Investigation of telomerase reverse transcriptase (TERT) gene promoter mutations in colorectal cancer

Among the different types of malignancies, colorectal cancer (CRC) is the third most common and also it is in the second place of the leading causes of cancer death in both men and women globally. In most of the cancer cells, telomere length is preserved by telomerase. Hence, telomere length and telomerase activity are essential for cancer initiation and the tumors' survival. In human, the promoter region of the TERT gene is considered to be the most important regulatory element for telomerase expression. TERT promoter mutations, such as the C228T and C250T, have been identified as important genetic events activating telomerase in different types of cancer. Consequently, these mutations may work as important markers in malignancies. In our study and for the first time in Turkey, the mutation analysis was performed in 43 pairs of tumor and matching normal tissues obtained from Turkish patients with colorectal cancers to determine the presence of mutations in the promoter region of the TERT gene and to investigate any possible association of the relevance of TERT promoter mutations to colorectal cancer. The mutations in the promoter region of TERT gene were examined in colorectal tumors and normal adjacent tissues by the Sanger-Bidirectional Sequencing technique. No mutations were observed in any of the specimens examined. We concluded from these results that the mutations in the promoter of the TERT gene may not be involved in CRC carcinogenesis and further investigations need to be performed for a stronger understanding.