Liposomes in tumor treatment: a double-edged sword.

While FDA-approved liposomal drugs (e.g., Doxil®) have demonstrated improved toxicity profiles and targeted delivery, emerging evidence reveals paradoxical pro-angiogenic and immunosuppressive effects that compromise therapeutic outcomes. This review examines the critical yet underappreciated role of complement system activation in mediating these adverse effects. We present a comprehensive analysis of the dynamic interactions between liposomal formulations, complement proteins, and the tumor microenvironment. By elucidating these mechanisms, we identify key challenges and opportunities for optimizing nanocarrier design. Our synthesis provides a framework for developing next-generation liposomal therapeutics with enhanced efficacy and reduced immunogenic potential, offering important insights for translational cancer nanomedicine.