TGFB1 and neoplasm: Similarly, transforming growth factor beta 1 (TGFβ1) normally acts as a tumor suppressor by inhibiting epithelial growth and promoting apoptosis [187], but pathway defects (e.g., SMAD loss) can lead to a cascade of downstream events that drive multiple oncogenic processes like sustained angiogenesis, loss of apoptosis, and immune evasion [187].