ABSTRACT Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder that affects 5-20% of reproductive age women. PCOS clinical symptoms include hirsutism, menstrual dysfunction, infertility, obesity and metabolic syndrome. There is a wide heterogeneity in clinical manifestations and metabolic complications. The pathogenesis of PCOS is not fully elucidated, but four aspects seem to contribute to the syndrome to different degrees: increased ovarian and/or adrenal androgen secretion, partial folliculogenesis arrest, insulin resistance and neuroendocrine axis dysfunction. A definitive etiology […]

Vitamin D deficiency and diabetes mellitus are two common conditions and they are widely prevalent across all ages, races, geographical regions, and socioeconomic conditions. Epidemiologic studies have shown association of vitamin D deficiency and increased risk of chronic diseases, such as cancer, cardiovascular disease, type 2 diabetes, and autoimmune diseases, such as multiple sclerosis and type 1 diabetes mellitus. The identification of 1,25(OH)2D receptors and 1-α-hydroxilase expression in pancreatic beta cells, in cells of the immune system, and in various […]

The determinant of the diabetic nephropathy is hyperglycemia, but hypertension and other genetic factors are also involved. Glomerulus is the focus of the injury, where mesangial cell proliferation and extracellular matrix occur because of the increase of the intra- and extracellular glucose concentration and overexpression of GLUT1. Sequentially, there are increases in the flow by the poliol pathway, oxidative stress, increased intracellular production of advanced glycation end products (AGEs), activation of the PKC pathway, increase of the activity of the […]

Medullary thyroid carcinoma (MTC) is a rare malignant neoplasia, which may occur on sporadic form or on a hereditary basis. Germ line mutations in the RET proto-oncogene is responsible for hereditary MTC. However, most MTC occur in individuals without family history where the pathogenesis is still unclear. Single nucleotide polymorphisms (SNPs) of the RET gene have been described in the general population as well as in patients with MTC. Even though these allelic variants do not seem to confer any […]

This review describes the molecular basis of pituitary adenomas with emphasis on GH-secreting tumors (somatotropinomas). The roles of tumor suppressor genes (such as RB1 and MEN-1) and oncogenes (such as gsp and PTTG) in tumor initiation and promotion are discussed. The characterization of these molecular markers may contribute to the understanding of tumor behavior, helping in the therapeutical management. However, despite recent advances, the sequence of genetic abnormalities participating in the pathogenesis of these adenomas is not completely known.

Neoplastic transformation results from a series of genetic alterations involving activation of protooncogenes and inactivation of tumor suppressor genes. Activation of ras protooncogenes by point mutation is the most frequent genetic alteration in spontaneous thyroid neoplasias. The goal of this study was to evaluate ras gene expression in the nodular goiter. Seventy-nine patients submitted to thyroidectomy and with a histological diagnosis of nodular goiter were included in the study. Tissues were obtained from both tumor and normal thyroid during surgery […]

Corticotropinomas represent approximately 80% of the etiology of Cushing’s syndrome in adults. In the past decade remarkable advances in the knowledge of the normal anterior pituitary development, in the pathogenesis of the pituitary tumors, as well as in the factors involved in the tumoral progression have been made. General principles of tumorigenesis are valid in corticotrophic tumors and it is clear that this is a multistep and multifactorial process, resulting from the interaction of initiating and promoting events. Most of […]