The E6 gene polymorphism of Human papillomavirus 16 in relation to the risk of cervical cancer in Tunisian women

Human papillomavirus type 16 (HPV-16) is the most prevalent HPV type worldwide and in Tunisia and the major carcinogenic HPV type found in cervical precancers and cancers. Previous studies have reported that genetic diversity of HPV16-E6 oncoprotein might be associated with cervical intraepithelial neoplasia progression. In this study we aimed to investigate the prevalence of HPV-16 E6 variants in precancerous lesions in Tunisian population to assess potential correlation with disease severity. Positive HPV cervical samples were obtained from the Laboratory of Anatomy Pathology of Pasteur Institute of Tunis. Cytological study was performed to identify cervical precancerous lesions. HPVs were typed using Reverse Line Hybridization. Only samples with HPV-16 single infection were selected for HP16-E6 genetic diversity investigation. HPV-16 E6 gene amplification was performed by PCR using specific primers and sequenced by Sanger Sequencing. The multiple alignment of generated sequences was performed using MEGAX software. Phylogenetic tree was constructed using Maximum Likehood method. The ternary complex of E6, E6AP and p53 core domain was used to perform in silico point mutations and thermodynamic calculations to assess stability and binding affinity. Genetic analysis of Tunisian E6-HPV16 sequences showed the presence of three lineages: European (A), African (C) and Asian American (D). Interestingly, the EUR variants were identified as the dominant lineage of HPV-16 and HPV-16 E6 350 G (L83V) was the most detected mutation in precancerous lesions. Modelling data showed that African variants induced the largest destabilizing effect on E6 structure and decreasing thereby in the affinity toward E6AP. Therefore, women infected with European variants are associated with low and high intraepithelial lesions. The findings give useful information for personalized decision algorithms of intra-epithelial cervical neoplasia in Tunisian women.

Distribution of high-risk human papillomavirus in women with ASC-US or LSIL in Tunisian women: Place of HPV testing for women triage in Tunisia

The present study aimed to evaluate the distribution of oncogenic HPVs in Tunisian women diagnosed with ASC-US or LSIL in order to highlight the importance of HPV testing in the management of women with minor cytological lesions. The study involved 213 cervical samples from women aged from 18 to 82 years and diagnosed with ASC-US or LSIL. HPV detection and genotyping was performed by nested PCR followed by reverse Line Blotting. HPV DNA was identified in 161 cases (76.3%). Oncogenic HPV genotypes were detected in 53.1% of cases. The most frequent high-risk genotypes in this study were HPV16 (28.8%) followed by: HPV51 (9.6%), HPV18, HPV31 HPV56 (7.1%) and HPV45 (5.1%). Thus, 24 % of studied women were not infected by HPV and about 47% of infections are without oncogenic HPV. These results highlight the value of HPV testing in the decision algorithm of management of minor abnormalities lesions.

TLR9 and Glioma: Friends or Foes?

Toll-like receptor 9 (TLR9) is an intracellular innate immunity receptor that plays a vital role in chronic inflammation and in recognizing pathogenic and self-DNA in immune complexes. This activation of intracellular signaling leads to the transcription of either immune-related or malignancy genes through specific transcription factors. Thus, it has been hypothesized that TLR9 may cause glioma. This article reviews the roles of TLR9 in the pathogenesis of glioma and its related signaling molecules in either defending or promoting glioma. TLR9 mediates the invasion-induced hypoxia of brain cancer cells by the activation of matrix metalloproteinases (2, 9, and 13) in brain tissues. In contrast, the combination of the TLR9 agonist CpG ODN to radiotherapy boosts the role of T cells in antitumor effects. The TLR9 agonist CpG ODN 107 also enhances the radiosensitivity of human glioma U87 cells by blocking tumor angiogenesis. CpG enhances apoptosis in vitro and in vivo. Furthermore, it can enhance the antigen-presenting capacity of microglia, switch immune response toward CD8 T cells, and reduce the number of CD4CD25 Treg cells. CpG ODN shows promise as a potent immunotherapeutic drug against cancer, but specific cautions should be taken when activating TLR9, especially in the case of glioblastoma.

New insights in the clinical implication of HOXA5 as prognostic biomarker in patients with colorectal cancer

BACKGROUND

Homeobox A5 (HOXA5) is a member of the HOX protein family which is involved in several carcinogenesis pathways, and is dysregulated in many cancer types. However, its expression and function in human colorectal cancer (CRC) is still largely unknown.

OBJECTIVE

This study aimed to evaluate HOXA5 expression in Tunisian patients with CRC in order to define new potential biomarker.

METHODS

An immunohistochemical labeling using an HOXA5 antibody was performed on 85 formalin fixed paraffin embedded specimens from patients with CRC. Six normal colon mucosa cases were used as controls.

RESULTS

HOXA5 expression showed a cytoplasmic staining in both tumor and stromal/endothelial cells. Loss or low HOXA5 expression was seen in tumor cells in 74/85 cases (87.06%) and in stromal/endothelial cells, in 77/85 (90.59%). In control group of normal colon mucosa HOXA5 was moderately expressed in all the cases. The abnormal expression, was significantly associated to lymph nodes metastasis in tumor cells (p= 0.043) and in stromal/endothelial cells (p= 0.024).

