While 5′–3′ RNA ligases, such as T4 Rnl of bacteriophages have been known and extensively utilised in biological laboratories for a considerable period of time,7,8 Rlig1 is the first ligase of this type to be identified in humans and is conserved in chordates.1 Additionally, Rlig1 has been found to be mutated in various cancers.9–12 Prior investigation by us showed that Rlig1-deficient human embryonic kidney (HEK293) cells exhibited increased sensitivity to menadione treatment in comparison to their wild-type (WT) counterparts. This evidence concerns the gene RLIG1 and cancer.