[The case of tumor escape mechanism by changing their tumor-associated antigens].

A 53-year-old woman presented with a diagnosis of advanced gallbladder cancer at our hospital. She was evaluated with CT scan and given a diagnosis of Stage IVb due to the multiple lymph nodes metastases and significant invasion to the artery. However, we underwent simple cholecystectomy followed by immunotherapy that was the hope of herself and her family. The serum level of DUPAN-2 was gradually elevated to 6,800 U/mL, and the metastases to the liver were detected. After we started the dendritic cell vaccine pulsed with autologous tumor-lysate with S-1, DUPAN-2 decreased to 980 U/ mL. The CT scan showed complete response (CR) in the liver metastases and partial response (PR) in the lymph node metastases. However, the serum level of CEA elevated since the MUC-1 peptide was used instead of autologous tumor- lysate, even DUPAN-2 did not. The liver metastases were in control, but the lymph nodes metastases had progressed. She died of the progressed lesion later in approximately one year from the operation. This case demonstrated a possibility of the tumor escape mechanism by changing their tumor-associated antigens.