## 5 Results  
There was no significant difference in patient age and BMI between the study group and the control group (age: \(p\) = 0.083, BMI: \(p\) = 0.385). Details are presented in Table 3.  
There was no correlation between sex in the considered groups (\(p\) = 0.343). Similarly, no association was found for hypertension (\(p\) = 0.205) and smoking (\(p\) = 0.911). However, a correlation was found between the occurrence of diabetes (\(p\) < 0.05). In the study group, the calculated odds ratio indicates that the chance of developing diabetes was more than five times higher than in the control group (OR = 5.8, 95% CI: 1.3-26.9). Details are presented in Table 4.  
Comparisons of the concentrations of measured parameters showed that the concentrations of IGF-1R (\(p\) = 0.289) and ERK2 (\(p\) = 0.901) did not show statistically significant differences between groups. The concentration of EGFR was significantly lower (\(p\) < 0.001) in the control group compared to the study group (Table 5). Details of EGFR are shown in Figure 1 and the Supplementary Material (Table S2). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Variant**} & \multicolumn{2}{c}{**Control Group**} & \multicolumn{2}{c}{**Study Group**} & \multirow{2}{*}{\(\chi^{2}\)} & \multirow{2}{*}{\(p\)} \\  & & **n (\%)** & & & \\ \hline \multirow{2}{*}{**Sex**} & Male & 23 (37\%) & 36 (45\%) & \multirow{2}{*}{0.90} & \multirow{2}{*}{0.343} \\  & Female & 39 (63\%) & 44 (55\%) & & \\ \hline \multirow{2}{*}{**Diabetes**} & Yes & 2 (3\%) & 13 (16\%) & \multirow{2}{*}{6.27} & \multirow{2}{*}{\(<\)0.05} \\  & No & 60 (97\%) & 67 (84\%) & & \\ \hline \multirow{2}{*}{**Hypertension**} & Yes & 17 (27\%) & 30 (38\%) & \multirow{2}{*}{1.60} & \multirow{2}{*}{0.205} \\  & No & 45 (73\%) & 50 (62\%) & & \\ \hline \multirow{2}{*}{**Smoking**} & Yes & 9 (14\%) & 12 (15\%) & \multirow{2}{*}{0.01} & \multirow{2}{*}{0.911} \\  & No & 53 (86\%) & 68 (85\%) & & \\ \hline \hline \end{tabular} Legend: \(\chi^{2}\)—Chi-square test of independence statistic value, \(p\)—statistical significance.  
\end{table} 
Table 4: Characteristics of the study and control groups. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \begin{tabular}{c} **Control Group** \\ **M \(\pm\) SD** \\ \end{tabular} & \begin{tabular}{c} **Study Group** \\ **M \(\pm\) SD** \\ \end{tabular} & \
\begin{tabular}{c} **t** \\ **\end{tabular} &
\begin{tabular}{c} **_p_** \\ **\end{tabular} \\ \hline
**Age [years]** & 52.7 \(\pm\) 11.5 & 56.2 \(\pm\) 12.5 & 1.75 & 0.083 \\ \hline
**BMI [kg/m2]** & 26.3 \(\pm\) 4.1 & 26.2 \(\pm\) 5.3 & 0.87 & 0.385 \\ \hline \hline \end{tabular} Legend: M \(\pm\) SD—mean \(\pm\) standard deviation, t—Student’s \(t\)-test statistic value, \(p\)—statistical significance.  
\end{table} 
Table 3: Comparison of demographic characteristics between the study and the control group. There were no significant difference between concentrations of proteins and age, Ki-67, and clinical stage. However, a significant negative correlation was found between EGFR and BMI in the control group (\(p\) < 0.05). Details are presented in Table 6. There was also no significant difference between concentrations of proteins and other parameters like histological grade, metastasis, liver metastasis, lymph node metastasis, and bone metastasis. There were no differences depending on the location of the primary tumor in the IGF-1R variable (\(p\) = 0.968) and in the ERK2 variable (\(p\) = 0.980); however, there were differences in EGFR concentration (\(p\) < 0.001). Higher EGFR values were found in GEP-NETs (Table 7). Analyses performed for the location of the primary lesion (lung, pancreas, small intestine,