[Indoleamine 2,3-Dioxygenase Activity during Fulvestrant Therapy for Aromatase Inhibitor-Resistant Metastatic Breast Cancer].
We evaluated the clinical significance of indoleamine 2,3-dioxygenase (IDO) during fulvestrant therapy for aromatase inhibitor (AI)-resistant metastatic breast cancer. IDO activity can be measured by the tryptophan (Trp)/kynurenine (Kyn) ratio. Trp and Kyn were measured with high performance liquid chromatography (HPLC). Patients with AI resistant metastatic breast cancer had a 28.6% response rate to fulvestrant therapy, and the clinical benefit rate was 76.2%. AI-resistant metastatic breast cancer patients with distant metastases had a lower serum Trp/Kyn level than patients who had local recurrences. During fulvestrant therapy, IDO activity significantly decreased in the fulvestrant responder group compared to that in the fulvestrant non-responder group. During fulvestrant therapy, the IDO activity correlated with the number of metastatic lesions. These results suggest that measuring the Trp/Kyn ratio is useful for evaluating immunological metastatic status during endocrine therapy.
Division of Breast and Endocrine Surgery, Dept. of Surgery, Nihon University School of Medicine.
Kenichi
K
Sakurai
Shigeru
S
Fujisaki
Shuhei
S
Suzuki
Keita
K
Adachi
Saki
S
Nagashima
Yuki
Y
Masuo
Ryouichi
R
Tomita
Kenji
K
Gonda
Katsuhisa
K
Enomoto
Sadao
S
Amano
Sadanori
S
Matsuo
Nao
N
Umeda
D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D047072:Aromatase Inhibitors / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology* / Q000473:pathology; D019008:Drug Resistance, Neoplasm; D004958:Estradiol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D000077267:Fulvestrant; D006801:Humans; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000032:analysis* / Q000378:metabolism; D008875:Middle Aged; D009362:Neoplasm Metastasis; D012008:Recurrence
D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D000077267:Fulvestrant; D004958:Estradiol