As I mentioned in a previous post one of the nice talks in Lyon came from Vito Quaranta, from Vanderbilt University in Nashville, USA.
He is and MD collaborating with researchers in the States and Europe (eg Sandy Anderson from Dundee) to develop models on tumour invasion. That is the defining feature that separates tumours from benign to malign (eg cancer).
In order to know if a cancer is invasive MDs tend to look at the way the tumour grows. A tumour with a smooth margin is unlikely to be invasive whereas one with fingering is likely to be so.
Of course I am interested to know if there are alternative studies that could be used to predict the evolution of the cancer that are not based on how the tumour shape looks like. First because in many cases physicians don't have accurate images of the contour of tumours (or sometimes haven't got enough information about what is the result of tumour growth). Second, and maybe most important, because the current shape of a tumour doesn't say much about the potential evolution of it towards malignancy. Maybe a different measure (based on the phenotypic composition of tumour cells) could help not only to tell if a tumour is malignant or benign but if the chances of becoming invasive are high or not.
In any case his presentation showed some interesting results on how the microenvironment affects the evolution of the cancer. Homogeneous microenvironments, that is, those in which space can be created with the same ease everywhere, lead to smooth contours whereas inhomogeneous ones lead to fingering. Interestingly these inhomogeneous microenvironments tend to lead to tumours with little diversity in terms of phenotype: when it is difficult for a tumour cell to create space only invasive phenotypes tend to survive.