Transmembrane protein 170B (TMEM170B)

Transmembrane protein 170B (TMEM170B) is a highly conserved, multi-pass transmembrane protein encoded on chromosome 6 in humans. TMEM170B is primarily localized in the plasma membrane and cytoplasm[1][2][3][7]. It acts as a negative regulator of the canonical Wnt/β-catenin signaling pathway, particularly in cancer biology[1][2][3][6][7]. Downregulation of TMEM170B—especially via the oncogenic microRNA miR-27a—enhances nuclear translocation of β-catenin and increases expression of downstream genes (such as TCF4, CD44, c-Myc, and cyclin D1), promoting cancer cell proliferation, colony formation, and worse patient outcomes in breast and pancreatic cancers[1][2][3][6][7]. Conversely, TMEM170B overexpression suppresses tumor cell growth and migration by inhibiting stabilization and activity of β-catenin[1][2][3][6][7]. TMEM170B is considered a tumor suppressor and decreased expression is a negative prognostic marker for several epithelial cancers[2][3][6][7]. There are no known therapeutic drugs directly targeting TMEM170B, but modulation of its regulatory microRNAs (such as miR-27a) is an area of research focus[3].

Other names

TMEM170B

Drugs or agents that upregulate TMEM170B or prevent its downregulation (e.g., by targeting miR-27a) could theoretically inhibit Wnt/β-catenin signaling and tumor progression.