**5. Conclusions and future perspectives**

Developments in proteomics to identify clinically relevant proteins has been widely used in scientific research. Sample preparation has been considered as one of the key steps during analysis, and as such a variety of protocols to minimize variability and to obtain best sensitivity and protein recovery from the material have been used.

Constant development of technologies that could be applied in a medical context and potentially used for screening of patient samples have been rising in recent years. Technological evolution has also had an impact to provide platforms for proteome screening of limited cell numbers, i.e. some technologies have clearly demonstrated success on the single cell level. Cellular heterogeneity at the cellular level results during tumour development that can confound analysis. Therefore, advancement of the tools for profiling of cellular subpopulations or regions of tumours has great potential to provide novel insight in mechanisms of tumour growth. Moreover, integration of developed tools with machine learning algorithms to discover and map molecules that manifest pathological development will likely lead to a better understanding of mechanisms of oncogenesis and potentially uncover therapeutic targets.
