This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
The critical mitogen for uterine fibroid growth is 
Select and explain. 
A. Estrogen, B. Progesterone, C. IGF - I & II, D. Corticosterone
B: Progesterone
Answer: B: Progesterone 
Explanation: Cell proliferation, extracellular matrix accumulation and cell hypertrophy which all lead to leiomyoma growth are controlled by progesterone directly.