Diagnostic potential of major and trace elements in the serum of bladder cancer patients.

Major and trace elements may play a role in the diagnosis of diseases. In this study, we investigated the concentration of 26 major and trace elements in the serum by inductively coupled plasma (ICP) - optical emission spectrometry (OES) and ICP-sector field-mass spectrometry (sf-MS). We analyzed the serum from a discovery cohort of 6 bladder cancer (BCa) patients and 12 healthy controls as well as from a validation cohort of 21 BCa patients, 29 non-tumor bladder patients (with acute and chronic inflammation) and 18 healthy controls. Patients were recruited after written consent was obtained at one medical center. Serum was prepared from peripheral blood prior to surgical treatment. Differences in the levels of major and trace elements were determined by a nonparametric Mann-Whitney test and Kruskal-Wallis statistics. In the discovery cohort, we measured significantly increased levels of calcium, mercury, potassium, lithium, nickel, phosphorus and strontium and a significantly decreased level of sodium in BCa patients compared with healthy controls. These findings were reassessed in our validation cohort. We measured significantly increased levels of boron, calcium, cadmium, copper, chromium, lead, lithium, potassium, magnesium, nickel, sulfur, strontium, titan, vanadium and zinc and significantly decreased levels of iron and molybdenum. When we studied the concordance for the discovery and validation cohorts, concentrations of five elements were detected as significantly increased in BCa patients compared with healthy controls: calcium, lithium, potassium, nickel, and strontium. Interestingly, the levels of three elements (calcium, potassium and strontium) were also significantly increased in non-tumor bladder patients compared with healthy controls. But no element was significantly altered between non-tumor bladder patients and BCa patients. In summary, we suggest that determination of the elements calcium, lithium, nickel and strontium in the serum could be a new and promising tool for the early diagnosis of BCa.