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High frequency of mitochondrial genome instability in human endometrial carcinomas.

Liu VW, Yang HJ, Wang Y, Tsang PC, Cheung AN, Chiu PM, Ng TY, Wong LC, Nagley P, Ngan HY - Br. J. Cancer (2003)

Bottom Line: About 56% (28 out of 50) of cases carry one or more somatic changes in mtDNA including deletion, point mutation and mitochondrial microsatellite instability (mtMSI), namely the change in length of short base-repetitive sequences of mtDNA.In particular, mtMSI was frequently detected in 89% (25 out of 28) of all the cases carrying somatic changes followed by point mutations (25%; seven out of 28) and deletion (3.5%; one out of 28).The CCCCCTCCCC sequences located in the Hypervariable Regions I and II of the D-loop and 12S rRNA gene are instability hot spot regions in endometrial carcinomas.

View Article: PubMed Central - PubMed

Affiliation: Department of Obstetrics and Gynaecology, Queen Mary Hospital, University of Hong Kong.

ABSTRACT
To investigate the occurrence of somatic mitochondrial DNA (mtDNA) mutations in human primary endometrial carcinomas, we sequenced the D-loop region, the 12S and 16S rRNA genes of mtDNA of cancer tissues and their matched normal controls. About 56% (28 out of 50) of cases carry one or more somatic changes in mtDNA including deletion, point mutation and mitochondrial microsatellite instability (mtMSI), namely the change in length of short base-repetitive sequences of mtDNA. In particular, mtMSI was frequently detected in 89% (25 out of 28) of all the cases carrying somatic changes followed by point mutations (25%; seven out of 28) and deletion (3.5%; one out of 28). The CCCCCTCCCC sequences located in the Hypervariable Regions I and II of the D-loop and 12S rRNA gene are instability hot spot regions in endometrial carcinomas. It is suggested that errors in replication may account for the high frequency of mtMSI in human endometrial carcinomas. The relatively high prevalence of mtMSI may be a potential new tool for detection of endometrial cancer.

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Related in: MedlinePlus

Detection of mtMSI in endometrial carcinomas by polyacrylamide gel electrophoresis. A homopolymeric C stretch interrupted by a T (CCCCCTCCCC) at 16184–16193 was analysed. As a control, U46 carried the wild-type sequence in this segment of mtDNA in both the normal (N) and tumour (T) tissues. The PCR product is a single band of 109 bp and band shifting was not observed. In contrast, both U44 and G29 carried a germline polymorphism T to C at np 16189 to produce an interrupted C stretch. Instability at this C stretch gave rise to heteroplasmic sequences and resulted in band shifting or smearing in PCR products derived from tumour samples. In sample U44, PCR product raised from normal tissue was a single band carrying C10, while the multiple PCR products (carrying C10, C11, and C12) were seen in the tumour sample, giving rise to a smeared band on the gel. Similarly, in sample G29, PCR product raised from normal was a single band carrying C7, while multiple PCR products (carrying C7, C8, C9 and C10) were seen in the tumour sample. The lane marked (M) contains 50 bp DNA markers (sizes of two bands shown in bp).
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fig3: Detection of mtMSI in endometrial carcinomas by polyacrylamide gel electrophoresis. A homopolymeric C stretch interrupted by a T (CCCCCTCCCC) at 16184–16193 was analysed. As a control, U46 carried the wild-type sequence in this segment of mtDNA in both the normal (N) and tumour (T) tissues. The PCR product is a single band of 109 bp and band shifting was not observed. In contrast, both U44 and G29 carried a germline polymorphism T to C at np 16189 to produce an interrupted C stretch. Instability at this C stretch gave rise to heteroplasmic sequences and resulted in band shifting or smearing in PCR products derived from tumour samples. In sample U44, PCR product raised from normal tissue was a single band carrying C10, while the multiple PCR products (carrying C10, C11, and C12) were seen in the tumour sample, giving rise to a smeared band on the gel. Similarly, in sample G29, PCR product raised from normal was a single band carrying C7, while multiple PCR products (carrying C7, C8, C9 and C10) were seen in the tumour sample. The lane marked (M) contains 50 bp DNA markers (sizes of two bands shown in bp).

Mentions: Finally, in a clinical context, the high frequency of mitochondrial genome instability, in combination with PCR-based assays of high sensitivity, may be a potential new tool for endometrial cancer detection (Parrella et al, 2001). Somatic mtMSI involving the change in DNA length, even though the difference is only 1 or 2 bp, can be readily detected by polyacrylamide gel electrophoresis (Figure 3Figure 3


High frequency of mitochondrial genome instability in human endometrial carcinomas.

