TERT Promoter Mutations and Their Impact on Gene Expression Profile in Papillary Thyroid Carcinoma.

BACKGROUND: Telomerase reverse transcriptase promoter (TERTp) mutations are related to a worse prognosis in various malignancies, including papillary thyroid carcinoma (PTC). Since mechanisms responsible for the poorer outcome of TERTp(+) patients are still unknown, searching for molecular consequences of TERTp mutations in PTC was the aim of our study. METHODS: The studied cohort consisted of 54 PTCs, among them 24 cases with distant metastases. BRAF V600E, RAS, and TERTp mutational status was evaluated in all cases. Differences in gene expression profile between TERTp(+) and TERTp(-) PTCs were examined using microarrays. The evaluation of signaling pathways and gene ontology was based on the Gene Set Enrichment Analysis. RESULTS: Fifty-nine percent (32/54) of analyzed PTCs were positive for at least one mutation: 27 were BRAF(+), among them eight were TERTp(+), and 1 NRAS(+), whereas five other samples harbored RAS mutations. Expression of four genes significantly differed in BRAF(+)TERTp(+) and BRAF(+)TERTp(-) PTCs. Deregulation of pathways involved in key cell processes was observed. CONCLUSIONS: TERTp mutations are related to higher PTC aggressiveness. CRABP2 gene was validated as associated with TERTp mutations. However, its potential use in diagnostics or risk stratification in PTC patients needs further studies.

Coexistence of TERT Promoter Mutations and the BRAF V600E Alteration and Its Impact on Histopathological Features of Papillary Thyroid Carcinoma in a Selected Series of Polish Patients.

TERT promoter (TERTp) mutations are important factors in papillary thyroid carcinomas (PTCs). They are associated with tumor aggressiveness, recurrence, and disease-specific mortality and their use in risk stratification of PTC patients has been proposed. In this study we investigated the prevalence of TERTp mutations in a cohort of Polish patients with PTCs and the association of these mutations with histopathological factors, particularly in coexistence with the BRAF V600E mutation. A total of 189 consecutive PTC specimens with known BRAF mutational status were evaluated. TERTp mutations were detected in 8.5% of cases (16/189) with the C228T mutation being the most frequent. In six of the PTC specimens (3.2%), four additional TERTp alterations were found, which included one known polymorphism (rs2735943) and three previously unreported alterations. The association analysis revealed that the TERTp hotspot mutations were highly correlated with the presence of the BRAF V600E mutation and their coexistence was significantly associated with gender, advanced patient age, advanced disease stage, presence of lymph node metastases, larger tumor size, and tumor-capsule infiltration. While correlations were identified, the possibility of TERTp mutations being key molecular modulators responsible for PTC aggressiveness requires further studies.

Oral and oropharyngeal papillomas are not associated with high-risk human papillomavirus infection.

The role of different types of human papillomavirus (HPV) in the development of oral and oropharyngeal papillomas remains unclear. High-risk HPV (HR-HPV) was shown to be involved in the pathogenesis of significant proportion of squamous cell carcinomas of the oropharynx. In this study, we hypothesized that in some oropharyngeal papillomas, low-risk HPV (LR-HPV) and HR-HPV infection could co-exist, similar to what is observed in genital warts, and thus contribute to the elevated risk of malignancy. To test this hypothesis, we used real-time PCR to assess the presence of HPV DNA of 16 types (2 LR-HPV and 14 HR-HPV), in 75 formalin-fixed and paraffin-embedded histopathological samples of oral and oropharyngeal papillomas and in 57 squamous cell carcinomas from the same regions. We investigated the biological activity of HPV by demonstrating accumulation of P16(INK4A) protein in the viral-infected tissue samples. The presence of the LR-HPV genome from the HPV6 or HPV11 types was confirmed in 42 (56%) papillomas and in no carcinomas. HPV6/HPV11 co-infection was detected in 17 (22.7%) of the papillomas. HR-HPV DNA presence and HR-HPV activity hallmarks were not observed in any of the investigated papillomas. Thus, a causative role for HR-HPV or its contribution to LR/HR-HPV co-infection in the pathogenesis of oral or oropharyngeal papillomas is unlikely. Additionally, HR-HPV and LR-HPV infections seem to be mutually exclusive in papillomas and squamous cell carcinomas of the oral cavity and oropharynx.