Therefore, we collected primary tumor cell cultures (PDCs) from SBS7a+ and SBS7a– patients (Melanoma #8, Melanoma #14: SBS7a+ patients; Melanoma #9, Melanoma #19: SBS7a– patients) (Materials and methods) and evaluated the response of PDCs to PRKDC inhibitor (NU7441). Here, PRKDC is linked to melanoma.