Since much is known about PARP1-3 (Bryant et al., 2005; Farmer et al., 2005; Murai et al., 2012; Ray Chaudhuri and Nussenzweig, 2017; Alemasova and Lavrik, 2019; Rodriguez-Vargas et al., 2019; Bilokapic et al., 2020) and the Tankyrases (PARP5a/5b) (Lakshmi et al., 2017; Li et al., 2019), this review will focus on the lesser-studied PARP family members, their roles in maintenance of genomic stability and cellular homeostasis, and their potential as cancer targets (Hottiger et al., 2010; Morales et al., 2014; Xu et al., 2020; Challa et al., 2021). This evidence concerns the gene TNKS and cancer.