Romei et al. discovered in two separate studies that the prevalence of the M918T RET mutation was much lower in tumors smaller than 2 cm than in larger tumors with no significant difference when the smaller tumors were subdivided into tumors smaller than 1 cm and 1–2 cm, suggesting that the mutation frequently occurs in the late stages of tumor proliferation and transformation [44,45]. The gene discussed is RET; the disease is neoplasm.