Verification of MYC, ATF3 and JUN expression after HAL-PDT by Western blotting. Cell extracts were prepared at at 1 h, 2 h and 4 h after HAL-PDT (A). Since PDT affected the expression of well-known house keeping proteins such actin (induced) and tubulin (repressed) the total protein content was measured and the gels were stained after electrophoresis, thus normalize against total protein content. The fold-changes obtained by the microarray analysis for the selected genes are presented for comparison. Fold-change of three repeated experiments presented as the mean ± St. Dev (B).