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: Pathology
The most important cytokine for the synthesis and deposition of connective tissue proteins is 
Select and explain. 
A. PDGF, B. FGF-2, C. TGF-β, D. MMP
C: TGF-β
Answer: C: TGF-β 
Explanation: The laying down of connective tissue occurs in two steps: 

Migration and proliferation of fibroblasts into the site of injury.
Deposition of ECM proteins produced by these cells. 

These processes are orchestrated by locally produced cytokines and growth factors, including PDGF, FGF-2 and TGF-β.
TGF-β is the most important cytokine for the synthesis and deposition of connective tissue proteins.