EGFR and ovarian cancer: Based on the theory of RNA interference (RNAi)2–4, the present study combined molecular imaging and gene therapy with SPIO as the MRI negative contrast agent, PLL as the gene carrier, and ovarian cancer EGFR as the gene target, in order to design the shRNA (short hairpin RNA), and construct the specific SPIO-sh RNA molecules probe (SPIO-shRNA, hereinafter referred to as probe).