λ-Carrageenan, a seaweed-derived polysaccharide, is commonly utilized as a proinflammatory agent in basic research and has also been identified as a potent antitumor agent [1].

When administered intratumorally every two days at a dose of 50 mg/kg, λ-Carrageenan impedes the progression of tumors in mice bearing B16-F10 and 4T1 cells [1]. This compound exerts a pronounced antitumor impact, enhancing the immune response within the tumor by facilitating the infiltration of immunostimulatory cells and augmenting the production of proinflammatory cytokines [1].