Indoleamine-2,3-dioxygenase and Interleukin-6 associated with tumor response to neoadjuvant chemotherapy in breast cancer.

Purpose: Indoleamine-2,3-dioxygenase (IDO) and Interleukin-6 (IL-6) contribute to poor therapeutic effects, tumor relapse and aggressive tumor growth. IDO and IL-6 incorporate a positive feedback signal loop to maintain IDO and IL-6 constitutive expression and facilitate tumor progression.

Results: IDO expression was associated with IL-6 expression and plasma IL-6 level (0.05). Concentrating on clinicopathological features prior neoadjuvant chemotherapy, both IDO expression and plasma IL-6 level were associated with clinical T stage and N stage (0.05). IL-6 expression was associated with clinical T stage (0.016). The co-expression of IDO/IL-6 was correlated with clinical T, N stage and estrogen receptor (ER) status (<0.05). IDO, IL-6 expression, clinical T stage, pathological T stage, ER status and Luminal type were correlated with clinical response to neoadjuvant chemotherapy (<0.05). Multivariate analysis showed that IDO expression were correlated with clinical response to neoadjuvant chemotherapy (0.034). IL-6 expression and pathological T stage were correlated with pCR (<0.05). In the multivariate analysis, postoperative pathological T stage associated with pCR (0.041). In the prognostic analysis, only clinical T stage was significant correlated with overall survival (=0.003).

Materials And Methods: 46 breast cancer patients received neoadjuvant chemotherapy enrolled in this study. Immunohistochemistry was applied for evaluating IDO and IL-6 expression in biopsy tissues prior neoadjuvant chemotherapy. Immunofluorescence was applied to observe the co-localization of IDO and IL-6. Serum IL-6 level was examined via ELISA. The associations between IDO, IL-6, Serum IL-6 level and clinicopathological features, response to neoadjuvant chemotherapy were analyzed.

Conclusion: IDO and IL-6 expression associated with advanced breast cancer and poor response to neoadjuvant chemotherapy.