The breast cancer cell line MCF-7 was treated with doxorubicin. Protein expression differences between treated and non-treated cells were semiquantitatively determined using the precursor acquisition independent from ion count (PAcIFIC) mass spectrometric method. The acquired proteomic data sets were searched for regulated Reactome pathways and Gene Ontology annotation terms using a new algorithm (SetRank). Using this approach, we described significantly changed pathways (p-value of 0.05 or less) already known to be influenced by chemotherapeutic drugs, such as chromatin organization, DNA binding, embryo development, condensed chromosome, sequence-specific DNA binding, response to oxidative stress and response to toxin. Additionally, we found pathways such as central nervous system neuron differentiation, neuron projection membrane and SNAP receptor activity explaining side-effects of doxorubicin chemotherapy, characterized as ‘chemo brain’, on a molecular level.