion in NSCLC has not been well validated and established.

METHODS

Samples of NSCLC-associated malignant pleural effusions (MPE) and benign effusions (BPE) were collected. The pleural fluid MK (pMK), pleural fluid adenosine deaminase (pADA), pleural fluid lactate dehydrogenase (pLDH), pleural fluid glucose (pGLU), pleural fluid ferritin (pFER), pleural fluid CA199 (pCA199), pleural fluid CA125 (pCA125), pleural effusion white cell count (pWBC), and pleural effusion red cell count (pRBC) were analyzed, and the clinical data of each group were collected for statistical analysis.

RESULT

The level of pMK, pCA125, pMK + pCA125, and pMK + pCA125 + pADA in the MPE was significantly higher than the BPE group (P = .003, .000, .000, .000). The pADA level in the BPE was significantly higher than the MPE group (P = .003). It showed that the area under the ROC curve (AUC) (0.816) of jointly detection pMK, pCA125, and pADA was significantly higher than other markers for the diagnosis of MPE. Therefore, joint detection of pMK + pCA125 + pADA suggested that the sensitivity, specificity, and AUC was 82.54%, 74.19% at the cutoff 0.47 and diagnostic performance was higher than others.

CONCLUSION

Joint detection of pMK + pCA125 + pADA can be used as a good indicator for the identification of MPE of NSCLC.

Tyrosinase mRNA RT-PCR Analysis as an Additional Diagnostic Tool for the Identification of Melanoma Cells in Biological Fluid Samples other than Blood: A Preliminary Report

Reverse transcription polymerase chain reaction (RT-PCR) of tyrosinase mRNA has been applied for the detection of melanoma cells in the peripheral blood, lymph nodes and bone marrow of melanoma patients. We evaluated the diagnostic accuracy of RT-PCR in comparison to standard cytology and immunocytochemistry (ICC) for the identification of melanoma cells in biological fluids other than blood. Tyrosinase expression was evaluated together with standard cytology and ICC (anti-S100, HMB-45 and Melan-A antibodies) in biological fluid samples collected from 17 melanoma patients according to the site of metastatic involvement or clinical suspicion (eight cerebrospinal fluid (CSF) samples; three pleural effusions; four ascites; one bile sample, one pericardial effusion); 17 samples collected from patients with non-melanoma metastatic cancer were used as controls. Tyrosinase expression in the biological fluid sample was compared with the expression determined at the same time in peripheral blood. Positive tyrosinase expression was found in 12/17 melanoma and 3/17 non-melanoma cancer patients. Cytology/ICC showed the presence of neoplastic cells in only 7/12 melanoma samples with positive tyrosinase expression: radiological evidence of disease involvement was found in all these patients (three meningeal, two pleural, two peritoneal). Clear-cut radiological evidence of disease involvement at the sampling site was found in the five patients with negative cytology/ICC and positive RT-PCR (one CSF; four serous membrane effusions); all patients died of disease progression within four months of sampling. The five patients who were negative for both cytology/ICC and RT-PCR did not show any clinical evidence of disease recurrence at the sampling site. Only five of the 12 metastatic patients with positive tyrosinase expression in biological fluid showed positivity for tyrosinase in the peripheral blood. These preliminary results suggest that the analysis of biological fluids other than blood could be considered as a new potential clinical field of application for the tyrosinase mRNA assay.

Clinical value of jointly detection serum lactate dehydrogenase/pleural fluid adenosine deaminase and pleural fluid carcinoembryonic antigen in the identification of malignant pleural effusion

BACKGROUND

Limited data are available for the diagnostic value, and for the diagnostic sensitivity and specificity of joint detection of serum lactate dehydrogenase (sLDH)/pleural fluid adenosine deaminase (pADA) and pleural fluid carcinoembryonic antigen (pCEA) in malignant pleural effusion (MPE).

METHODS

We collected 987 pleural effusion specimens (of which 318 were malignant pleural effusion, 374 were tubercular pleural effusion, and 295 were parapneumonic effusion specimens) from the First Affiliated Hospital of Wenzhou Medical University from July 2012 to March 2016. The pADA, sLDH, pleural fluid LDH (pLDH), serum C-reactive protein (sCRP), pleural fluid protein, pCEA, white blood cell (WBC), and red blood cell (RBC) were analyzed, and the clinical data of each group were collected for statistical analysis.

