OS by VLA-4 expression. Distributions of OS were estimated by the method of Kaplan and Meier. Tickmarks indicate censored values. The P values for the trends for survival were not significant: for percentage expression of α₄, 0.62, and for MFI, 0.96. This figure represents the OS by α₄ percentage expression with percentage positive dichotomized at 40% trial value. This value of 40% approximates the value of 34.5% chosen by Matsunaga et al as the breakpoint between α₄ “positive” and “negative.”⁹