Papillary Thyroid Carcinoma Tissue miR-146b, -21, -221, -222, -181b Expression in Relation with Clinicopathological Features.

We analyzed miR-146b, miR-21, miR-221, miR-21, and miR-181b in formalin fixed paraffin-embedded papillary thyroid carcinoma (PTC) tissue samples of 312 individuals and evaluated their expression relationship with clinicopathological parameters. A higher expression of miR-21 was related to unifocal lesions (p < 0.011) and autoimmune thyroiditis (0.007). miR-221, miR-222 expression was higher in the PTC tissue samples with extrathyroidal extension (p = 0.049, 0.003, respectively). In a group of PTC patients with pT1a and pT1b sized tumors, the expression of miR-146b, miR-21, miR-221, and miR-222 in PTC tissue samples was lower than in patients with pT2, pT3, and pT4 (p = 0.032; 0.0044; 0.003; 0.001; 0.001, respectively). Patients with lymph node metastases had higher expression of miR-21, -221, -222, and -181b (p < 0.05). A high expression of miR-146b, miR-21, miR-221 panel was associated with decreased overall survival (OS) (Log rank p = 0.019). Univariate analysis revealed that presence of metastatic lymph nodes and high expression of miR-146b, miR-21, and miR-221 panels were associated with increased hazard of shorter OS. After multivariate analysis, only sex (male) and age (≥55 years) emerged as independent prognostic factors associated with shorter OS (HR 0.28 (95% CI 0.09-0.86) and HR 0.05 (95% CI 0.01-0.22), respectively). In conclusion, 5 analyzed miRs expression have significant relations to clinicopathologic parameters so further investigations of these molecules are expedient while searching for prognostic PTC biomarkers.

Plasma-Derived miRNA-222 as a Candidate Marker for Papillary Thyroid Cancer.

We analyzed five miRNA molecules (miR-221; miR-222; miR-146b; miR-21; miR-181b) in the plasma of patients with papillary thyroid cancer (PTC), nodular goiter (NG) and healthy controls (HC) and evaluated their diagnostic value for differentiation of PTC from NG and HC. Preoperative PTC plasma miRNA expression (n = 49) was compared with plasma miRNA in the HC group (n = 57) and patients with NG (n = 23). It was demonstrated that miR-221; miR-222; miR-146b; miR-21 and miR-181b were overexpressed in preoperative PTC plasma samples compared to HC (p < 0.0001; p < 0.0001; p < 0.0001; p < 0.0001; p < 0.002; respectively). The upregulation in tumor tissue of these miRNAs was consistent with The Cancer Genome Atlas Thyroid Carcinoma dataset. A significant decrease in miR-21; miR-221; miR-146b and miR-181b expression was observed in the plasma of PTC patients after total thyroidectomy (p = 0.004; p = 0.001; p = 0.03; p = 0.036; respectively). The levels of miR-222 were significantly higher in the preoperative PTC compared to the NG group (p = 0.004). ROC curve (receiver operating characteristic curve) analysis revealed miR-222 as a potential marker in distinguishing PTC from NG (AUC 0.711; p = 0.004). In conclusion; circulating miR-222 profiles might be useful in discriminating PTC from NG.

Association of MicroRNA Expression and BRAFV600E Mutation with Recurrence of Thyroid Cancer.

Many miRNAs and cancer-related mutations have been proposed as promising molecular markers of papillary thyroid carcinoma (PTC). However, there are limited data on the correlation between miRNA expression, BRAFV600E mutation, and PTC recurrence. Therefore, to evaluate the potential of BRAFV600E mutation and five selected miRNAs (-146b, -222, -21, -221, -181b) in predicting PTC recurrence, these molecular markers were analyzed in 400 formalin-fixed, paraffin-embedded PTC tissue specimens. The expression levels of miRNAs were measured using qRT-PCR. It was demonstrated that expression levels of all analyzed miRNAs are significantly higher in recurrent PTC than in non-recurrent PTC (p < 0.05). Moreover, higher expression levels of miR-146b, miR-222, miR-21, and miR-221 were associated with other clinicopathologic features of PTC, such as tumor size and lymph node metastases at initial surgery (p < 0.05). No significant differences in the frequency of BRAFV600E mutation in recurrent PTC and non-recurrent PTC were determined. Our results suggest that miRNA expression profile differs in PTC that is prone to recurrence when compared to PTC that does not reoccur after the initial surgery while BRAFV600E mutation frequency does not reflect the PTC recurrence status. However, the prognostic value of the analyzed miRNAs is rather limited in individual cases as the pattern of miRNA expression is highly overlapping between recurrent and non-recurrent PTC.

Different DNA methylation pattern of HPV16, HPV18 and HPV51 genomes in asymptomatic HPV infection as compared to cervical neoplasia.

Epigenetic alterations of human papillomavirus (HPV) genome play an important role in virus life cycle and carcinogenic progression. The aim of the current study was to investigate the correlation between the grade of cervical pathology and DNA methylation status within the L1 gene and the long control region (LCR) of HPV16, HPV18 and HPV51. HPV genomes were analyzed using bisulfite DNA modification procedure with the subsequent amplification of target DNA regions and sequencing. A collection of 202 cervical specimens was analyzed: 157 HPV16-positive specimens, 21 HPV18-positive specimens and 24 HPV51-positive specimens. This study revealed that methylation of CpG was significantly more prevalent in L1 gene as compared to LCR region of all three studied HPV types and the degree of DNA methylation level correlated with the severity of cervical neoplasia. An increased DNA methylation level of HPV16 promoter region in case of cervical cancer was determined.

Integration of human papillomavirus type 16 in cervical cancer cells.