RESULTS

The level of sLDH/pADA, pCEA, and RBC from the MPE group was markedly higher than the tuberculosis pleural effusion (TB) group (Mann-Whitney U=28422.000, 9278.000, 30518, P=.000, .000, .000) and the parapneumonic pleural fluid group (Mann-Whitney U=5972.500, 7113.000, 36750.500, P=.000, .000, .000). The receiver operating characteristic curve ROC showed that the area under the ROC curve (AUC) (=0.924, 0.841) of pCEA and sLDH/pADA (cutoff=4.9, 10.6) were significantly higher than other markers for the diagnosis of MPE. Thus, joint detection of pCEA and sLDH/pADA suggested that the sensitivity, specificity, and AUC was 0.94, 81.70, and 94.32 at the cutoff 0.16 and diagnostic performance was higher than pCEA or sLDH/pADA.

CONCLUSION

Joint detection of sLDH/pADA and pCEA can be used as a good indicator for the identification of benign and MPE with higher sensitivity and specificity than pCEA or sLDH/pADA.

Diagnostic yield of cytologic analysis of pericardial effusion in dogs

Background

Pericardial effusion cytology is believed by many to be of limited value, yet few studies have evaluated its diagnostic utility.

Objectives

To determine the diagnostic utility of cytologic analysis of pericardial effusion in dogs and to determine if consideration of additional data could improve the diagnostic yield.

Animals

Two hundred and fifty‐nine dogs with cytologic analysis of pericardial effusion performed between April 1990 and June 2012.

Methods

Electronic medical records from a university teaching hospital were retrospectively reviewed; signalment, complete blood count, serum biochemistry, cytologic analysis of pericardial effusion, and echocardiographic data were recorded. Cytology was classified as diagnostic (infectious or neoplastic) or nondiagnostic (hemorrhagic or other) and groups were compared with multiple Student's t‐tests.

Results

Cytology was grouped as nondiagnostic (92.3%) or diagnostic (7.7%) and characterized as hemorrhagic (90%), neoplastic (4.6%), infectious (3.1%), or other (2.3%). Overall cytologic analysis of pericardial effusion diagnostic utility was 7.7% and increased to 20.3% if the effusion hematocrit (HCT) <10%; echocardiographic evidence of a mass did not result in a significant increase in the diagnostic utility.

Conclusions and Clinical Importance

The diagnostic utility of cytologic analysis of canine pericardial effusion is variable depending on the underlying etiology. In this group of dogs, the diagnostic yield of cytologic analysis was greater for pericardial effusion samples in which the HCT was less than 10%.

The diagnostic value of apolipoprotein E in malignant pleural effusion associated with non-small cell lung cancer

BACKGROUND

Apolipoprotein E (apoE) levels have been shown to be elevated in pleural effusion of patients with non-small cell lung cancer (NSCLC). However, the diagnostic value of apoE in pleural effusion in NSCLC has not been well validated and established.

METHODS

Samples of malignant pleural effusions (MPE) and benign effusions were collected and analyzed for apoE, tumor markers, and other biochemical changes.

RESULTS

ApoE levels were significantly higher in MPE (n=160) than in benign pleural effusions (n=40). They were higher in adenocarcinoma-associated MPE than in squamous cell carcinoma- and large cell carcinoma-associated MPE. The receiver operating characteristic curve showed that the sensitivity and specificity of apoE for the diagnosis of MPE were 87.5% and 85.3%, respectively, at the cutoff 105 ng/ml, and the area under the curve (AUC) was 0.748. For the diagnosis of adenocarcinoma-associated MPE, apoE achieved sensitivity and specificity of 70.8% and 83.30%, respectively, and the AUC was the highest of all the markers.

CONCLUSIONS

ApoE levels are significantly increased in the pleural effusion of patients with NSCLC. Increased concentration of apoE in a pleural effusion is a potential marker for the diagnosis of MPE as well as for differential diagnosis of MPE in NSCLC.

