Nuclear receptor expression in human differentiated thyroid tumors

Area of Science:

• Endocrinology
• Oncology
• Molecular Biology

Background:

• Nuclear receptors (NRs) are crucial in endocrine signaling and metabolism.
• NRs are key therapeutic targets for hormone-dependent cancers.
• Limited research exists on NR roles in thyroid cancer.

Purpose of the Study:

• Systematically examine the expression of 48 human NRs in benign and malignant thyroid tissues.
• Investigate NR expression differences in papillary thyroid carcinoma (PTC) based on BRAF mutation status.

Main Methods:

• Quantitative real-time PCR profiled 48 human NRs in multinodular goiter (MNG), PTC, follicular carcinoma (FC), and Hürthle cell carcinoma (HCC).
• Immunohistochemistry (IHC) assessed protein expression of Rev-erbα and LXR-β.
• Tissue microarrays included benign and malignant thyroid tissues.

Main Results:

• LXR-β and ROR-γ were prominently expressed across all thyroid tissues.
• PTC showed overexpression of RXR-γ and Rev-erbα compared to MNG.
• BRAF(V600E) PTC exhibited altered NR expression (upregulation of RXR-γ, Rev-erbα; downregulation of AR, ERR-γ, ROR-γ) versus wild-type BRAF.
• FC displayed EAR-2 overexpression and PPAR-α/δ underexpression.
• HCC showed a distinct profile with widespread NR downregulation.
• IHC confirmed Rev-erbα and LXR-β protein localization in tumor cells, with stronger Rev-erbα staining in PTC.

Conclusions:

• This study provides the first systematic analysis of NR expression in thyroid cancer.
• Identified tumor-specific NR expression patterns and BRAF-dependent differences in PTC.
• These findings support further research into NR mechanisms and potential therapeutic applications in thyroid cancer.