TSC22 domain family, member 1 (TSC22D1) is one of the TGF-beta-stimulated clone-22 (TSC-22). TSC-22 was reported to be a differentiation-inducing factor that negatively regulates the growth of salivary gland cancer cells. TSC22D1, which encodes transforming growth factor beta-stimulated clone 22 (TSC-22), is thought to be a tumor suppressor because its expression is lost in many glioblastoma, salivary gland, and prostate cancers. TSC-22 is the founding member of the TSC-22/DIP/Bun family of leucine zipper transcription factors. TSC-22 may play an important role in maintaining the differentiated phenotype in salivary gland tumors, and may be a possible target of leukemia therapy. TSC22D1 forms homodimers via its conserved leucine zipper domain and heterodimerizes with TSC22D4. TSC22D1 has transcriptional repressor activity.