Integrin “inside-out” signaling is upregulated in trisomy 12 CLL cells. The expression of molecules involved in integrin signaling was assessed by quantitative RT-PCR in CLL cells with and without trisomy 12 and healthy B cells. (A) The expression of RASGRP2 (CALDAG-GEFI) is increased in trisomy 12 CLL cells comparable to healthy B cells. In contrast, RAP1B (B) and RASSF5 (RAPL) (C) are overexpressed in trisomy 12 CLL cells compared with healthy B cells and nontrisomy 12 CLL cells.