HER2: critical player in postsurgical cancer cell proliferation

In an effort to determine whether surgery helps to spread remnant breast cancer cells, particularly cells that overexpress HER2, Italian researchers compared histologic sections of primary breast cancers with specimens of re-excised residual tumors obtained within 48 days of the first surgery.

While the investigators found no overall change in tumor proliferation between initial and repeat surgeries, a subset of specimens that overexpressed HER2 displayed a 10% increase in proliferative cells upon re-excision.

In addition, the researchers found that wound drainage fluid and postsurgical serum samples contain growth factors that stimulate proliferation of HER2-positive breast carcinomas. This finding, they suggest, helps to explain why HER2 expression is associated with a poor prognosis and why invasive diagnostic procedures often lead to increased residual tumor growth with other types of cancer.

Lastly, the investigators determined that treatment of HER2-positive tumor cells with trastuzumab abolished drainage fluid-induced proliferation, suggesting a potential therapeutic role for this and other monoclonal antibodies in pre-, peri-, and postoperative settings.

Tagliabue E, Agresti R, Carcangiu L, et al. Role of HER2 in wound-induced breast carcinoma proliferation. Lancet. 2003;362:527-533.