Why is breast cancer common but heart cancer rare?

Malignant cancers strike certain organs, such as the colon or breast, more often than others. Researchers propose that this vulnerability in some organs may be due to natural selection. Humans can tolerate tumors in large or paired organs more easily than in small, critical organs, such as the heart, and so the larger organs may have evolved fewer mechanisms to defend against cancerous cells.
Source: ScienceDaily Headlines - Category: Science Source Type: news