Proteasomes that are important intracellular proteolytic components maintaining the dynamic balance of the protein composition of the cell may be involved in the progression of breast cancer (BC).
OBJECTIVE
To study the prognostic role of proteasomal activity in patients with BC.
SUBJECTS AND METHODS
The investigation involved 65 patients with the morphologically verified diagnosis of BC with the process stage T13N03M0. Locoregional relapses occurred in 7.7% of the patients within 10 years after surgical intervention. The activity of proteasomes was identified in the tumor and intact tissue taken during a radical surgical intervention, according to the hydrolysis of fluorogenic oligopeptides. A statistical analysis was carried out using the generally accepted methods in the Statistica 12.0 program.
RESULTS
The presented investigation revealed an increase in the chymotrypsin-like and caspase-like activity of proteasomes by 2.52 and 2.53 times, respectively, compared with intact breast tissue; the median values of the corresponding activity were equal to 15.91 and 20.22 IU/mg of protein (p<0.01). The proteasomal activity coefficients showing the ratio between the activity of proteasomes in the tumor and unaltered tissue were also estimated. There was a relationship of the change in the chymotrypsin-like and caspase-like activity of proteasomes to the development of locoregional relapses of BC in the ten-year period. Of priority are the data that the high chymotrypsin-like activity of proteasomes in the tumor and the high coefficient of their caspase-like activity are predictors for the development of a relapse in patients with BC.
CONCLUSION
The found patterns on the relationship of proteasomal activity to the 10-year relapse-free survival are described for the first time and are important for the development of personalized medicine, as they will be able to prescribe adequate treatment to prevent the progression of BC.
