ATF4 and adult T-cell leukemia/lymphoma: Shikonin increased ROS accumulation in Adult T cell leukemia/lymphoma (ATLL) cells, stimulated ERS and promoted the expression of p-eIF2α, ATF4, XBP-1, p-JNK, and CHOP, which induced apoptosis; moreover, shikonin suppressed the growth of ATLL cells in xenograft mice (Boonnate et al., 2023).