Gene 540 (2014) 266–267
Contents lists available at ScienceDirect
Gene journal homepage: www.elsevier.com/locate/gene
Letter to the Editor The absence of TERT promoter mutations in primary gastric cancer
Dear Editor, Telomerase activation through the induction of telomerase reverse transcriptase (TERT) is an essential step in malignant transformation, and widely occurs in various types of cancer including gastric cancer (Daniel et al., 2012). The primary determinant for the cancer-specific telomerase activation is the transcriptional de-repression of the TERT gene (Daniel et al., 2012). The regulatory mechanism underlying TERT transcription in oncogenesis has been extensively studied for many years, but remains incompletely understood. The somatic TERT promoter mutations named C228T and C250T have recently been identified in various human malignancies, and these mutations create de novo ETS1 binding motifs that stimulate TERT transcription and enhance telomerase activity (Horn et al., 2013; Huang et al., 2013). Huang et al. found the C228T mutation in 1 of 12 gastric cancer cell lines, indicating the presence of this genetic event in gastric cancer (Huang et al., 2013). However, it is currently unclear whether the TERT promoter mutation also occurs in primary gastric cancer. To address this issue, we sequenced the TERT promoter region in primary tumors derived from 200 patients with gastric cancer. The patients' clinical and histopathological characteristics are listed in Table 1. Genomic DNA was extracted from tumor specimens, and the TERT core promoter region was PCR-amplified with the specific primers as described (Liu et al., 2013). Sanger sequencing was then performed and analyzed. Two thyroid cancer-derived cell lines SW1736 (carrying C228T) and U-hth 74 (carrying C250T) were included as positive controls. We found that none of 200 tumors from patients with gastric cancer were positive for the TERT promoter C228T or C250T mutation. The published data have shown that the TERT promoter mutation occurs most frequently in bladder cancer, melanoma, hepatocellular carcinoma, glioblastoma, aggressive thyroid cancer, etc., while is uncommon in esophageal, lung, prostate, and breast cancer, and hematological malignancies (Horn et al., 2013; Huang et al., 2013; Killela et al., 2013; Liu et al., 2013; Rachakonda et al., 2013). It is unclear what causes such differential mutation incidences among different types of malignancies. Based on our titration experiments, TERT promoter mutations were readily detectable in DNA mixture from 15% TERT promoter-mutant cells and 85% mutation-negative cells using Sanger sequencing, while all the 200 gastric cancer specimens included in the present study had at least 50% cellularity, based on pathological examination. Therefore, our negative finding is unlikely due to the presence of insufficient tumor DNA. Killela et al. hypothesized that the TERT promoter mutation occurred more frequently in tumor types exhibiting high rates of alternating-lengthening of telomere (ALT) (although TERT
Abbreviations: TERT, telomerase reverse transcriptase.
http://dx.doi.org/10.1016/j.gene.2014.02.051 0378-1119/© 2014 Elsevier B.V. All rights reserved.
promoter mutations and ALT are mutually exclusive in a given tumor) (Killela et al., 2013). This may provide a potential explanation for the present finding, because telomere maintenance is predominantly achieved by telomerase activation in gastric cancer (Li et al., 2008). However, in thyroid carcinomas, we observed that this genetic event is age- and shorter telomere-dependent rather than ALT-relevant (Liu et al., 2013). While the present paper was under review, Qu et al. (2013) reported that two out of 268 patients with gastric cancer were identified to have TERT promoter mutations, which suggests the rarity of this genetic event in gastric cancer (b1%), consistent with our finding. Taken together, the TERT promoter mutation is generally not a mechanism contributing to telomerase activation in gastric cancer. Sincerely, Tiantian Liu Xiuming Liang Magnus Björkholm Jihui Jia Dawei Xu Conflict of interest We declare that we have no conflict of interest. Acknowledgments This study was supported by the National Basic Research Program of China (Grant No. 973 Program 2012CB911202), the Adolf H Lundin Charitable Foundation, the Swedish Cancer Society, the Swedish
Table 1 Characteristics of 200 patients with gastric cancer. Age (years) Range (median)
32–84 (60)
Gender Male Female
156 44
Tumor size (diameter, cm) ≤3.0 N3.0
0 200
Histopathology Moderately differentiated adenocarcinoma Moderately to poorly differentiated adenocarcinoma Poorly differentiated adenocarcinoma Mucous adenocarcinoma
29 39 119 13
Metastasis Yes No
171 29
Letter to the Editor
