Quantitative real-time reverse transcription: polymerase chain reaction of prostate-specific antigen (PSA) for detection of circulating prostatic cells in patients with clinically localized prostate cancer

Crystal-reconstructed BiVO4 semiconductor photoelectrochemical sensor for ultra-sensitive tumor biomarker detection

In this study, we developed a crystal-reconstructed-BiVO₄ aptamer photoelectrochemical (PEC) biosensor by a high-energy laser treatment technique. This biosensor achieves a limit of detection (LOD) (0.82 ag mL^-1), linear detection range (1 ag mL^-1 to 2 ng mL^-1), and resolution ratio (∼18 molecules per mL) for prostate-specific antigen (PSA) tumor biomarker detection. Furthermore, reconstructed surface microstructure and oxygen vacancy doping energy formation after crystal reconstruction induce the stereo-hindrance effect and photogenerated hole energy is reduced during PSA target detection. In this case, a photocurrent inhibition phenomenon for PSA detection is noticed. Based on this photocurrent inversion phenomenon, some dysoxidizable nucleonic acid tumor (miRNA-21) and virus biomarkers (RdRp-COVID) can be detected with a LOD level of ∼10^-16 M by linking the corresponding base paring probe on the surface of the crystal-reconstructed photoanode. In addition to high sensitivity, this PEC biosensor presents high detection specificity, stability, and accuracy in clinical verification. Thus, this crystal-reconstructed PEC biosensor shows application potential in the fields of multi-tumor or viral biomarker detection.

Prostate-specific markers to identify rare prostate cancer cells in liquid biopsies

Despite improvements in early detection and advances in treatment, patients with prostate cancer continue to die from their disease. Minimal residual disease after primary definitive treatment can lead to relapse and distant metastases, and increasing evidence suggests that circulating tumour cells (CTCs) and bone marrow-derived disseminated tumour cells (BM-DTCs) can offer clinically relevant biological insights into prostate cancer dissemination and metastasis. Using epithelial markers to accurately detect CTCs and BM-DTCs is associated with difficulties, and prostate-specific markers are needed for the detection of these cells using rare cell assays. Putative prostate-specific markers have been identified, and an optimized strategy for staining rare cancer cells from liquid biopsies using these markers is required. The ideal prostate-specific marker will be expressed on every CTC or BM-DTC throughout disease progression (giving high sensitivity) and will not be expressed on non-prostate-cancer cells in the sample (giving high specificity). Some markers might not be specific enough to the prostate to be used as individual markers of prostate cancer cells, whereas others could be truly prostate-specific and would make ideal markers for use in rare cell assays. The goal of future studies is to use sensitive and specific prostate markers to consistently and reliably identify rare cancer cells.

Electrokinetics for sample preparation of biological molecules in biological samples using microfluidic systems

Sample preparation is the first part of every analytical method, but is often considered only after the optimization of the method. It is traditionally performed using a range of techniques requiring extensive manual handling, with solid-phase extraction, liquid–liquid extraction, protein precipitation and ultracentrfiguation, among others, being used depending on the targets and the application. In this article, we will focus on alternatives based on electrokinetics for applications including sample clean-up, concentration and derivatization of large biological molecules (DNA, peptides and proteins) of diagnostic importance, as well as small molecules as a tool for therapeutic drug monitoring. This article describes these approaches in terms of mechanisms, applicability and potential to be integrated into a lab-on-a-chip device for directly processing biological samples. Examples dealing with treated or clean samples have been excluded except where they show exceptionally high value.

Prevalence of circulating tumor cells in localized prostate cancer

BACKGROUND

Circulating tumor cells (CTC) predict overall survival in patients with metastatic prostate cancer. The objective of this study is to measure CTC before radical prostatectomy in intermediate- and high-risk prostate cancer patients.

MATERIALS AND METHODS

The study accrued 12 patients and 10 provided adequate peripheral blood sample. Blood was drawn preoperatively and assayed for CTC using the CellSearch system. Patients were categorized as CTC positive (≥ 1 CTC) or CTC negative (no CTC).

