Levels of some insulin signaling system factors in blood in non-muscle invasive bladder cancer as well as in its combination with type 2 diabetes mellitus

The aim of the research was to evaluate the changes of C-peptide and IGF-binding protein IGFBP-1 levels in the blood serum in non-muscle-invasive bladder cancer as well as in its combination with type 2 diabetes mellitus.

Patients and methods. In patients with non-muscle-invasive (NMI) bladder cancer (BC) aged 47-75 years of both sexes, the levels of C-peptide and IGF-binding protein IGFBP-1 in the blood serum were studied using ELISA methods, while traditional markers of diabetes mellitus were simultaneously assessed. The main group consisted of patients suffering from both NMI BC and type 2 diabetes mellitus (T2DM) (n=11), the control group consisted of patients with NMIBC without T2DM (n=20). The results were compared with the indicators in patients with T2DM without oncological pathology and conditionally healthy people of the same age. Statistical analysis was performed using the «Statistic 12» software package.

Results. In patients with NMI BC, against the background of the insulin content in the blood within the normal range, a sharp decrease in the level of proinsulin C-peptide (more than 11 times) and an increase in the content of IGFBP-1 protein (more than 2.5 times) were observed compared with the indicators in the group of donors and patients with type 2 diabetes mellitus without oncological pathology. A positive statistical relationship between the level of C-peptide and the insulin content in the blood, noted in the absence of a malignant process, was not been revealed in patients with NMI BC. In the presence of comorbid type 2 diabetes mellitus, these changes in the studied parameters in patients with NMIBC were expressed to a lesser extent; statistical relationships between the parameters were noted that were not found in patients without comorbid type 2 diabetes mellitus. The content of C-peptide and IGFBP-1 in the blood of patients and donors was highly variable, especially in the case of NMIBC (variation coefficient up to 130%).

Conclusion. The obtained results expand the understanding of changes in the insulin signaling system in NMIBC and its combination with T2DM and allow us to determine the directions of necessary research. The issues about the biological significance of shifts in the content of C-peptide and IGFBP-1 in the blood in NMIBC, characteristic of hypoinsulinemia, and about the influence of various medicines of hypoglycemic therapy on the state of the insulin signaling system in comorbid T2DM require further researches.