Effects of CD44 on insect cell proliferation. TN insect cells were permanently transfected with ROD1  or CD44 as indicated in Methods and their growth in culture was compared with parallel control cell cultures transfected with β-galactosidase. The increase in cell numbers observed in ROD1 or CD44 transfected cultures was expressed as percentage of the number of cells observed in β-galactosidase transfected cells after the same day in culture. The values are mean ± SEM, from 5 to 6 experiments. Only the effects of ROD1 were statistically different from the controls (Krustal-Wallis and Dunn's multiple comparisons test). *, P < 0.05. **, P < 0.01.