Thus, considering PARP3 implication in the maintenance of genomic integrity, as well as previous results suggesting a negative correlation between PARP3 expression and telomerase activity in non-small cell lung tumours, our main aim in this work consists of investigating in human cancer cell lines the possible role of PARP3 on the regulation of telomerase activity, which may be of relevance in the pathogenesis of NSCLC. Here, PARP3 is linked to cancer.