Screening for Prostate Cancer with Prostate-Specific Antigen: What's the Evidence?

Characterization and validation of long noncoding RNAs as new candidates in prostate cancer

Background

Long noncoding RNAs (lncRNAs) have been proved to be an important regulator in gene expression. In almost all kinds of cancers, lncRNAs participated in the process of pathogenesis, invasion, and metastasis. Meanwhile, compared with the large amounts of patients, there is rare knowledge about the role of lncRNAs in prostate cancer (PCa).

Material/Method

In this study, lncRNA expression profiles of prostate cancer were detected by Agilent microarray chip, 5 pairs of case and control specimens were involved in. Differentially expressed lncRNAs were screened out by volcano plot for constructing lncRNA-miRNA-mRNA central network. Then, the top ten up-regulated and down-regulated lncRNAs were validated by qRT-PCR in another 5 tumor specimens and 7 para-cancerous/benign contrasts. Furthermore, we searched for the survival curve of the top 10 upregulated and downregulated lncRNAs.

Results

A total of 817 differentially expressed lncRNAs were filtered out by the criteria of fold change (FC) and t-test p < 0.05. Among them, 422 were upregulated, whereas 395 were downregulated in PCa tissues. Gene ontology and KEGG pathway analyses showed that many lncRNAs were implicated in carcinogenesis. lnc-MYL2-4:1 (FC = 0.00141, p = 0.01909) and NR_125857 (FC = 59.27658, p = 0.00128) had the highest magnitude of change. The subsequent qPCR confirmed the expression of NR_125857 was in accordance with the clinical samples. High expression of PCA3, PCAT14 and AP001610.9 led to high hazard ratio while low expression of RP11-279F6.2 led to high hazard ratio.

Conclusions

Our study detected a relatively novel complicated map of lncRNAs in PCa, which may have the potential to investigate for diagnosis, treatment and follow-up in PCa. Our study revealed the expression of NR_125857 in human PCa tissues was most up-regulated. Further studies are needed to investigate to figure out the mechanisms in PCa.

Secondary prostate cancer screening outcomes by race in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Screening Trial

BACKGROUND

Despite disparities in prostate cancer incidence and mortality rates between black and white men, there is still insufficient data available to assess potential differences in the benefits and harms of prostate cancer screening by race. Although the Prostate, Lung, Colorectal, and Ovarian (PLCO) Screening Trial is underpowered to detect a difference by race in prostate-cancer specific mortality, because of the large study size, there are still sufficient numbers to examine secondary screening outcomes. The objective of this analysis is to examine whether differences exist between black and white participants with respect to screening false-positive rates, biopsy follow-up of men with positive screens, tumor characteristics, and overdiagnosis of prostate cancer.

METHODS

Participants from the PLCO included men aged 55-74 years at baseline. Cancer diagnoses and deaths were identified through study update questionnaires, records of biopsy procedures, and linkage with the National Death Index. Cancer characteristics were obtained by medical abstractors. We used chi-squared tests to assess differences in false-positive rates, biopsy follow-up, and tumor characteristics. We used Cox proportional hazards models to compare incidence and mortality rates adjusting for age and survival rates adjusting for Gleason scores.

RESULTS

Black men were slightly more likely (14.5%) to have a false-positive PSA test compared to white men (12.4%; P = 0.02) but less likely to have a false-positive digital rectal exam (DRE) (10.9% vs 14.2%, respectively; P < 0.001). Among all men who were screened, black men were significantly more likely to undergo a biopsy than white men (16.5% vs 13.8%, respectively [P = 0.003]) but there was no difference when limited to those with a positive PSA test. Prostate cancer tumors were more likely to be aggressive and to have metastasized in black men compared to white men. Disparities in incidence, mortality, and survival rates were comparable to those seen in population-based data.

CONCLUSIONS

There was evidence that false-positive test results differed by race and screening test. Consistent with previous studies, cancer outcomes, and tumor characteristics were all more unfavorable in black men.

The likelihood of having a serum PSA level of ≥2.5 ng/mL according to the degree of fatty liver disease in a screened population

INTRODUCTION

We sought to investigate the impact of fatty liver disease (FLD) on prostate cancer (PCa) screening by estimating the odds of having a prostate-specific antigen (PSA) value over the cutoff used to prompt for the recommendation of prostate biopsy.

METHODS

Between 2007 and 2013, 18 533 native Korean men eligible to receive a serum PSA test, liver profiles, and abdominal ultrasonography were recruited. Logistic regression was used to estimate the odds of an abnormal PSA (≥2.5 ng/mL) in these men (age 45-75 years, PSA≤10 ng/mL) in relation to FLD. The FLD status was categorized as normal, mild, moderate, and severe grade by abdominal sonography.

RESULTS

A total of 16 563 men (89.4%) were included in the study after applying the inclusion criteria. Liver profiles were negatively correlated with the serum PSA level. After controlling for age and obesity, there was a statistically significant trend towards a lower likelihood of having a serum PSA level of ≥2.5 ng/mL with severe FLD, having a 34.7% lower likelihood (odds ratio 0.653, 95% confidence interval 0.477-0.88; p<0.01) compared to men in the normal group.

CONCLUSIONS

Severe FLD is an independent predictor of a lower likelihood of having abnormal PSA level. Further studies are needed to better define these results in clinical biopsy practice.