Methylation Status of P16Ink4a in Human Papillomavirus-Associated Cancer of Oral Cavity and Oropharynx in Northeastern Thailand

Background:

Over-expression of p16^INK4a protein is a biomarker for human papillomavirus (HPV)-associated cervical cancer. However, absence of p16^INK4a protein expression in HPV-associated cancer of the oral cavity and oropharynx has been reported. Among a number of possible reasons for this is methylation, which is frequently noted in the promoter region of p16^INK4a and is associated with silencing of the gene and disease severity.

Methods:

We investigated the relationships between p16^INK4a protein expression, HPV infection and methylation status of the p16^INK4a promoter in cancers of the oral cavity and oropharynx. Fifty-three formalin-fixed paraffin-embedded (FFPE) cancer tissue samples from the oral cavity (49 cases) and oropharynx (4 cases) were studied. P16^INK4a protein expression was determined using immunohistochemical staining (IHC). Additional oral tissues lacking squamous intraepithelial lesions (SILs), and cervical tissues with high-level SILs, were used as negative and positive controls, respectively. High-risk HPV infection was detected using HPV E6/E7 mRNA in situ hybridization. Methylation status of the p16^INK4a promoter was investigated using sodium bisulfite treatment and methylation-specific PCR (MS-PCR).

Results:

HPV infection was found in 40.8% (20/49) and 50.0% (2/4) of oral cavity and oropharynx cancers, respectively. Promoter methylation of p16^INK4a occurred in 73.6 % of all cases and differed significantly in frequency between HPV-positive (90.9%, 20/22) and HPV-negative (61.3%, 19/31) samples. Expression of p16^INK4a was found in 35.8% (19/53) and commonly detected in samples with p16^INK4a unmethylation (79.5%). Interestingly, the silencing of p16^INK4a (64.2%, 34/53) was significantly associated with methylation status (91.2%, 31/34), especially in HPV-infected samples in which the p16^INK4a promoter was methylated (52.9%, 18/34).

Conclusions:

This result demonstrated high frequency of p16^INK4a promoter methylation status in HPV-associated HNSCC subsets that could influence the silent p16^INK4a expression and might promote disease severity.

High Levels of EBV-Encoded RNA 1 (EBER1) Trigger Interferon and Inflammation-Related Genes in Keratinocytes Expressing HPV16 E6/E7

Different types of cells infected with Epstein-Barr virus (EBV) can release exosomes containing viral components that functionally affect neighboring cells. Previously, we found that EBV was localized mostly in infiltrating lymphocytes within the stromal layer of cervical lesions. In this study, we aimed to determine effects of exosome-transferred EBV-encoded RNAs (EBERs) on keratinocytes expressing human papillomavirus (HPV) 16 E6/E7 (DonorI-HPV16 HFKs). Lipid transfection of in vitro-transcribed EBER1 molecules (ivt EBER1) into DonorI-HPV16 HFKs caused strong induction of interferon (IFN)-related genes and interleukin 6 (IL-6). To gain insights into the physiological situation, monocyte-derived dendritic cells (moDCs), low passage DonorI-HPV16 HFKs and primary keratinocytes were used as recipient cells for internalization of exosomes from wild-type EBV (wt EBV) or B95-8 EBV-infected lymphoblastoid cell lines (LCLs). qRT-PCR was used to determine the expression of EBER1, HPV16 E6/E7, IFN-related genes and IL-6 in recipient cells. The secretion of inflammatory cytokines was investigated using cytometric bead array. Wt EBV-modified exosomes induced both IFN-related genes and IL-6 upon uptake into moDCs, while exosomes from B95-8 EBV LCLs induced only IL-6 in moDCs. Internalization of EBV-modified exosomes was demonstrated in DonorI-HPV16 HFKs, yielding only EBER1 but not EBER2. However, EBER1 transferred by exosomes did not induce IFN-related genes or IL-6 expression and inflammatory cytokine secretion in DonorI-HPV16 HFKs and primary keratinocytes. EBER1 copy numbers in exosomes from wt EBV-infected LCLs were 10-fold higher than in exosomes from B95-8 LCLs (equal cell equivalent), whereas ivt EBER1 was used at approximately 100-fold higher concentration than in exosomes. These results demonstrated that the induction of IFN-related genes and IL-6 by EBER1 depends on quantity of EBER1 and type of recipient cells. High levels of EBER1 in cervical cells or infiltrating dendritic cells may play a role in the inflammation-to-oncogenesis transition of HPV-associated cervical cancer through modulation of innate immune signals.

Human papillomavirus (HPV) infection in a case-control study of oral squamous cell carcinoma and its increasing trend in northeastern Thailand

Human papillomavirus (HPV) is an independent risk factor for development of oral squamous cell carcinoma (OSCC). This study aimed to investigate the role of HPV infection and the trend in percentage of HPV-associated OSCC over a 5-year period in northeastern Thailand. In this case-control study, 91 exfoliated oral cell samples and 80 lesion cell samples from OSCC cases and exfoliated oral cells from 100 age/gender-matched controls were collected. HPV infection was investigated by PCR using GP5+/GP6+ primers followed by HPV genotyping using reverse line blot hybridization. Quantitative RT-PCR was used to evaluate HPV oncogene transcription. Temporal trends of HPV infection were evaluated in archived formalin-fixed paraffin-embedded (FFPE) OSCC tissues using in situ hybridization. HPV DNA was found in 17.5% (14/80) of lesion samples from OSCC cases and 29.7% (27/91) of exfoliated oral cell samples from the same cases. These values were significantly higher than in exfoliated oral cell samples from controls (13%, 13/100). HPV-16 was the genotype most frequently found in OSCC cases (92.8%, 13/14 infected cases). Interestingly, HPV oncogene mRNA expression was detected and correlated with OSCC cases (P < 0.005). Of 146 archived FFPE OSCC samples, 82 (56.2%) were positive for high-risk HPV DNA and 64 (43.8%) cases were positive for HPV E6/E7 mRNA expression. There was a trend of increasing percentage of HPV-associated OSCC from 2005 to 2010. This was especially so for females with well-differentiated tumors in specific tongue sub-sites. We suggest that HPV infection plays an important role in oral carcinogenesis in northeastern Thailand.

E6D25E, HPV16 Asian variant shows specific proteomic pattern correlating in cells transformation and suppressive innate immune response

HPV16 Asian variant (HPV16As) containing E6D25E oncogene, is commonly associated with cervical cancers of Asian populations. To explore a mechanism of E6D25E oncoprotein in carcinogenesis, we compared protein profiles in human keratinocytes expressing E6D25E with E6 of HPV16 prototype (E6Pro). A human cervical keratinocyte cell line, HCK1T, was transduced with retroviruses containing E6D25E or E6Pro genes. Biological properties of E6D25E or E6Pro transduced HCK1T cells were characterized. Protein profiles of the transduced HCK1T cells were analyzed using 2D-PAGE and characterized by mass spectrometry and western blotting. Reactomes of modulated proteins were analyzed by using the Reactome Knowledgebase. The E6D25E and E6Pro oncoproteins were comparable for their abilities to degrade p53 and suppress the induction of p21, and induce cell proliferation. Interestingly, the protein profiles of the HCK1T cells transduced with E6D25E showed specific proteomic patterns different from those with E6Pro. Among altered proteins, more than 1.5-fold up- or down- regulation was observed in E6D25E-expressing cells for gp96 and keratin7 which involved in activation of TLR signaling and transformation of squamocolumnar junction cells, respectively. This report describes new cellular proteins specifically targeted by E6D25E oncoprotein that may contribute to impair immune response against viral infection and cell transformation associated with oncogenic property of HPV16As variant.

