TGFB1 and systemic sclerosis: Results of RT-PCR (Figure 4A) showed that the transcript levels of Col1a2 and Col3a1 were dramatically increased (16.1 ± 2.99-folds and 1.7 ± 0.14-folds, respectively) after the stimulation of exogenous TGF-β1, and exhibited an SSc-like phenotype.