Illustration of tumor heterogeneity summarized based on findings from scLT studies. The primary tumor comprises various cell populations, including tumor-initiating cells capable of initiating a new tumor upon transplantation, metastasis-initiating cells (seeder) with the ability to establish secondary tumors in different sites, drug-resistant cells further classified into cycling persisters (drug-induced transiently resistant proliferative cells) and noncycling persisters (preexisting resistant cells), and drug-sensitive cells susceptible to elimination during treatment. Cell fate is influenced by a combination of genetic and nongenetic information, and it exhibits dynamic changes, known as cell plasticity, under specific circumstances. scLT studies have revealed the existence of “shedder,” “seeder,” “cycling persisters,” and “noncycling persisters.”