Effect of human papillomavirus 16 oncoproteins on oncostatin M upregulation in oral squamous cell carcinoma

Human papillomavirus (HPV) infection modulates several host cytokines contributing to cancer development. Oncostatin M (OSM), an IL-6 family cytokine, acts to promote cell senescence and inhibit growth. Its dysregulation promotes cell survival, cell proliferation and metastasis in various malignancies. The effect of HPV on OSM dysregulation has not been investigated. To elucidate this, immunohistochemistry was used on formalin-fixed, paraffin-embedded oral squamous cell carcinoma (OSCC) tissues: HPV-positive (50) and HPV-negative (50) cases. Immortalized human cervical keratinocytes expressing HPV16E6 (HCK1T, Tet-On system) were used to demonstrate the role of HPV16E6 in OSM expression. In addition, a vector containing HPV16E6/E7 was transiently transfected into oral cancer cell lines. Cell viability, cell-cycle progression and cell migration were evaluated using flow cytometry and a wound healing assay, respectively. The results showed various intensities of OSM expression in OSCC. Interestingly, the median percentages of strongly stained cells were significantly higher in HPV-positive OSCCs than in HPV-negative OSCCs. To explore the role of HPV oncoproteins on OSM expression, the expression of HPV16E6 in the HCK1T Tet-On condition was induced by doxycycline and HPV16E6 was found to significantly upregulate levels of OSM mRNA and protein, with concomitant upregulation of c-Myc. In addition, the levels of OSM mRNA and protein in E6/E7 transiently transfected oral cancer cells also gradually increased in a time-dependent manner and these transfected cells showed greater viability and higher migration rates and cell-cycle progression than controls. This result demonstrates that HPV16 oncoproteins upregulate OSM and play an important role to promote OSCC development.

Aberrant methylation of PCDH10 and RASSF1A genes in blood samples for non-invasive diagnosis and prognostic assessment of gastric cancer

Background. Assessment of DNA methylation of specific genes is one approach to the diagnosis of cancer worldwide. Early stage detection is necessary to reduce the mortality rate of cancers, including those occurring in the stomach. For this purpose, tumor cells in circulating blood offer promising candidates for non-invasive diagnosis. Transcriptional inactivation of tumor suppressor genes, like PCDH10 and RASSF1A, by methylation is associated with progression of gastric cancer, and such methylation can therefore be utilized as a biomarker.

Methods. The present research was conducted to evaluate DNA methylation in these two genes using blood samples of gastric cancer cases. Clinicopathological data were also analyzed and cumulative survival rates generated for comparison.

Results. High frequencies of PCDH10 and RASSF1A methylations in the gastric cancer group were noted (94.1% and 83.2%, respectively, as compared to 2.97% and 5.45% in 202 matched controls). Most patients (53.4%) were in severe stage of the disease, with a median survival time of 8.4 months after diagnosis. Likewise, the patients with metastases, or RASSF1A and PCDH10 methylations, had median survival times of 7.3, 7.8, and 8.4 months, respectively. A Kaplan–Meier analysis showed that cumulative survival was significantly lower in those cases positive for methylation of RASSF1A than in their negative counterparts. Similarly, whereas almost 100% of patients positive for PCDH10 methylation had died after five years, none of the negative cases died over this period. Notably, the methylations of RASSF1A and PCDH10 were found to be higher in the late-stage patients and were also significantly correlated with metastasis and histology.

Conclusions.PCDH10 and RASSF1A methylations in blood samples can serve as potential non-invasive diagnostic indicators in blood for gastric cancer. In addition to RASSF1A methylation, tumor stage proved to be a major prognostic factor in terms of survival rates.

Polymorphisms and functional analysis of the intact human papillomavirus16 e2 gene

High risk human papillomavirus (HR-HPV) E2 proteins play roles in transcriptional regulation and are commonly functionally disrupted when the HPV genome integrates into host chromosomes. Some 15-40% of cancer cases, however, contain an intact E2 gene or episomal HPV. In these cases, polymorphism of the E2 gene might be involved. This study aimed to determine polymorphisms of the E2 gene in episomal HPV16 detected in high grade squamous intraepithelial lesions and squamous cell carcinomas and altered functions compared to the E2 prototype. The E2 gene was amplified and sequenced. Two expression vectors containing E2 gene polymorphisms were constructed and transfected in SiHa and C33A cells, then E6 gene as well as Il- 10 and TNF-α expression was determined by quantitative RT-PCR. Expression vectors and reporter vectors containing the HPV16 long control region (LCR) were co-transfected and transcriptional activity was determined. The results showed that a total of 32 nucleotides and 23 amino acids were changed in all 20 cases of study, found in the transactivation (TA) domain, hinge (H) region and DNA binding (DB) domain with 14, 5 and 13 nucleotide positions. They mostly caused amino acid change. The expressing vectors containing different E2 gene polymorphisms showed E6 mRNA suppression, TNF-α mRNA suppression and IL-10 induction but no statistically significant differences when compared to the E2 prototype. Moreover, promoter activity in HPV16 LCR was not affected by E2 protein with different gene polymorphisms, in contrast to nucleotide variations in LCR that showed an effect on transcription activity. These results demonstrated that E2 gene polymorphisms of episomal HPV16 did not affect transcriptional regulation and suggested that nucleotide variation as well as epigenetic modification of the LCR might play a role in inducing malignant transformation of cells containing episomal HPV16.

Epidermal growth factor receptor pathway mutation and expression profiles in cervical squamous cell carcinoma: therapeutic implications

Background

Cervical squamous cell carcinoma (CSCC) is a major cause of female mortality worldwide. This study has examined epidermal growth factor receptor (EGFR) pathway markers that represent actionable pharmacological targets.

Methods

HPV16 positive CSCCs (n = 105 patients) from Madhya Pradesh, India were screened for KRAS and PIK3CA mutations by PNA-clamp real-time PCR. Immunohistochemistry (IHC) was performed for EGFR, PIK3CA, PTEN, phospho-AKT, phospho-mTOR and phospho-44/42 MAPK (ERK1/2).

Results

KRAS mutations were detected in 0/91 (0%) and PIK3CA mutations in 19/95 (20.0%) informative specimens: exon 9, E542 (n = 3) and E545 (n = 15); exon 20, H1047R (n = 1). PIK3CA mutation detection was associated with older mean patient age [48.2 vs. 56.6 years (P = 0.007)] and with post-menopausal age: 5/45 (11.1%) patients <50 years vs. 14/50 (28.0%) patients ≥50 years (P = 0.045; OR = 3.11). EGFR expression was present in 60/101 (59.4%) CSCCs and was associated with PIK3CA mutation detection (P < 0.05) but not age (P > 0.05). EGFR and phospho-AKT staining showed associations with tumor grade and/or lymph node status (P < 0.05). Significant associations were not found for the other study markers (P > 0.05).

Conclusion

These data show that PIK3CA mutation acquisition is related to patient age and EGFR expression. The absence of KRAS mutations supports the potential of anti-EGFR therapies for CSCC treatment. The relatively high PIK3CA mutation rates indicate that PI3K may be a therapeutic target for a significant subset of CSCC patients. Qualitatively distinct IHC staining profiles for the marker panel were noted patient to patient; however, across patients, consistent linear relationships between up- and downstream pathway markers were not observed. Evaluation of the expression status of potential cancer pathway targets may be of value in addition to molecular profiling for choosing among therapeutic options.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0611-0) contains supplementary material, which is available to authorized users.

