Human TPSA(Total Prostate Specific Antigen) ELISA Kit

BACKGROUND: We investigated an ultrasensitive prostate-specific antigen (uPSA) immunoassay (MesoScale; lower limit of detection (LLD) of 0.0035 pg/mL) to monitor patients with prostate cancer (PCa) following radical prostatectomy (RP) and to examine whether changes in PSA in the conventionally undetectable range (<1 pg/mL) can predict biochemical relapse (BCR). METHODS: We measured uPSA in serial serum samples (N = 100) collected from 20 RP cases with a third-generation ELISA (LLD of 1 pg/mL) and the fifth-generation MesoScale assay. We analyzed the PSA nadir changes to classify patients into BCR or non-BCR groups, observed the trends in PSA kinetics, and associated BCR status with clinicohistopathological features. RESULTS: The ELISA could quantify PSA in only 38% of the RP samples, detecting BCR in 7 of 20 patients with PCa. The MesoScale assay quantified PSA in all samples, showing 8 of 20 patients with BCR. However, there was no significant difference between the median time to BCR detection based on ELISA (1016 days) compared with MesoScale data (949 days). Gleason scores were higher in the BCR groups compared with non-B CR. There was no significant difference for other clinicohistopathological parameters. CONCLUSIONS: The uPSA MesoScale technology could track miniscule changes in serum PSA in the range of 0.003-1 pg/mL in all RP cases. However, PSA kinetics and nadir at concentrations <2 pg/mL fluctuated, and increases below this range could not reliably suggest signs of BCR. Instead, ultrasensitive fifth-generation PSA assays may hold clinical potential for measuring the low concentrations of PSA in women for various medical contexts.

Background Precision medicine approaches for managing patients with metastatic castrate-resistant prostate cancer (mCRPC) are lacking. Non-invasive approaches for molecular monitoring of disease are urgently needed, especially for patients suffering from bone metastases for whom tissue biopsy is challenging. Here we utilized baseline blood samples to identify mCRPC patients most likely to benefit from abiraterone plus prednisone (AAP) or enzalutamide. Methods Baseline blood samples were collected for circulating tumor cell (CTC) enumeration and qPCR-based gene expression analysis from 51 men with mCRPC beginning treatment with abiraterone or enzalutamide. Results Of 51 patients (median age 68 years [51-82]), 22 received AAP (abiraterone 1000 mg/day plus prednisone 10 mg/day) and 29 received enzalutamide (160 mg/day). The cohort was randomly divided into training (n = 37) and test (n = 14) sets. Baseline clinical variables (Gleason score, PSA, testosterone, and hemoglobin), CTC count, and qPCR-based gene expression data for 141 genes/isoforms in CTC-enriched blood were analyzed with respect to overall survival (OS). Genes with expression most associated with OS includedMSLN,ARG2,FGF8,KLK3,ESRP2,NPR3,CCND1, andWNT5A. Using a Cox-elastic net model for our test set, the 8-gene expression signature had a c-index of 0.87 (95% CI [0.80, 0.94]) and was more strongly associated with OS than clinical variables or CTC count alone, or a combination of the three variables. For patients with a low-risk vs. high-risk gene expression signature, median OS was not reached vs. 18 months, respectively (HR 5.32 [1.91-14.80],p = 0.001). For the subset of 41 patients for whom progression-free survival (PFS) data was available, the median PFS for patients with a low-risk vs high-risk gene expression signature was 20 vs. 5 months, respectively (HR 2.95 [1.46-5.98],p = 0.003). Conclusions If validated in a larger prospective study, this test may predict patients most likely to benefit from second-generation antiandrogen therapy.