Etiopathogenesis of Differentiated Thyroid Carcinomas

Abstract

INTRODUCTION:Thyroid malignomas are a heterogeneous group of neoplasm consisting of most frequent differentiated encountered carcinomas, papillary and follicular thyroid carcinoma, then medullary thyroid carcinoma originating from neuroendocrine calcitonin-producing C-cells and rare forms of thyroid lymphomas arising from intrathyroidal lymphatic tissue, thyroid sarcomas and poorly differentiated anaplastic thyroid carcinoma. There are increasing numbers of epidemiological studies and publications that have suggested increased incidence rate of thyroid carcinomas. We have read, analysed and compare available reviews and original articles investigating different etiological factors in the development of thyroid carcinomas through Google Scholar and PubMed Database.DISCUSSION:Aetiology involved in the development of thyroid carcinomas is multifactorial and includes external influences, as well as constitutional predispositions and genetic etiological factors. The actual effect of environmental and constitutional factors is on promoting genetic and epigenetic alterations which result in cell proliferation and oncogenesis. Until now are identified numerous genetic alterations, assumed to have an important role in oncogenesis, with MAPK and PI3K-AKT as crucial signalling networks regulating growth, proliferation, differentiation and cell survival/apoptosis.CONCLUSION:This new molecular insight could have a crucial impact on diagnosis and also on improving and selecting an appropriate treatment to the patients with thyroid malignancies.

Distribution of histopathological types of thyroid tumors in 1999-2015 compared to 1966-1988 year period

“…This can be the consequence of various factors such as differences in diagnostic practices, accessability of health care or the different etiopathogenetic factors such as level of iodine supplementation, and exposure to radiation or different mutagenic factors (21)(22)(23)(24)(25)(26). Etiology involved in the development of TC is multifactorial and includes external influences, as well as genetic predispositions (6,14). When it comes to external influences apart from irradiation (the most common cause among children) (21)(22)(23)(24) another external factor that is linked to the development of these malignancies is the inappropriate iodine intake (25,26).…”

“…The ATC is a rare form of TC, characterized by aggressive biology and represents only 1-2% of all TC cases (13). Non-epithelial thyroid tumors and secondary metastatic deposits in the thyroid gland are a rare occurrence of thyroidal malignancy (10,14). Epidemiological studies worldwide have shown increase in incidence rate of TC, mostly due to increase of PTC cases, but also observed a change in the ratio between FTC and PTC cases that was related to modifications in iodine intake (16)(17)(18).…”

Risk Factors for Predicting Osteoporosis in Patients Who Receive Thyrotropin Suppressive Levothyroxine Treatment for Differentiated Thyroid Carcinoma

“…All patients had received radioiodine treatment for DTC in Ankara University Medical Faculty Department of Nuclear Medicine. Patient inclusion criteria were based on several parameters: (1) low or intermediate risk group DTC diagnosis according to the American Thyroid Association (ATA) 2015 guidelines; (2) receiving LT4 suppression therapy after initial treatment; (3) available routine follow-up data after initial therapy; (4) known preoperative thyroid hormone status; (5) sufficient and available demographic and medical history data to fill-in the study form; and (6) be physically fit enough to undergo a femur and lumbar vertebra bone density study (6).…”

“…Differentiated thyroid carcinoma (DTC) is the most common endocrine neoplasia. Although the incidence of DTC is increasing its mortality rate remains stable (1,2). After initial treatment with a thyroidectomy with/without radioiodine treatment, patients are treated with levothyroxine (LT4) therapy to suppress thyrotropin-stimulating hormone (TSH) since suppression of serum TSH levels reduces tumor recurrence rates (3).…”

Silencing circRNA protein kinase C iota (circ-PRKCI) suppresses cell progression and glycolysis of human papillary thyroid cancer through circ-PRKCI/miR-335/E2F3 ceRNA axis

“…The incidence of PTC is on the rise and recurrence happens in more than 25% PTC patients [3]. It has been well-ingrained that genetic changes, epige-netic alterations and environmental factors are the basis for carcinogenesis of cancers including thyroid cancer [4].…”