Quantifying protrusions as tumor-specific biophysical predictors of cancer invasion in in vitro tumor micro-spheroid models

An important hallmark in cancer research is the discovery of suitable features capable to reliably predict tumor invasiveness, and consequently, their metastatic potential at an early stage. Current methods are based on molecular biomarker screening and imaging that may not reveal the altered properties of tumor cells, being also labor-intensive and costly. Biophysical-based methodologies provide a new framework assessing—and even predicting—the invasion potential of tumors with improved accuracy. In particular, the stochastic fluctuations of cancer invasive protrusions can be used as a tumor-specific biophysical indicator of its aggressiveness. In this methodology, tumor micro-spheroids with different metastatic capabilities were employed as in vitro models to analyze protrusion activity. It is described the procedure for extracting the descriptive biophysical parameters characteristic of protrusion activity, which magnitude depends on the invasion capability of tumors. Next, a simple mathematical approach is employed to define a predictive index that correlates with tumor invasiveness. Overall, this innovative approach may provide a simple method for unveiling cancer invasiveness and complement existing diagnosis methodologies.