Telomerase activity assay for the diagnosis of malignant pleural effusion: A meta-analysis

The telomerase activity assay has been established for the detection of malignant pleural effusion (MPE), however, the overall diagnostic accuracy of the telomerase activity assay for MPE remains unclear. We performed a systematic search in the Pubmed, Embase and Cochrane databases to identify published studies that have evaluated the diagnostic role of the telomerase activity assay for MPE. Sensitivity, specificity and other measures of accuracy of the telomerase activity assay in the diagnosis of MPE were pooled using the random effects models. A summary receiver operating characteristic (SROC) curve was used to summarize overall test performance. A total of eight studies met the inclusion criteria for the meta-analysis. The pooled sensitivity and specificity for diagnosing MPE were 0.76 [95% confidence intervals (CI), 0.72–0.80] and 0.87 (95% CI, 0.83–0.91), respectively. The positive likelihood ratio was 5.19 (95% CI, 2.36–11.42), the negative likelihood ratio was 0.25 (95% CI, 0.11–0.53) and the diagnostic odds ratio was 23.18 (95% CI, 6.11–87.83). The area under the SROC curve was 0.92. The telomerase activity assay plays a role in the diagnosis of MPE with a relatively high specificity. The results of a telomerase activity assay should be interpreted together with the combination of other test results and clinical findings.

Telomerase detection in the diagnosis and prognosis of cancer

Telomerase, a critical enzyme responsible 'for cellular immortality, is usually repressed in somatic cells except for lymphocytes and self-renewal cells, but is activated in approximately 85% of human cancer tissues. The human telomerase reverse transcriptase (hTERT) is the catalytic component of human telomerase. In cancers in which telomerase activation occurs at the early stages of the disease, telomerase activity and hTERT expression are useful markers for the detection of cancer cells. In other cancers in which telomerase becomes upregulated upon tumor progression, they are useful as prognostic indicators. However, careful attention should be paid to false-negative results caused by the instability of telomerase and of the hTERT mRNA and the presence of PCR inhibitors, as well as to false-positive results caused by the presence of alternatively spliced hTERT mRNA and normal cells with telomerase activity. Recently, methods for the in situ detection of the hTERT mRNA and protein have been developed. These methods should facilitate the unequivocal detection of cancer cells, even in tissues containing a background of normal telomerase-positive cells.

Diagnostic molecular biomarkers for malignant pleural effusions

Malignant pleural effusions (MPEs) are a common and important cause of cancer-related mortality and morbidity. Prompt diagnosis using minimally invasive tests is important because the median survival after diagnosis is only 4–9 months. Pleural fluid cytology is pivotal to current MPE diagnostic algorithms but has limited sensitivity (30–60%). Consequently, many patients need to undergo invasive diagnostic tests such as thoracoscopic pleural biopsy. Recent genomic, transcriptomic, methylation and proteomic studies on cells within pleural effusions have identified novel molecular diagnostic biomarkers that demonstrate potential in complementing cytology in the diagnosis of MPEs. Several challenges will need to be addressed prior to the incorporation of these molecular tests into routine clinical diagnosis, including validation of molecular diagnostic markers in well-designed prospective, comparative and cost–effectiveness studies. Ultimately, minimally invasive diagnostic tests that can be performed quickly will enable clinicians to provide the most effective therapies for patients with MPEs in a timely fashion.

Telomerase activity in effusions: a comparison between telomere repeat amplification protocol in situ and conventional telomere repeat amplification protocol assay

CONTEXT

We previously found telomere repeat amplification protocol (TRAP) in situ helpful in the diagnosis of malignancy in effusions, whereas varying sensitivities and specificities for malignancy were reported by investigators using extract-based TRAP.

OBJECTIVE

To compare the 2 methods and to elucidate the discrepancies between them.

DESIGN

Twenty-three effusions were analyzed. Telomerase activity of whole cell lysate was measured with a Telo TAGGG telomerase polymerase chain reaction ELISA PLUS kit with modifications to exclude polymerase chain reaction inhibitors. TRAP in situ was performed on cytospins. An estimate of total TRAP activity in the specimen was made based on the amount of positive cells, their fluorescence intensity, and the proportion of different cell types in the specimen. The estimate was compared with the level of telomerase activity in cell lysate-based TRAP.

