Background: The Transforming growth factor beta-1 preproprotein is proteolytically processed to generate a latency-associated peptide (LAP) and a mature TGF-beta 1 peptide. TGF-beta 1 bound to LAP is inactive, while the active form consists solely of the mature peptide homodimer. The mature TGF-beta 1 peptide may also form heterodimers with other TGFB family members. Ligands of this family bind various TGF-beta receptors leading to recruitment and activation of SMAD family transcription factors that regulate gene expression. TGF-beta 1 regulates cell proliferation, differentiation and growth, and can modulate expression and activation of other growth factors including interferon gamma and tumor necrosis factor alpha. This gene is frequently upregulated in tumor cells. [taken from NCBI Entrez Gene (Gene ID: 7040)].