Thyroid carcinoma
see Thyroid carcinoma intracranial metastases.
Thyroid carcinoma is uncommon cancer and accounts for approximately 1% of all new malignant diseases. 1) Moreover, brain metastases from thyroid carcinoma are especially rare, occurring in approximately 0.9% to 1.5% of thyroid carcinoma cases 2).
Classification
Papillary thyroid cancer or papillary thyroid carcinoma is the most common type of thyroid cancer, representing 75 percent to 85 percent of all thyroid cancer cases. It occurs more frequently in women and presents in the 20–55 year age group.
Hypercortisolism may also be due to ectopic secretion of ACTH usually by tumors, most commonly small-cell carcinoma of the lung, thymoma, carcinoid tumors, pheochromocytomas, and medullary thyroid carcinoma.
Brain tumor polyposis syndrome 2 (BTP2)/Familial adenomatous polyposis is an autosomal dominant syndrome with tumors of the brain (the main brain tumor associated with BPT2 is medulloblastoma), benign colonic polyposis and colorectal carcinomas. Other cancers include osteomas, thyroid cancer & hepatoblastoma. BTP2 results form heterozygous germline mutations in the APC tumor suppressor gene 3).
The expression levels of circ_0058124, microRNA-940 (miR 940) and mitogen-activated protein kinase 1 (MAPK1) were assessed by quantitative polymerase chain reaction (q-PCR). The circular characteristic of circ_0058124 was identified by oligo (dT)18 primers, Ribonuclease R (RNase R) and Actinomycin D (ActD), and its localization were determined by nuclear-cytoplasmic separation assay. Also, cell proliferation was detected by colony formation assay, and cell migration and invasion were assessed by transwell assay. Further, Seahorse XF Extracellular Flux Analyzer was used to measure the oxygen consumption rate (OCR) of cells. Besides, dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays were used to identify the mechanism of circ_0058124. Western blot (WB) analysis was used to test the MAPK1 protein level. In addition, mice xenograft models were constructed to test the effect of circ_0058124 on Thyroid Cancer (TC) tumor growth in vivo.
Circ_0058124 was highly expressed in TC and is a stable cyclic transcript, mainly located in the cytoplasm. Circ_0058124 knockdown suppressed proliferation, migration, invasion and metabolic abilities in TC cells. MiR-940 could be absorbed by circ_0058124, and the inhibition effect of its overexpression on TC progression could be reversed by overexpressed-circ_0058124. MAPK1 was a target of miR-940, and the suppression effect of its silencing on TC progression could be inverted by miR-940 inhibitor. Besides, MAPK1 expression was regulated by circ_0058124 and miR-940. Interference of circ_0058124 also reduced TC tumor growth in vivo.
Circ_0058124 might play a carcinogenic role in TC progression by regulating the miR-940/MAPK1 axis, which might provide a new idea for the treatment of TC 4).