Human breast cancer biopsies induce eosinophil recruitment and enhance adjacent cancer cell proliferation.

Chronic inflammation is known to facilitate cancer progression and metastasis. Less is known about the effect of acute inflammation within the tumor microenvironment, resulting from standard invasive procedures. Recent studies in mouse models have shown that the acute inflammatory response triggered by a biopsy in mammary cancer increases the frequency of distal metastases. Although tumor biopsies are part of the standard clinical practice in breast cancer diagnosis, no studies have reported their effect on inflammatory response. The objective of this study is to (1) determine whether core needle biopsies in breast cancer patients trigger an inflammatory response, (2) characterize the type of inflammatory response present, and (3) evaluate the potential effect of any acute inflammatory response on residual tumor cells. The biopsy wound site was identified in the primary tumor resection tissue samples from breast cancer patients. The inflammatory response in areas adjacent (i.e., immediately around previous biopsy site) and distant to the wound biopsy was investigated by histology and immunohistochemistry analysis. Proliferation of tumor cells was also assayed. We demonstrate that diagnostic core needle biopsies trigger a selective recruitment of inflammatory cells at the site of the biopsy, and they persist for extended periods of time. While macrophages were part of the inflammatory response, an unexpected accumulation of eosinophils at the edge of the biopsy wound was also identified. Importantly, we show that biopsy causes an increase in the proliferation rate of tumor cells located in the area adjacent to the biopsy wound. Diagnostic core needle biopsies in breast cancer patients do induce a unique acute inflammatory response within the tumor microenvironment and have an effect on the surrounding tumor cells. Therefore, biopsy-induced inflammation could have an impact on residual tumor cell progression and/or metastasis in human breast cancer. These findings may carry relevance in the clinical management of breast cancer.

A framework for the role of acute inflammation in tumor progression.

Breast cancer remains the second leading cancer-related death in women in the United States. Despite improvements in early detection, prevention, and treatment, the mortality rate in breast cancer remains high secondary to the potential for cancer recurrence and the development of metastasis. To minimize breast cancer-related morbidity and mortality, understanding the factors leading to an increased risk of metastasis and developing clinical interventions that reduce this risk is essential. While the association between chronic inflammation and cancer progression is well documented in the literature, the role of acute inflammation and its impact on tumor proliferation and metastasis is less well understood. Here, we will review recently published preclinical studies in mouse models indicating that acute inflammation caused by clinical interventions plays an important role in the risk of peripheral metastases. In addition, we will address the potential impact that these findings may have on the clinical management of breast cancer.