Intratumoral heterogeneity and biomarkers for transformation into small cell lung carcinomas from lung adenocarcinomas

Recent advances in next-generation sequencing have opened a new prospect in the field of cancer genomics and cancer evolution. Using next-generation sequencing, researchers have revealed that the occurrence of somatic events such as mutations and copy number alterations is associated with tumor evolution and genomic diversity in tumors, which is known as tumor heterogeneity (1). Tumor heterogeneity includes interpatient tumor heterogeneity (2), intratumoral heterogeneity (3,4), intermetastatic heterogeneity (5-8), and intrametastatic heterogeneity (9)