[Characterization of Metal Elements in Atmospheric PM2.5 and Health Risk Assessment in Heze in Winter from 2017 to 2018].

Atmospheric PM2.5 samples were collected in Heze, Shandong Province, from a total of three sampling sites at Heze College, Huarun Pharmacy, and a wastewater treatment plant between October 15, 2017 and January 31, 2018, to determine the concentrations of 21 metal elements in PM2.5 using inductively coupled plasma mass spectrometry (ICP-MS). The degree of elemental enrichment was also discussed, the health risks and potential heavy metal ecological risks were assessed. The results showed that ρ (PM2.5) ranged from 26.7 to 284.1 µg·m-3 at the three sampling sites during the sampling period, and the concentration values did not differ significantly, all of which were at high pollution levels. The highest concentrations of K were found in the three sampling sites, accounting for 31.03%, 39.47%, and 38.43% of the total, respectively, mainly due to the high contribution of biomass burning in autumn and winter in Heze, a large agricultural city. The highest concentrations of Zn, 89.70, 84.21, and 67.68 ng·m-3, were found in the trace elements at the three sampling sites, respectively. The enrichment factor results showed that the enrichment factor values of Zn, Pb, Sn, Sb, Cd, and Se were higher than 100, among which the enrichment factors of Cd and Se were higher than 2 000 and 4 000, respectively, which were significantly influenced by anthropogenic activities and might have been related to industrial production, metal smelting, road sources, and coal combustion emissions. The health risk results showed that there was some potential non-carcinogenic risk (HQ>0.1 for children and adults) for As and a combined potential non-carcinogenic risk (HI>0.1) and some potential carcinogenic risk (CRT>1×10-6) for both children and adults at the three sampling sites. There was a more significant carcinogenic risk (CRT>1×10-4) for adults at the wastewater treatment plant, and the slightly higher carcinogenic risk for adults than that for children may have been related to the longer outdoor activity and higher PM2.5 exposure for adults. The elements with the highest potential ecological risk values were Cd, As, and Pb, with Cd exhibiting a very high potential ecological risk that should be taken seriously. All three sampling sites showed a very high combined potential ecological risk, with the intensity spatially expressed as Heze College>Huarun Pharmacy>wastewater treatment plant.

Chemodiversity of organic nitrogen emissions from light-duty gasoline vehicles is governed by engine displacements and driving speed.

Organic nitrogen emissions from light-duty gasoline vehicles (LDGVs) is believed to play a pivotal role in atmospheric particulate matter (PM) in urban environments. Here, the characterization of organic nitrogen emitted by LDGVs with varying engine displacements at different speed phases was analyzed using a Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) at molecular level. For the LDGV with small engine displacements, the nitrogen-containing organic (CHON) compounds exhibit higher abundance, molecular weight, oxygen content and aromaticity in the extra-high-speed phase. Conversely, for the LDGV with big engine displacements, more CHON compounds with elevated abundance, molecular weight, oxygen content and aromaticity were observed in the low-speed phase. Our study assumed that the formation of CHON compounds emitted from LDGVs is mainly the oxidation reaction during fuel combustion, so the potential precursor-product pairs related to oxidation process were used to study the degree of combustion reaction. The results show that the highest proportion of oxidation occurs during extra-high-speed phase for LDGV with small engine displacements, and during low-speed phase for LDGV with big engine displacements. These results offer a novel perspective for comprehending the mechanism behind vehicle emissions formation and contribute valuable insights for crafting effective air pollution regulations.

Pro-prion, as a membrane adaptor protein for E3 ligase c-Cbl, facilitates the ubiquitination of IGF-1R, promoting melanoma metastasis.

Aberrant activation of receptor tyrosine kinase (RTK) is usually a result of mutation and plays important roles in tumorigenesis. How RTK without mutation affects tumorigenesis remains incompletely understood. Here we show that in human melanomas pro-prion (pro-PrP) is an adaptor protein for an E3 ligase c-Cbl, enabling it to polyubiquitinate activated insulin-like growth factor-1 receptor (IGF-1R), leading to enhanced melanoma metastasis. All human melanoma cell lines studied here express pro-PrP, retaining its glycosylphosphatidylinositol-peptide signal sequence (GPI-PSS). The sequence, PVILLISFLI in the GPI-PSS of pro-PrP, binds c-Cbl, docking c-Cbl to the inner cell membrane, forming a pro-PrP/c-Cbl/IGF-1R trimeric complex. Subsequently, IGF-1R polyubiquitination and degradation are augmented, which increases autophagy and tumor metastasis. Importantly, the synthetic peptide PVILLISFLI disrupts the pro-PrP/c-Cbl/IGF-1R complex, reducing cancer cell autophagy and mitigating tumor aggressiveness in vitro and in vivo. Targeting cancer-associated GPI-PSS may provide a therapeutic approach for treating human cancers expressing pro-PrP.