CONCLUSION

HOXA5 immunostaining results suggest the valuable role of this protein in colorectal carcinogenesis. Moreover, the association of lymph node metastasis to HOXA5 abnormal expression underlies its crucial role in colorectal cancer dissemination and prognosis.

Dysregulated PDGFR alpha expression and novel somatic mutations in colorectal cancer: association to RAS wild type status and tumor size

Background

Platelet derived growth factor receptor alpha (PDGFRα) has been considered as a relevant factor in tumor proliferation, angiogenesis and metastatic dissemination. It was a target of tyrosine kinase (TK) inhibitors emerged in the therapy of diverse cancers. In colorectal cancer, the commonly used therapy is anti-epithelial growth factor receptor (EGFR). However, both RAS mutated and a subgroup of RAS wild type patients resist to such therapy. The aim of this study is to investigate PDGFRα protein expression and mutational status in colorectal adenocarcinoma and their association with clinicopathological features and molecular RAS status to provide useful information for the identification of an effective biomarker that might be implicated in prognosis and treatment prediction.

Methods

Our study enrolled 103 formalin fixed paraffin-embedded (FFPE) colorectal adenocarcinoma. PDGFRα expression was investigated by immunohistochemistry (IHC). Hotspot exon 18 of PDGFRA was studied by PCR followed by Sanger sequencing and RAS status was determined by real time quantitative PCR. Thirteen normal colon tissues were used as negative controls.

Results

PDGFRα staining was detected in the cytoplasm of all tissues. Low expression was observed in all normal colon mucosa. In adenocarcinoma, 45% (45/100) of cases showed PDGFRα overexpression. This overexpression was significantly associated with mutations in exon 18 (P = 0.024), RAS wild type status (P < 10^–3), tumor diameter (P = 0.048), whereas there was no association with tumor side (P = 0.13) and other clinicopathological features.

Conclusion

Overexpression of PDGFRα in adenocarcinoma suggests its potential role in tumor cells growth and invasion. The association between PDGFRα overexpression in both tumor and stromal adenocarcinoma cells with RAS wild type status suggests its potential role in anti-EGFR therapy resistance and the relevance of using it as specific or adjuvant therapeutic target.

Expression of Toll-like receptor 9 increases with progression of cervical neoplasia in Tunisian women--a comparative analysis of condyloma, cervical intraepithelial neoplasia and invasive carcinoma

Toll-like receptors (TLRs) are expressed in immune and tumor cells and recognize pathogen-associated molecular patterns. Cervical cancer (CC) is directly linked to a persistent infection with high risk human papillomaviruses (HR-HPVs) and could be associated with alteration of TLRs expression. TLR9 plays a key role in the recognition of DNA viruses and better understanding of this signaling pathway in CC could lead to the development of novel immunotherapeutic approaches. The present study was undertaken to determine the level of TLR9 expression in cervical neoplasias from Tunisian women with 53 formalin-fixed and paraffin-embedded specimens, including 22 samples of invasive cervical carcinoma (ICC), 18 of cervical intraepithelial neoplasia (CIN), 7 of condyloma and 6 normal cervical tissues as control cases. Quantification of TLR9 expression was based on scoring four degrees of extent and intensity of immunostaining in squamous epithelial cells. TLR9 expression gradually increased from CIN1 (80% weak intensity) to CIN2 (83.3% moderate), CIN3 (57.1% strong) and ICC (100% very strong). It was absent in normal cervical tissue and weak in 71.4% of condyloma. The mean scores of TLR9 expression were compared using the Kruskall-Wallis test and there was a statistical significance between normal tissue and condyloma as well as between condyloma, CINs and ICC. These results suggest that TLR9 may play a role in progression of cervical neoplasia in Tunisian patients and could represent a useful biomarker for malignant transformation of cervical squamous cells.

Type-Specific Human Papillomavirus Distribution in Invasive Squamous Cervical Carcinomas in Tunisia and Vaccine Impact

BACKGROUND

High risk human papillomaviruses (HPVs) are the leading cause of cervical cancer (CC) and Pap smear screening has not been successful in preventing CC in Tunisia. HPV vaccination that targets HPV16 and 18 offers a new efficient prevention tool. Identification of HPV types in CC is thus essential to determine the impact of HPV vaccine implementation. The aim of this study is to provide specific data from Tunisia.

MATERIALS AND METHODS

A total of 89 histological confirmed paraffin embedded samples isolated from patients with CC diagnosed between 2001 and 2011 were collected from five medical centres from Northern and Southern Tunisia. HPV DNA was detected using a nested PCR (MY09/MY11-GP5+/GP6+) and genotyping was assessed using a reverse blot line hybridisation assay that enables the detection of 32 HPV types.

