Peptide showed good research value and application prospect in tumor immunotherapy because of its mature and stable synthesis process and good tumor penetration and biological compatibility.The number of peptide drugs entering clinical trials has been increasing in recent years,it plays an increasingly important role in tumor drug therapy.

Tumor targeting peptides can recognize tumor tissues and tumor associated micro environment, including tumor metastasis. These tumor-targeting peptides have a strong affinity for specific receptors/markers present in tumors and in tumor blood vessels .Thus, they can be used to deliver drugs selectively in tumors.They are also commonly known as tumor homing peptide because they travel through the bloodstream to the tumor site/vasculature.

RGD peptide is a kind of short peptide containing Arginine - Glycine - Aspartate (Arg - Gly - Asp).Tumor cells or neovascularization can specifically express certain integrins, such as αvβ3, which can bind RGD peptide with certain affinity and become a new target for tumor treatment.

Bankpeptide has rich experience in the synthesis of RDG peptides and can provide a variety of RGD peptides, RGD cyclic peptides.

NGR peptide is a kind of short peptide containing Asparagine - Arginine - Glycine (Asn - Gly - Arg) which can be specifically connect to the  cells expressing aminopeptidase CD13.

CD13 is a transmembrane metalloproteinases ,which is one of the important regulatory factor angiogenesis production has not been activated on normal vascular endothelial cells, and highly expressed in the endothelial cells in tumor angiogenesis, thus NGR modified liposomes by endothelial cells and tumor angiogenesis of specificity ligand CD13 combining liposome targeting tumor area to achieve targeted therapeutic purposes.

Cell-penetrating peptide is a kind of small molecules short peptide with transmembrane transport capacity. Their sequence length is generally no more than 30 amino acids and they are rich in basic amino acids in the sequence.

Human immunodeficiency virus type 1 activation of transcription factor TAT (Hiv-1 TAT) is the first cell penetrating peptide, which penetrates peptides into cells through a non-toxic and efficient way.

An important feature of cell penetrating peptides (CPPs) is that it can carry a variety of bioactive substances of different sizes and properties into cells, including small molecular compounds, dyes, peptides, peptide nucleo acid (PNA), proteins, plasmid DNA siRNA, 200nm liposomes, phage particles and superparamagnetic particles and so on . This property makes it possible to be a good vector for targeted drugs.

As a carrier, CPPs has the advantages of low toxicity and no cell type restrictions. Although CPPs can transport different types of substances into cells, its practical application focuses on the cell transport of oligonucleotides (ONs) and their analogues.