In order to achieve the objective of tumor targeting gene delivery, recombinant spider silk-based nanoparticles containing DNA-binding domains poly(l-lysine) and tumor-homing peptides (THPs) such as F3 (KDEPQRRSARLSAKPAPPKPEPKPKKAPAKK), Lyp1 (CGNKRTRGC), and CGKRK have been developed to deliver target-specific plasmid DNA (pDNA) to the tumor cells (MDA-MB-435 and MDA-MB-231) with low cytotoxicity, significant enhancement of target specificity to tumor cells and high efficiency [97,98]. The gene discussed is PTPN22; the disease is neoplasm.