GK-1 peptide reduces tumor growth, decreases metastatic burden, and increases survival in a murine breast cancer model

•An anti-neoplastic effect of GK-1 in a murine breast cancer model is proposed.•The GK-1 effect relies on increasing IL-12 and necrosis at the primary tumor.•GK-1 reduces the concentration of pro-metastatic chemokines at the lungs. GK-1 is a parasite-derived peptide adjuvant of 18 amino acid-length that enhances T-cell function and increases survival in B16-F10 melanoma tumor-bearing mice. This study was designed to evaluate in vivo the antitumor efficacy of GK-1 on 4T1 mouse mammary carcinoma. BALB/c mice with palpable primary tumors were weekly intravenously injected three times with saline solution or three different concentrations (10, 50, or 100μg per mouse) of GK-1. GK-1 significantly increased lifespan (p