PARPBP (PARP1 binding protein) is a DNA repair protein that suppresses inappropriate homologous recombination and maintains genomic stability by antagonizing RAD51-DNA homologous recombination structure formation [UniProt]. It binds single-strand DNA and positively regulates PARP1's poly(ADP-ribosyl)ation activity, functioning as a key component of the DNA damage response [UniProt]. Mechanistically, PARPBP expression is regulated by transcriptional factors including ETV2 in tuberous sclerosis complex-deficient cells 1, and its alternative splicing can be modulated by snoRNA SNORA70E in cancer contexts 2. PARPBP also contributes to drug resistance; KIF18b-induced PARPBP overexpression sustains oxaliplatin resistance in colorectal cancer through promoter hypomethylation 3. Clinically, elevated PARPBP expression associates with poor prognosis across multiple cancers. In lung adenocarcinoma, high PARPBP correlates with advanced pathologic stages and activates MEK/ERK signaling 4. In hepatocellular carcinoma, elevated PARPBP predicts shortened survival and is an independent prognostic factor 5. Similarly, PARPBP overexpression in nasopharyngeal cancer promotes migration and invasion via UBE2C regulation 6, and in ovarian cancer, PARPBP alternative splicing variants enhance malignant phenotypes 2. Genomic studies identify PARPBP as a lung cancer susceptibility gene in East Asian populations 7, suggesting potential therapeutic targeting.