RESULTS

Median age was 64.5 years (range 49-77 years), median prostate specific antigen was 7.4 ng/ml (range 5.7-25.7 ng/ml). Seven patients had intermediate-risk and 3 patients had high-risk prostate cancer. One patient was found to be CTC positive.

CONCLUSIONS

Our pilot study shows that CTC are rare in patients with clinically localized disease despite intermediate- to high-risk features. CTC may not be the optimal marker to predict prognosis or detect residual disease after radical prostatectomy.

Quantitative RT-PCR analysis of PSA and prostate-specific membrane antigen mRNA to detect circulating tumor cells improves recurrence-free survival nomogram prediction after radical prostatectomy

BACKGROUND

Circulating tumor cell (CTC) analysis is a potential new biomarker in prostate cancer. We hypothesize that quantitative detection of CTCs in patients pre- and post-radical prostatectomy (RP) using quantitative TaqMan® fluorogenic RT-PCR will improve the accuracy of the Kattan nomogram to predict the probability of recurrence-free survival (RFS) post-RP.

METHODS

Ninty-two patients who underwent RP between 2004 and 2009 had venous blood samples taken pre- (Day - 1) and post-operatively (Day + 7). We performed quantitative Taqman® RT-PCR to detect circulating prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) mRNA. We calculated both the logarithmic ratio of Day + 7/Day - 1 for PSA (PSAr) and PSMA (PSMAr) expression (log(Day+7/Day-1) ) and the Kattan nomogram predicted probability of disease recurrence for each patient. We then analyzed how the AUC-ROC analysis for the Kattan nomogram prediction alone (K) compared to the addition of the PSAr and PSMAr in predicting 5-year RFS.

RESULTS

The mean age (years), PSA (ng/ml), and follow-up (mo) was 65.1, 9.13, and 72, respectively. The AUCs for K, PSAr + K, and PSMAr + K were 0.752 (95%CI 0.620-0.860), 0.830 (95%CI 0.740-0.911), and 0.837 (95%CI 0.613-0.923), respectively (P = 0.03). The Kattan 5-year PSA RFS was 75%. The actual 5-year PSA RFS survival rate was 77%.

CONCLUSIONS

Data from modern quantitative RT-PCR to detect circulating prostate-derived PSA and PSM mRNA pre- and post-RP improves the accuracy of the Kattan nomogram to predict biochemical recurrence.

Detection of prostate specific transcripts in the peripheral blood during brachytherapy predicts postoperative PSA kinetics

BACKGROUND

We evaluated whether detection of prostate-specific antigen (PSA) and human kallikrein 2 (hK2) transcripts in the peripheral blood during brachytherapy could predict biochemical outcome.

METHODS

Eighty-one patients who underwent (125)Iodine-based brachytherapy for localized prostate cancer (Gleason score <8, PSA <20 ng/ml, stage <T3), participated in the study. Brachytherapy was given to 35 patients as monotherapy, to 36 in combination with androgen deprivation therapy (ADT), and to 10 in combination with external beam radiation and ADT. Blood samples from 80 patients were available for analysis. Nested RT-PCR means was used to detect mRNA expression of PSA and hK2 in the peripheral blood. Their expression was analyzed before, during and 1 month after brachytherapy. Patients' biochemical outcome (blood PSA levels) during 3 years of follow-up was correlated with the PCR results.

RESULTS

The incidence of PSA and hK2 mRNA expression in the peripheral blood was significantly higher during than before or after the procedure. Patients with concurrent positive PSA and hK2 PCR results during brachytherapy had higher postoperative blood PSA values and a slower decline rate of PSA compared with patients with negative PSA and hK2 PCR results. No correlations were found between pre- and postbrachytherapy PCR results and biochemical outcome. ADT was the only significant factor that affected PSA and hK2 mRNA expression during brachytherapy.

CONCLUSIONS

Our short-term results suggest that detection of PSA and hK2 transcripts in the peripheral blood of prostate cancer patients during brachytherapy could serve as a predictor of biochemical outcome.