Translocase of outer mitochondrial membrane 34,Tomm34 (translocase of the outer mitochondrial membrane 34) is an additional component of the cellular chaperone system involved in protein folding. As the name suggests, Tomm34 was initially identified as being involved in mitochondrial protein processing. Subsequent studies have shown that Tomm34 interacts with both Hsp70 and Hsp90 and modifies their protein folding activities. In cancer, high levels of Tomm34 have been reported in bladder, colorectal and breast cancers compared to their normal tissue counterparts. In these cancers, Tomm34 promotes colorectal cancer cell growth and is a biomarker of poor outcome in early invasive breast cancer and bladder cancer. As a tumour-associated protein, Tomm34 peptide vaccination is under investigation as a therapeutic option for colorectal cancer, with significant Tomm34 cytotoxic T-lymphocyte (CTL) response observed.,URCC3, HTOM34P