Ratio of free-to-total prostate specific antigen correlates with tumor volume in patients with increased prostate specific antigen

Electrochemical immunosensing of tumor markers

The rising incidence and mortality rates of cancer have led to a growing need for precise and prompt early diagnostic approaches to effectively combat this disease. However, traditional methods employed for detecting tumor cells, such as histopathological and immunological techniques, are often associated with complex procedures, high analytical expenses, elevated false positive rates, and a dependence on experienced personnel. Tracking tumor markers is recognized as one of the most effective approaches for early detection and prognosis of cancer. While onco-biomarkers can also be produced in normal circumstances, their concentration is significantly elevated when tumors are present. By monitoring the levels of these markers, healthcare professionals can obtain valuable insights into the presence, progression, and response to treatment of cancer, aiding in timely diagnosis and effective management. This review aims to provide researchers with a comprehensive overview of the recent advancements in tumor markers using electrochemical immunosensors. By highlighting the latest developments in this field, researchers can gain a general understanding of the progress made in the utilization of electrochemical immunosensors for detecting tumor markers. Furthermore, this review also discusses the current limitations associated with electrochemical immunosensors and offers insights into paving the way for further improvements and advancements in this area of research.

Phage Display's Prospects for Early Diagnosis of Prostate Cancer

Prostate cancer (PC) is the second most diagnosed cancer among men. It was observed that early diagnosis of disease is highly beneficial for the survival of cancer patients. Therefore, the extension and increasing quality of life of PC patients can be achieved by broadening the cancer screening programs that are aimed at the identification of cancer manifestation in patients at earlier stages, before they demonstrate well-understood signs of the disease. Therefore, there is an urgent need for standard, sensitive, robust, and commonly available screening and diagnosis tools for the identification of early signs of cancer pathologies. In this respect, the "Holy Grail" of cancer researchers and bioengineers for decades has been molecular sensing probes that would allow for the diagnosis, prognosis, and monitoring of cancer diseases via their interaction with cell-secreted and cell-associated PC biomarkers, e.g., PSA and PSMA, respectively. At present, most PSA tests are performed at centralized laboratories using high-throughput total PSA immune analyzers, which are suitable for dedicated laboratories and are not readily available for broad health screenings. Therefore, the current trend in the detection of PC is the development of portable biosensors for mobile laboratories and individual use. Phage display, since its conception by George Smith in 1985, has emerged as a premier tool in molecular biology with widespread application. This review describes the role of the molecular evolution and phage display paradigm in revolutionizing the methods for the early diagnosis and monitoring of PC.

Value of Percent Free Prostate-Specific Antigen for the Prediction of Pathological Stage in Men with Clinically Localized Prostate Cancer

Purpose

To analyze if the percentage of free prostate-specific antigen (PSA) can provide additional information to the combination of local clinical stage, serum PSA and Gleason score in the prediction of final stage and pathological features of prostate cancer.

Materials and Methods

A group of 480 men with clinically localized prostate cancer underwent lymphadenectomy and radical prostatectomy. Total and free PSA were measured in preoperative serum. Clinical stage was T1 in 70.4% of patients and T2 in 29.6%. The biopsy Gleason score ranged between 2 and 4 in 5.6%, between 5 and 7 in 78.4%, and was higher than 7 in 16%. Total serum PSA was below 4.1 ng/mL in 4.3%, between 4.1 and 10 ng/mL in 66.4%, between 10.1 and 20 ng/mL in 22.5%, and higher than 20 in 6.7% of patients. The tumor was organ-confined in 49.8% and specimen-confined in 64.2%, and its pathological features were favorable in 35%.

Results

Multiple logistic regression analysis demonstrated that percent free PSA has independent predictive value for pathological stage only in the subset of patients with cT1 tumors and serum PSA between 4.1 and 10 ng/mL. In this group the probability of organ-confined cancer was 68.3% if the percent free PSA was above 15 and 56.3% if it was lower (p<0.001). The probability of specimen-confined disease was 86.6% and 71.3%, respectively (p<0.007), and the probability of favorable pathology was 59.8% and 39.6%, respectively (p<0.002). We also found higher rates of organ- and specimen-confined tumors and favorable pathology for every Gleason score when the percent free PSA was higher than 15.

Conclusions

Percent free PSA seems to provide additional information to the combination of clinical stage and Gleason score for the prediction of pathological features only in patients with clinical stage T1c and serum PSA between 4.1 and 10 ng/mL.