Acidification impacts on the molecular composition of dissolved organic matter revealed by FT-ICR MS.

Solid-phase extraction (SPE) is a traditional pretreatment procedure widely used for dissolved organic matter (DOM) desalination and enrichment prior to the Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis, and the extracts are usually acidified to pH = 2 with hydrochloric acid (HCl) before passing through the cartridge. However, little is known about the effects of acidification on the integrity and molecular composition of DOM. Here, the differences in the molecular compositions in acidified and nonacidified DOM samples of soil, seawater and atmospheric aerosol were performed by FT-ICR MS. The results showed that the quantity and intensity of aromatic compounds with high oxygen content (e.g., polyphenols, tannin-like and highly oxygenated organic compounds) were greatly enhanced after acidification, while highly saturated compounds (lipid-like and aliphatic/peptide-like) were absent. The underlying reason is the variation of solubility and hydrolysis of DOM under acidic conditions. Meanwhile, the effect of acidification on the molecular composition of DOM was also dependent on their original environmental media. Based on these results, we suggest that the extracts of soil samples are selectively acidified according to the focus of research, while the extract is acidified for seawater samples and the pH of the extract can be unadjusted for aerosol samples before the SPE procedure. These findings provide a reference for the selection of suitable pretreatment methods for different experimental purposes and for the comprehensive characterization of samples with different properties.

Telomere elongation-based DNA-Catalytic amplification strategy for sensitive SERS detection of telomerase activity.

Telomerase has been regarded as a biomarker for cancer diagnosis as well as the clinical treatment and the reliable detection of intracellular telomerase activity is of great significance. By developing a telomere elongation-based DNA-catalytic amplification strategy, a novel surface-enhanced Raman scattering (SERS) method is proposed for the assay of telomerase activity. In the presence of telomerase and nucleotide mixture dNTPs, the telomerase substrate (TS) primer extended and generated a long single-strand DNA (ssDNA) containing the telomere repeat units (TTAGGG)n, which could catalyze the entropy-driven circuit reaction (EDCR). One of the products of EDCR was ingeniously used as the catalyst of catalytic hairpin assembly (CHA) occured on magnetic beads (MBs). As a result, a large amount of ROX-labeled Raman probes could be anchored on the surface of MBs and used for SERS detection. Using this strategy, the assay can detect telomerase activity from cell extracts equivalent down to single HeLa cell.

Dual cycle amplification and dual signal enhancement assisted sensitive SERS assay of MicroRNA.

A sensitive surface-enhanced Raman scattering (SERS) approach has been developed for detection of microRNA (miRNA) based on target-triggered dual signal amplification including strand displancement amplification (SDA) and hybridization chain reaction (HCR). With the assistant of polymerase and nicking endonuclease (NEase), target miRNA combines with the single stranded template DNA to generate a great amount of trigger DNA which can induce HCR. Coupled the dual cycle amplification of SDA and HCR with the dual enhancement of gold nanoparticles (AuNPs), a low detection limit of 0.5 fM for miRNA is obtained using the proposed strategy. With high sensitivity, universality, rapid analysis, and high selectivity, this method has a great potential for detecting biomolecules with trace amounts in bioanalysis and clinical biomedicine.

Sensitive SERS detection of DNA methyltransferase by target triggering primer generation-based multiple signal amplification strategy.

A novel and sensitive surface-enhanced Raman scattering (SERS) method is proposed for the assay of DNA methyltransferase (MTase) activity and evaluation of inhibitors by developing a target triggering primer generation-based multiple signal amplification strategy. By using of a duplex substrate for Dam MTase, two hairpin templates and a Raman probe, multiple signal amplification mode is achieved. Once recognized by Dam MTase, the duplex substrate can be cleaved by Dpn I endonuclease and two primers are released for triggering the multiple signal amplification reaction. Consequently, a wide dynamic range and remarkably high sensitivity are obtained under isothermal conditions. The detection limit is 2.57×10(-4)UmL(-1). This assay exhibits an excellent selectivity and is successfully applied in the screening of inhibitors for Dam MTase. In addition, this novel sensing system is potentially universal as the recognition element can be conveniently designed for other target analytes by changing the substrate of DNA MTase.

