PTPN22 and breast cancer: LyP-1-peptide: CysGlyAsnLysArgThrArgGlyCys; LyP-1 is an active targeting moiety to gC1qR receptor; pH-sensitive aconityl linkage between PEG and polypeptide fragments contributes to the increased release at pH 5.0; DH up to 200 nm; effective accumulation in MDA-MB-231 breast cancer cells; profound inhibitory effect in an in vitro metastasis inhibition model