[Levels and clinical significances of interleukin 11 in breast tissue and serum of bone metastasis of breast cancer].

OBJECTIVE

To explore the expression level and clinical significance of interleukin-11 (IL-11) in the tissue and serum samples of in breast cancer bone metastasis patients.

METHODS

Peripheral blood samples were collected from 180 breast cancer patients at Tianjin Medical University Cancer Hospital from May 2007 to January 2009 and confirmed by histological pathology. According to the occurrence of bone metastases, they were divided into 2 groups of bone metastasis (MBC-B) and without bone metastasis (PBC) (n = 90 each). Another 20 healthy controls were selected from the same hospital during the same period after excluding a history of endocrine and metabolic diseases and other chronic diseases. Peripheral blood samples were collected to detect the expression level of IL-11 by enzyme-linked immunosorbent assay. At the same time, tumor tissue samples were collected from 40 breast cancer patients with bone metastasis and 40 breast cancer patients without bone metastasis. And their complete archive data were available. The expression levels of IL-11 in tumor tissue samples were detected by tissue chip and immunohistochemistry. The IL-11 mRNA expression levels of different breast tissue samples were analyzed by fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR). Independent prognostic indicators of postoperative patient survival were screened and layered by the median level of serum concentration. Log-rank test was employed for survival analysis.

RESULTS

The serum concentrations of IL-11 in MBC-B, PBC and healthy control groups were (242.9 ± 56.3), (85.9 ± 35.7) and (66.4 ± 20.3) µg/L. And it had statistically significant difference (F = 43.532, P < 0.05); MBC-B group was significantly higher than PBC group (t = 40.44, P < 0.001). High expression rates of IL-11 were 57.5% and 14.3% in MBC-B and PBC groups. MBC-B group was significantly higher than PBC group (χ² = 36.626, P < 0.01). The survival time of breast cancer patients with bone metastases and high levels of IL-11 was 25.2 months and it was shorter than those with bone metastases and low levels of IL-11 (44.6 months). The difference was statistically significant (χ² = 9.550, P < 0.01).

CONCLUSION

The expression level of IL-11 is associated with the occurrence of bone metastasis in breast cancer. And breast cancer with a high expression level of IL-11 may be more susceptible to bone metastases.