*2.5. TRIOBP-1 in Cancer*

TRIOBP-1 has been identified in cell lines from a range of different cancers including lung carcinoma [42], glioblastoma [43], esophageal [44], pancreatic [45], prostate, lung, and breast cancer [46]. Studies with glioblastoma showed that TRIOBP (from the specificity of the antibody used: TRIOBP-1, 5, and/or 6) was more abundant in the tumors themselves than in the surrounding tissues [43]. Analysis of existing datasets suggested that it was also over-expressed in classical, mesenchymal, neuronal, and pro-neuronal glioblastoma [43]. Further analysis in glioblastoma cell lines demonstrated that knockdown of TRIOBP-1 (and TRIOBP-5/6) reduced the proliferation and migration of these cells [43].

Another interesting line of research comes from study of the microRNA *miR-3178*, a target of the cancer-suppressing protein SP1, which was shown to have anti-metastatic properties in a mouse model [46]. *MiR-3178* inhibits the expression of *TRIOBP-1* and *5*, as measured at both the transcript and protein levels, through binding to their untranslated 3' exon. Crucially, while *miR-3178* inhibits the migration and integration of metastatic cells, this effect can be reversed by expression of TRIOBP-1 [46]. Together, there is therefore evidence that TRIOBP-1 affects tumor metastasis through its known roles in actin modulation as well as potentially through its roles in the cell cycle.
