TGFB1 and systemic sclerosis: Moreover, serum VEGF levels can reflect interstitial lung involvement in SSc50,51; Toll-like receptor signaling pathway not only intervene the process of innate immunity system which contributes to both the onset and progression of SSc, but also involves in the pathogenesis of fibrosis through augmenting transforming growth factor-β1 (TGF-β1) response to increase matrix production and progressive connective tissue remodeling52,53.