RESULTS

TRAP in situ: Thirteen of 14 malignant cases and 2 of 2 equivocal cases showed moderate/strong reactivity. Five of 7 benign effusions were negative; in 2 of 7, mesothelial cells showed weak reactivity. Cell lysate-based TRAP assay: In 4 cases no internal standard was detected, indicating the presence of polymerase chain reaction inhibitors. The relative telomerase activities were 33.1 to 72.7 with a considerable overlap between malignant (48 +/- 9, mean +/- SD) and benign (43 +/- 9) cases.

CONCLUSIONS

The TRAP in situ results correlated to final diagnoses, whereas the cell lysate-based TRAP assay did not differentiate between malignant and benign cases. The varying proportions of positive cells and the variation in fluorescence intensity in the TRAP in situ slides explained some of the discrepancies. The problems encountered with TRAP performed on cell lysates are partly overcome using TRAP in situ.

Clinical utility of vascular endothelial growth factor in diagnosing malignant pleural effusions

While the early diagnosis of cancer has been fully respected, it is still however often difficult for clinicians to confirm malignant pleural effusions (PE), which essentially indicate the end-stage cancer. It has now been demonstrated that vascular endothelial growth factor (VEGF) is a pivotal angiogenesis factor and associated with tumor growth and metastasis. The aim of this study was then to assess the diagnostic performance of VEGF in malignant PE. In this controlled and blinded prospective study, 113 consecutive patients with PE were recruited. For each eligible case, the VEGF levels of pleural fluid (PF) and serum were examined simultaneously using enzyme immunoassay. The reference standard for malignant PE was clinical evaluation and PF cytology with pleural biopsy, other examination and follow-up added as needed. According to the final diagnoses, 81 qualified cases were grouped as malignant (n=32) and benign (n=49) PE. For PF VEGF level, the mean in malignant group was higher than that in benign group (1358+/-1493 pg/mL vs. 422+/-317 pg/mL, p=0.001). As did for serum VEGF level (650+/-533 pg/mL vs. 137+/-189 pg/mL, p<0.001). Using receiver operating characteristic analysis, the determined diagnostic cut-off points of VEGF levels of PF and serum for malignant PE were 959.25 pg/mL and 212.36 pg/mL, with sensitivities of 47%, 69% and specificities of 96%, 88%, respectively. For cascade connection and parallel operation of PF VEGF and serum VEGF, the sensitivities were 34%, 81% at specificities of 98%, 86%, respectively. These findings suggest that VEGF could be used in diagnosing malignant PE as a useful adjunct of conventional algorithm. Different VEGF test strategies, including test on PF, serum and both, may be selected according to practical needs.

Real-time telomerase activity measurements for detection of cancer

Since the hallmark report of the PCR-based telomeric repeat amplification protocol (TRAP) in 1994, there has been a flurry of investigations of telomerase activity on normal, benign, premalignant and cancerous samples representative of the various stages of tumorigenesis. Basic research and technological advances in human genetics, biochemistry and model systems have brought much progress towards the understanding of human infectious, hereditary and somatically acquired diseases. The knowledge of carcinogenesis has increased very rapidly in the past few years, particularly with the development of automated molecular biologic analysis of tumors and preneoplastic lesions. Despite the wide variety of studies on the potential use of telomerase as a cancer biomarker, the variability of reported telomerase activity and the lack of a transferable detection method have prevented it from becoming a routine clinical application. Real-time PCR is a clinically transferable method and the advancement of real-time measurements of telomerase will facilitate moving telomerase activity and technologies towards clinical validation. It is expected that the next 5 years will see telomerase integrated into the initial detection and follow-up monitoring of cancer patients. The hope is that the use of telomerase will finally translate into a diagnostic to help realize longer survival and a better quality of life.

