Pilot study for bladder cancer detection with volatile organic compounds using ion mobility spectrometry: a novel urine-based approach.

PURPOSE: Despite many efforts, no reliable urinary marker system has so far shown the potential to substitute cystoscopy. Measuring volatile organic compounds (VOCs) from urine is a promising alternative. VOCs are metabolic products which can be measured from the headspace of urine samples. Previous studies confirmed that the urine of bladder tumor patients has a different VOC profile than healthy controls. In this pilot study, the feasibility of discriminating VOCs from urine of bladder cancer patients from that of healthy control subjects was investigated. Aim of this study was to investigate whether VOC-based diagnosis of bladder cancer from urine samples is feasible using multicapillary column ion mobility spectrometry (MCC/IMS) and to identify potential molecular correlates to the relevant analytes. METHODS: Headspace measurements of urine samples of 30 patients with confirmed transitional cell carcinoma (TCC) and 30 healthy controls were performed using MCC/IMS. In the results of the measurements, peaks showing significant differences between both groups were identified and implemented into a decision tree with respect to achieve group separation. Molecular correlates were predicted using a pre-defined dataset. RESULTS: Eight peaks with significantly differing intensity were identified, 5 of which were highly significant. Using a six-step decision tree, MCC/IMS showed a sensitivity of 90% and specificity of 100% in group separation. CONCLUSION: VOC-based detection of bladder cancer is feasible. MCC/IMS is a suitable method for urine-based diagnosis and should be further validated. The molecular characteristics and metabolic background of the analytes require further workup.

A founder COL4A4 pathogenic variant resulting in autosomal recessive Alport syndrome accounts for most genetic kidney failure in Romani people.

Introduction: Romani people have a high prevalence of kidney failure. This study examined a Romani cohort for pathogenic variants in the COL4A3, COL4A4, and COL4A5 genes that are affected in Alport syndrome (AS), a common cause of genetic kidney disease, characterized by hematuria, proteinuria, end-stage kidney failure, hearing loss, and eye anomalies. Materials and methods: The study included 57 Romani from different families with clinical features that suggested AS who underwent next-generation sequencing (NGS) of the COL4A3, COL4A4, and COL4A5 genes, and 83 family members. Results: In total, 27 Romani (19%) had autosomal recessive AS caused by a homozygous pathogenic c.1598G>A, p.Gly533Asp variant in COL4A4 (n = 20) or a homozygous c.415G>C, p.Gly139Arg variant in COL4A3 (n = 7). For p.Gly533Asp, 12 (80%) had macroscopic hematuria, 12 (63%) developed end-stage kidney failure at a median age of 22 years, and 13 (67%) had hearing loss. For p.Gly139Arg, none had macroscopic hematuria (p = 0.023), three (50%) had end-stage kidney failure by a median age of 42 years (p = 0.653), and five (83%) had hearing loss (p = 0.367). The p.Gly533Asp variant was associated with a more severe phenotype than p.Gly139Arg, with an earlier age at end-stage kidney failure and more macroscopic hematuria. Microscopic hematuria was very common in heterozygotes with both p.Gly533Asp (91%) and p.Gly139Arg (92%). Conclusion: These two founder variants contribute to the high prevalence of kidney failure in Czech Romani. The estimated population frequency of autosomal recessive AS from these variants and consanguinity by descent is at least 1:11,000 in Czech Romani. This corresponds to a population frequency of autosomal dominant AS from these two variants alone of 1%. Romani with persistent hematuria should be offered genetic testing.

Non-invasive Detection of Bladder Tumors Through Volatile Organic Compounds: A Pilot Study with an Electronic Nose.

BACKGROUND/AIM: Cystoscopy, the standard diagnostic for bladder tumors, is uncomfortable, invasive, and expensive. The available urine-based marker systems all lack accuracy. Measuring volatile organic compounds (VOCs) from urine is a promising alternative. This pilot study evaluates the feasibility of discriminating bladder cancer patients' urine from healthy controls with an electronic nose. MATERIALS AND METHODS: Headspace measurements of urine samples of 30 patients with confirmed transitional cell carcinoma (TCC) and 30 healthy controls were performed with Cyranose 320 calculating Mahalanobis distance and linear discriminant analysis. Histology reports following TUR-BT were correlated with urine findings. RESULTS: After storage at -20°C, Cyranose correctly detected 28/30 already confirmed TCC samples and 26/30 healthy controls (p<0.01), sensitivity 93.3%, specificity 86.7%. Storage at -80°C led to similar results: 28/30 tumor samples and 28/30 control samples were correctly allocated; sensitivity and specificity both 93.3%. CONCLUSION: VOC detection is a promising tool to detect bladder tumors. Further research will test against possible confounders like bacteriuria.

Familial hematuria: A review.

The most frequent cause of familial glomerular hematuria is thin basement membrane nephropathy (TBMN) caused by germline COL4A3 or COL4A4 gene mutations. Less frequent but important cause with respect to morbidity is Alport syndrome caused by germline COL4A5 gene mutations. The features of Alport syndrome include hematuria, proteinuria and all males with X-linked disease and all individuals with recessive disease will develop end stage renal disease, usually at early youth. In X-linked Alport syndrome, a clear genotype-phenotype correlation is typically observed in men. Deleterious COL4A5 mutations are associated with a more severe renal phenotype and more frequent high-frequency sensorineural hearing loss and ocular abnormalities. Less severe COL4A5 mutations result in a milder phenotype, with less frequent and later onset extrarenal anomalies. The phenotype in females is highly variable, mostly due to inactivation of one of the X chromosomes. Isolated cases may be caused by de novo COL4A5 mutations or by gonosomal mosaicism. Untreated autosomal recessive Alport syndrome, caused by COL4A3 and COL4A4 mutations, is typically associated with ESRD at the age of 23-25 years and extrarenal symptoms in both men and women. The TBMN phenotype is associated with heterozygous carriers of COL4A3, COL4A4 mutations. Molecular genetic testing is the gold standard for diagnosing these diseases. Although genotype-phenotype correlations exist, the phenotype is influenced by modifying factors, which remain mainly undefined. No therapy is available that targets the cause of Alport syndrome; angiotensin-converting enzyme inhibitor therapy delays renal failure and improves lifespan.

Genomics and the prediction of xenobiotic toxicity.

The systematic identification and functional analysis of human genes is revolutionizing the study of disease processes and the development and rational use of drugs. It increasingly enables medicine to make reliable assessments of the individual risk to acquire a particular disease, raises the number and specificity of drug targets and explains interindividual variation of the effectiveness and toxicity of drugs. Mutant alleles at a single gene locus for more than 20 drug metabolizing enzymes are some of the best studied individual risk factors for adverse drug reactions and xenobiotic toxicity. Increasingly, genetic polymorphisms of transporter and receptor systems are also recognized as causing interindividual variation in drug response and drug toxicity. However, pharmacogenetic and toxicogenetic factors rarely act alone; they produce a phenotype in concert with other variant genes and with environmental factors. Environmental factors may affect gene expression in many ways. For instance, numerous drugs induce their own and the metabolism of other xenobiotics by interacting with nuclear receptors such as AhR, PPAR, PXR and CAR. Genomics is providing the information and technology to analyze these complex situations to obtain individual genotypic and gene expression information to assess the risk of toxicity.