Sub-group analysis involving 39 patients whose primary lesions were 1.5–4.0 mm and received adjuvant LDI revealed that patients with MTAP-positive primary melanomas had a significantly longer RFS (P < 0.05) and OS (median survival 80 months versus 35 months) compared to patients with MTAP-negative tumors. The gene discussed is MTAP; the disease is melanoma.