Background/Aim: We have previously reported the identification of the cytotoxic chemotype compound-I (CC-I) from a chemical library screening against glioblastoma. Materials and Methods: The biological activity of CC-I on drug-resistant neuroblastomas [e.g., HFE gene variant C282Y stably transfected human neuroblastoma SH-SY5Y cells (C282Y HFE/SH-SY5Y), SK-N-AS] was characterized using cell culture models and in vivo mouse tumor models. Results: CC-I had potent cytotoxicity on therapy-resistant neuroblastoma cells and limited cytotoxicity on human primary dermal fibroblast cells. In addition, CC-I showed a robust anti-tumor effect on therapyresistant human neuroblastoma C282Y HFE/SH-SY5Y cells but not on SK-N-AS cells in a subcutaneous tumor model. CC-I induced phosphorylation of heat shock protein 27 (HSP27), protein kinase B (Akt), and c-Jun N-terminal kinase (JNK) in C282Y HFE/SH-SY5Y neuroblastoma cells. Conclusion: CC-I may be an effective therapeutic option for therapy-resistant neuroblastomas, especially if they express the C282Y HFE gene variant. Its anti-tumor effects are possibly through HSP27-Akt-JNK activation. Neuroblastoma is the second most common solid tumor discovered in children (1). It begins in the nerve cells outside of the brain, most often in the adrenal glands located on top of both kidneys. Nearly 90% of neuroblastomas are diagnosed by age 10 (2). In the United States, neuroblastoma occurs in about 800 children (age up to 14) each year, which accounts for 6% of all childhood cancers (3). The International Neuroblastoma Risk Group Staging System was developed by the International Neuroblastoma Risk Group for the standardization of neuroblastoma risk classification and for clinical trials (4). Risk factors for neuroblastoma include age at diagnosis, disease stage, tumor histology, and N-myc proto-oncogene protein (MYCN) amplification status (5). Although the 5-year survival rate for low-risk neuroblastoma is 95%, the 5-year survival rate for high-risk neuroblastoma is only 40-50% (3). About half of the neuroblastomas are metastatic at diagnosis, and advanced disease remains difficult to treat successfully despite the aggressive multimodality therapy. Treatment for neuroblastoma usually involves a variety of approaches such as chemotherapy, radiation, surgery, stem cell transplantation, biological agents, and immunotherapy (6, 7). The majority of patients with high-risk neuroblastoma will relapse despite receiving aggressive multimodal therapy, while an additional 10% to 20% will be refractory to induction therapy (8, 9). Because of disease heterogeneity among highrisk cases, subsequent management with salvage chemotherapy can be very challenging. Therefore, developing new treatment agents against neuroblastoma, especially therapy-resistant neuroblastoma, is urgently needed. We previously reported the identification of compound CC-I, a thiobarbituric acid derivative, from the screening of the ChemBridge small molecule library compounds, as an effective agent against drug-resistant glioblasto...