In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

 EBV utilizes CD21 / CR2 as its receptor on B cells to initiate the infection process .
CD21 / CR2

 These data suggest that these kappa B - specific proteins have a role in the coordinate regulation of this growth factor - growth factor receptor gene system that controls T cell proliferation .
growth factor receptor

 These data suggest that these kappa B - specific proteins have a role in the coordinate regulation of this growth factor - growth factor receptor gene system that controls T cell proliferation .

growth factor receptor