Peptide aptamers are specific binders that are artificially created using in 
vitro evolution systems. The peptide aptamers that can detect malignant cells in 
vivo, or can bind surfaces of various materials will enable us to develop novel 
types of cancer diagnosis and cancer therapy agents by combining with various 
nano-carriers. Here, the development of peptide aptamer research is described in 
terms of artificial protein research. Also, two examples of nano-carriers are 
introduced, i. e., a ferritin, a natural caged protein, and carbon nanohorns, 
members of the carbon nanomaterial family, by focusing their potential roles in 
cancer diagnosis and cancer therapy.