The first pathway is crucial for PTC initiation (e.g., mutations of the BRAF and RAS genes or gene fusions of RET/PTC and TRK); the second pathway is thought to be critical in FTC initiation (e.g., mutations in RAS, PIK3CA, and AKT1, inactivation of PTEN). The gene discussed is RET; the disease is thyroid cancer, nonmedullary, 2.