Spermatogenic leucine zipper protein 1 (Spz1) is a basic helix-loop-helix-leucine zipper (bHLH-Zip) transcription factor expressed specifically in the testis and epididymis of adult mice. It plays an important regulatory role during spermatogenesis [, ]. It also mediates mitogen-activated protein kinase cell proliferation, transformation, and tumorigenesis []. TIP60-dependent acetylation of the SPZ1-TWIST complex has been shown to activate VEGF (vascular endothelial growth factor) expression, which regulates tumour metastasis and promotes several physiological and pathological events including angiogenesis, vascular hyperpermeability, cancer metastasis, and cancer stem cell transition [].