Liu VW, Yang HJ, Wang Y, Tsang PC, Cheung AN, Chiu PM, Ng TY, Wong LC, Nagley P, Ngan HY - Br. J. Cancer (2003)

Detection of mtMSI in endometrial carcinomas by polyacrylamide gel electrophoresis. A homopolymeric C stretch interrupted by a T (CCCCCTCCCC) at 16184–16193 was analysed. As a control, U46 carried the wild-type sequence in this segment of mtDNA in both the normal (N) and tumour (T) tissues. The PCR product is a single band of 109 bp and band shifting was not observed. In contrast, both U44 and G29 carried a germline polymorphism T to C at np 16189 to produce an interrupted C stretch. Instability at this C stretch gave rise to heteroplasmic sequences and resulted in band shifting or smearing in PCR products derived from tumour samples. In sample U44, PCR product raised from normal tissue was a single band carrying C10, while the multiple PCR products (carrying C10, C11, and C12) were seen in the tumour sample, giving rise to a smeared band on the gel. Similarly, in sample G29, PCR product raised from normal was a single band carrying C7, while multiple PCR products (carrying C7, C8, C9 and C10) were seen in the tumour sample. The lane marked (M) contains 50 bp DNA markers (sizes of two bands shown in bp).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2376924&req=5

fig3: Detection of mtMSI in endometrial carcinomas by polyacrylamide gel electrophoresis. A homopolymeric C stretch interrupted by a T (CCCCCTCCCC) at 16184–16193 was analysed. As a control, U46 carried the wild-type sequence in this segment of mtDNA in both the normal (N) and tumour (T) tissues. The PCR product is a single band of 109 bp and band shifting was not observed. In contrast, both U44 and G29 carried a germline polymorphism T to C at np 16189 to produce an interrupted C stretch. Instability at this C stretch gave rise to heteroplasmic sequences and resulted in band shifting or smearing in PCR products derived from tumour samples. In sample U44, PCR product raised from normal tissue was a single band carrying C10, while the multiple PCR products (carrying C10, C11, and C12) were seen in the tumour sample, giving rise to a smeared band on the gel. Similarly, in sample G29, PCR product raised from normal was a single band carrying C7, while multiple PCR products (carrying C7, C8, C9 and C10) were seen in the tumour sample. The lane marked (M) contains 50 bp DNA markers (sizes of two bands shown in bp).
Mentions: Finally, in a clinical context, the high frequency of mitochondrial genome instability, in combination with PCR-based assays of high sensitivity, may be a potential new tool for endometrial cancer detection (Parrella et al, 2001). Somatic mtMSI involving the change in DNA length, even though the difference is only 1 or 2 bp, can be readily detected by polyacrylamide gel electrophoresis (Figure 3Figure 3

Bottom Line: About 56% (28 out of 50) of cases carry one or more somatic changes in mtDNA including deletion, point mutation and mitochondrial microsatellite instability (mtMSI), namely the change in length of short base-repetitive sequences of mtDNA.In particular, mtMSI was frequently detected in 89% (25 out of 28) of all the cases carrying somatic changes followed by point mutations (25%; seven out of 28) and deletion (3.5%; one out of 28).The CCCCCTCCCC sequences located in the Hypervariable Regions I and II of the D-loop and 12S rRNA gene are instability hot spot regions in endometrial carcinomas.

View Article: PubMed Central - PubMed

Affiliation: Department of Obstetrics and Gynaecology, Queen Mary Hospital, University of Hong Kong.

ABSTRACT
To investigate the occurrence of somatic mitochondrial DNA (mtDNA) mutations in human primary endometrial carcinomas, we sequenced the D-loop region, the 12S and 16S rRNA genes of mtDNA of cancer tissues and their matched normal controls. About 56% (28 out of 50) of cases carry one or more somatic changes in mtDNA including deletion, point mutation and mitochondrial microsatellite instability (mtMSI), namely the change in length of short base-repetitive sequences of mtDNA. In particular, mtMSI was frequently detected in 89% (25 out of 28) of all the cases carrying somatic changes followed by point mutations (25%; seven out of 28) and deletion (3.5%; one out of 28). The CCCCCTCCCC sequences located in the Hypervariable Regions I and II of the D-loop and 12S rRNA gene are instability hot spot regions in endometrial carcinomas. It is suggested that errors in replication may account for the high frequency of mtMSI in human endometrial carcinomas. The relatively high prevalence of mtMSI may be a potential new tool for detection of endometrial cancer.

Show MeSH
Related in: MedlinePlus