Immunological persistence of a seasonal influenza vaccine in people more than 3 years old.

To evaluate antibody persistence of Aleph inactivated split influenza vaccine, 3308 healthy Chinese people more than 3 years old were enrolled in a hemagglutination inhibition (HI) assay before vaccination, 641 were screened by HI assay negative, 437 of which received one dose of Aleph inactivated split influenza vaccine and 204 of which received one dose of control vaccine (recombinant hepatitis B). After vaccination, the receivers were collected blood at 1st month, 3rd month, 6th month and 12th month for Aleh influenza vaccine antibody persistence assess. The antibody test were determined by hemagglutination inhibition (HI) assay. There were significant difference in antibody geometric mean titer between experimental group and control at 1st month and 3rd month after vaccination. Influenza antibody could persist at least up to 3rd month. Because of the local spring influenza epidemic, we could not analyze the results of 6th and 12th month. Aleph influenza vaccines showed good immune persistence in healthy volunteers at least in the 3 months after vaccination. Influenza viruses are important human respiratory pathogens. Immunization is widely acknowledged to currently be the most effective method of minimizing the impact of pandemic influenza. Through we have checked many references about Influenza vaccine, the duration of protective antibody for influenza vaccines are still not available. Based on this situation and our previous work, (11) Influenza vaccine antibody duration analyze are necessary. This manuscript presents data on the persistence of Hemagglutination Inhibition (HI) immune response against the A/California/7/2009(H1N1), A/Peth/16/2009(H3N2) strain and B/Brisbane/60/2008. 641 were screened from 3302 volunteers by HI test of influenza A and confirmed enrollment based on the antibodies titer less than 1:10. After administered with one dose of Aleph influenza vaccine, blood samples were collected. 437 subjects (3-10 y: 131; 11-17 y: 110; 18-54 y: 69; ≥ 55 y: 127) were vaccinated influenza vaccine as test group. 204 subjects (3-10 y: 70; 11-17 y: 47; 18-54 y: 28; ≥ 55 y: 59) were vaccinated recombinant hepatitis B vaccine as control group. Immunogenicity end points were based on the European licensure criteria for pandemic influenza vaccines. The persistence of HI immune response against the vaccine strain was assessed through GMT. The immunogenicity of the Aleph influenza vaccine induced all reached the standards at 1st month and GMTs peak could persist at least up to 3rd month. (This study has been registered at clinicaltrials.gov under registration no. NCT01758185.). Because of the local spring influenza epidemic we could not analyze the results of 6th and 12th month. Aleph influenza vaccines showed good immune persistence in healthy volunteers at least in the 3 months after vaccination.

[Expression of miR-200a in colorectal carcinoma cell lines and its effect on LoVo cells].

OBJECTIVE: To detect miR-200a expression in human colorectal carcinnoma (CRC) cell lines and explore the role of miR-200a in regulating the biological behavior of CRC cells. METHODS: Real-time quantitative RT-PCR (qRT-PCR) was used to detect miR-200a expression levels in 6 CRC cell lines (HCT116, HT29, LS174T, SW480, SW620 and LoVo). miR-200a mimics were transiently transfected into LoVo, and the changes in cell proliferation, apoptosis, migration, and cell-cell adhesion were assessed using CCK-8 assay, TUNEL assay, transwell migration assay, and homogenous adhesion experiment, respectively. RESULTS: The expression of miR-200a was down-regulated in the 6 CRC cell lines, among which the highly metastatic LoVo cell line showed the lowest expression and the tumorigenic but non-metastatic CRC cell line HCT116 had the highest expression. Overexpression of miR-200a depressed cell proliferation and migration but promoted cell apoptosis and cell-cell adhesion in LoVo cells. CONCLUSION: miR-200a plays a role in regulating the invasiveness and metastasis of CRC, and overexpression of miR-200a causes a significant reduction of cell proliferation and migration and promotes apoptosis and cell-cell adhesion in LoVo cells.

