Levels of K-ras 4B mRNA relative to GAPDH. Sample size (N) values for K-ras 4A determinations were as follows: HPL, N = 10; H441, N =10; H1395, N = 2; H1944, N = 3; H2126, N = 3; A549, N = 3. ** P < 0.01 vs. HPL cells, Kruskal-Wallis test, followed by Dunn’s multiple comparisons test. * P< 0.05 vs. HPL, Mann-Whitney pair-wise test.