title: Measurement of aberrant glycosylation of prostate specific antigen can improve specificity in early detection of prostate cancer.
abstract: BACKGROUND
  We previously identified prostate cancer (PCa)-associated aberrant glycosylation of PSA, where α2,3-linked sialylation is an additional terminal N-glycan on free PSA (S2,3PSA). We then developed a new assay system measuring S2,3PSA using a magnetic microbead-based immunoassay. We compared the diagnostic accuracy of conventional PSA and percent-free PSA (%fPSA) tests.
  
  
  METHODS
  We used MagPlex beads to measure serum S2,3PSA levels using anti-human fPSA monoclonal antibody (8A6) for capture and anti-α2,3-linked sialic acid monoclonal antibody (HYB4) for detection. We determined the cutoff values in a training test and measured serum S2,3PSA levels in 314 patients who underwent biopsy, including 138 PCa and 176 non-PCa patients with PSA of <10.0 ng/ml. Serum S2,3PSA levels were presented as mean fluorescence intensity (MFI). Receiver operating characteristic curves were used to evaluate the diagnostic accuracy of total PSA, %fPSA, and S2,3PSA.
  
  
  RESULTS
  We determined an MFI cutoff value of 1130 with a sensitivity of 95.0% and specificity of 72.0% for the diagnosis of PCa in the training test. In the validation study, the area under the curve for the detection of PCa with S2,3PSA was 0.84, which was significantly higher than that with PSA or %fPSA.
  
  
  CONCLUSIONS
  Although the present study is small and preliminary, these results suggest that the measurement of serum S2,3PSA using a magnetic microbead-based immunoassay may improve the accuracy of early detection of PCa and reduce unnecessary prostate biopsy.
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Yoneyama
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan. Electronic address: coyama@cc.hirosaki-u.ac.jp.
authors.forename: Chikara
authors.initials: C
authors.lastname: Ohyama
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Hatakeyama
authors.affiliation: Department of Urology , Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Narita
authors.affiliation: Department of Urology , Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Habuchi
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Koie
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Food and Nutrition, Junior College Division, University of Aizu, 1-1 Aza Kadota, Oaza Yahata, Ikki-machi, Aizuwakamatsu 965-0003, Fukushima, Japan; Department of Biochemistry, University of Shizuoka, School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 442-8002, Shizuoka, Japan.
authors.forename: Kazuya I P J
authors.initials: KI
authors.lastname: Hidari
authors.affiliation: Department of Biochemistry, University of Shizuoka, School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 442-8002, Shizuoka, Japan.
authors.forename: Maho
authors.initials: M
authors.lastname: Yamaguchi
authors.affiliation: Department of Biochemistry, University of Shizuoka, School of Pharmaceutical Sciences, 52-1 Yada, Suruga-ku, Shizuoka 442-8002, Shizuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki 036-8562, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tobisawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D055088:Early Detection of Cancer; D006031:Glycosylation; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods / Q000706:statistics & numerical data; D007610:Kallikreins / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D011993:Recombinant Fusion Proteins; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: Cancer associated aberrant glycosylation; Immunoassay; Prostate specific antigen; α2,3-linked sialylation