Research Council, the Cancer Society in Stockholm, the Karolinska Institutet Foundations, and the National Natural Science Foundation of China (Nos: 30770118, 30800406, 30972775, 81071721, 81000868, 81371781). The funding sponsors have no roles in the study design, collection, analysis and interpretation of data, discussion and manuscript submission. References Daniel, M., Peek, G.W., Tollefsbol, T.O., 2012. Regulation of the human catalytic subunit of telomerase (hTERT). Gene 498, 135–146. Horn, S., et al., 2013. TERT promoter mutations in familial and sporadic melanoma. Science 339, 959–961. Huang, F.W., et al., 2013. Highly recurrent TERT promoter mutations in human melanoma. Science 339, 957–959. Killela, P.J., et al., 2013. TERT promoter mutations occur frequently in gliomas and a subset of tumors derived from cells with low rates of self-renewal. Proceedings of the National Academy of Sciences of the United States of America 110, 6021–6026. Li, W., et al., 2008. Expression of the full-length telomerase reverse transcriptase (hTERT) transcript in both malignant and normal gastric tissues. Cancer Letters 260, 28–36. Liu, T., et al., 2013. The age- and shorter telomere-dependent TERT promoter mutation in follicular thyroid cell-derived carcinomas. Oncogene. http://dx.doi.org/10.1038/ onc.2013.446. Qu, Y., et al., 2013. Low frequency of TERT promoter mutations in a large cohort of gallbladder and gastric cancers. International Journal of Cancer. http://dx.doi.org/ 10.1002/ijc.28633 (Nov 28). Rachakonda, P.S., et al., 2013. TERT promoter mutations in bladder cancer affect patient survival and disease recurrence through modification by a common polymorphism. Proceedings of the National Academy of Sciences of the United States of America 110, 17426–17431.
Tiantian Liu Department of Microbiology, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Department of Medicine, Division of Haematology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Department of Medicine, Centre for Molecular Medicine (CMM), Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden
267
Xiuming Liang Department of Microbiology, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Magnus Björkholm Department of Medicine, Division of Haematology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Department of Medicine, Centre for Molecular Medicine (CMM), Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Jihui Jia Department of Microbiology, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Corresponding author at: Department of Microbiology, School of Medicine, Shandong University, Jinan 250012, PR China. E-mail address: [email protected]. Dawei Xu Department of Medicine, Division of Haematology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Department of Medicine, Centre for Molecular Medicine (CMM), Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Corresponding author at: CMM, L8:00, Karolinska University Hospital and Karolinska Institutet, SE-171 76 Stockholm, Sweden. E-mail address: [email protected].
9 November 2013
Contents lists available at ScienceDirect
Gene journal homepage: www.elsevier.com/locate/gene
Letter to the Editor The absence of TERT promoter mutations in primary gastric cancer
Dear Editor, Telomerase activation through the induction of telomerase reverse transcriptase (TERT) is an essential step in malignant transformation, and widely occurs in various types of cancer including gastric cancer (Daniel et al., 2012). The primary determinant for the cancer-specific telomerase activation is the transcriptional de-repression of the TERT gene (Daniel et al., 2012). The regulatory mechanism underlying TERT transcription in oncogenesis has been extensively studied for many years, but remains incompletely understood. The somatic TERT promoter mutations named C228T and C250T have recently been identified in various human malignancies, and these mutations create de novo ETS1 binding motifs that stimulate TERT transcription and enhance telomerase activity (Horn et al., 2013; Huang et al., 2013). Huang et al. found the C228T mutation in 1 of 12 gastric cancer cell lines, indicating the presence of this genetic event in gastric cancer (Huang et al., 2013). However, it is currently unclear whether the TERT promoter mutation also occurs in primary gastric cancer. To address this issue, we sequenced the TERT promoter region in primary tumors derived from 200 patients with gastric cancer. The patients' clinical and histopathological characteristics are listed in Table 1. Genomic DNA was extracted from tumor specimens, and the TERT core promoter region was PCR-amplified with the specific primers as described (Liu et al., 2013). Sanger sequencing was then performed and analyzed. Two thyroid cancer-derived cell lines SW1736 (carrying C228T) and U-hth 74 (carrying C250T) were included as positive controls. We found that none of 200 tumors from patients with gastric cancer were positive for the TERT promoter C228T or C250T mutation. The published data have shown that the TERT promoter mutation occurs most frequently in bladder cancer, melanoma, hepatocellular carcinoma, glioblastoma, aggressive thyroid cancer, etc., while is uncommon in esophageal, lung, prostate, and breast cancer, and hematological malignancies (Horn et al., 2013; Huang et al., 2013; Killela et al., 2013; Liu et al., 2013; Rachakonda et al., 2013). It is unclear what causes such differential mutation incidences among different types of malignancies. Based on our titration experiments, TERT promoter mutations were readily detectable in DNA mixture from 15% TERT promoter-mutant cells and 85% mutation-negative cells using Sanger sequencing, while all the 200 gastric cancer specimens included in the present study had at least 50% cellularity, based on pathological examination. Therefore, our negative finding is unlikely due to the presence of insufficient tumor DNA. Killela et al. hypothesized that the TERT promoter mutation occurred more frequently in tumor types exhibiting high rates of alternating-lengthening of telomere (ALT) (although TERT
Abbreviations: TERT, telomerase reverse transcriptase.
