Iroquois-class homeodomain protein IRX-4 (IRX4)

Iroquois-class homeodomain protein IRX-4 (IRX4) is a highly conserved transcription factor in the Iroquois homeobox gene family, characterized by a homeodomain DNA-binding motif[1][2]. IRX4 is crucial in embryonic patterning, particularly for cardiac ventricular differentiation, and more broadly in vertebrate tissue differentiation and organogenesis[6][2]. In adult tissues, deregulation of IRX4 has been implicated in several cancers (notably prostate cancer, oral and lung cancers, and others), where it may promote proliferation, migration, invasion, and stemness, in part by modulating androgen receptor signaling and interacting with transcriptional co-factors such as FOXA1[1][3]. Recent work identified a novel micropeptide (IRX4_PEP1) encoded within the IRX4 locus that drives prostate cancer cell proliferation, chemoresistance, and Wnt pathway dysregulation[3]. Key genetic polymorphisms in the regulatory region of IRX4 influence cancer risk and therapeutic response, suggesting both mechanistic and biomarker roles for IRX4 in oncology[1][3]. Currently, IRX4 is not directly targeted by approved drugs, though its emerging role in cancer biology highlights it as a candidate for future targeted therapies and as a biomarker for disease stratification and therapeutic guidance[1][3].

Other names

Iroquois homeobox 4IRXA3Iroquois homeobox protein 4Homeodomain protein IRXA3iroquois-class homeodomain protein IRX-4

No drugs directly target IRX4 in practice; proposed mechanisms (if therapeutically targeted) would likely involve inhibition of its transcriptional activity, modulation of its protein–protein interactions (notably with FOXA1 and possibly Wnt pathway components), or epigenetic modulation[1][3].