EGFR and neoplasm: pH-sensitive H-peptide can switch from hydrophobicity to hydrophilicity in an acidic environment (pH from 6.0 to 6.5 in the tumor microenvironment) due to the protonation of imidazolyl groups, whose conformation changes induced an open and polar structure, thereby exposing the hidden P-peptides for targeting epithelial growth factor receptor (EGFR) on human tongue squamous carcinoma SAS cells and R-peptides for targeting nuclei.