## 3 Results  
The 20S proteasome and UCH-L1 concentrations in the blood serum and urine of patients with bladder cancer and healthy donors were measured using the SPRi biosensor, and the results are presented in Table 2 and Figure 2.  
A significant difference in serum and urine concentrations of 20S proteasome and UCH-L1 was observed between patients with bladder cancer and healthy subjects. The 20S proteasome concentrations in the serum of bladder cancer patients and healthy donors were in the ranges 3.75-36.42 \(\mathrm{\SIUnitSymbolMicro mL}\) and 0.89-4.01 \(\mathrm{\SIUnitSymbolMicro mL}\), respectively, while the urine 20S proteasome concentration was in the range 0.32-3.81 \(\mathrm{\SIUnitSymbolMicro mL}\) for cancer patients and 0.07-0.68 \(\mathrm{\SIUnitSymbolMicro mL}\) for healthy donors. The serum UCH-L1 concentration was in the range 1.47-22.61 \(\mathrm{\SIUnitSymbolMicro mL}\) for \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Bladder Cancer Patients**} & \multicolumn{2}{c}{**Healthy Donors**} & & \\ \hline  & **Average** & **Median** & **Average** & **Median** & \(p\) & **Test** \\ \hline Proteasome serum [\(\mathrm{\SIUnitSymbolMicro mL}\)] & 15.45 & 15.13 & 2.72 & 2.89 & \(<\)0.0001 & T-Student for independent \\ \hline Proteasome urine [\(\mathrm{\SIUnitSymbolMicro mL}\)] & 1.69 & 1.81 & 0.26 & 0.24 & \(<\)0.0001 & U-Mann \\  & & & & & Whitney \\ \hline UCHL-1 serum [\(\mathrm{\SIUnitSymbolMicro mL}\)] & 4.97 & 4.72 & 0.45 & 0.45 & \(<\)0.0001 & U-Mann \\  & & & & & Whitney \\ \hline UCHL-1 urine [\(\mathrm{\SIUnitSymbolMicro mL}\)] & 0.63 & 0.66 & 0.18 & 0.18 & \(<\)0.0018 & U-Mann–Whitney \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Concentrations of 20S proteasome and UCH-L1 in the examined samples. Figure 2: Concentrations of 20S proteasome and UCH-L1 in the serum and urine of bladder cancer patients and healthy subjects. (**A**) and (**C**) in serum samples and (**B**) and (**D**) in urine samples. cancer patients and 0.07-0.35 ng/mL for healthy donors. The urine UCH-L1 concentration was in the range 0.32-3.81 mg/mL for cancer patients and 0.29-0.65 ng/mL for healthy donors. The 20S proteasome concentrations in serum and urine were significantly higher in patients with bladder cancer (median values 15.13 mg/mL and 1.81 mg/mL, \(p<0.001\)) than in the controls (median 2.89 mg/mL and 0.24 mg/mL, \(p<0.001\)). Similarly, the UCH-L1 concentration in serum and urine was significantly elevated in subjects with bladder cancer (median 4.72 ng/mL and 0.66 ng/mL, \(p<0.001\)) versus healthy subjects (median 0.45 ng/mL and 0.18 ng/mL, \(p<0.001\)). The results are presented in Figure 2.  
The 20S proteasome and UCH-L1 concentration results were analysed in terms of various cancer parameters. The following factors were taken into account: the recurrent nature of the tumour, tumour stage, tumour grade, size, and multiplicity of the tumour. The serum and urine concentrations of 20S proteasome and UCH-L1 in correlation with clinicopathological characteristics are shown in Tables 3 and 4. Concentrations of 20S proteasome and UCH-L1 were detectable in all serum and urine samples. There was no significant difference in serum and urine concentrations of 20S proteasome and UCH-L1 between females and males, nor was there any correlation of these concentrations with age, either in the control group or in patients with bladder cancer. The median values of serum 20S proteasome and UCH-L1 concentration were statistically higher in patients with muscle-invasive tumour than in those with non-muscle-invasive tumour (\(p=0.0264\) for 20S proteasome, \(p=0.0001\) for UCH-L1). The concentrations were also statistically higher in patients with high-grade tumour (\(p=0.0036\) for 20S proteasome, \(p=0.0001\) for UCH-L1) than in those with low-grade tumour. Similar dependencies were found for 20S proteasome concentration in urine (higher for muscle-invasive tumour and high-grade tumour; \(p=0.0448\) and \(p=0.0033\), respectively).