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
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.