Fig 1.
The principle of the conventional and in-house Eu+3-NP-based CA15-3 lectin assays.
In the conventional CA15-3 immunoassay, the capture and tracer mAbs bind to the protein and glycan epitopes of CA15-3. Alternatively, in the lectin assay, the CA15-3 is captured with mAbs and detected with lectins, which have been coated on the surface of Eu3+-NPs. This method allows multivalent binding of the tracer to the glycan moieties of BC-CA15-3.
Fig 2.
Lectin NPs binding to BC-associated CA15-3 from cell line ZR-75-1 (ATCC CRL-1500) using the lectin assay principle depicted in Fig 1.
The different lectin Eu+3-NPs used are shown on the x-axis and the y-axis displays the signal to background ratios using either biotinylated Ma695 (bioMa695) or biotinylated Ma552 (bioMa552) as the capture mAb.
Fig 3.
ROC plot displaying the AUC of conventional CA15-3 (green), CA15-3MGL (purple) and CA15-3WGA (red) from metastatic breast cancer patients (n = 53) and healthy control (n = 20).
The 95% confidence intervals of the ROCs are depicted as shaded areas and displayed numerically in brackets. The color of shadings corresponds to the plotted lines and the overlap of conventional CA15-3 and CA15-3MGL is dark green, the overlap of all assays is brown and the overlap of CA15-3MGL and CA15-3WGA is dark red.
Table 1.
CA15-3 levels by conventional CA15-3, CA15-3MGL, and CA15-3WGA assay for healthy controls and for metastatic BC patients at study baseline.
Table 2.
CA15-3 levels with different assays depending on the best response to the chemotherapy treatment.
Fig 4.
Correlation of the conventional CA15-3 and CA15-3Lectin assays.
A: Scatterplot of baseline conventional CA15-3 levels and baseline CA15-3MGL levels in metastatic breast cancer patients. r = 0.68, p<0.001 B: Enlargement of the scatterplot for the patients with the lowest CA15-3 levels for both conventional CA15-3 and CA15-3MGL. Very low baseline CA15-3MGL levels < 5 U/mL were observed in 29 patients (44.6%), dashed vertical line at x-axis C: Scatterplot of baseline conventional CA15-3 levels and baseline CA15-3WGA levels in metastatic breast cancer patients. r = 0.90, p<0.001. D: Enlargement of the scatterplot for the patients with conventional CA15-3 < 250 U/mL and CA15-3WGA < 130 U/mL, 85% of the study patients.
Fig 5.
CA15-3 levels of 19 patients who had a disease progression at the time of final plasma sampling and a previous reference plasma available while on study treatment (Reference).
A. Conventional CA15-3. Two patients with very high CA15-3 levels were excluded (Reference CA15-3 110.6 U/mL, Final 986.4 U/mL and Reference 1825.5 U/mL, Final 3909.7 U/mL) B. CA15-3MGL. C. CA15-3WGA. One patient with very high CA15-3WGA level was excluded (Reference CA15-3WGA 393.1 U/mL, Final CA15-3WGA 430.9 U/mL).