Cervical cancer remains an important cause of women morbidity and mortality. The progression of cervical pathology correlates with the HPV integration into the host genome. However, the data on the viral integration status in cervical dysplasias are controversial. The aim of the current study was to evaluate the status of HPV integration in two types of cervical pathology - invasive and non invasive cervical cancer (e.g. carcinoma in situ). 156 women were included in the study: 66 women were diagnosed with invasive cervical cancer (CC) and 90 with non invasive cervical cancer (carcinoma in situ, CIS). 74.2% [95% PI: 63.64÷84.76] of specimens collected from women with diagnosed CC and 85.6% [95% PI: 85.53÷92.85] of CIS specimens were positive for HPV. The most prevalent HPV genotype in both groups was HPV16. To evaluate HPV integration, three selected HPV16 E2 gene fragments were analyzed by PCR. In the majority of CC and CIS specimens the amplification of all three HPV16 E2 gene fragments was observed. The episomal HPV16 form was detected in the majority of CC and CIS specimens. The deletion of all three HPV16 E2 gene fragments was detected in 9.4% of CC specimens and 2.2% of CIS specimens. Finally, integration status could not be used as diagnostical additional test to distinguish between invasive and non invasive cervical cancer.

Distribution of human papillomavirus type 16 variants in Lithuanian women with cervical cancer.

BACKGROUND AND OBJECTIVE: Cervical cancer usually is caused by HPV 16. However, HPV 16 varies within type; different genotypes are described as prototype or variants. Prevalence of different variants differ according the geographic regions and has an unequal impact for cervical cancer development. Our study aimed to identify which variant of HPV 16 was most prevalent in biological samples taken from Lithuanian women with cervical cancer. MATERIALS AND METHODS: A total of 122 HPV 16 positive cervical samples (invasive cancer and cervical intraepithelial neoplasia) were investigated and sequenced to identify different variants. HPV 16 was detected using type specific PCR, exact sequence of the virus was obtained by viral DNA sequencing. RESULTS: Adequate HPV sequence was detected in 106 cases from 122 (86.9% of all cases). After histological confirmation, 96 cases were included in the final analysis. In 33 cases (34.4%) HPV 16 prototype was detected; in 50 cases (52.1%), L83V variant; and in remaining 13 cases (13.5%), multivariant of HPV 16. The frequency of L83V variant in invasive cancer and carcinoma in situ samples was the same (66.7% and 62.0%, respectively; P=0.696). Of analyzed multivariants, 10 were attributed to the European phylogenetic line; 1, to the North American, and 1, to the Asian-American. One sample was not attributed to any of the known phylogenetic lines. CONCLUSIONS: The European HPV 16 L83V variant is usually associated with high risk of cervical cancer among women. However, statistically significant difference was not achieved when comparing difference of L83V variants between investigated groups and in HPV 16 L83V variant and prototype distribution in CIN3/Ca in situ and cancer.

Studies on the prevalence of oncogenic HPV types among Lithuanian women with cervical pathology.

Human papillomavirus (HPV) is the main cause of cervical cancer. Therefore, the detection of oncogenic HPV types is important in predicting the risk of cervical cancer. The aim of the current study was to estimate the prevalence of 16 carcinogenic and potentially carcinogenic HPV types in the study group of Lithuanian women with various grades of cervical pathology in comparison to healthy women. A total of 824 cervical specimens were investigated for HPV DNA: 547 specimens of women with abnormal cytology and 277 specimens of healthy women. Cytological diagnosis was confirmed by histology. For the detection of HPV infection, HPV DNA was amplified by PCR using three different primer systems. HPV DNA was detected in 67.6% of specimens collected from women with abnormal cytology and 24.2% of specimens collected from healthy women. The frequency of HPV-positive specimens correlated with the severity of cervical pathology: it ranged from 50.0% in the subgroup of atypical squamous cells to 80.6% in cervical cancer. In cases confirmed by histology the frequency of HPV-positive specimens ranged from 68.6% in the subgroup of cervical intraepithelial neoplasia grade 1 to 89.2% in cervical intraepithelial neoplasia grade 3 or carcinoma in situ. HPV DNA-positive samples were further investigated for the presence of 16 HPV types by multiplex PCR. The most common HPV type was HPV 16 (detected in 42.3% of HPV-positive specimens) followed by HPV 31 (10.1%), HPV 33 (8.2%), and HPV 56 (5.7%). In contrast, the frequency of HPV 18 was lower as compared to other countries.

The use of recombinant pseudotype virus-like particles harbouring inserted target antigen to generate antibodies against cellular marker p16INK4A.

Protein engineering provides an opportunity to generate new immunogens with desired features. Previously, we have demonstrated that hamster polyomavirus major capsid protein VP1-derived virus-like particles (VLPs) are highly immunogenic and can be employed for the insertion of foreign epitopes at certain surface-exposed positions. In the current study, we have designed pseudotype VLPs consisting of an intact VP1 protein and VP2 protein fused with the target antigen--cellular marker p16(INK4A)--at its N terminus. Both proteins coexpressed in yeast were self-assembled to pseudotype VLPs harbouring the inserted antigen on the surface. The pseudotype VLPs were used for generation of antibodies against p16(INK4A) that represents a potential biomarker for cells transformed by high-risk human papillomavirus (HPV). The pseudotype VLPs induced in immunized mice a strong immune response against the target antigen. The antisera raised against pseudotype VLPs showed specific immunostaining of p16(INK4A) protein in malignant cervical tissue. Spleen cells of the immunized mice were used to generate monoclonal antibodies against p16(INK4A) protein. The specificity of antibodies was proven by the immunostaining of HPV-transformed cells. In conclusion, the current study demonstrates the potential of pseudotype VLPs with inserted target antigen as a new type of immunogens to generate antibodies of high diagnostic value.