Table 4.

Comparison of matrix metalloproteinase-9 expression scores with nodal status by Kruskal-Wallis ANOVA

Nodal status	Parenchyma			Stroma			Average MMP 9 expression
	Mean	SD	Mean rank	Mean	SD	Mean rank	Mean	SD	Mean rank
N0	2.10	0.738	7.30	1.00	0.667	6.40	1.80	0.789	7.20
N1	3.40	0.507	19.60	2.40	0.507	18.40	3.13	0.516	18.43
N2	3.40	0.548	19.60	3.00	0.000	25.00	3.60	0.548	23.30
Total	2.97	0.850	2.03	0.928	2.77	0.935
F	15.274			20.283			`16.818
P	0.000			0.000			0.000
Pairwise comparisons by Mann-Whitney U-test
	P			P			P
N0 versus N1	0.000*			0.000*			0.000*
N0 versus N2	0.008*			0.001*			0.004*
N1 versus N2	1			0.023			0.095

*P<0.05. MMP 9: Matrix metalloproteinase-9, SD: Standard deviation