Telomeric zinc-finger associated protein (TZAP) in cancer biology: friend or foe?

The new identified protein telomeric zinc-finger associated protein (TZAP) is a negative regulator of telomere length. Since telomere length and telomere maintenance mechanisms are essential to cancer progression, TZAP is considered a new player in cancer biology. Here we aimed to analyze TZAP using the Cancer Genome Atlas data in a Pan-Cancer approach. We gathering data from TCGA Pan-Cancer studies utilizing cBioPortal, GEPIA and UALCAN. In total we analyzed 33 types of cancer (n=9664) and their respective controls (n=711). TZAP is transcribed in all cancers but less than 5% of all tumors show any somatic changes. TZAP was downregulated in kidney chromophobe carcinoma, and upregulated in esophageal cancer, head and neck squamous cell carcinomas, kidney renal clear cell carcinoma and in liver hepatocellular carcinoma. Globally, TZAP expression is related to favorable prognosis, associated to better overall and disease-free survival. Looking to specific tumors, TZAP expression has a dual behavior. Its downregulation is associated with poor prognosis in cervical squamous cell carcinoma, in kidney renal clear cell carcinoma, kidney papillary cell carcinoma, lung adenocarcinoma and pancreas adenocarcinoma. On the contrary, in adrenocortical carcinoma, colon and rectal cancer, brain lower grade glioma and prostate adenocarcinoma the upregulation of TZAP is related with poor prognosis. TZAP expression has a positive correlation with TRF1 and TRF2 in normal tissue but not in cancer. Our analyses indicate that TZAP has an important role in oncology and may be considered as a potential biomarker.