Up-Regulation of miR-21 Is Associated with Cervicitis and Human Papillomavirus Infection in Cervical Tissues

MicroRNA-21 (miR-21) is recognized as an oncomir and shows up-regulation in many types of human malignancy. The aim of this study was to investigate the association of miR-21 expression associated with HPV infection in normal and abnormal cervical tissues. Cervical tissue samples with different cytological or histopathological grades were investigated for HPV by PCR and for miR-21 and programmed cell death, protein 4 (PDCD4) expression using quantitative real-time PCR (qRT-PCR). Laser capture microdissection (LCM) of stromal and epithelial tissues and in situ hybridization (ISH) using locked nucleic acid (LNA) probes were performed on a subset of fixed specimens. Cell line experiments were conducted on fibroblasts stimulated in culture media from HeLa cells, which were then assessed for miR-21, PDCD4, IL-6 and α-SMA expression by qRT-PCR. Twenty normal cervical cell, 12 cervicitis, 14 cervical intraepithelial neoplastic I (CIN I), 22 CIN II-III and 43 cervical squamous cell carcinoma (SCC) specimens were investigated. miR-21 levels were significantly lower in normal than in abnormal tissues. The expression of miR-21 in HPV negative normal cytology was significantly lower than in HPV positive samples in abnormal tissue and SCC. The miR-21 expression was significantly higher in HPV negative cervicitis than HPV negative normal cells. LCM and ISH data showed that miR-21 is primarily expressed in the tumor-associated stromal cell microenvironment. Fibroblasts treated with HeLa cell culture media showed up-regulated expression of miR-21, which correlated with increased expression of α-SMA and IL-6 and with down-regulation of PDCD4. These results demonstrate that miR-21 is associated with HPV infection and involved in cervical lesions as well as cervicitis and its up-regulation in tumor-stroma might be involved in the inflammation process and cervical cancer progression.

Activity of Andrographolide and Its Derivatives on HPV16 Pseudovirus Infection and Viral Oncogene Expression in Cervical Carcinoma Cells

Andrographolide (Androg) has been reported to contain antiviral and antitumor activities, but the effects of Androg on human papillomavirus (HPV) infection and cervical cancer have not been elucidated. This study investigated the effects of Androg and its derivatives, namely, 14-deoxy-11,12-didehydroandrographolide (14-DDA) and 3,19-isopropylidene andrographolide (IPAD), on HPV16 pseudovirus (HPV16PsV) infectivity, HPV16 E6 oncogene expression and cervical cancer cell apoptosis. The result demonstrated that all compounds inhibited HPV16PsV infection and that 14-DDA showed the highest potency. Only Androg suppressed long control region (LCR) transcription activity of HPV16 in transiently transfected C33A cells and significantly inhibited E6 oncogene expression in SiHa cells in a dose-dependent manner. A twofold subcytotoxic concentration of IPAD exhibited an inhibitory effect on E6 oncogene expression at 48-h posttreatment. Interestingly, p53 protein was restored in a downstream process and was detected earlier by IPAD treatment than by Androg treatment. This result corresponded to the level of cell apoptosis and cell cycle arrest at the G2/M phase. E6 oncogene expression was also suppressed in CaSki cells treated with Androg and IPAD leading to cell apoptosis. These findings imply that Androg and its derivatives have different activities and may be effective agents for HPV prevention and cervical cancer treatment.

Synergistic effects of acyclovir and 3, 19-isopropylideneandrographolide on herpes simplex virus wild types and drug-resistant strains

Background

An andrographolide analogue, 3, 19-isopropylideneandrographolide (IPAD), exerts an inhibitory effect on replication of wild-type herpes simplex virus serotype 1 (HSV-1). In this study, we examined the anti-viral activity of IPAD on HSV wild types (HSV-1 strain KOS and HSV-2 clinical isolate) and HSV-1 drug-resistant strains (DRs). Synergistic effects of IPAD with acyclovir (ACV) were also evaluated.

Methods

MTT and cytopathic effect (CPE) reduction assays were performed to determine cytotoxicity and anti-viral activities, respectively. A combination assay was used to determine synergistic effects of IPAD and ACV. Presence of viral DNA and protein in experimental cells was investigated using the polymerase chain reaction and western blotting, respectively.

Results

A non-cytotoxic concentration of IPAD (20.50 μM) completely inhibited CPE formation induced by HSV wild types and HSV-1 DRs after viral entry into the cells. The anti-HSV activities included inhibition of viral DNA and protein synthesis. The minimum inhibitory concentrations of ACV for HSV wild types and HSV-1 DRs were 20.20 and 2,220.00 μM, respectively. Combination of ACV with IPAD showed synergistic effects in inhibition of CPE formation, viral DNA and protein synthesis by HSV wild types as well as HSV-1 DRs. For the synergistic effects on HSV wild types and HSV-1 DRs, the effective concentrations of ACV were reduced.

Conclusions

These results showed the inhibitory potential of IPAD on HSV wild types and HSV-1 DRs and suggested that IPAD could be used in combination with ACV for treatment of HSV-1 DRs infections.

Rhinovirus infection in children hospitalized with acute bronchiolitis and its impact on subsequent wheezing or asthma: a comparison of etiologies

BACKGROUD

Children who suffer a viral lower respiratory infection early in life are prone to subsequent wheezing and asthma: RSV and rhinovirus are thought to be the primary causative pathogens. Epidemiologic and long-term data on these pathogens in Thailand are limited.

OBJECTIVES

To detect the causative pathogens in children hospitalized with a first episode of acute wheezing and to compare the respective impact on the recurrence of wheezing and development of asthma.

METHOD

We conducted a 5-year cohort study of children under 2 hospitalized with acute bronchiolitis at two tertiary hospitals. Nasopharyngeal secretions were collected at admission to determine the causative pathogens by RT-PCR.

RESULTS

145/170 samples (85%) were positive for pathogens. RSV, rhinovirus, influenza, bacteria and hMPV was found in 64.7%, 18.2%, 17.6%, 12.9% and 3.5% of children respectively. The majority (94/152; 62%) of participants reported having recurrent wheezing within the first year of follow-up (mean duration 5.5 ± 7.2 months). Only 16% still had wheezing episodes after 5 years. Asthma was diagnosed in 41 children (45%), most of whom were treated with inhaled corticosteroid. There were no statistically significant differences among the various etiologies.

CONCLUSION

Rhinovirus ranked second after RSV as the cause of hospitalizations of children with acute bronchiolitis. More than half of these children had recurrent wheezing which mostly disappeared before the age of 6. Nearly half were subsequently diagnosed with asthma at the 5th year of follow-up. The specific pathogens did not account for a statistically significant difference in subsequent wheezing or asthma development.

Gene-environment interaction involved in cholangiocarcinoma in the Thai population: polymorphisms of DNA repair genes, smoking and use of alcohol

OBJECTIVE

Cholangiocarcinoma (CCA) is the most common malignancy in a Northeast Thai population. Smoking and alcohol drinking are associated with the production of free radical intermediates, which can cause several types of DNA lesions. Reduced repair of these DNA lesions would constitute an important risk factor for cancer development. We therefore examined whether polymorphisms in DNA base-excision repair (BER) genes, XRCC1 G399A and OGG1 C326G, were associated with CCA risk and whether they modified the effect of smoking and alcohol drinking in the Thai population.

