Expressional Analysis of Vascular Endothelial Growth Factor A (VEGFA) in Patients with Thyroid Cancer

Abstract

Carcinogenesis of cells in the tissues of the thyroid gland leads to formation of thyroid cancer. Development of thyroid cancer involves a multifactorial route that is associated with various risk factors, such as exposure to ionizing radiation in early life, genetic predisposition, iodine intake in diet, environmental carcinogens, and genetic instability etc. These different risk factors can lead to a variety of mutations within proto-oncogenes and activating them as oncogenes. VEGF-A is one such proto-oncogene that plays a key role in tumour angiogenesis. The purpose of this study was to explore the association of respective gene with thyroid cancer pathogenesis. To test the hypothesis that VEGF-A expression patterns has influence in thyroid cancer metastasis and sustenance, a population based case-control study was conducted in 77 thyroid tumour samples along with adjacent control tissue samples. Quantitative real time-PCR (qPCR) was used for mRNA expression variation in VEGF-A gene. Expression analysis showed that VEGF-A expression level was very highly significantly downregulated (p<0.001) in tissues of thyroid cancer compared to adjacent control tissues. Non-significant (p>0.05) increase of VEGF-A expression mRNA with age group, gender, and advanced stages of T, N, and M stages was also observed in thyroid cancer samples compared to the controls. However, when compared for the expression levels relative to the proliferation marker, Ki67, very highly significant upregulation in thyroid tumour samples was seen in the same study cohort. Based on these results we can conclude that VEGF-A under expression at transcriptional level may be playing a key role in progression and/or spread of thyroid cancer.