We revealed that seven genes (cyclin E2 (CCNE2), cell division cycle-associated 5 (CDCA5), RAD51 recombinase (RAD51), transcription factor 19 (TCF19), kinetochore-associated 1 (KNTC1), minichromosome maintenance 10 replication initiation factor (MCM10), and nei-like DNA glycosylase 3 (NEIL3)) were related to cell cycle regulation, and positively associated with tumorigenesis and progression in breast cancer. The gene discussed is CCNE2; the disease is breast cancer.