Identification and preliminary clinical evaluation of a 50.8-kDa serum marker for prostate cancer.
OBJECTIVE
To identify a 50.8-kDa biomarker to perform a preliminary clinical evaluation of its utility as an aid in the early detection of prostate cancer.


METHODS
The 50.8-kDa protein, previously called NMP48, was partially purified from the serum of an individual with prostate cancer and identified by peptide mass fingerprinting of tryptic peptides from an in-gel digest. Serum samples were obtained from men with biopsy-confirmed prostate cancer, high-grade prostatic intraepithelial neoplasia, and benign histologic features, from men with clinically defined benign prostatic hyperplasia, and from controls without prostatic disease. These samples were analyzed for the presence of the biomarker by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry.


RESULTS
The 50.8-kDa protein was identified by peptide mass fingerprinting as being related to vitamin D-binding protein. It was found in 96% of the sera from individuals with prostate cancer (n = 52) including 11 of 12 specimens that exhibited prostate-specific antigen values of less than 4 ng/mL. The 50.8-kDa protein was found in 10 of 19 samples from men with prostatic intraepithelial neoplasia; however, it was not detected in the sera of 5 (75%) of 20 individuals with benign prostatic histologic features, 7 (70%) of 10 with clinical benign prostatic hyperplasia, 8 (80%) of 10 patients who had previously undergone radical prostatectomy, or 48 (96%) of 50 specimens from healthy controls.


CONCLUSIONS
Although the study cohort was relatively small, the data suggest that an assay for the 50.8-kDa protein may be useful for the early detection of prostate cancer. Additional elucidation of its structure may yield insight into the development of this disease.
Hlavaty
John J
JJ
Matritech, Inc., Newton, Massachusetts 02460, USA.
Partin
Alan W
AW
Shue
Matthew J
MJ
Mangold
Leslie A
LA
Derby
Jennifer
J
Javier
Teofilo
T
Kelley
Shane
S
Stieg
Adam
A
Briggman
Joseph V
JV
Hass
G Michael
GM
Wu
Ying-Jye
YJ
D000595:Amino Acid Sequence; D014408:Biomarkers, Tumor / Q000097:blood* / Q000737:chemistry; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009367:Neoplasm Staging; D010449:Peptide Mapping / Q000379:methods; D011470:Prostatic Hyperplasia / Q000097:blood / Q000175:diagnosis; D019048:Prostatic Intraepithelial Neoplasia / Q000097:blood / Q000175:diagnosis; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis; D017386:Sequence Homology, Amino Acid; D014809:Vitamin D-Binding Protein / Q000097:blood / Q000737:chemistry
D014408:Biomarkers, Tumor; D014809:Vitamin D-Binding Protein