Gastric Cancer
Copyright ©The Author(s) 2003. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 15, 2003; 9(9): 1925-1929
Published online Sep 15, 2003. doi: 10.3748/wjg.v9.i9.1925
Variations of mitochondrial D-loop region plus downstream gene 12S rRNA-tRNAphe and gastric carcinomas
Cheng-Bo Han, Fan Li, Yu-Jie Zhao, Jia-Ming Ma, Dong-Ying Wu, Yu-Kui Zhang, Yan Xin
Cheng-Bo Han, Dong-Ying Wu, Yan Xin, Tumor Institute, First Affiliated Hospital, China Medical University, Shenyang, 110001, Liaoning Province, China
Fan Li, Department for High Ranking Officials, First Affiliated Hospital, China Medical University, Shenyang 110001, Liaoning Province, China
Yu-Jie Zhao, Jia-Ming Ma, Yu-Kui Zhang, Biochip Center, China Medical University, Shenyang 110001, Liaoning Province, China
Author contributions: All authors contributed equally to the work.
Supported by the National Natural Science Foundation of China, No. 30070845 and the Natural Science Foundation of Liaoning Province, No. 2001101001
Correspondence to: Dr. Yan Xin, The Fourth Laboratory of Tumor Institute, The First Affiliated Hospital, China Medical University, Shenyang 110001, Liaoning Province, China.
Telephone: +86-24-23256666 Ext 6351 Fax: +86-24-23252377
Received: March 20, 2003
Revised: April 3, 2003
Accepted: April 11, 2003
Published online: September 15, 2003

AIM: To explore the instabilities, polymorphisms and other variations of mitochondrial D-loop region and downstream gene 12S rRNA-tRNAphe in gastric cancers, and to study their relationship with gastric cancer.

METHODS: Three adjacent regions (D-loop, tRNAphe and 12S rRNA) were detected for instabilities, polymorphisms and other variations via PCR amplification followed by direct DNA sequencing in 22 matched gastric cancerous tissues and para-cancerous normal tissues.

RESULTS: PolyC or (CA)n instabilities were detected in 13/22(59.1%) gastric cancers and 9/22(40.9%) in the control (P > 0.05). There existed 2/12(16.7%) and 6/10(60%) alterations of 12S rRNA-tRNAphe in well differentiated gastric cancers and poorly differentiated ones, respectively (P < 0.05). Some new variations were found, among which np 318 and np 321 C-T transitions in D-loop region were two of the five bases for H-strand replication primer. np 523 AC-deletion and np 527 C-T transition occurred at mtTF1 binding site (mtTFBS), which were associated with the transcription of downstream mitochondrial genome. Seven samples showed the np 16182 polyC instabilities, five of which simultaneously showed np 16189 T-C transitions.

CONCLUSION: There is no statistic significance of instabilities and polymorphisms in mitochondrial D-loop region between gastric cancerous and para-cancerous normal tissues, which suggests that the instability might relate to heredity or be dependent on aging. There is a significant correlation between differentiation degree of gastric cancer and variant frequencies of 12S rRNA-tRNAphe. The poorly differentiated gastric cancers are more prone to 12S rRNA-tRNAphe variations, or gastric cancers with 12S rRNA-tRNAphe variations are more likely to be poorly differentiated. np 16189 T-C transition may be one of the important reasons for polyC instability in gastric cancer.

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