5. ConclusionSingle cell heterogeneity is a great challenge to cancer diagno-sis and treatment, because a single mutated cell will accumulatediverse mutations with its progression in the heterogeneousmicroenvironment [59]. Therefore, we should further promote thestudy on single cell heterogeneity either in biomarker developmentor in treatment research. Herein, we first listed several detectiontargets used in the single cell heterogeneity study, including CTCs, DTCs, CSCs, ctDNA and cfDNA, followed by discussion of detec-tion fields and methods we could use. Three dimensional culturesystems, auto-fluorescence cell imaging platform and other DNAlabeling ways could be used to study the heterogeneity in cell mor-phology. Single cell sequencing is preferable in detecting genomicsheterogeneity at single cell level while single cell western blot-ting could be applied to study proteomics heterogeneity. All thesedetection targets and methods play a substantial role in revealingsingle cell heterogeneity in cancer, ultimately helping to improvecancer diagnosis and treatment, thus realizing the final goal of real-izing precision medicine.