EGFR and colorectal carcinoma: Therefore, the aims of the present study were to develop and characterize novel in vitro CRC models that resembled CRC heterogeneity and to assess whether it is possible to quantify the level of EGFR in ex vivo fresh CRC tissue samples, orthotopic tumor in mice and newly developed cell lines models by using EGF conjugated with IRDye 800CW (EGF-NIR) probe.