We evaluated the impact of pharmacological B12 and G-CSF, alone or in combination with cisplatin, on hormone receptor-positive (MCF-7) and triple-negative (MDA-MB-231) breast cancer cells, conducting in vitro assays of cell viability, cytotoxicity, caspase activation, mitochondrial membrane potential, and cytolytic protein expression. The gene discussed is CSF3; the disease is breast cancer.