Expressions of Id-1 and Id-2 in Hyperplastic Thyroid Tissue and Thyroid Carcinoma

BACKGROUND: Id proteins are a family of helix-loop-helix proteins and are regarded to be negative regulators of cell differentiation. In general, Id-1 and Id-2 expressions are upregulated during tumor development and progression in a variety of neoplasms, and these expressions may be associated with aggressive tumor behavior. However, little is known about the roles of Id-1 and Id-2 in thyroid neoplasms. METHODS: The expressions of Id-1 and Id-2 were assessed immunohistochemically in 310 normal, hyperplastic, and neoplastic thyroid tissues using tissue microarrays. RESULTS: Normal thyroid tissues rarely expressed Id-1 or Id-2. Moreover, whilst Id-1 expression was more elevated in malignant thyroid tissue than in hyperplastic thyroid tissue, Id-2 expression was more variable. No significant differences were observed between histologic subtypes of thyroid carcinomas with respect to Id-1 or Id-2 expression. Follicular adenomas showed higher expressions of Id-1 and Id-2 than thyroid carcinomas. No significant association was found between clinicopathological parameters and Id-1 expression, though Id-2 expression was significantly reduced in metastatic, stage IV tumors. CONCLUSION: The expressions of Id-1 and Id-2 were elevated in hyperplastic and neoplastic thyroid tissues. However, neither appears suitable as a marker of malignancy or an aggressive phenotype, although Id-2 expression in advanced thyroid carcinomas may reflect a favorable prognosis.

Inhibitory effect of FHL2 on Id1-mediated suppression of proliferation and invasive capacity of breast cancer cells MCF-7 / 解放军医学杂志

Objective To investigate the inhibitory effect of four and a half LIM protein 2(FHL2) on inhibitor of differentiation 1(Id1)-mediated suppression of transcriptional regulation activity and Id1-promoted invasive growth of human breast cancer cells MCF-7.Methods The effect of FHL2 on Id1-mediated transcriptional repression in MCF-7 cells was determined by cotransfection and relative biluciferase assay.The cell proliferation was determined by MTT assay,and the invasive capacity of MCF-7 cells was determined by Transwell assay.Results The transcriptional repression effect of Id1 on basic helix-loop-helix(bHLH) factor E47-mediated transcription activity in MCF-7 cells,and Id1-promoted proliferation and invasive growth of MCF-7 cells were significantly suppressed by FHL2.Conclusion FHL2 can inhibit the proliferation and invasive growth of human breast cancer cells via repressing Id1-mediated functional activity.The results provide a basis for further investigating the functional roles of FHL2-Id1 signal pathway in the carcinogenesis and development of human breast cancer.