PTEN and thyroid gland follicular carcinoma: Expression profiling of control, single, and double mutant thyroid glands, compared with follicular and anaplastic tumors developed by Ptenthyr−/− and [Pten, p53]thyr−/− mice respectively, revealed a substantial similarity between Ptenthyr−/− and [Pten, p53]thyr−/− hyperplasias and Ptenthyr−/− follicular carcinomas, emphasizing the driver role of PI3K activation in the establishment of neoplastic transformation.