SenTraGor™ reagent is a major discovery in the field of senescence. The inventors, Professors Vassilis Gorgoulis (National Kapodistrial University of Athens; Biomedical Research Foundation of the Academy of Athens; University of Manchester) and Paul Townsend (University of Manchester) developed SenTraGor™ reagent, the commercial brand of GL13 compound. This innovative compound is highly lipophilic and binds to lipofuscin, a hallmark of senescent cells. SenTraGor™ staining allows recognition of senescent cells in any biological material, including archival (Formalin Fixed Paraffin Embeded - FFPE), by visualizing cytoplasmic lipofuscin accumulation, via a hybrid histochemical/immunohistochemical assay. SenTraGor™ applications include: Immunohistochemistry (IHC), Immunocytochemistry (ICC), Immunofluorescence (IF), Flow Cytometry Analysis (FACS), co-Immunohistochemistry (co-IHC) and co-Immunocytochemistry (co-ICC). This new method is highly specific, sensitive and deprived of false positive and negative results.