A label-free fluorescence assay for trypsin based on the electron transfer between oligonucleotide-stabilized Ag nanoclusters and cytochrome c.

A label-free fluorescent assay for the detection of trypsin by using oligonucleotide-templated silver nanoclusters (Ag NCs) and cytochrome c (Cyt c) has been demonstrated. When negatively charged Ag NCs and positively charged Cyt c are mixed, they tend to form a hybrid complex, and then lead the fluorescence of Ag NCs to be quenched significantly due to electron transfer between Ag NCs and the heme cofactor of Cyt c. In the presence of trypsin, it catalyzes the hydrolytic cleavage of Cyt c to small peptide fragments, and releases the heme moiety from the Ag NCs/Cyt c complex; the quenched fluorescence restores therewith. By virtue of this specific response, the fluorescent biosensor has a linear range of from 0.7 to 4 µg mL(-1) and from 9 to 120 µg mL(-1) with a detection limit of 58.7 ng mL(-1). Aside from the easy manufacture aspect, our method also possesses a high signal-to-background ratio (~11), excellent selectivity and good biocompatibility, which makes it a promising bioanalysis for a trypsin activity assay.

Isocitrate dehydrogenase mutation is associated with tumor location and magnetic resonance imaging characteristics in astrocytic neoplasms.

The molecular subsets of glioma behave in biologically distinct ways. The present study detected isocitrate dehydrogenase (IDH) 1 and IDH2 mutations in glioma to analyze whether IDH-mutated gliomas are situated in certain preferential areas and to investigate their correlation with magnetic resonance imaging (MRI) characteristics. A series of 193 patients with astrocytic neoplasms (111 diffuse and 82 anaplastic astrocytomas), grouped according to prelabeled anatomical structures and the risk of surgery, were retrospectively reviewed for IDH1 and IDH2 mutations to compare the tumor location and MRI features. A total of 111 IDH1 mutations at codon 132 (57.5%) and six IDH2 mutations at codon 172 (3.1%) were detected. The IDH1/2 mutations were found to predict longer survival, independent of the histological type in this series of patients. The IDH-mutated gliomas were predominantly located in a single lobe, such as the frontal lobe, temporal lobe or cerebellum and rarely in the diencephalon or brain stem. Furthermore, according to the risk of surgery, the IDH-mutated tumors were rarely located in the high-risk regions of the brain, where surgery exhibits a high mortality rate intraoperatively and postoperatively. In addition, gliomas with IDH mutations were significantly more likely to exhibit a unilateral pattern of growth, sharp tumor margins, homogeneous signal intensity and less contrast enhancement on MRI. The results of the current study suggested that the prolonged survival of patients with IDH-mutated gliomas is primarily due to a less aggressive biological behavior according to tumor site and MRI features.

A randomized, controlled, blinded study of the safety, immunogenicity and batch consistency of Aleph inactivated split influenza vaccine made in China in Chinese people.

To evaluate the safety, immunogenicity and batch consistency of Aleph inactivated split influenza vaccine, 3308 healthy Chinese people more than 3 years old were enrolled in a randomized, controlled, blinded study and divided into four age groups: 3-10 years, 11-17 years, 18-54 years, and more than 55 years. Each age group was then randomized (2:1) to receive either influenza vaccine or control vaccine (recombinant hepatitis B) for one dose. Also each influenza vaccine group was randomized (1:1:1) to receive three different batches of influenza vaccine. Systematic and local adverse reactions for 28 days after vaccination were recorded, and influenza antibody titer was determined by hemagglutination inhibition (HI) assay at 28 days after vaccination. There were significant differences in seroconversion and seroprotection rates achieved post-immunization of three strains of influenza antibody (H1N1, H3N2, B) between experimental group and control group in all age groups (P<0.05). In addition, there were no statistically significant differences in local and systematic reaction rates after vaccination between the experimental and control group in all age groups (P>0.05), except for the systematic reaction rates in the 18-54 years and ≥ 55 years age groups (P<0.05). Thus, Aleph inactivated split influenza vaccine has good safety and immunogenicity.

[Comparison of epithelial-mesenchymal transition-related markers between cancer tissue and tumor emboli].

