Another notable enzyme is polβ, which is encoded by POLB gene and is one of the key enzymes in BER, and the expression levels of polβ in melanoma, colon, and breast cancers were reported to be significantly higher compared with the adjacent normal tissues [46,47], and polβ can extend DNA at a concentration as low as 5 nM [24]. The gene discussed is POLB; the disease is melanoma.