BACKGROUND: MicroRNAs (miRNAs) are small, noncoding RNAs that play an important role in regulating various biological processes through their interaction with cellular messenger RNAs. Extracellular miRNAs in serum, plasma, saliva, and urine have recently been shown to be associated with various pathological conditions including cancer. METHODS: With the goal of assessing the distribution of miRNAs and demonstrating the potential use of miRNAs as biomarkers, we examined the presence of miRNAs in 12 human body fluids and urine samples from women in different stages of pregnancy or patients with different urothelial cancers. Using quantitative PCR, we conducted a global survey of the miRNA distribution in these fluids. RESULTS: miRNAs were present in all fluids tested and showed distinct compositions in different fluid types. Several of the highly abundant miRNAs in these fluids were common among multiple fluid types, and some of the miRNAs were enriched in specific fluids. We also observed distinct miRNA patterns in the urine samples obtained from individuals with different physiopathological conditions. CONCLUSIONS: MicroRNAs are ubiquitous in all the body fluid types tested. Fluid type–specific miRNAs may have functional roles associated with the surrounding tissues. In addition, the changes in miRNA spectra observed in the urine samples from patients with different urothelial conditions demonstrates the potential for using concentrations of specific miRNAs in body fluids as biomarkers for detecting and monitoring various physiopathological conditions.

Aristolochic acid (AA), a component of all Aristolochia‐based herbal medicines, is a potent nephrotoxin and human carcinogen associated with upper urinary tract urothelial carcinoma (UUC). To investigate the clinical and pathological characteristics of AA‐induced UUC, this study included 152 UUC patients, 93 of whom had been exposed to AA based on the presence of aristolactam‐DNA adducts in the renal cortex. Gene sequencing was used to identify tumors with A:T‐to‐T:A transversions in TP53, a mutational signature associated with AA. Cases with both aristolactam‐DNA adducts and A:T‐to‐T:A transversions in TP53 were defined as AA‐UUC, whereas patients lacking both of these biomarkers were classified as non‐AA‐UUC. Cases with either biomarker were classified as possible‐AA‐UUC. Forty (26%), 60 (40%), and 52 (34%) patients were classified as AA‐UUC, possible‐AA‐UUC and non‐AA‐UUC, respectively. AA‐UUC patients were younger (median ages: 64, 68, 68 years, respectively; p=0.189), predominately female (65%, 42%, 35%, respectively; p=0.011), had more end‐stage renal disease (28%, 10%, 12%, respectively; p=0.055), and were infrequent smokers (5%, 22%, 33%, respectively; p=0.07) compared to possible‐AA‐UUC and non‐AA‐UUC patients. All 14 patients who developed contralateral UUC had aristolactam‐DNA adducts; ten of these also had signature mutations. The contralateral UUC‐free survival period was shorter in AA‐UUC compared to possible‐ or non‐AA‐UUC (p=0.019 and 0.002, respectively), whereas no differences among groups were observed for bladder cancer recurrence. In conclusion, AA‐UUC patients tend to be younger and female, and have more advanced renal disease. Notably, AA exposure was associated with an increased risk for developing synchronous bilateral and metachronous contralateral UUC.

We investigated the epidemiology of upper urinary tract stone disease in Taiwan using a nationwide, population based database. This study was based on the National Health Insurance Research Database of Taiwan, which contains data on all medical beneficiary claims from 22.72 million enrollees, accounting for almost 99% of the Taiwanese population. The Longitudinal Health Insurance Database 2005, a subset of the National Health Insurance Research Database, contains data on all medical benefit claims from 1997 through 2010 for a subset of 1 million beneficiaries randomly sampled from the 2005 enrollment file. For epidemiological analysis we selected subjects whose claims records included the diagnosis of upper urinary tract urolithiasis. The age adjusted rate of medical care visits for upper urinary tract urolithiasis decreased by 6.5% from 1,367/100,000 subjects in 1998 to 1,278/100,000 in 2010. There was a significantly decreasing trend during the 13-year period in visits from female and all subjects (r(2) = 0.86, p = 0.001 and r(2) = 0.52, p = 0.005, respectively). In contrast, an increasing trend was noted for male subjects (r(2) = 0.45, p = 0.012). The age adjusted prevalence in 2010 was 9.01%, 5.79% and 7.38% in male, female and all subjects, respectively. The overall recurrence rate at 1 and 5 years was 6.12% and 34.71%, respectively. Male subjects had a higher recurrence rate than female subjects. Our study provides important information on the epidemiology of upper urinary tract stone disease in Taiwan, helping to quantify the burden of urolithiasis and establish strategies to decrease the risk of urolithiasis.

Although Asian people have the lowest incidence and mortality rates of prostate cancer in the world, these rates have risen rapidly in the past two decades in most Asian countries. Prostate cancer has become one of the leading male cancers in some Asian countries. In 2000, the age-adjusted incidence was over 10 per 100 000 men in Japan, Taiwan, Singapore, Malaysia, the Philippines and Israel. Although some of the increases may result from enhanced detection, much of the increased incidence may be associated with westernization of the lifestyle, with increasing obesity and increased consumption of fat. The differences in incidences between native Americans and Asian immigrants are getting smaller, reflecting a possible improvement of diagnostic efforts and changes of environmental risk factors in Asian immigrants. Nevertheless, the huge variations in incidences among ethnic groups imply that there are important genetic risk factors. The stage distributions of prostate cancer in Asian populations are still unfavorable compared to those of Western developed countries. However, a trend towards diagnosing cancer with more favorable prognosis is seen in most Asian countries. Both genetic and environmental risk factors responsible for elevated risks in Asian people are being identified, which may help to reduce prostate cancer incidence in a chemopreventive setting.