TGase 2 expression is associated with increased invasion or migration of NSCLC cells. The levels of invasiveness for the H1703 and HCC-95 cells were compared in a Matrigel invasion assay system (A and B). Representative fields of cells that migrated through the Matrigel to the underside of the membrane were either photographed (A) or counted randomly in 10 fields, with the average numbers of invading cells (±s.d.) plotted (B). Transient transfection of TGM2 siRNA decreased the invasiveness for H1703, as shown in the representative fields of cells photographed (C) and the average numbers of invading cells plotted (D). Compared with the HCC-95 cells (E), the cell migration was higher in NCI-H1703 cells having a higher level of TGase 2 (F). The migration was reduced by the treatment of NCI-H1703 with TGM2 siRNA and the resultant down-regulation of TGase 2 (G and H). The cell migration status was photographed after the indicated time period.