DESIGN

A nested case-control study within the cohort study was conducted: 219 participants with primary CCA were each matched with two non-cancer controls from the same cohort on sex, age at recruitment and the presence/absence of Opisthorchis viverrini eggs in stools. Smoking and alcohol consumption were assessed on recruitment. Polymorphisms in BER genes were analysed using a PCR with high-resolution melting analysis. The associations were assessed using conditional logistic regression.

RESULTS

Our results suggest that, in the Thai population, polymorphisms in XRCC1 and OGG1 genes, particularly in combination, are associated with increased susceptibility to CCA, and that their role as modifiers of the effect of smoking and alcohol consumption influences the risk of CCA.

CONCLUSIONS

Better ways of reducing habitual smoking and alcohol consumption, targeted towards subgroups which are genetically susceptible, are recommended. CCA is a multifactorial disease, and a comprehensive approach is needed for its effective prevention. This approach would also have the additional advantage of reducing the onset of other cancers.

Association of Epstein-Barr virus infection with oral squamous cell carcinoma in a case-control study

BACKGROUND

Besides the well-known risk factors, Epstein-Barr virus (EBV) might play a significant role in oral squamous cell carcinoma (OSCC). To explore the role of EBV in OSCC, the prevalence of EBV infection in oral exfoliated cells of OSCC cases and controls in northeastern Thailand was investigated, and the association of EBV in tumor lesion cells was further confirmed.

METHODS

Oral exfoliated cells were collected from OSCC cases and non-cancer controls. Cells from tumor lesions were taken from OSCC patients for further strong confirmation of the association of EBV with OSCC. EBV DNA was detected by polymerase chain reaction (PCR) using primers specific for EBV DNA polymerase. The EBV DNA positive samples were confirmed further by nested PCR.

RESULTS

Epstein-Barr virus was detected in the oral exfoliated cells of 45.05% of OSCC patients and 18.08% of the non-cancer control (P < 0.001). Similarly, EBV was detected in 32.5% of the tumor lesions. Betel quid chewing was statistically significantly associated with EBV prevalence (OR = 2.08), whereas no association with tobacco smoking and alcohol consumption. Alcohol consumption and betel quid chewing were significantly associated with OSCC (OR = 3.05 and OR = 5.05, respectively), but tobacco smoking was not associated. Interestingly, EBV was significantly associated with OSCC (OR = 3.76).

CONCLUSIONS

Epstein-Barr virus prevalence is associated with OSCC and seems to be enhanced by betel quid chewing, suggesting that EBV may, together with betel quid chewing, act as an important etiological risk factor of OSCC.

Human papillomavirus genotypes and cervical cancer in northeast Thailand

Human papillomavirus (HPV) is a major cause of cervical cancer. More than 100 HPV genotypes have been identified; however the distribution varies geographically and according to ethnicity. The purpose of this study was to investigate the prevalence and distribution of HPV subtypes among Northeast Thai women. Subjects included 198 cases of SCCA and 198 age-matched, healthy controls. HPV-DNA was amplified by PCR using the consensus primers GP5+/6+ system followed by reverse line blot hybridization genotyping. The prevalence of high-risk HPV infection was 21 (10.1%) and 152 (76.8%) in the controls and in the cases, respectively. High-risk HPV significantly increased the risk for cervical cancer with an OR of 42.4 (95%CI: 22.4-81.4, p<0.001) and an adjusted OR of 40.7-fold (95%CI: 21.5-76.8, p <0.001). HPV-16 was the most prevalent HPV type in the SCCA (56.2%) followed by HPV-58 (17.8%) and HPV-18 (13.6%); whereas HPV-58 (46.4%) was a prominent genotype in the controls followed by HPV-16 (39.3%) and unidentified HPV types (25.0%). These findings indicate that HPV infection remains a critical risk factor for SCCA; particularly, HPV-16, HPV-58 and HPV-18. In order to eradicate cervical cancer, sustained health education, promoted use of prophylactics and a HPV-58 vaccine should be introduced in this region.

Genome-wide analysis of high risk human papillomavirus E2 proteins in human primary keratinocytes

The E2 protein is expressed in the early stage of human papillomavirus (HPV) infection that is associated with cervical lesions. This protein plays important roles in regulation of viral replication and transcription. To characterize the role of E2 protein in modulation of cellular gene expression in HPV infected cells, genome-wide expression profiling of human primary keratinocytes (HPK) harboring HPV16 E2 and HPV18 E2 was investigated using microarray. The Principle Components Analysis (PCA) revealed that the expression data of HPV16 E2 and HPV18 E2-transduced HPKs were rather closely clustered. The Venn diagram of modulated genes showed an overlap of 10 common genes in HPV16 E2 expressing HPK and HPV18 E2 expressing HPK. These genes were expressed with significant difference by comparison with control cells. In addition, the distinct sets of modulated genes were detected 14 and 34 genes in HPV16 E2 and HPV18 E2 expressing HPKs, respectively.

E2 proteins of high risk human papillomaviruses down-modulate STING and IFN-κ transcription in keratinocytes

In the early stages of human papillomavirus (HPV) infection, the viral proteins elicit specific immune responses that can participate to regression of ano-genital lesions. HPV E6 protein for instance can reduce type I interferon (IFN) including IFN-κ that is involved in immune evasion and HPV persistence. To evaluate the role of E2 protein in innate immunity in HPV16-associated cervical lesions, genome-wide expression profiling of human primary keratinocytes (HPK) transduced by HPV16 E2 was investigated using microarrays and innate immunity associated genes were specifically analyzed. The analyses showed that the expression of 779 genes was modulated by HPV16E2 and 92 of them were genes associated with innate immunity. Notably IFN-κ and STING were suppressed in HPK expressing the E2 proteins of HPV16 or HPV18 and the trans-activation amino-terminal domain of E2 was involved in the suppressive effect. The relationship between STING, IFN-κ and interferon stimulated genes (ISGs) in HPK was confirmed by gene silencing and real time PCR. The expression of STING and IFN-κ were further determined in clinical specimens by real time PCR. STING and IFN-κ were down-modulated in HPV positive low grade squamous intraepithelial lesions compared with HPV negative controls. This study demonstrates that E2 proteins of high risk HPV reduce STING and IFN-κ transcription and its downstream target genes that might be an immune evasion mechanism involved in HPV persistence and cervical cancer development.

Association of human papillomavirus type 16 long control region mutation and cervical cancer

BACKGROUND

The variation of human papillomavirus (HPV) genes or HPV variants demonstrates different risks of cervical cancer. Mutation in the long control region (LCR) at YY1-motifs is one of the mechanisms for enhancing viral oncogene expression during the course of cancer cell progression. In Thai women, cervical cancers are almost always associated with HPV16 variant sub-lineage Asian (HPV16As); however, the mechanism involved remains elusive. The aim of this study was to understand further the oncogenic potential of HPV16As.

METHODS

A total of 82 HPV16-positive specimens from Thai women were selected from formalin-fixed paraffin-embedded cervical tissues, and the full length E6 gene of each specimen was amplified and sequenced. LCRs of the HPV16As-positive cases were amplified and sequenced to analyze their polymorphisms. Transcriptional activities of the HPV16As LCRs were then compared with sub-lineage European (EUR), sub-lineage Asian-American 1 (AA1) and HPV16 prototype by insertion of the LCRs into the pGL3-Basic vector.

