Evaluation of telomere length and telomerase activity in neurofibromatosis (NF1) tumors

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease that occurs with an incidence of 1/2500 in society and gives symptoms such as milk coffee spots on the skin, freckles, benign tumors of different sizes called neurofibromas and malignant peripheral nerve sheat tumors (MPNST). In addition, tumor development may happen in the spinal cord, cranial nerves, and brain, also bone deformities such as scoliosis. Clinical studies show a lot of variability. One of the views about these clinical variations is the existence of modifier factors in the NF1 gene. One of these modifying factors is telomeres, and another is microRNAs (miRNA). Telomere length and telomerase activity have been found to be associated with many diseases today. miRNAs, which are one of the small non-coding RNAs, are RNAs that function as post-transcriptional regulators of gene expression. miRNAs have been found to play an important role in cancer, including tumors associated with NF1. In this thesis study, it was aimed to evaluate telomere lengths, telomerase activities and miRNA gene expressions in cutaneous and plexiform neurofibroma tumor tissues obtained from NF1 patients according to the control tissue. For this purpose, 11 freshly frozen tissues were selected and telomere length, telomerase activity and gene expression of 19 selected miRNAs were evaluated by quantitative real-time PCR method in these tissues. According to the results of the analysis, shortening in telomere length, decrease in telomerase activity and high expression in miRNA analysis were observed in plexiform neurofibroma tumor tissues compared to control tissues. Differences in telomere length, telomerase activity and miRNA expression levels were also observed in cutaneous neurofibroma tumor tissues compared to control tissues. Any changes in telomere length and telomerase activity may affect disease progression. It may indicate that telomerase activity and TERT expression level are potential markers for high-grade malignancy in NF1 patients.