Pro-oncogenic cytokines and growth factors are differentially expressed in the post-surgical wound fluid from malignant compared to benign breast lesions

Purpose: The accumulation of wound fluid known as seroma in the chest cavity following breast surgery is a common occurrence that can persist for many weeks. While the pro-inflammatory composition of seroma is well established, there has been remarkably little research to determine whether seroma contains pro-oncogenic factors, and whether this is influenced by previous malignant disease.

Methods: We developed a clinical trial in which we obtained post-surgical seroma fluids from women with benign or malignant disease 1 or 2 weeks following lumpectomy or mastectomy. We conducted an analysis of more than 80 different cytokines, chemokines and growth factors.

Results: We found that surgical cavity seroma from breast cancer patients has a higher expression of key tumor-promoting cytokines and lower expression of important tumor-inhibiting factors when compared to benign lesions from non-cancer patients. Patients with high body mass index also had higher levels of leptin regardless of malignancy.

Conclusions: We conclude that the breast post-surgical tumor cavity contains factors that are pro-inflammatory regardless of malignant or benign disease, but in malignant disease there is significant enrichment of additional pro-oncogenic chemokines, cytokines and growth factors, and reduction in tumor-inhibiting factors. These results are consistent with tumor conditioning of surrounding normal stromal tissue and creation of a pro-oncogenic environment that persists long after surgical removal of the tumor.