RESULTS

The HPV16 DNA sequences were classified as HPV16 prototype (18.3%), Asian (As, 61%), Asian American-1 (AA1, 8.5%), European (EUR, 7.3%), Asian African-2 (AFR2, 3.7%) and Java-135C (J135C, 1.2%). The prevalence of HPV16As was 30% in low-grade squamous intraepithelial lesion (LSIL), while that in high-grade squamous intraepithelial lesion (HSIL) and squamous cell cervical carcinoma (SCC) were 63.9% and 66.7%, respectively, which demonstrates a significant association of HPV16As with the disease severity. LCR polymorphisms from 43 HPV16As positive cases were analyzed by PCR-sequencing. Thirty-eight nucleotide variation positions spanned nucleotide positions 7157-82. Ten new mutations found in the HPV16As LCRs were located predominantly at the enhancer and proximal to the 3'-end of the early promoter. The LCRs of the common HPV16As, EUR and AA1 showed 5, 13 and 23-fold higher activity than the HPV16 prototype LCR, while those of the new nucleotide variations of As showed 19 (As-sv1) and 30 (As-sv14) -fold higher activity than the HPV16 prototype.

CONCLUSIONS

HPV16As DNA sequence variation, especially at the proximal to early promoter in the LCR, enhances transcriptional activity. This could be one of the possible mechanisms for HPV16As-associated cervical cancer development.

Differential methylation of E2 binding sites in episomal and integrated HPV 16 genomes in preinvasive and invasive cervical lesions

Enhanced expression of the HPV 16 E6-E7 oncogenes may trigger neoplastic transformation of the squamous epithelial cells at the uterine cervix. The HPV E2 protein is a key transcriptional regulator of the E6-E7 genes. It binds to four E2 binding sites (E2BSs 1-4) in the viral upstream regulatory region (URR). Modification of E2 functions, for example, by methylation of E2BSs is hypothesized to trigger enhanced expression of the viral E6-E7 oncogenes. In the majority of HPV-transformed premalignant lesions and about half of cervical carcinomas HPV genomes persist in an extra-chromosomal, episomal state, whereas they are integrated into host cells chromosomes in the remaining lesions. Here we compared the methylation profile of E2BSs 1-4 of the HPV 16 URR in a series of 18 HPV16-positive premalignant lesions and 33 invasive cervical cancers. CpGs within the E2BSs 1, 3, and 4 were higher methylated in all lesions with only episomal HPV16 genomes compared with lesions displaying single integrated copies. Samples with multiple HPV16 integrated copies displayed high methylation levels for all CpGs suggesting that the majority of multiple copies were silenced by extensive methylation. These data support the hypothesis that differential methylation of the E2BSs 1, 3 and 4 is related to the activation of viral oncogene expression in cervical lesions as long as the viral genome remains in the episomal state. Once the virus becomes integrated into host cell chromosomes these methylation patterns may be substantially altered due to complex epigenetic changes of integrated HPV genomes.

Risk factors for cholangiocarcinoma in high-risk area of Thailand: role of lifestyle, diet and methylenetetrahydrofolate reductase polymorphisms

BACKGROUND AND AIM

Cholangiocarcinoma (CCA) is the most common cancer in Northeast Thailand. Endemicity of Opisthorchis viverrini (OV) - a known carcinogen - is responsible, but although infection is very common, the lifetime risk of CCA is only 5%. Other co-factors must exist, including aspects of lifestyle or diet along with variations in genetic susceptibility to them. Change in methylenetetrahydrofolate reductase (MTHFR) activity may influence both DNA methylation and synthesis. This study investigates risk factors for CCA with a focus on lifestyle, diet and MTHFR polymorphisms.

METHODS

Nested case-control study within cohort study was conducted. 219 subjects with primary CCA were each matched with two non-cancer controls from the same cohort on sex, age at recruitment and presence/absence of OV eggs in stool. Lifestyle and dietary data were obtained at recruitment. MTHFR polymorphisms were analyzed using PCR with high resolution melting analysis. The associations were assessed using conditional logistic regression.

RESULTS

Consumption of alcohol, raw freshwater fish and beef sausage increased the risk of CCA, while fruit and/or vegetables consumption reduced risk. There were interactions between MTHFR and preserved freshwater fish and beef. These dietary items are either a source of OV or of pre-formed nitrosamine, folate and antioxidants that are of possible relevance in OV carcinogenesis.

CONCLUSIONS

Primary prevention of CCA in high-risk population is based upon efforts to reduce OV infection. Reduced consumption of alcohol and preserved meats, and increased consumption of dietary folate, actions with a wider preventive potential, may also help in the reduction of CCA burden.

A potential andrographolide analogue against the replication of herpes simplex virus type 1 in vero cells

Andrographolide (AD), and 14-deoxyandrographolide (DAD) isolated from Andrographis paniculata Nees, Acanthaceae, and 3,19-isopropylideneandrographolide (IPAD), a semi-synthetic compound of AD, were examined for anti-HSV-1 activity in vitro. The inhibitory effects of these compounds on viral entry and replication steps were determined using pre- and post-infection assays, respectively. All the three compounds exhibited less than 50% inhibitory act against viral entry. In the post-infection, IPAD displayed absolute inhibition, whereas AD and DAD gave moderate activity. IPAD was selected to determine for the stage of anti-replication by time-of-addition and time-of-removal assays. From the time of removal assay, IPAD activity began after 4 h and completed at 16 h post infection which corresponded to the early genes expression. Its ability to inhibit HSV-1 was confirmed by polymerase chain reaction and the expression of viral glycoproteins C and D by western blot analysis. No viral enveloped glycoproteins D and C expressions were found. IPAD exhibited anti-HSV-1 replication relating to the early step of replication. Structure-activity relationships of andrographolide against HSV-1 was proposed, it is the first report of this ent-labdane diterpene.

Stage of action of naturally occurring andrographolides and their semisynthetic analogues against herpes simplex virus type 1 in vitro

Andrographolide, an ENT-labdane diterpene, has been found to have activities against many viruses. Three free hydroxyls at C-3, C-14, and C-19 are involved in the activities. No stage of action has ever been explored. In this study, the naturally occurring compounds of andrographolide, 14-deoxy-11,12-didehydroandrographolide and 14-deoxyandrographolide, and eight semisynthetic analogues, modified at the three free OHs of andrographolide, were explored for their anti-HSV-1 activities. The concentrations that produced 80 % viable cells were used to test for both pre- and postinfections by using cytopathic effect reduction assays on Vero cell cultures. Three analogues, 14-acetyl-3,19-isopropylideneandrographolide, 14-acetylandrographolide, and 3,14,19-triacetylandrographolide, significantly exhibited preinfection step activity against the virus. For postinfection activity, only 3,19-isopropylideneandrographolide showed absolute inhibition of HSV-1 replication. Meanwhile, andrographolide exhibited slight inhibitory activities of 34.48 ± 6.93 % and 56.90 ± 2.65 % against HSV-1 for pre- and postinfection, respectively. The results confirm that the three hydroxyl moieties play a role in the anti-HSV-1 activity of andrographolide. From the study, it can be concluded that 14-acetyl analogues are good for blocking the viral entry, and 3,19-isopropylideneandrographolide, a cyclic dioxane analogue, is good for exerting postinfection anti-HSV-1 activity.

Atypical bacterial pathogen infection in children with acute bronchiolitis in northeast Thailand

BACKGROUND

Atypical bacterial pathogens--including Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Chlamydia trachomatis--are important infectious agents of the respiratory system. Most current information pertains to adults and little is known about the role of these organisms in lower respiratory tract infections among young children with acute bronchiolitis.

