Introduction

Lack of specificity in PSA test for early detection of prostate cancer (PCa) is one of the major issues all over the world. Therefore, the development of novel assay system with improved specificity is urgently needed. We identified PCa-associated aberrant glycosylation of PSA (S2,3PSA) and developed an automated-microcapillary electrophoresis-based immunoassay system (μTAS method). Furthermore, we successfully applied this assay system for clinical setting.

Methods

S2,3PSA was clearly differentiated by the lectin reactivity to recognize aberrant glycosylation on free PSA (fPSA) and calculate the ratio (%) in the microfluidic separation channel with fPSA antibody-label conjugates. We measured %S2,3PSA by utilizing μTAS method with extremely shortened assay time (9 min) and evaluated the cutoff values in biopsy proven patient samples (103 with PCa and 50 with non-PCa ) including PSA less than 20.0 ng/ml. Receiver operating characteristic (ROC) curves were used to evaluate diagnostic accuracy for %S2,3PSA in comparison with other methods.

Results

%S2,3PSA of PCa was significantly higher than those of non-PCa (p < 0.0001) and the appropriate cutoff value was determined to be 40% of S2,3PSA ratio in terms of diagnostic accuracy. The area under the curve (AUC) for the detection of PCa with %S2,3PSA ratio was 0.851, which was significantly more effective than that with total PSA (AUC; 0.658). And also, good correlation in this assay with Gleason score after radical prostatectomy (pGS) was suggested for the discrimination of high risk PCa. Especially, high-risk PCa patients with GS≥4+3 could be separated by the S2,3PSA percentage cut off of 50%, achieving a high performance (AUC; 0.921).

Conclusions

Although the present study is still preliminary, these results suggest that the newly developed serum %S2,3PSA test may contribute improved diagnostic accuracy having good correlation with prostatectomy Gleason score. Additional validation studies are warranted.

Funding

none