RESULTS

HPV DNA was detected in all samples. Twelve high risk types were detected; HPV16 and/or 18 were predominant, accounting together for 92.1% of all the CC cases (HPV16: 83.1%). Single infections accounted for 48.8% of the cases and were mostly linked to HPV 16 (32.6%) and less frequently to HPV 18 (2.4%). The other high risk HPV single infections were linked to HPV 35 (4.6%), 45 (4.6%), 58 (2.3%) and 59 (2.3%). Multiple infections with mixing of 2 to 4 genotypes predominately featrued HPV16 and/or 18 with HPV 35 and 45 (96.6 %) and less frequently with HPV 59, 40, 66, 73 and 58. There was no statistically significant variation in the relative distribution of HPV types with age.

CONCLUSIONS

These results strongly indicate that prophylactic HPV vaccines can have a major impact in preventing CC in Tunisia.

The role of Toll-like receptor 9 in gynecologic cancer

Toll-like receptor 9 (TLR9) plays a major role in the fight against DNA viruses infections. Despite its antitumor properties, inappropriate activation of TLR9 during chronic inflammation may cause the activation of transcription factors inducing pro-cancerous activities. Thus, the relationship between TLR9 and cancer remains highly confrontational especially in gynecological cancers and cervical cancer induced by viruses. In this review, we focus on the beneficial and detrimental role of TLR9 in gynecological carcinogenesis. TLR9 contributes to tumor regression by inducing cytotoxic T cell response (CTL), reducing the numbers of myeloid-derived suppressor cells (MDSCs), the tumor-associated macrophages (TAMs) and the regulatory T cells (T regs). It can however, also promote tumor progression and invasiveness of cervical tissue. Therefore, the dichotomous role of TLR9 needs to be carefully investigated in the setting of neoplastic disease.

[Screening of cervical HPV infection at the reproductive health centre of ariana]

Cervical cancer is the leading cause of cancer mortality among women in developing countries. Over 99 per cent of cases are linked to genital infection with Human Papillomaviruses (HPVs), which are the most common sexually-transmitted viruses worldwide and infect an estimated 660 million people. In light of the advances of the development of HPV vaccines in the world, the challenges to introducing and sustaining such vaccines in the public sector are faced by our countries, generating the need of understanding the local epidemiology of the disease. aim : This study aims to obtain some relevant data on local disease burden in a big health care centre of Tunis. method : In this study, 133 healthy Tunisian women are screened for HPV infection with detection of 37 genotypes. Samples are collected on dry cotton swabs and genotyping use PCR and linear array assay. results : 7,8 % of women were infected and HPV 16 was the only High-risk genotype encountered. 62,5% of infected women doesn't show any cytological abnormality on pap smears. Low and High grade epithelial lesions were associated with HPV 16. Conclusion : There is currently few and sparse data in Tunisia. This work represents to our knowledge the first HPV cervical infection screening study in Tunisia in a basic health centre. The most relevant data is the High frequency of High risk HPV infections related to HPV 16. More than a half of cervical smears in infected women does not show any cytological abnormality and thus, pap smear screening is not appropriated to detect this infection.

Selective mineral elements concentration of the intestinal mucosa role of the lysosomes of duodenal enterocytes in the handling of mineral elements after intragastric administration

Intragastric administration to rats of four soluble lanthanides cerium, lanthanum, europium, thulium and of three soluble elements of group IIIA aluminium, indium and gallium has been shown in previous studies. In this work two new rare earths gadolinium and terbium were studied using the same protocols and the same methods (transmission electron microscopy and ion microanalysis). among the previously studied elements, some of them were administered simultaneously on the one hand aluminium and indium, and on the other hand, lanthanum and cerium. These metals were looked for in intestinal mucosa, liver and kidney. The results showed: a) gadolinium and terbium were selectively concentrated in lysosomes of duodenal enterocytes, precipitated as non-soluble phosphate salts and eliminated with the cell's turn-over in less than 48 hr; b) Administered simultaneously, they precipitated in the same lysosome. c/ none of them was observed in the liver or kidney even with high dose. This study brings up to nine the number of elements forming a non-soluble phosphate salts, explaining their precipitation in lysosomes. None of them have a physiological role, two are toxic (aluminium and indium). This rapid intralysosomal concentration is an efficient mechanism which limits the diffusion of the foreign substances through the digestive barrier, then permits their elimination along with the cytoptose phenomenon in the intestinal lumen.

[Lanthanides and microanalysis. Effects of oral administration of two lanthanides: ultrastructural and microanalytical study]

The subcellular localization of cerium and lanthanum in the intestinal mucosa was studied after oral administration of cerium chloride or lanthanum chloride or lanthanum chloride followed 30 minutes after of cerium chloride to young adults Wistar rats. Two methods of observation and microanalysis were used. The transmission electron microscopy revealed the presence of dense electron granulations in the lysosmes of the duodenum enterocyte, when these elements were administrated simultaneously. The ion mass microanalysis permits to detect the presence of La and Ce as bright points outlining the intestinal villi. These points correspond to the lysosomes containing the granulations previously described. These granulations are formed by the cerium and the lanthanum associated to the phosphor and forming probably insoluble salts of Ce/La phosphate.