Ernst L. Wynder, MD

In this issue, Love and Vogel bring attention to the fact that most breast cancers are not inherited but are the result of several, varied hormonal influences. This is an important message because prevention of breast cancer for some women can be accomplished by hormone manipulation from moderate exercise, maintaining low body mass, abstention from alcohol, and lactation. The authors discuss the physiologic role of delayed pregnancy but avoid the issue in terms of preventive strategy. Many women choose to delay pregnancy in pursuit of career development for economic reasons. This makes for a difficult choice in terms of breast cancer risk, but one that should be addressed. The article proposes that lobular maturation and exposure of the breast to hormones are two key processes in breast cancer. Indeed, emerging data also suggest that excess hormonal exposure in utero may influence adult breast cancer risk.