Pregnancy stimulates tumor angiogenesis in breast carcinoma.

The mechanisms responsible for the poor prognosis of pregnancy-associated breast cancer (PABC) remain not well-understood. We studied angiogenesis and lymphangiogenesis as they are known prognostic factors in breast cancer. We conducted a case control study of breast cancer comparing women with and without PABC matched for age and histological parameters. Surgical specimen sections were immunostained with anti-CD31 for angiogenesis and anti-D2-40 for lymphangiogenesis, then analyzed using vessel density, ratio of the vascular area and the Chalkley count. Seventeen patients with PABC and 22 controls were included. Angiogenesis was significantly increased in tumor tissues, and tended to be higher in healthy breast tissues from the PABC group compared to controls. In contrast, no difference between the two groups was found concerning lymphangiogenesis both in tumor and healthy breast tissues. Pregnancy enhances angiogenesis in breast cancer. This phenomenon appears to explain the poor prognosis of PABC.