Figure 2
From: BRAFV600E mutation in anaplastic thyroid carcinomas and their accompanying differentiated carcinomas
Anaplastic transformation in multi-step carcinogenesis and fetal cell carcinogenesis. In multi-step carcinogenesis (A), anaplastic carcinoma cells are generated by three pathways. A thyrocyte is transformed into a papillary carcinoma cell by a BRAF mutation, then further transformed into an anaplastic carcinoma cell. A thyrocyte without a BRAF mutation is transformed into a follicular carcinoma cells, then further transformed into an anaplastic carcinoma cell. Anaplastic carcinomas are also generated from some unknown precursors. In fetal cell carcinogenesis (B), both anaplastic and differentiated carcinoma cells are generated from thyroid cancer stem cells. A thyroid cancer stem cell with a BRAF mutation can generate anaplastic or papillary carcinoma cells but not follicular carcinoma cells, since a BRAF mutation blocks the papillary carcinoma cell from differentiating into a follicular carcinoma cell.
