These nanotheranostic agents initially have a diameter of approximately 90 nm, enabling passive tumor tissue targeting, followed by aggregation in the acidic tumor microenvironment for enhanced retention and MR signal enhancement.[162a] Human serum albumin (HAS) has been reported to be engaged as a biocompatible NDC loading doxorubicin (DOX), and the HAS‐DOX complex was modified with protonation of carboxylic groups to enhance the hydrophobicity, allowing for the aggregation of the complex in tumor microenvironments. The gene discussed is ALB; the disease is neoplasm.