Number of apoptotic cells as a prognostic marker in invasive breast cancer

Apoptosis plays an important role in tumorigenesis. Tumour growth is determ ined by the rate of cell proliferation and cell death. We counted the numbe r of apoptotic cells in haematoxylin and eosin (H&E)-stained tumour section s in series of 172 grade I and II invasive breast cancers with long-term fo llow-up. The number of apoptotic cells in ten high-power fields were conver ted to the number of apoptotic cells per mm(2) to obtain the apoptotic inde x (Al). The Al showed a positive correlation to the mitotic activity index (MAI) (P = 0.0001), histological grade (P < 0.0001) and worse tumour differ entiation. Patients with high Al showed shorter overall survival than patie nts with low Al in the total group as well as in the lymph node-positive gr oup. Tumour size, MAI, lymph node status and Al were independent prognostic indicators in multivariate analysis. The Al was shown to be of additional prognostic value to the MAI in the total patients group as well as in the l ymph node-positive group. The correlation between the Al and the MAI points to linked mechanisms of apoptosis and proliferation. Since apoptotic cells can be counted with good reproducibility in H&E-stained tumour sections, t he Al may be used as an additional prognostic indicator in invasive breast cancer. (C) 2000 Cancer Research Campaign.