Chapters authored
Molecular Alterations and Expression Dynamics in the Etiopathogenesis of Thyroid Cancer
Thyroid carcinoma is the most prevalent endocrine malignancy and accounts for 2% of all human cancers. In the past decade, knowledge of genetic alterations of thyroid cancer (TC) has rapidly expanded, which has provided new insights into thyroid cancer etiology and has offered novel diagnostic tools and prognostic markers that enable improved and personalized management of thyroid cancer patients. Alterations in key signaling effectors seem to be the hallmark of distinct forms of thyroid neoplasia. Mutations or rearrangements in genes that encode Mitogen activated protein kinase (MAPK) pathway effectors seem to be required for transformation. Mutations in BRAF were the most recently identified MAPK effector in thyroid cancer. BRAF V600E is the most common alteration in sporadic papillary carcinoma. Three RAS proto-oncogenes (NRAS, HRAS & KRAS) are implicated in human thyroid tumorigenesis. High incidence of thyroid cancer worldwide indicates the importance of studying genetic alterations that lead to its carcinogenesis. BRAF and RAS alterations represent a novel indicator of the progression and aggressiveness of thyroid carcinogenesis. The GSα-adenylyl cyclase-cyclic AMP (cAMP) cascade is effected in thyroid cancer. Promoter hypermethylation of multiple genes especially TSHR has been identified to play a role in thyroid cancers, in particular showing a close association with BRAF mutational status. So, the main aim of the study was to elucidate the involvement of BRAF and RAS gene mutations along with BRAF expression and thyroid-stimulating hormone receptor (TSHR) hypermethylation in North Indian patients and investigate their association with clinicopathological characteristics.
Part of the book: Thyroid Cancer