Antitumor activity of a novel STAT3 inhibitor and redox modulator in non-small cell lung cancer cells

NSC-743380 is a novel STAT3 inhibitor that suppresses the growth of several NCI-60 cancer cell lines derived from different tissues and induces regression of xenograft tumors in vivo at various doses. To evaluate the antitumor activity of NSC-743380 in lung cancer cells, we analyzed the susceptibility of 50 NSCLC cell lines to this compound using cell viability assay. About 32% (16 of 50) of these cell lines were highly susceptible to this compound, with a 50% inhibitory concentration (IC₅₀) of < 1 μM. In mechanistic studies, the increased numbers of apoptotic cells as well as increased PARP cleavage showed that cytotoxic effects correlate with apoptosis induction. Treatment with NSC-743380 inhibited transcription factor STAT3 activation and induced ROS production in sensitive human lung cancer cell lines but not in resistant cells. Blocking ROS generation with the antioxidant NDGA dramatically abolished NSC-743380-induced growth suppression and apoptosis, but had minimal effect on NSC-743380-induced STAT3 inhibition, suggesting that STAT3 inhibition is not caused by ROS production. Interestingly, knockdown of STAT3 with use of shSTAT3 induced ROS generation and suppressed tumor cell growth. Moreover, scavenging ROS induced by STAT3 inhibition also diminished antitumor activity of STAT3 inhibition. In vivo administration of NSC-743380 suppressed tumor growth and p-STAT3 in lung tumors. Our results indicate that NSC-743380 is a potent anticancer agent for lung cancer and that its apoptotic effects in lung cancer cells are mediated by induction of ROS through STAT3 inhibition.

Androgen regulated genes in human prostate xenografts in mice: relation to BPH and prostate cancer

Benign prostatic hyperplasia (BPH) and prostate carcinoma (CaP) are linked to aging and the presence of androgens, suggesting that androgen regulated genes play a major role in these common diseases. Androgen regulation of prostate growth and development depends on the presence of intact epithelial-stromal interactions. Further, the prostatic stroma is implicated in BPH. This suggests that epithelial cell lines are inadequate to identify androgen regulated genes that could contribute to BPH and CaP and which could serve as potential clinical biomarkers. In this study, we used a human prostate xenograft model to define a profile of genes regulated in vivo by androgens, with an emphasis on identifying candidate biomarkers. Benign transition zone (TZ) human prostate tissue from radical prostatectomies was grafted to the sub-renal capsule site of intact or castrated male immunodeficient mice, followed by the removal or addition of androgens, respectively. Microarray analysis of RNA from these tissues was used to identify genes that were; 1) highly expressed in prostate, 2) had significant expression changes in response to androgens, and, 3) encode extracellular proteins. A total of 95 genes meeting these criteria were selected for analysis and validation of expression in patient prostate tissues using quantitative real-time PCR. Expression levels of these genes were measured in pooled RNAs from human prostate tissues with varying severity of BPH pathologic changes and CaP of varying Gleason score. A number of androgen regulated genes were identified. Additionally, a subset of these genes were over-expressed in RNA from clinical BPH tissues, and the levels of many were found to correlate with disease status. Our results demonstrate the feasibility, and some of the problems, of using a mouse xenograft model to characterize the androgen regulated expression profiles of intact human prostate tissues.

Identification of novel androgen-responsive genes by sequencing of LongSAGE libraries

BACKGROUND

The development and maintenance of the prostate is dependent on androgens and the androgen receptor. The androgen pathway continues to be important in prostate cancer. Here, we evaluated the transcriptome of prostate cancer cells in response to androgen using long serial analysis of gene expression (LongSAGE) libraries.

RESULTS

There were 131 tags (87 genes) that displayed statistically significant (p

CONCLUSION

These processes may represent the molecular mechanisms of androgen-dependency of the prostate. Genes that participate in these pathways may be targets for therapies or biomarkers of prostate cancer.

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Key Words Collapse

MESH Headings

• Androgens/metabolism
• Animals
• Cell Line, Tumor
• Gene Expression Profiling/methods
• Gene Expression Regulation, Neoplastic
• Genes, Neoplasm
• Humans
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Prostatic Neoplasms/genetics
• RNA, Neoplasm/genetics

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Grants

• R01 CA105304 NCI NIH HHS
• CA105304 NCI NIH HHS

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Affiliation(s)

Tammy L Romanuik Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
Gang Wang Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
Robert A Holt Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
Steven JM Jones Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
Marco A Marra Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
Marianne D Sadar Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada

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Total and Gleason grade 4/5 cancer volumes are major contributors of human kallikrein 2, whereas free prostate specific antigen is largely contributed by benign gland volume in serum from patients with prostate cancer or benign prostatic biopsies

PURPOSE

We measured concentrations of human glandular kallikrein 2 (hK2), total prostate specific antigen (tPSA), free PSA (fPSA) and percent fPSA to evaluate their relationship to total prostate gland volume, benign prostatic hyperplasia (BPH) volume, total prostate cancer (PCa) volume (CaVol) and the volume of Gleason grades 4/5 cancer (CaVolGl4) in the serum of 256 patients with PCa undergoing radical retropubic prostatectomy and 185 with negative systematic sextant biopsies.

MATERIALS AND METHODS

Free and total PSA was measured using the Delfia Prostatus (Perkin-Elmer, Turku, Finland) total/free PSA assay and hK2 was measured using a research immunofluorometric assay. Transrectal ultrasound was used to determine total prostate and BPH volume. Total CaVol and CaVolGl4/5 were calculated using a volumetric program in specimens from 158 men with pT2a/b and 98 with pT3a or greater PCa. The Pearson correlation was performed after logarithmic conversion of PSA and hK2 levels. Benign gland, and pT2a/b and pT3a or greater PCa cases were subdivided into small vs large prostate gland volumes (42 cc or less vs greater than 42 cc).

