Lack of genomic rearrangements involving the aromatase gene CYP19A1 in breast cancer
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Increased intratumoral expression of aromatase, the key enzyme for estrogen biosynthesis, is predicted to be of critical importance in the development of breast cancer. Recently, several germline rearrangements at 15q21 have been shown to cause overexpression of the aromatase gene CYP19A1 and resulting aromatase excess syndrome. To determine whether submicroscopic genomic rearrangements at 15q21 are involved in aromatase overexpression in breast cancer tissues, we investigated copy-number alterations in genomic DNA obtained from 44 tumor samples. Comparative genomic hybridization analysis identified no deletion or duplication at 15q21 in the 44 samples. These results, in conjunction with previous data, indicate that aromatase overexpression in breast cancer tissues is likely to result from a promoter switch of CYP19A1 and/or accumulation of CYP19A1-expressing cells, rather than from cryptic transactivation of CYP19A1 because of genomic rearrangements at 15q21.
KeywordsBreast cancer Aromatase CYP19A1 Gene expression Genomic rearrangement
Aromatase excess syndrome
Comparative genomic hybridization
This work was supported by the Grant-in-Aid for Scientific Research on Innovative Areas (22132004) from the Ministry of Education, Culture, Sports, Science and Technology, by the Grant-in-Aid for Scientific Research (B) (23390249) from the Japan Society for the Promotion of Science, by the Grant for Research on Intractable Diseases from the Ministry of Health, Labor and Welfare, and by the Grants from National Center for Child Health and Development, from Takeda foundation, and from Daiichi-Sankyo Foundation of Life Science.
Conflict of interest
The authors declare that no conflict of interests exists.
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