A recent synthetic lethal screen showed that ATR‐ or CHK1‐inhibitors potentiate caspase‐dependent apoptosis in POLD1‐deficient cancers.[38] Another study showed that pharmacologic blockade of B‐family DNA polymerases using aphidicolin combined with CHK1 inhibitors also led to synergistic inhibition of cancer cell proliferation.[39] However, aphidicolin is too toxic to be used in humans, and currently no other suitable drug candidates are able to block the DNA polymerase family exist. The gene discussed is ATR; the disease is cancer.