Tumor angiogenesis and metastasis - correlation in invasive breast cancer

The growth and development of a cancer involves a broad spectrum of events. One key event is the stimulation of new blood vessels which penetrate the tumor and supply it with increased amounts of oxygen and nutrients. Current estimates suggest that early cancers grow slowly and are relatively dormant. When they reach about a million cells (which represents a tumor of only a few millimeters) further growth can not occur without the development of new blood vessels to vascularize the tumor. In addition to providing improved blood supply to the tiny tumor, the new blood vessels provide routes for metastatic cells to crawl out of the primary tumor and circulate to distant parts of the body. A study of 49 breast cancers was undertaken to determine if the number of blood vessels within the tumor correlates with metastatic disease in the patients. Of the 49 patients, 30 had metastatic disease and 19 did not. If the notion that more blood vessels provide more opportunity for metastasis is correct, then more blood vessels would be expected to be found in the tumors from the patients with metastatic disease. This is precisely what was observed. Researchers without knowledge of the patient's history counted blood vessels under the microscope in tissue sections of breast cancer specimens. An average of 101 blood vessels could be seen in a high power field of the microscope among the patients with metastatic disease. Among patients without metastatic disease, an average of 45 blood vessels were observed. These results confirm the importance of vascularization in the progression of a tumor, and indicate that vascularization is also an important step in setting the stage for metastatic spread of cancer cells. (Consumer Summary produced by Reliance Medical Information, Inc.)