Expression of interleukin 11 and its receptor and their prognostic value in human breast cancer

Background: Recent experimental evidence has shown a potential role of interleukin (IL)-11 and its receptor in breast cancer development and progression. However, there is little clinical information to support this hypothesis. We examined the expression of IL-11 and its receptor in primary breast cancer tissue samples and correlated their level of expression with the clinical outcome. Methods: Primary breast cancer samples (n = 109) and matched background tissue obtained from patients in the cohort (n = 33) were processed for frozen section and RNA extraction. Frozen sections from matched tissues were immunostained with IL-11 and IL-11 receptor antibodies. Staining intensity was analyzed by computer image analysis. RNA was reverse-transcribed and quantified before analysis by quantitative polymerase chain reaction. Results were expressed as the number of transcripts (standardized by beta-actin). The data were compared with the clinical outcome of the disease. Results: The intensity of staining for both IL-11 and the IL-11 receptor was distinctly high in tumor samples (P < .01). The transcript level of IL-11 was significantly higher in node-positive tumor samples compared with node-negative samples (P = .02). Tumors with a poor prognostic index and poor histological grade showed a higher level of IL-11. A higher level of IL-11 was linked to poorer survival with Kaplan-Meier survival analysis. Conclusions: IL-11 can be a predictor of poor prognosis in human breast cancer.