Limitations of detection of malignancy in pleural effusions using ELISA-based TRAP assay: comparison with cytological examination

OBJECTIVE

Telomerase is active in almost all cancers from various organs but is not detectable in most normal cells. Thus, telomerase activity might be a universal and specific marker for diagnosing malignancy. The aim was to evaluate the potential use of the ELISA-based TRAP assay to detect malignancy in pleural effusion, and to compare it with conventional cytological examination.

METHODS

Using the ELISA-based TRAP assay, telomerase activity was examined in 94 consecutive pleural effusions submitted for cytological examination.

RESULTS

According to the results of cytology, the 94 samples were divided into two groups: group I, 79 non-malignant pleural effusions, including group IA, no association with a malignant tumour, a control group (n = 63), and group IB, associated with a malignant tumour (n = 16); and group II, 15 malignant pleural effusions. Telomerase activity was detected in five of 63 samples in group IA (7.9%), four of 16 samples in group IB (25%), and six of 15 samples in group II (40%). All five false-positive effusions were from patients with tuberculosis. Comparing group II with group IA, the TRAP assay showed 40% sensitivity, 92.1% specificity, 54.5% positive and 86.6% negative predictive value, and 82.1% accuracy. However, the detection rate of the TRAP assay (88.9%) was higher than that of the cytological examination (66.7%) in lung cancer-inflicted pleural effusions.

CONCLUSION

The ELISA-based TRAP assay is relatively insensitive; therefore, it is unsuitable as a routine diagnostic tool for pleural effusion. False-positive telomerase activity due to lymphocytic contamination may weaken its diagnostic value for malignant effusions in a tuberculosis-endemic area.

Telomere repeat amplification protocol (TRAP) in situ reveals telomerase activity in three cell types in effusions: malignant cells, proliferative mesothelial cells, and lymphocytes

Telomerase Repeat Amplification Protocol (TRAP) in situ was performed on cytospin preparations from 65 effusions from the serous cavities (45 pleural and 19 ascitic fluids and one pericardial fluid) submitted for routine diagnosis and the results were correlated to cytological morphology. Three types of cells with nuclear fluorescence were identified: malignant cells, hyperplastic mesothelial cell and lymphocytes. Of 38 cytologically malignant effusions, 12 showed strong reactivity in all malignant cells, three strong reactivity in part of the malignant population, whereas 12 showed moderate reactivity in the whole and five in part of the malignant population, respectively. In five malignant effusions weak reactivity was found in all (one case) and in scattered (four cases) malignant cells. Two effusions contained telomerase-negative malignant cells. Two pleural and two ascitic fluids contained proliferative mesothelial cells with weak or, in one case, moderate reactivity. Lymphocytes usually showed weak telomerase activity. Telomerase was expressed in almost all malignant tumours metastatic to serous cavities. Heterogeneity in tumour populations was demonstrated, which may have diagnostic implications, especially in cytology. Weak or moderate reactivity was found in lymphocytes and in some mesothelial proliferations and may explain the low specificity for malignancy sometimes obtained with the TRAP extract method. The weak reactivity found in lymphocytes may reduce the specificity when the extract method is used but causes no diagnostic problem with the TRAP in situ method.

Telomerase activity and hTERT mRNA expression in body fluids

Telomerase is a ribonucleoprotein enzyme associated with cellular immortality, and its activity is detectable in most human tumors and immortalized cells. In the present study, we examined telomerase activities and gene expression of human telomerase reverse transcriptase (hTERT) to detect malignant cells in body fluid. Twenty-eight cytological fluids were obtained from 28 patients, including 12 patients with benign cases and 16 patients with malignant tumors (14 ascitic fluids, 12 pleural fluids, 1 peritoneal washing, and 1 pericardial fluid). Telomerase activity was measured using a quantitative telomeric repeat amplification protocol (TRAP), and the hTERT messenger RNA (mRNA) expression was detected by reverse-transcription polymerase chain reaction (RT-PCR). Of the 16 malignant cases, telomerase activity was detected in 8 cases, and 10 cases involved expression of (hTERT) (mRNA). Neither telomerase activity nor hTERT mRNA expression was detected in benign cases. The telomerase activity and mRNA expression exhibited sensitivities of 50 and 62.5%, respectively, and both methods showed a specificity of 100%. The hTERT mRNA expression is a more sensitive marker than telomerase activity. Our results suggest that measurement of mRNA expression of hTERT in body fluid is useful as an adjunctive tool for cytological diagnosis.

