Less DeltamtDNA4977 than normal in various types of tumors suggests that cancer cells are essentially free of this mutation
Genet. mol. res. (Online)
;
3(3): 395-409, 2004. tab, ilus, graf
Article
in English
| LILACS
| ID: lil-482169
ABSTRACT
Levels of mtDNA(4977) deletions (DeltamtDNA(4977)) have been found to be lower in tumors than in adjacent non-tumoral tissues. In 87 cancer patients, DeltamtDNA(4977) was detected by multiplex polymerase chain reaction (PCR) amplification in 43 (49%) of the tumors and in 74 (85%) of the samples of non-tumoral tissues that were adjacent to the tumors. DeltamtDNA(4977) deletions were detected in 24% of the breast tumors, 52% of the colorectal tumors, 79% of the gastric tumors, and 40% of the head and neck tumors as compared with 77, 83, 100, and 90% of the adjacent respective non-tumoral tissues at the same DNA template dilution. Based on limiting dilution PCR of 16 tumors and their adjacent non-tumoral tissues, it was found that the amount of DeltamtDNA(4977) was 10- to 100-fold lower in the tumor than in the respective control non-tumoral tissues. Real-time PCR experiments were performed to quantify the number of DeltamtDNA(4977) deletions per cell, by determining the mitochondrial-to-nuclear DNA ratio. In all of the cases of breast, colorectal, gastric, and head and neck cancer the proportion of DeltamtDNA(4977) in tumors was lower than that of the respective non-tumoral tissue. Traces of DeltamtDNA(4977) in tumors were apparently due to contamination of tumor tissue with surrounding non-tumoral tissue, as evidenced by tumor microdissection and in situ PCR techniques, suggesting that tumors are essentially free of this mutation. Although the metabolic effect of DeltamtDNA(4977) may be minimal in normal (non-tumor) tissue, in tissue under stress, such as in tumors, even low levels of DeltamtDNA(4977) deletions may be intolerable.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Stomach Neoplasms
/
Breast Neoplasms
/
Colorectal Neoplasms
/
Sequence Deletion
/
Head and Neck Neoplasms
/
Mutation
Type of study:
Observational study
Limits:
Female
/
Humans
Language:
English
Journal:
Genet. mol. res. (Online)
Journal subject:
Molecular Biology
/
Genetics
Year:
2004
Type:
Article
Affiliation country:
Brazil
/
United States
Institution/Affiliation country:
A.C. Camargo Cancer Hospital/BR
/
Gene Therapy Center/BR
/
Genon Genética/BR
/
Ludwig Institute for Cancer Research/BR
/
NIH/US
/
University of São Paulo/BR
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