A 25-year-old woman comes to the office because of a 6-month history of increasingly severe low back pain and heavy menses. Her temperature is 37.1°C (98.8°F), pulse is 75/min, respirations are 13/min, and blood pressure is 115/79 mm Hg. Physical examination shows no abnormalities. An endometrial biopsy specimen shows regular tubular endometrial glands with abundant mitotic figures in the endometrial glands and stroma. Which of the following proteins or enzymes regulate the
progression of cells into this phase of this patient's menstrual cycle?
A) Transforming growth factor beta (TGF-β)
B) Cyclin-dependent kinase (CDK)
C) Plasminogen activator inhibitor-1 (PAI-1)
D) Interleukin-1 (IL-1)