Sensitive New Assay System for Serum Wisteria floribunda Agglutinin-Reactive Ceruloplasmin\nThat Distinguishes Ovarian Clear Cell Carcinoma from Endometrioma

Wisteria floribunda agglutinin (WFA)-reactive\nceruloplasmin (CP) is a candidate marker for ovarian clear cell carcinoma\n(CCC) reported in our previous paper. Herein, a new measurement system\nwas developed to investigate its potential as a serum marker for CCC.\nSite-specific glycome analysis using liquid chromatography/mass spectrometry\nshowed that WFA-CP from CCC binds to WFA via the GalNAcβ1,4GlcNAc\n(LDN) structure. We used mutant recombinant WFA (rWFA), which has\na high specificity to the LDN structure, instead of native WFA, to\nincrease the specificity of the serum sample measurement. To improve\nthe sensitivity, we used a surface plasmon field-enhanced fluorescence\nspectroscopy immunoassay system, which is approximately 100 times\nmore sensitive than the conventional sandwich enzyme-linked immunosorbent\nassay system. With these two improvements, the specificity and sensitivity\nof the serum rWFA-CP measurement were dramatically improved, clearly\ndistinguishing CCC from endometrioma, from which CCC originates. This\nrWFA-CP assay can be used clinically for the serodiagnosis of early-stage\nCCC, which is difficult to detect with existing serum markers.