BACKGROUND: Tafazzin (TAZ), a transmembrane protein contributes in mitochondrial 
structural and functional modifications through cardiolipin remodeling. TAZ 
mutations are associated with several diseases, but studies on the role of TAZ 
protein in carcinogenesis and radiotherapy (RT) response is lacking. Therefore 
we investigated the TAZ expression in rectal cancer, and its correlation with 
RT, clinicopathological and biological variables in the patients participating 
in a clinical trial of preoperative RT.
METHODS: 140 rectal cancer patients were included in this study, of which 65 
received RT before surgery and the rest underwent surgery alone. TAZ expression 
was determined by immunohistochemistry in primary cancer, distant, adjacent 
normal mucosa and lymph node metastasis. In-silico protein-protein interaction 
analysis was performed to study the predictive functional interaction of TAZ 
with other oncoproteins.
RESULTS: TAZ showed stronger expression in primary cancer and lymph node 
metastasis compared to distant or adjacent normal mucosa in both non-RT and RT 
patients. Strong TAZ expression was significantly higher in stages I-III and 
non-mucinious cancer of non-RT patients. In RT patients, strong TAZ expression 
in biopsy was related to distant recurrence, independent of gender, age, stages 
and grade (p = 0.043, HR, 6.160, 95% CI, 1.063-35.704). In silico 
protein-protein interaction study demonstrated that TAZ was positively related 
to oncoproteins, Livin, MAC30 and FXYD-3.
CONCLUSIONS: Strong expression of TAZ protein seems to be related to rectal 
cancer development and RT response, it can be a predictive biomarker of distant 
recurrence in patients with preoperative RT.