NEW YORK--Cell-adhesion molecules (proteins on the cell surface that interlock with those of other cells) appear to play an important role in checking tumor metastasis, says Dr. Rachel Hazan, a biochemist at Memorial Sloan-Kettering Cancer Center.
Tumor cells may lose their adhesive properties and detach from the primary tumor, allowing them to travel through the lymph system and bloodstream to other organs (see illustration ).
"Metastasis is, of course, the major cause of death from breast cancer," said Dr. Hazan, who works in Memorial's Breast Cancer Research Laboratory, headed by Breast Service Chief Patrick I. Borgen. "So understanding how metasta-sis happens and learning to control it could have enormous advantages for these patients."
Studies at Memorial Sloan-Kettering and elsewhere have shown that in metastasizing cancer cells, the E-cadherin protein, an essential adhesion molecule, is often absent or dysfunctional. Research by Dr. Hazan and her colleagues is focusing on catenins, proteins within cells that regulate the functioning of adhesion molecules.
Beta-catenin, for example, appears to regulate the functioning of E-cadherin, and Dr. Hazan is studying how beta-catenin interacts with enzymes linked to cancer progression.
Using Memorial Sloan-Kettering's vast tumor bank, Dr. Hazan is attempting to correlate the levels of E-cadherin present in breast cancer tissue samples with clinical and pathological data. To date, her work has corroborated other research showing that E-cadherin levels decrease as breast cancer progresses.
New therapies that could result from this early research would aim to restore adhesive properties to tumor cells to prevent metastasis.