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Human breast cancer tissue expresses high level of type 1 5'-deiodinase
Marcin Grzegorz Debski1, Janusz Pachucki, Michal Ambroziak
1Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Banacha, Warsaw, Poland. debskim@wp.pl
Abstract:
Type 1 5'-deiodinase is one of two isoenzymes that participate in conversion of prohormone thyroxine into triiodothyronine (T3). A decrease in type 1 5'-deiodinase expression was observed in renal clear cell carcinoma, thyroid cancer, and lung cancer. The aim of this study was to evaluate type 1 5'-deiodinase activity and mRNA level in breast cancer tissue and non-cancerous surrounding breast tissue. Material was collected from 36 patients undergoing radical mastectomy or local tumor resection. In all non-cancerous breast tissues, type 1 50-deiodinase activity was found to be at a very low or immeasurable level, and type 1 5'-deiodinase mRNA was detected only in 2 out of the 36 samples. By contrast, 20 out of the 36 breast cancer tissues, mainly grades G1 and G2, expressed abundant type 1 5'-deiodinase activity and/or a high mRNA level. Our data demonstrated the presence of type 1 5'-deiodinase in well-differentiated breast cancer tissue. High enzymatic activity of type 1 50-deiodinase can potentially lead to an increase in the production of T3, which may affect target gene transcription, including genes responsible for energy expenditure, growth, differentiation, and proliferation.
Insights
Type 1 5'-deiodinase is significantly present in breast cancer tissue, unlike in normal tissue. This enzyme
Area of Science:
- Endocrinology
- Oncology
- Molecular Biology
Background:
- Type 1 5 deiodinase is crucial for converting thyroxine to triiodothyronine (T3).
- Reduced type 1 5 deiodinase expression is noted in renal clear cell carcinoma, thyroid cancer, and lung cancer.
Purpose of the Study:
- To assess type 1 5 deiodinase activity and mRNA levels in breast cancer tissue versus non-cancerous surrounding tissue.
- To investigate the role of type 1 5 deiodinase in breast cancer development and progression.
Main Methods:
- Enzyme activity assays were performed on tissue samples.
- Messenger RNA (mRNA) levels of type 1 5 deiodinase were quantified.
- Samples were collected from 36 patients undergoing breast surgery.
Main Results:
- Type 1 5 deiodinase activity and mRNA were very low or undetectable in non-cancerous breast tissue.
- 20 out of 36 breast cancer tissues (grades G1 and G2) showed abundant type 1 5 deiodinase activity and/or high mRNA levels.
- The enzyme was present in well-differentiated breast cancer tissue.
Conclusions:
- Type 1 5 deiodinase is present in well-differentiated breast cancer.
- Elevated type 1 5 deiodinase activity may increase T3 production, potentially influencing genes involved in cell growth and proliferation.
- This finding suggests a potential role for type 1 5 deiodinase in breast cancer.