METHODS

This study detected these pathogens in the nasopharyngeal secretions of children between 1 month and 2 years of age admitted with acute bronchiolitis to hospitals in Khon Kaen, northeast Thailand. The M pneumoniae and C pneumoniae in the nasopharyngeal secretions were detected using multiplex and nested-polymerase chain reaction (PCR), whereas PCR and restriction fragment length polymorphism were used to investigate C trachomatis. These samples were also tested by multiplex reverse transcriptase PCR for respiratory viruses, including respiratory syncytial virus (RSV), influenza A, influenza B, and human metapneumovirus.

RESULTS

Of the 170 samples taken from hospitalized children with acute bronchiolitis, 12.9% were infected with atypical bacteria and 85.3% with respiratory viruses. RSV was the most common causative viral agents found in 64.7% of the samples. M pneumoniae was the most common atypical bacterial pathogen (14/170, 8.2%) and most of the patients infected with it were between 6 and less than 12 months of age (71 cases). Of the infected cases in this age group, 7 of 14 were infected with M pneumoniae and 4 of 4 with C pneumoniae. Both M pneumoniae (13/14) and C pneumoniae (4/4) had etiologies indicating viral coinfections. Four (2.4%) of all of the cases had C trachomatis infections and all of these were infected with RSV, including three patients less than 6 months of age.

CONCLUSION

These results suggest that in children with virus-induced acute bronchiolitis coinfection with M pneumoniae, C pneumoniae, or C trachomatis can be expressed differently in each age group. These atypical bacteria may be the important infectious agents that induce severe illness of acute bronchiolitis.

MTHFR polymorphisms and Opisthorchis viverrini infection: a relationship with increased susceptibility to cholangiocarcinoma in Thailand

Opisthorchis viverrini (OV) infection is the major risk factor for cholangiocarcinoma (CCA). Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme in folate metabolism. Change in MTHFR activity may influence both DNA methylation and synthesis, crucial steps in carcinogenesis. This study aimed to investigate the association between MTHFR polymorphisms and OV infection with CCA risk in a high-incidence area of Thailand. A nested case-control study within cohort study was carried out: 219 subjects with primary CCA were matched with two non-cancer controls from the same cohort on sex, age at recruitment and presence/ absence of OV eggs in stool. At the time of recruitment information on consumption of foodstuffs potentially contaminated by OV was obtained by questionnaire. MTHFR polymorphisms were analyzed using PCR with high resolution melting analysis. Associations between variables and the risk of CCA were assessed using conditional logistic regression. Risk of CCA was related to consumption of a dish of raw freshwater fish (Koi- Pla) with clear dose-response effects, and there were joint effects on CCA risk between MTHFR polymorphisms and consumption of dishes containing raw- and/or semi-raw freshwater fish. This study provides evidence to support a relationship of increased susceptibility to CCA in individuals with MTHFR variants, especially for those individuals who have OV infection or consume semi-raw freshwater fish (acting either as a source of OV or of pre-formed nitrosamine). Folate may play an important role in OV-related cholangiocarcinogenesis by upsetting the balance between DNA methylation and synthesis in the folate pathway.

Combined p16INK4a and human papillomavirus testing improves the prediction of cervical intraepithelial neoplasia (CIN II-III) in Thai patients with low-grade cytological abnormalities

Thailand is in the process of developing a national cervical screening program. This study examined p16INK4a staining and HPV prevalence in abnormal cervical samples with atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL), to evaluate the efficacy of combined HPV and p16INK4a detection to predict CIN II-III. Totals of 125 ASCUS and 87 LSIL cases were re-evaluated by Pap test and cervical cells of ASCUS and LSIL cases were prepared on slides for p16INK4a detection by immunocytochemistry. HPV genotyping of DNA extracts was performed by GP5+/6+ PCR and reverse line blot hybridization. Histopathologic tests were performed to identify cervical lesion. Total of 212 cases were diagnosed to normal (20), ASCUS (112), LSIL (78) and HSIL (2). HPV was detected in ASCUS (49/112, 43.8%), LSIL (60/78, 76.9%) and HSIL (2/2, 100%) cases. The majority of HPV positive samples typed for high-risk HPV. 55.7% (107/192) of abnormal cases (ASCUS, LSIL and HSIL) were positive p16INK4a. For the 111 HPV DNA positive cases, 34 of 49 (69.4%) ASCUS cases and 49 of 60 (81.7%) LSIL cases were p16INK4a positive. 140 biopsies were taken and histological classified: CIN negative (65 cases), CIN I (56 cases) and CIN II-III (19 cases). HPV DNA detection predicted CIN II-III with sensitivity and specificity of 84% and 49%, whereas p16INK4a staining showed higher sensitivity (89.5%) and specificity (56.2%). The prediction of CIN II-III was significantly better by combination of positive HPV DNA and p16INK4a with 93.8% sensitivity and 59.2% specificity. Detection of HPV DNA combined with p16INK4a in cervical cells can predict CIN II-III and may improve the screening diagnosis of Thai women at risk for CIN II-III or cancer.

Human papilloma virus prevalence, genotype distribution, and pattern of infection in Thai women

BACKGROUND

The pattern of infection in cervical lesions with respect to HPV subtype has not been systematically studied in Thai women. The aim here was to determine HPV prevalence, genotype, and infection pattern in cervical lesions and to estimate the potential efficacy of an HPV prophylactic vaccine.

DESIGN

Formalin-fixed paraffin-embedded cervical tissue blocks of 410 Thai patients from 8 institutes in 4 regions of Thailand (northern, southern, north-eastern, and central) were studied. The samples included 169 low grade squamous intraepithelial lesions (LSILs), 121 high grade squamous intraepithelial lesions (HSILs), and 120 squamous cell carcinomas (SCCs). HPV-DNA was amplified by PCR using consensus primers GP5+ and GP6+. The HPV genotype was then determined by reverse linear blot assay that included 37 HPV-specific 5'-amino-linked oligonucleotide probes. Patterns of infection were classified as single infection (one HPV type), double infection (two HPV types), and multiple infection (three or more HPV types).

RESULTS

The mean age of the subjects was 42 years. The prevalence of HPV infection was 88.8%. The highest HPV prevalence was found in the southern region (97.1%) and the lowest in the central region (78.6%). HPV-DNA was detected in 84.6% of LSILs, 90.1% of HSILs, and 93.3% of SCCs. A total of 20 HPV genotypes were identified. The five most common high risk HPV were HPV16 (83.2%), HPV18 (59.3%), HPV58 (9.3%), HPV52 (4.1%), and HPV45 (3.8%). In double and multiple infection patterns, the most common genotypes were HPV16/18 (27.8%) and HPV11/16/18 (54.9%). HPV6 was found only in LSIL and never in combination with other subtypes. HPV11 was most common in LSIL.

CONCLUSION

There is no difference of HPV type distribution in women from 4 regions of Thailand with prominent HPV16 and HPV18 in all cases. The bivalent and quadrivalent vaccines have the potential to prevent 48.6 % and 74.5% of cervical cancers in Thai women. The potential of cancer prevention would rise to 87.6% if other frequent HR-HPV types (HPV58, 52, and 45) were also targeted by an HPV vaccine.

Risk factors for colon cancer in Northeastern Thailand: interaction of MTHFR codon 677 and 1298 genotypes with environmental factors

BACKGROUND

Polymorphisms in methylenetetrahydrofolate reductase (MTHFR), such as MTHFR C677T and A1298C, are associated with several cancers. This study aimed to evaluate the effects of MTHFR polymorphisms on colon cancer risk and possible interactions with environmental factors in a population from northeastern Thailand.

