7561 Background: In this retrospective analysis, we tested if the timing of interferon (iFN) as adjuvant or as treatment of the relapse, when correlated with CEACAM-1 intensity, affects survival. Methods: After ethics approval was obtained, paraffin blocks from 27 patients previously diagnosed with malignant melanoma were analyzed using immunohistochemical staining with monoclonal CEACAM-1 antibody. The patients were grouped based on intensity; weakly positive (intensity 0–1) and strongly positive (intensity 2–3). Each group was analyzed based on survival status, pathological stage, and the time iFN was started. Results: Grade 3 intensity was identified in 10 patients, 6 of whom died (60%) and 4 patients are alive (2 relapsed but are disease-free). None of these patients had T4 or N1–2 disease at presentation. Adjuvant low-dose iFN was given in 4/10 patients, and 3/4 patients (75%) were alive at 3–5 years follow-up. High-dose iFN was given at the time of relapse in 6/10 patients and 5/6 patients died (83%) from disease progression. Grade 2 intensity was identified in 7 patients and 4 of them died (57%) and 3 patients are alive (2 relapsed but are disease-free). Adjuvant iFN was given in 4/7 patients and 3/4 remained alive (75%). iFN was started at the time of the first relapse in 3/7 patients; all 3/3 died (100%). Grade 1 intensity was observed in 10 patients and 3/10 died (30%). Out of 7 patients alive, 5 relapsed, but remained disease-free after local treatment at 4–7 years follow-up. Adjuvant iFN was given in 6/10 patients with 50% success rate (3/6 died). In 4/10 patients, iFN was given at first relapse and 4/4 (100%) are alive and disease-free at 4–7 years follow-up. Conclusions: Grade 2 and 3 intensity for CEACAM-1 correlates with poor prognosis despite early stage at diagnosis, but adjuvant iFN seems to correlate with survival benefit. Grade 1 intensity patients have a high survival rate and the timing of iFN was associated with good survival in both settings. No significant financial relationships to disclose.