OBJECTIVE: To explore whether cancer cells abide by the mechanism of epithelial-mesenchymal transition (EMT) in the process of invasion and metastasis by comparing histology and protein expression of E-cadherin and vimentin among primary, metastatic carcinomas and their emboli. METHODS: A total of 68 tissue specimens in 59 cases of primary adenocarcinoma or squamous cell carcinoma and their lymphatic metastasis were collected, of which there were 13 well differentiated, 11 moderately differentiated, 30 poorly differentiated tumors and 14 lymphatic metastases. The morphology and the expression of E-cadherin and vimentin proteins were assessed by H-E stain and immunohistochemistry. RESULTS: The overall morphology of the primary cancers and their tumor emboli was similar. Among 54 primary cancers, 50 cases were positive for E-cadherin and 22 cases were positive for vimentin. Fifty-one cases were positive for E-cadherin and 22 cases were positive for vimentin in the tumor emboli, with no statistical difference (P = 0.804, P = 0.842). Among 14 cases of lymphatic metastasis, 12 cases were positive for E-cadherin and 6 cases were positive for vimentin, and the tumor emboli in 12 cases were positive for E-cadherin and 7 cases were positive for vimentin, with statistical difference (P = 0.084, P = 0.878). There were no significant difference of E-cadherin and vimentin protein expression between the cancer tissue and its emboli (P = 0.410, P = 0.824). A subset of tumor cells in cancer emboli expressed E-cadherin at a high level without vimentin expression, whereas other cells in tumor emboli showed an opposite expression pattern. CONCLUSIONS: There is no significant difference of EMT characteristics among primary cancer, lymphatic metastases and their cancer emboli. Cancer thrombus contains both EMT and non-EMT cells. Further studies are required to elucidate the role of EMT in the processes of tumor invasion and metastasis.

[Observation of special staining of human colorectal carcinoma cell lines cultured on nitrocellulose membrane].

OBJECTIVE: To observe the special staining of cells cultured on nitrocellulose (NC) membrane and evaluate the application of the novel method for cell culture and pathological staining. METHODS: Human colorectal carcinoma SW1116 cell line and SW480 cell line were cultured using nitrocellulose membrane as the culture matrix, with the same cells cultured on slides serving as the control. RESULTS: The cells cultured on NC membrane appeared transparent with sharp edge and purple background by macroscopic observation, showing on obvious difference in terms of cell morphology and number from the cells cultured on glass slides. Irregular polygonal SW1116 cells and SW480 cells were found on the NC membrane, on which the cells grew in colony and showed blue nucleus and red cytoplasm. CONCLUSIONS: NC membrane produces no cytotoxicity and can be used for cell culture without affecting the normal cell morphology and number during cell culture, thus providing a new means for cell culture and pathological staining.

[Correlation between T lymphoma invasion and metastasis 1 expression and epithelial-mesenchymal transition in human colorectal carcinomas].

OBJECTIVE: To investigate the relationship between T lymphoma invasion and metastasis 1 (Tiam1) and epithelial-mesenchymal transition (EMT) in human colorectal carcinomas. METHODS: Tiam1, E-cadherin, CK, and vimentin expressions in normal colorectal epithelium, colorectal carcinomas (CRC) and CRC with lymphatic metastasis were determined by immunohistochemistry using a two-step method. RESULTS: Tiam1 expression was significantly higher in CRC than in normal colorectal epithelium (P<0.01) in close correlation to the degree of tumor differentiation (P<0.05). Higher Tiam1 expression was detected in CRC with lymphatic metastasis than in primary CRC (P<0.05). The expressions of E-cadherin and CK in CRC tissues were significantly lowered in comparison with those in normal colorectal epithelium (P<0.01), showing a correlation to tumor differentiation (P<0.01) but not to lymphatic metastasis. Vimentin was significantly overexpressed in CRC (P<0.01) and correlated to tumor differentiation (P<0.01) but not to lymphatic metastasis. Tiam1 expression was inversely correlated to E-cadherin and CK, but positively to vimentin. CONCLUSION: Tiam1 is related to the metastasis of colorectal carcinoma, and may induce EMT to promote CRC metastasis.

[Imaging features of primary bone lymphoma and its histopathology].

