Prevalence of BRAFV600E Mutation and Human Parvovirus B19 Infection in Thyroid Cancer

Abstract

Background: Thyroid carcinoma, the most prevalent endocrine malignancy, has increased rapidly in recent decades. A single-base substitution in the BRAF gene is identified as the most common genetic event in thyroid carcinoma. Infections with both DNA and RNA viruses can induce chronic inflammatory diseases and cancer. Human parvovirus B19 (B19V) infection has been implicated in thyroid cancer as the most common inflammation of the endocrine system. Objectives: The study aimed to determine the prevalence of the BRAFV600E gene mutation and the presence of B19V infection in malignant and non-malignant thyroid tissue samples. Methods: A cross-sectional study was performed from January 2012 to December 2017 on 108 paraffin-embedded thyroid tissues from patients with thyroid cancer tumor and nodular goiter. After DNA extraction, PCR restriction fragment length polymorphism (PCR-RFLP) and nested PCR assays were used to detect the BRAFV600E gene mutation and B19V DNA in tissue specimens, respectively. To confirm PCR-RFLP reliability, the amplified products were subjected to DNA sequencing. Statistical analysis was performed to determine a possible correlation between the occurrence of BRAFV600E mutations and clinicopathological characteristics, such as tumor subtypes, gender, age, and B19V presence. Results: Overall, BRAFV600E mutation was detected in 77 out of 108 patients (71.3%) using PCR-RFLP, confirmed by DNA sequencing analysis. Using nested PCR, human parvovirus B19 DNA was detected in 14 out of 108 (13%) of the formalin-fixed, paraffin-embedded (FFPE) tissue specimens. Statistical analysis showed a significant difference in the prevalence of the BRAFV600E mutation in thyroid cancer patients when compared with the control group (P ≤ 0.001). Conclusions: Since cytological examinations depend on fine needle aspiration of the thyroid (FNAB) cannot be conclusive; hence it might be suggested that detection of the BRAFV600E gene mutation can be considered as a feasible assay. However, a low detection rate of the B19V DNA in FFPE tissue samples suggests that B19V infection is not associated with thyroid cancer.