Expressions of human telomerase mRNA component (hTERC) and telomerase reverse transcriptase (hTERT) mRNA in effusion cytology

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA onto chromosomal ends. Its activity has been reported to be a novel diagnostic marker of malignant potential. However, no study has investigated the diagnostic importance of the expressions of human telomerase mRNA component (hTERC) and telomerase reverse transcriptase (hTERT) mRNA in effusion cytology. We investigated the expressions of hTERC and hTERT using in situ hybridization in 20 malignant cytologic specimens from 20 patients with adenocarcinomas disseminating into the pleura or peritoneum, and 16 benign cytologic specimens in pleural or peritoneal fluid (including reactive mesothelial cells) from 16 patients with non-neoplastic diseases. Expressions of hTERC and hTERT mRNA were detected in 95% and 90% of the 20 malignant cytology specimens, respectively, and were apparent within the cytoplasm of malignant cells. However, no expression was detected in reactive mesothelial cells in the 16 benign cytologic specimens. The expressions of hTERC and hTERT mRNA would appear to be a useful addition to cytology examination for diagnosis based on effusion cytology.

Analysis of telomerase activity and detection of its catalytic subunit, hTERT

The discovery of the enzyme telomerase and its subunits has led to major advances in understanding the mechanisms of cellular proliferation, immortalization, aging, and neoplastic transformation. The expression of telomerase in more than 85% of tumors provides an excellent tool for the diagnosis, prognosis, and treatment of cancer. However, the techniques employed in its detection appear to play a significant role in the interpretation of the results. The telomeric repeat amplification protocol (TRAP assay) has been the standard assay in the detection of telomerase activity and many variations of this technique have been reported. Recent advances in the development of the TRAP assay and the incorporation of techniques that provide a quantitative and qualitative estimate of telomerase activity are assessed in this review. In addition to histological and cytological examination of tissues, distribution patterns of the catalytic subunit of telomerase, hTERT, are frequently used in the prognosis of tumors. The methods involved in the detection of hTERT as a biomarker of cellular transformation are also analyzed.

A peritoneal dialysis patient with fatal culture-negative peritonitis. Case Discussion

Culture-negative peritoneal inflammation accounts for between 5 and 20% of cases of peritonitis in peritoneal dialysis patients. Diagnostic yields may be enhanced considerably by reculturing dialysate effluents using appropriate collection methods and optimal laboratory techniques (including prolonged low-temperature and anaerobic incubations). In patients with persistent culture-negative peritonitis, consideration should be given to the possibilities of unusual or fastidious microorganisms (especially fungi and mycobacteria) and non-infective causes (especially drug reactions, malignancy, visceral inflammation and retroperitoneal inflammation). In this paper, an illustrative case of persistent culture-negative peritonitis is presented followed by a discussion of the investigative approach to such patients, with particular emphasis on differential diagnosis and the limitations of currently available tests.

Pitfalls in TRAP assay in routine detection of malignancy in effusions

Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples). Of the malignant samples, 44/58 (76%) were positive by TRAP assay. Of the 14 telomerase-negative cytology-positive samples, RNA integrity was poor in 9, indicating suboptimal sample conservation for molecular analysis. In 3 of the remaining 5 samples with a negative TRAP assay, a high number of malignant cells was observed, and these cells might have been telomerase-negative. Thus, the sensitivity of TRAP assay for the presence of malignant cells was about 76%. In the cytologically nonmalignant effusions, the presence of telomerase activity was observed in 24% (55/233). Of these, 6% were highly suspicious for malignancy, 9% were doubtful, and 9% were cytologically nonmalignant effusions confirmed by a follow-up of 12 mo or more. According to these data, the specificity of the TRAP assay to detect tumor cells in effusions ranged only between 82-91%. Our results indicate that, although the TRAP assay is positive in 6-15% of putative malignant effusions, the relatively high number of TRAP false-negative and false-positive cases renders this test unsuitable for routine diagnostic purposes.