METHODS

This hospital-based case-control study was conducted during 2002-2006; 130 colon cancer cases and 130 age- and sex-matched controls were enrolled. Information was collected and blood samples were obtained for assay of MTHFR C677T and A1298C polymorphisms by polymerase chain reaction with restriction fragment length polymorphism techniques. Associations between variables of interest and colon cancer were assessed using conditional logistic regression.

RESULTS

Increased risk of colon cancer was associated with alcohol consumption and bowel habits. Alcohol drinkers who consumed < or = 0.50 or >0.50 units of alcohol per day had elevated risks (OR(adj) = 3.5; 95% CI: 1.19-10.25 and OR(adj) = 1.71; 95% CI: 0.74-3.96, respectively). The risk was also higher in subjects with frequent constipation (11.69; 2.18-62.79) and occasional constipation (3.43; 1.72-6.82). An interaction was observed between the MTHFR C677T polymorphism and freshwater fish consumption on colon cancer risk (P value for interaction = 0.031). Interactions were observed between the MTHFR A1298C polymorphism and bowel habits, family history of cancer, alcohol consumption, and beef consumption on colon cancer risk (P-value for interaction = 0.0005, 0.007, 0.067, 0.003, respectively).

CONCLUSIONS

In a Thai population, colon cancer risk was associated with alcohol and beef consumption, bowel habits, and family history of cancer. Interactions between MTHFR polymorphisms and environmental factors were also observed.

Cryotherapy for HPV clearance in women with biopsy-confirmed cervical low-grade squamous intraepithelial lesions

OBJECTIVE

To compare the clearance rate of HPV infection among women aged older than 30 years with biopsy-confirmed cervical low-grade squamous intraepithelial lesions (LSIL) 1 year after cryotherapy with the spontaneous clearance rate (observation).

METHOD

HPV DNA typing by polymerase chain reaction and reverse line blot hybridization were used to identify 14 high-risk types and 23 low-risk types. HPV DNA sequencing was also used for other types.

RESULT

Between December 2007 and March 2009, 100 women were recruited to the study and 60 cases had positive results on HPV testing. Twenty-nine patients were randomly allocated to the cryotherapy group and 31 to the observation group. At 1 year, 89.7% (26/29; 95% CI, 78.6-100%) of the cryotherapy group and 90.3% (28/31; 95% CI, 79.9-100%) of the observation group had negative results on HPV testing (0.6% difference; 95% CI, -15.8 to 14.6%, P=0.94).

CONCLUSION

Cryotherapy failed to increase the clearance of prevalent HPV infections among women with LSIL, although in both arms the clearance rates were above 80%. However, in coupling with visual inspection with acetic acid as a single visit approach, its effect on prevention of HSIL and cervical cancer is still promising. Therefore, cryotherapy should not be withdrawn from such programs.

Human metapneumovirus and respiratory syncytial virus detection in young children with acute bronchiolitis

This study was conducted to detect human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) in young children hospitalized with acute bronchiolitis, using reverse transcriptase polymerase chain reaction (RT-PCR). Nasopharyngeal secretions were collected from 170 children between 1 and 24 months of age admitted to two tertiary hospitals in northeastern Thailand, between 2002 and 2004. Acute bronchiolitis was defined as the first episode of wheezing associated with tachypnea, increased respiratory effort and an upper respiratory tract infection. Two-thirds (115/170) were positive for viral etiologies: 64.7% RSV (110/170) and 3.5% hMPV (6/170). One patient had a dual infection. hMPV was detected between August and November, while RSV was prevalent from July through March. The clinical manifestations among the 6 hMPV, RSV and non-RSV-infected children were similar. RSV was the leading cause of acute bronchiolitis in young children and hMPV had a low prevalence in northeastern Thailand.

Evaluation of primers and PCR performance on HPV DNA screening in normal and low grade abnormal cervical cells

High risk human papillomaviruses (HR-HPVs) are associated with increased risk of normal cervical cells developing to dysplasia and cervical carcinoma. Therefore, HR-HPV DNA testing can predict an endpoint of cervical carcinogenesis that is earlier than the development of cervical abnormalities. Not only the sensitivity of methods but also the amount of HPV DNA are very important and might be parameters to distinguish HPV detection. In this study, we evaluated the effects of primer sets and the polymerase chain reaction (PCR) performance with low viral load samples with normal cervical cytology (140 samples) and mild dysplasia (140 samples) using two consensus primers MY09/MY11 and GP5+/6+. The PCR was performed with single and nested PCR. Positive samples with both primer sets were then HPV genotyped by dot blot hybridization. Results showed higher sensitivity of single PCR using primer GP5+/GP6+ than primer MY09/MY11. HPV DNA was detected in 15% (21 of 140)and 20.7% (29 of 140) of normal cervical samples, respectively. For mild dysplasia samples, HPV DNA was detected in 37.1% (52 of 140) with MY09/MY11 and 50% (70 of 140) using GP5+/GP6+. In normal cervical samples, the positivity rate was increased to 38.5% (54 of 140) by nested PCR using primer GP5+/6+, but only 2 mild dysplasia samples that were negative by single GP5+/6+ were positive by auto-nested PCR. These results suggested that, in low viral load samples, the sensitivity of HPV DNA detection depends not only on primer sets but also PCR performance. HPV 16 was the most common in mild dysplasia samples (20.8%), whereas HPV type 58 was found in 11.1%. This study suggested that nested PCR might be necessary for HPV DNA detection in cervical samples of women participating in cervical cancer screening.

Usefulness of combining testing for p16 protein and human papillomavirus (HPV) in cervical carcinoma screening

OBJECTIVE

To evaluate the value of the combination of p16 and HPV detection in the screening for cervical cancer.

METHODS

186 patients with previous abnormal cervical lesion were studied. After colposcopic examination, two conventional Pap slides were prepared: the first was Papanicolaou-stained and examined by cytologist; the second was immunocytochemically stained for p16. Cervical cells were collected by brush using for HPV detection by Hybrid Capture II. Biopsy of any colposcopically abnormal lesions was performed.

RESULTS

The 186 cervical samples were classified cytologically as normal (148), ASCUS (13), low-grade (11), high-grade (12) dysplasia and squamous cell carcinoma (2). P16 and HPV were found in all high-grade dysplasia and SCC, and in 64% and 27% of low-grade dysplasia, 62% and 0% of ASCUS and 7.4% and 3.4% of normal, respectively. 18 of p16-positive cases (11%) were HPV-negative, 14 of them in the ASCUS and normal group. Compared to histological results, all of the p16-positive cases of squamous metaplasia, CIN II/III and SCC were HR-HPV-positive. Therefore, the cases that were positive for both with normal cytology (5 cases) or low-grade dysplasia (3 cases) may comprise a high-risk group for neoplastic change.

CONCLUSION

The combination of p16 and HPV detection may be useful in cervical cancer screening to identify high-risk patients requiring early and proper management.

Human papillomavirus and cervical cancer from a prospective study in Khon Kaen, Northeast Thailand

The risk of developing carcinoma of the cervix in women infected with human papillomavirus (HPV) was estimated in a nested case-control analysis of 33 cancers (invasive and in situ) and 113 controls, matched by age and sex, from an ongoing cohort study of lifestyle and cancer in a rural population of Northeast Thailand. Oncogenic HPV types were present in 10.8% of control women and in 31/33 of the carcinoma cases, corresponding to an odds ratio of 130.6 (95% CI 11.7-1457.0). There was no significant difference in risk between prevalent cancer cases (diagnosed less than 3 months after HPV testing) and incident cases (diagnosed an average of 2.1 years later). HPV 16 and 18 were the most prevalent oncogenic HPV types present. The results confirm that some two of three of cervical cancer cases in this population of Northeast Thailand are caused by HPV 16 and 18.

