Tumor heterogeneity refers to the presence of multiple subclones within a single tumor, each with distinct genetic and phenotypic characteristics. This diversity within the tumor can lead to variability in how the cancer responds to treatments. For instance, a treatment effective against one subclone may not work against another, leading to [drug resistance](#). Understanding and analyzing tumor heterogeneity through advanced techniques like [next-generation sequencing](#) can provide insights into more effective treatment combinations.