RESULTS

Total prostate and BPH volumes correlated closely with free PSA (r = 0.64 to 0.65, p <0.0001) in 143 patients with negative biopsy and a prostate of greater than 42 cc. Correlations of hK2 and tPSA with total prostate and BPH volumes were weaker (r = 0.35 to 0.36 and 0.45 to 0.46, respectively). In pT2a/b and pT3a or greater PCa cases hK2 most closely correlated with CaVol (range 0.31 to 0.62, p = 0.0072 and <0.0001) and with CaVolGl4/5 (range 0.26 to 0.56, p = 0.021 and <0.0001, respectively). The tPSA level correlated significantly with CaVol and CaVolGl4/5 except in glands 42 cc or greater harboring pT2a/b PCa (p = 0.08). Free PSA correlated significantly with CaVolGl4/5 only in pT3a or greater PCa (p <0.05), and with CaVol in pT3a or greater PCa and in small prostates harboring pT2a/b PCa.

CONCLUSIONS

Large benign prostate gland volume affects fPSA more than tPSA in serum. In PCa hK2 more closely correlates with total cancer volume and high grade PCa volume compared with tPSA or fPSA.

Value of Percent Free Prostate-Specific Antigen for the Prediction of Pathological Stage in Men with Clinically Localized Prostate Cancer

Purpose

To analyze if the percentage of free prostate-specific antigen (PSA) can provide additional information to the combination of local clinical stage, serum PSA and Gleason score in the prediction of final stage and pathological features of prostate cancer.

Materials and Methods

A group of 480 men with clinically localized prostate cancer underwent lymphadenectomy and radical prostatectomy. Total and free PSA were measured in preoperative serum. Clinical stage was T1 in 70.4% of patients and T2 in 29.6%. The biopsy Gleason score ranged between 2 and 4 in 5.6%, between 5 and 7 in 78.4%, and was higher than 7 in 16%. Total serum PSA was below 4.1 ng/mL in 4.3%, between 4.1 and 10 ng/mL in 66.4%, between 10.1 and 20 ng/mL in 22.5%, and higher than 20 in 6.7% of patients. The tumor was organ-confined in 49.8% and specimen-confined in 64.2%, and its pathological features were favorable in 35%.

Results

Multiple logistic regression analysis demonstrated that percent free PSA has independent predictive value for pathological stage only in the subset of patients with cT1 tumors and serum PSA between 4.1 and 10 ng/mL. In this group the probability of organ-confined cancer was 68.3% if the percent free PSA was above 15 and 56.3% if it was lower (p<0.001). The probability of specimen-confined disease was 86.6% and 71.3%, respectively (p<0.007), and the probability of favorable pathology was 59.8% and 39.6%, respectively (p<0.002). We also found higher rates of organ- and specimen-confined tumors and favorable pathology for every Gleason score when the percent free PSA was higher than 15.

Conclusions

Percent free PSA seems to provide additional information to the combination of clinical stage and Gleason score for the prediction of pathological features only in patients with clinical stage T1c and serum PSA between 4.1 and 10 ng/mL.

The free/total prostate-specific antigen ratio (%fPSA) is the best predictor of tumor involvement in the radical prostatectomy specimen among men with an elevated PSA

BACKGROUND

The relationship between the free-to-total prostate-specific antigen ratio (%fPSA) and prostate cancer (CaP) pathology remains controversial. Previous reports have shown a direct correlation between %fPSA and prostate volume as well as an indirect correlation between %fPSA and unfavorable CaP pathology, particularly among men with an elevated PSA. We evaluated the use of %fPSA to predict CaP pathology including percent of tumor involvement in the radical prostatectomy (RP) specimen.

METHODS

We prospectively analyzed 124 consecutive patients with CaP who underwent RP. In all patients, preoperative frozen serum was analyzed for assessment of %fPSA (Abbott Axsym). Pathologic review was performed using whole mount sections and total tumor volume was determined by planimetry. Statistical comparison between %fPSA and pathology was performed using log transformation.

RESULTS

Percent fPSA was indirectly correlated with prostate volume in both the entire group (N=124) and among those patients (N=87) with a total PSA >4 ng/mL (P<0.001). Overall, both %fPSA and total PSA also correlated with total tumor volume (P=0.03 and P=0.01, respectively) and Gleason sum (P<0.001 and P<0.01). When we evaluated the percent of tumor involvement (tumor density) defined as the volume of tumor per gland divided by total gland volume, for the entire population, both total PSA and %fPSA were predictive with equal significance (P<0.001). However, among the subset of patients with a PSA>4.0 ng/mL, there was only a significant correlation between tumor density and %fPSA as compared to total PSA (P<0.001 vs. P=0.06, respectively).

CONCLUSIONS

Independent of prostate volume, %fPSA is reflective of CaP pathology. Specifically, %fPSA was inversely correlated with tumor volume, Gleason sum and ECE. Among patients with modest PSA elevations, %fPSA was better than PSA in predicting percent of tumor involvement (tumor density) in the RP specimen.