Author(s): Inaba T, Ino K, Kajiyama H, Shibata K, Yamamoto E, , Inaba T, Ino K, Kajiyama H, Shibata K, Yamamoto E,
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Abstract OBJECTIVE: Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolizing enzyme that induces tolerance to host immune surveillance within the tumor microenvironment. The present study aimed to investigate IDO expression and its prognostic significance in invasive cervical cancer. METHODS: Immunohistochemical expression of IDO in tumor tissues and its association with clinicopathological factors and survival were analyzed in 112 stage IB-IIB cervical cancer patients treated with radical hysterectomy and pelvic lymphadenectomy. RESULTS: IDO was diffusely expressed in tumor cells in 29 (26\%) cases and focally expressed at the invasive front in 29 (26\%) cases, while the other 54 (48\%) cases were IDO-negative. IDO expression was positively correlated with clinical stage, lymph node metastasis, and lymph-vascular space invasion, but not with histological type. Patients with diffuse IDO expression had significantly reduced overall survival (OS) and disease-free survival (DFS) compared to patients with no IDO expression. The 5-year OS/DFS rates for the IDO-negative, focally positive, and diffusely positive groups were 92.3\%/84.9\%, 89.5\%/75.8\%, and 65.5\%/51.7\%, respectively. When we analyzed patients with stage IB disease alone (n=67), the OS and DFS for the IDO-diffusely positive group were significantly lower than those for the IDO-negative group. In multivariate analysis, diffuse IDO expression was found to be an independent prognostic factor for impaired OS and DFS. CONCLUSIONS: Diffuse expression of IDO in the tumor obtained from Stage IB-IIB cervical cancer patients who underwent radical hysterectomy was correlated with an unfavorable clinical outcome. These findings suggest that IDO may be a novel post-operative prognostic indicator for stage IB-IIB cervical cancer. Copyright 2010 Elsevier Inc. All rights reserved.
This article was published in Gynecol Oncol
and referenced in Journal of Cancer Science & Therapy