Immunocytochemical staining of p16INK4a protein from conventional Pap test and its association with human papillomavirus infection

The p16INK4a protein is immunocytochemically detected in liquid-based (LB) specimens as a diagnostic marker of cervical dysplasia and neoplasia. Its up-regulation is promoted by high-risk human papillomavirus (HR-HPV) infection. We aimed to detect p16INK4a on conventional Papanicolaou (Pap) test (CPT) slides and to determine the relationship between its overexpression and HR-HPV infection. CPT and LB Pap test (LBPT) slides (165 samples of each) were examined by immunocytochemical staining for p16INK4a. After polymerase chain reaction (PCR), HPV-DNA was genotyped by dot blot hybridization. The CPT slides displayed more numerous dispersed squamous cells and LBPT slides had a clearer background. Positive p16INK4a on CPT occurred in 0% (0/30), 52.5% (21/40), 54.3% (19/35), 100% (30/30), and 100% (30/30) in normal, atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesions (LSILs), high-grade SILs (HSILs), and squamous cell carcinomas (SCCs) cases, respectively. LBPT slides showed comparable results but were less sensitive. HPV-DNA was detected in 86.7, 70, 45, 57.14, and 10% in SCCs, HSILs, ASCUS, LSILs, and normal cervical cells, respectively. Because HR-HPV was identified in all HPV+ samples of high-grade dysplasia (HSILs and SCCs) and all positive p16INK4a samples infected with HR-HPV, the association of p16INK4a overexpression with HR-HPV infection was confirmed. This study suggests that immunocytochemical staining of p16INK4a on CPT slides is convenient and cost-effective for cervical cancer screening by the detection of dysplastic cells infected with HR-HPV.

Immunocytochemical detection of p16INK4a protein in scraped cervical cells

OBJECTIVE

To develop an immunocytochemical technique for p16INK4a protein detection in scraped cervical cells for cancer screening.

STUDY DESIGN

We took duplicate cervical scrapes from each participant, the first for a Pap smear and the second for p16INK4a protein detection. From a 50-microL cell suspension prepared from the scrape rinsing, a 10-microL aliquot was dropped in a 5-mm-diameter circle on a glass slide, air dried and fixed in 0.1% formal saline (1 hour) and in 95% ethanol (10 minutes). Using the immunocytochemical technique, slides from 30 samples of each Pap diagnosis class were stained sequentially with mouse monoclonal anti-p16INK4a (primary antibody), biotinylated goat antimouse IgG (secondary antibody), horse-radish peroxidase-labelled streptavidin and 3,3'-diaminobenzidine and mixed hydrogen peroxide, then counterstained with hematoxylin. A positive sample had to contain > or = 3 immunoreactive cells. Results were confirmed by western blot analysis of lysates from the remaining 40 microL of each cervical cell suspension.

RESULTS

Samples were grouped as control (normal cervical cells), mild dysplasia (ASCUS, LSIL) and high abnormality (HSIL, SCC). Using the immunocytochemical technique, > 95% of the positive (SiHa cells) but 0% of the negative controls (human embryonic lung fibroblast cells) showed immunoreactive cells. All slides displayed a clear background without mucus, and positive cells were stained in both the cytoplasm and nucleus. p16INK4a Protein was detected in 17 of 30 (56.67%) ASCUS and 10 of 30 (33.33%) LSIL and increased with the degree of abnormality to 93.33% (28 of 30) and 96.67% (29 of 30) in the HSIL and SCC group, respectively. Normal cervical cells and degenerated malignant cells were nonimmunoreactive. Western blot analysis confirmed similar positive samples in the low-abnormality group, while the whole high-abnormality group was immunoreactive. A sampling error might have caused the 2 HSIL and 1 SCC sample to be negative using our immunocytochemical technique.

CONCLUSION

p16INK4a Protein detection in scraped cervical cells using the immunocytochemical technique correlated with western blot analysis and was nontraumatic and precise. It offers a significant diagnostic adjunct to the Pap test for cervical cancer screening.

Etiology of acute lower respiratory tract infection in children at Srinagarind Hospital, Khon Kaen, Thailand

We investigated the etiology of acute lower respiratory infection (ALRI) in children under 5 admitted to Srinagarind Hospital. The causative bacteria and viruses were determined by hemoculture and viral isolation from blood and nasopharyngeal aspirate samples. Antigens of respiratory syncytial virus (RSV) and Chlamydia trachomatis were detected using EIA. The 74 children less than 5 years of age with ALRI enrolled in our study were diagnosed with pneumonia (75.7%), croup (16.2%), and bronchiolitis (8.1%), respectively. Examination of blood or nasopharyngeal aspirate revealed viral or bacterial infections in 26 and 22 cases, respectively, whereas 5 of the children aged under 1 year (10%) were diagnosed with pneumonia caused by Chlamydia trachomatis. RSV was the most common virus detected (24.3%) and was associated with pneumonia and bronchiolitis, while the parainfluenza virus was the primary cause of croup. In cases of pneumonia, bacterial infections were identified in almost all of the cases: and Streptococcus pneumoniae and Haemophilus influenzae were the most commonly isolated (at 8.9% each). Mixed infections were detected in 8 cases (10.8%). The incidence of RSV infection peaked during the especially warm and cool seasons, whereas the bacterial infections were primarily associated with the relatively cool season. Our study indicates that a combined pneumococcal and Hib vaccine and a RSV vaccine would reduce the high rate of pneumonia in children under 5 years of age in Northeast Thailand.

The relationship of human papillomavirus (HPV) detection to pap smear classification of cervical-scraped cells in asymptomatic women in northeast Thailand

OBJECTIVE

To correlate the detection of human papillomavirus (HPV) with the Pap smear classification of cervical-scraped cells from asymptomatic women living in northeast Thailand.

METHODS

A total of 260 asymptomatic women attending the Obstetrics and Gynecology's Outpatient Clinic, Srinagarind Hospital, Thailand, were interviewed for risk factors and cervical scrapes were taken. The cells were examined by Pap smear for cytological changes and by PCR for HPV DNAs--nononcogenic (HPVs 6 and 11) and oncogenic (HPVs 16, 18 and 33) types. Cervical biopsies were taken from women with abnormal Pap smears for histological examination.

RESULTS

Of the 260 cervical smear samples, the cervical cells were classified as normal and abnormal in 174 and 86, respectively. Twenty-three percent of all samples were positive for overall HPV DNA. HPV DNAs (mostly HPVs 6 and 11) were detected in 21% of normal cells, and the higher detection rate (27%) for HPV DNA in abnormal cells gradually increased in severity from 16% in Class 3 to 35 and 60% in Classes 4 and 5, respectively. Histologically 46, 90 and 100% of HPV detection was associated with CIS, SCC and adenocarcinoma, respectively. Almost all of the HPV DNAs detected were types 16, 18 or 33. There was no significant association between HPV infection and reproduction history, sexual behavior and demographic variables.

CONCLUSION

We speculated that an abnormal Pap smear and the detection of an oncogenic type HPV may indicate the presence of neoplastic cells in asymptomatic woman who might be at risk for the development of cervical cancer.