Deoxycytidine kinase (dCK) is an enzyme in the nucleoside biosynthetic pathway, specifically in the nucleotide salvage pathway. It catalyzes the phosphorylation of deoxycytidine and other nucleoside analogs, a crucial step for their activation and incorporation into DNA, thus playing an important role in DNA synthesis and repair [1,2,3].

In cancer research, inhibition of dCK has shown potential. In BRCA2-deficient cancers, dCK inhibition is synthetic lethal, suggesting it could be a new target for these cancers, offering an alternative to PARP inhibitors [1]. In acute myeloid leukemia, DCK mutations were found in some patients relapsing after cytarabine-based therapy, contributing to cytarabine resistance, and overexpression of wild-type DCK restored cytarabine sensitivity in resistant cell lines [2]. Also, in gemcitabine-resistant human cancer cells, DCK was frequently inactivated, and restoring DCK expression could reverse gemcitabine resistance [3].

In conclusion, dCK is essential for nucleotide salvage and DNA synthesis. Its role in cancer drug resistance and as a potential synthetic lethal target in BRCA2-deficient cancers makes it an important gene in oncology research. Understanding dCK's function through various genetic models helps in developing more effective cancer treatment strategies.