http://dx.doi.org/10.1016/j.gene.2014.02.051 0378-1119/© 2014 Elsevier B.V. All rights reserved.
promoter mutations and ALT are mutually exclusive in a given tumor) (Killela et al., 2013). This may provide a potential explanation for the present finding, because telomere maintenance is predominantly achieved by telomerase activation in gastric cancer (Li et al., 2008). However, in thyroid carcinomas, we observed that this genetic event is age- and shorter telomere-dependent rather than ALT-relevant (Liu et al., 2013). While the present paper was under review, Qu et al. (2013) reported that two out of 268 patients with gastric cancer were identified to have TERT promoter mutations, which suggests the rarity of this genetic event in gastric cancer (b1%), consistent with our finding. Taken together, the TERT promoter mutation is generally not a mechanism contributing to telomerase activation in gastric cancer. Sincerely, Tiantian Liu Xiuming Liang Magnus Björkholm Jihui Jia Dawei Xu Conflict of interest We declare that we have no conflict of interest. Acknowledgments This study was supported by the National Basic Research Program of China (Grant No. 973 Program 2012CB911202), the Adolf H Lundin Charitable Foundation, the Swedish Cancer Society, the Swedish
Table 1 Characteristics of 200 patients with gastric cancer. Age (years) Range (median)
32–84 (60)
Gender Male Female
156 44
Tumor size (diameter, cm) ≤3.0 N3.0
0 200
Histopathology Moderately differentiated adenocarcinoma Moderately to poorly differentiated adenocarcinoma Poorly differentiated adenocarcinoma Mucous adenocarcinoma
29 39 119 13
Metastasis Yes No
171 29
Letter to the Editor
Research Council, the Cancer Society in Stockholm, the Karolinska Institutet Foundations, and the National Natural Science Foundation of China (Nos: 30770118, 30800406, 30972775, 81071721, 81000868, 81371781). The funding sponsors have no roles in the study design, collection, analysis and interpretation of data, discussion and manuscript submission. References Daniel, M., Peek, G.W., Tollefsbol, T.O., 2012. Regulation of the human catalytic subunit of telomerase (hTERT). Gene 498, 135–146. Horn, S., et al., 2013. TERT promoter mutations in familial and sporadic melanoma. Science 339, 959–961. Huang, F.W., et al., 2013. Highly recurrent TERT promoter mutations in human melanoma. Science 339, 957–959. Killela, P.J., et al., 2013. TERT promoter mutations occur frequently in gliomas and a subset of tumors derived from cells with low rates of self-renewal. Proceedings of the National Academy of Sciences of the United States of America 110, 6021–6026. Li, W., et al., 2008. Expression of the full-length telomerase reverse transcriptase (hTERT) transcript in both malignant and normal gastric tissues. Cancer Letters 260, 28–36. Liu, T., et al., 2013. The age- and shorter telomere-dependent TERT promoter mutation in follicular thyroid cell-derived carcinomas. Oncogene. http://dx.doi.org/10.1038/ onc.2013.446. Qu, Y., et al., 2013. Low frequency of TERT promoter mutations in a large cohort of gallbladder and gastric cancers. International Journal of Cancer. http://dx.doi.org/ 10.1002/ijc.28633 (Nov 28). Rachakonda, P.S., et al., 2013. TERT promoter mutations in bladder cancer affect patient survival and disease recurrence through modification by a common polymorphism. Proceedings of the National Academy of Sciences of the United States of America 110, 17426–17431.
Tiantian Liu Department of Microbiology, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Department of Medicine, Division of Haematology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Department of Medicine, Centre for Molecular Medicine (CMM), Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden
267
Xiuming Liang Department of Microbiology, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Magnus Björkholm Department of Medicine, Division of Haematology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Department of Medicine, Centre for Molecular Medicine (CMM), Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Jihui Jia Department of Microbiology, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine and Second Hospital, Shandong University, Jinan, PR China Corresponding author at: Department of Microbiology, School of Medicine, Shandong University, Jinan 250012, PR China. E-mail address: [email protected]. Dawei Xu Department of Medicine, Division of Haematology, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Department of Medicine, Centre for Molecular Medicine (CMM), Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden Corresponding author at: CMM, L8:00, Karolinska University Hospital and Karolinska Institutet, SE-171 76 Stockholm, Sweden. E-mail address: [email protected].
9 November 2013
