Additionally, our study includes a mixed population of patients treated mTOR inhibitors-based combination therapy or mTOR inhibitors alone, and patients received placebo or non-placebo therapy were also included in our study. Therefore, the treatment design is not the same in all arms, and it might be another source of heterogeneity. Finally, it is not an individual patient data analysis, and meta-analyses based on published data tend to overestimate treatment effects compared with individual patient data analyses. In addition, it precludes a more comprehensive analysis such as adjusting for baseline factors and other differences that existed between the trials from which the data were pooled. In summary, our study demonstrates that the use of mTOR inhibitors seems to increase the risk of FAEs in patients with advanced solid tumors, but one should be cautious when interpreting these results due to the limitations of our study. Additionally, as this class of drugs gains greater clinical use, clinicians should be aware of the risks of FAEs with the administration of mTOR inhibitors in solid cancer, and closely monitoring is recommended during the therapy. As the role of monoclonal antibodies in biology and medicine becomes increasingly important, so does the precise evaluation of the epitopes being recognized by the antibodies. There are many methods allowing to precisely define amino acid residues that are involved in antibody binding, such as evaluation of binding of the antibody to synthetic peptides or to recombinant peptides expressed either in bacteria on in eukaryotic cells. Recently, saturation transfer difference spectroscopy NMR has been increasingly used in epitope-antibody studies, although majority of antibodies evaluated by this method bind carbohydrate antigens. In this paper we used a variety of methods, including STD-NMR, to precisely define the peptidic epitope of 2C3 MAb. The murine monoclonal antibody 2C3 is one of the widely used anti-DARC antibodies. Since its binding interferes with some of the DARC functions such as chemokine binding, and invasion of erythrocytes by P. vivax merozoites, precise ITH12575 knowledge on the recognized epitope seems necessary for its potential applications. Our results unequivocally re-establish the important role of Trp-26 in DARC recognition by the antibody confirming the data published by Wasniowska, as it cannot be replaced by any residue without significant decrease of affinity. However, when Trp-26 is substituted by Phe, binding of 2C3 MAb was not abolished completely, suggesting that the aromatic ring may substitute the indole ring. The role of Tyr-30 has also been clarified: it can be substituted with Ala without strongly decreasing the affinity, which stands in contrast with the results published previously. However, our results suggest that sulfation of Tyr-30 causes an increase of the antibody affinity to some extent. Moreover, when ECD1-nuc construct contained both Phe at position 26 and Glu at position 30, the binding of the antibody increased in comparison to the construct with Phe-26 only. Finally, phosphorylation of Tyr-30 on ECD1-nuc used to mimic sulfation, caused and increase of the 2C3 MAb affinity. These data suggest that the negative charge at Tyr-30 possibly increases the antibody-antigen interaction. Results of STD-NMR presented in this paper support these conlusions. Saturation transfer difference -NMR technique can be used to identify the proton resonances of a ligand in close contact with the binding protein: side chains within the ligand that interact most strongly show a strong STD effect. There are several reports in which interaction between receptor and peptide ligand or monoclonal antibody and oligosaccharide epitope is evaluated. However, only a handful of papers exist in which interactions between monoclonal antibody and peptide epitope are studied. Our results were obtained using a set of methods that are applicable for establishing epitope of any monoclonal antibody.We have demonstrated that using eukaryotic and prokaryotic expressed constructs, any doubts regarding antibody specificity can be clarified. We also showed usefulness of SPR analysis to demonstrate influence of post-translational modifications by carrying out enzymatic reactions “in situ” on the protein previously immobilized on the chip. In addition, we showed that STD-NMR technique can be used to evaluate binding of an antibody to a peptide, which to our knowledge is one of the first experiments of this kind described in literature. Tyrosine kinases play a critical role in signaling driven by growth factors and oncoproteins thus regulating cellular key functions like proliferation and cell death. Uncontrolled tyrosine kinase signaling is known to be associated with various malignancies. Tyrosine kinase inhibitors have a tremendous effect in chemotherapeutic treatment and revolutionized the treatment of chronic myelogenous leukemia. However, modified tyrosine kinase signaling is also associated with non-malignant disorders such as fibrotic and inflammatory diseases.