The DNA Damage Response (DDR) is a critical signal transduction mechanism that detects DNA damage and initiates a series of responses to maintain genomic stability and integrity. The initiation of this process is facilitated by specific sensor proteins such as ATM (for double-strand breaks, DSBs), ATR (primarily for single-strand breaks, SSBs, and replication stress), and DNA-PK (involved in non-homologous end joining repair), which recognize DNA damage and become activated. The activation of these proteins leads to the phosphorylation of downstream effector proteins, including CHK1 and CHK2 kinases and transcription factors such as p53, thereby regulating cell cycle checkpoints, the activation of DNA repair mechanisms, and, when necessary, the triggering of cell apoptosis.