Beta‐Microseminoprotein in Serum Correlates With the Levels in Seminal Plasma of Young, Healthy Males

Abstract

Beta-microseminoprotein (MSP) is one of the most abundant proteins secreted by the prostate gland. Because MSP is also synthesized in nonreproductive organs, the establishment of a solid relationship between the levels of MSP in serum and semen is crucial for future studies connecting MSP with aging or diseases of the prostate gland. We developed a specific, competitive, europiumbased immunoassay to measure MSP in serum and seminal plasma. We also produced recombinant MSP in insect cells using baculo virus and purified it to homogeneity by a novel approach with ethanol extraction and gel filtration. The median values of MSP in 205 young men were 12 mg/L (2.5-97.5 percentile, 4.9-26 mg/L) in serum and 0.53 g/L (2.5-97.5 percentile, 0.13-2.0 g/L) or 1.8 mg (2.5-97.5 percentile, 0.32-6.6 mg) in seminal plasma. MSP in serum showed significant correlation to MSP in seminal plasma (r 5 .50, P , .001). Significant correlations were also found in seminal plasma between MSP and prostate-specific antigen (PSA) (r 5 .65, P , .001) and between MSP and Zn 2+ (r 5 .54, P , .001). The yield of recombinant MSP in culture medium was 35 mg/L or higher, and recovery following ethanol extraction was 80%-90%. MSP in serum reflects the prostate secretion of MSP, and correlations were also found in seminal plasma between MSP and PSA and Zn 2+. This suggests that MSP in serum can be used as a marker of prostate secretion, despite the contribution from extra prostatic tissues.

Vasectomy and Prostate Cancer Risk in the European Prospective Investigation Into Cancer and Nutrition (EPIC)

“…Each control had been selected at random from the cohort of men who were alive and free of cancer (excluding nonmelanoma skin cancer) at the time of diagnosis of their index case, using an incidence density sampling protocol (further details on matching methods can be found in Travis et al). 21 Immunoassay measurements for total PSA, free PSA, 22 intact PSA, human kallikrein 2 (hK2), 23,24 and microseminoprotein-β (MSP) 25,26 were conducted in samples from 1,469 men on the AutoDELFIA 1235 automatic immunoassay system (PerkinElmer, Turku, Finland) at the Wallenberg Research Laboratories, Department of Translational Medicine, Lund University, Skåne University Hospital, Sweden. 27,28 All intra- and interassay coefficients of variation were < 9%.…”

Detection of High Grade Prostate Cancer among PLCO Participants Using a Prespecified 4-Kallikrein Marker Panel

“…Immunoassay measurements of total and free PSA, 15 intact PSA, 16 hK2, 17 and MSP, 18 were conducted on AutoDelfia ® 1235 automatic immunoassay systems (Wallenberg Research Laboratories, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden). Free and total PSA were measured using the dual-label DELFIA Prostatus ® total/free PSA-Assay (Perkin-Elmer, Turku, Finland) calibrated against the World Health Organization (WHO) 96/670 (PSA-WHO) and WHO 68/668 (free PSA-WHO) standards.…”

Growth inhibition properties of the putative prostate cancer biomarkers PSP94 and CRISP-3

“…However, both proteins can also be detected in serum where the level of PSP94 correlates with that in seminal plasma. 8 However, this correlation does not hold for CRISP-3, because the latter is also derived from other sources, including neutrophilic granulocytes. Several gene expression-profiling and immunohistochemical studies have revealed that the expression of the MSMB gene gradually decreases during development PCa, i.e., from primary PCa to the late, highly invasive, androgen-independent state (reviewed in Ref.…”