OBJECTIVE: To study the imaging features of primary bone of the lymphoma PLB on X-ray, CT and magnetic resonance imaging (MRI). METHODS: The data of 8 patients (6 males and 3 females, aged 9-60 years with a median age of 26.5 years) with pathologically confirmed PLB were retrospectively reviewed. Plain radiographs were obtained in all the 8 cases, CT scans performed in 5 and MRI examinations in 7. Four patients underwent X-ray, CT and MRI, two underwent CT and MRI, and one underwent X-ray and MRI. Surgical resection was performed in 7 cases and biopsy done in 2, and routine histopathological examination and immunohistochemistry were performed for all patients. RESULTS: The site of PLB focus was found in the pelvic bone in 4 cases, right frontal bone in 1 case, proximal femoral bone in 1 case, occipital clivus in 2 cases, and vertebral column in 1 case. Plain X-ray revealed in 4 cases roughly normal shape of the involved bone with stippled interior bone structure destruction; the other 4 cases presented with slight or moderate bone expansion with obvious signs of osteolysis. CT scans displayed areas of different sizes of osteolytic cortical and marrow cavity destruction with large soft tissue masses around the lesion. MRI found heterogeneous iso- to hyperintense signals in the lesions in the bone and soft-tissue masses on T2-weighted images but homogeneous isointense signals on T2-weighted images. The tumors were obviously enhanced after contrast-enhanced scans on CT and MRI. Histological examination identified B-cell lymphoma in 5 cases and T-cell lymphoma in 4 cases. CONCLUSION: PBL is characterized in imaging examinations by basically normal shape of the involved bones with possible bone expansion, obvious stippled osteolytic destruction, large soft-tissue mass around the lesion and obvious enhancement after contrast-enhanced scans.

[Primary diffuse large B-cell lymphoma of the heart: a clinicopathological study].

OBJECTIVE: To define the clinicopathological features of primary cardiac large B-cell lymphoma. METHOD: A case of primary cardiac large B-cell lymphoma was studied with conventional histopathological and immunohistochemical staining in combination with literature review. RESULTS: The lesion appeared to originate in the right atrium and involved the venae cavae and the left atrium. Microscopic examination showed diffuse proliferation of large atypical lymphocytes with abundant cytoplasm, vestiealer nuelei, thick nuclear membrane and conspicuous nucleoli. Giant tumor cells scattered in the lesion. The neoplastic cells were positive for CD20 and CD79a. CONCLUSION: Primary cardiac lymphoma is extremely rare, and its pathogenesis remains unclear. With non-specific clinical manifestations, the majority of primary cardiac lymphomas are of B-cell lineage and a bad prognosis.

[Expression and diagnostic application of C4.4A protein in squamous cell carcinoma and adenocarcinoma].

OBJECTIVE: To investigate the diagnostic utility of C4.4A gene expression in discriminating a squamous cell carcinoma (SCC) from an adenocarcinoma by immunohistochemistry. METHODS: Immunohistochemical staining was performed to detect the expression of C4.4A protein in 157 cases of SCC and 177 cases of adenocarcinoma of various organs. RESULTS: Overall, 141 of 157 cases of SCC strongly expressed C4.4A protein. In contrast, only 8 of 177 adenocarcinomas showed partial or scattered cell expression of C4.4A protein. The statistic difference between the two groups was highly significant (chi(2) = 244.93, P = 0.000), and also when the tumors were stratified according to the degree of differentiation (P = 0.000). CONCLUSION: C4.4A protein expression may serve as a valuable tumor marker in discriminating a squamous cell carcinoma from an adenocarcinoma, and therefore, may greatly facilitate the differential diagnosis of an epithelial malignancy.

[Expression of CD25+ lymphocytes in nasopharyngeal carcinoma and its association with EBV infection].

OBJECTIVE: To investigate the expression of CD25(+) lymphocytes in nasopharyngeal carcinoma (NPC) tissue and the influence of Epstein-Barr virus (EBV) infection on CD25 expression. METHODS: Immunohistochemistry was used to detect CD25 expression in the NPC tissues and in situ hybridization employed to detect EBV infection with chronic nasopharyngitis tissue as the control sample. RESULTS: Significant difference was noted in the expression of CD25(+) lymphocytes between NPC and chronic inflammatory tissues. The expression was higher in undifferentiated NPC than in keratinizing squamous cell carcinoma and non-keratinizing carcinomas. The NPC tissue was all EBV-positive except for one sample, which was identified as keratinizing carcinoma, but the control samples were all negative for EBV infection, which was correlated with CD25 expression. CONCLUSION: The expression of CD25(+) lymphocytes is higher in NPC tissues and correlated to EBV infection.