(IMAGE) CNRS Caption Image of human tumour cells invading a collagen matrix. The nuclei are stained in blue and the portion of the extracellular matrix degraded by the cells is red. Credit Guilherme Nader/Institut Curie Usage Restrictions none License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.