Quantitative assessment of serum heat shock protein 27 for the diagnosis of epithelial ovarian cancer using targeted proteomics coupled with immunoaffinity enrichment.

•An LC–MS/MS-based targeted proteomics coupled with immunoaffinity enrichment was developed.•We applied this method for the quantification of serum HSP27, and the resulting LOQ can achieve 500 pg/ml.•HSP27 provided the additional sensitivity and specificity required to improve the diagnostic and prognostic value of the CA125 test.