Midkine promotes perineural invasion in human pancreatic cancer

Table 2 Associations between midkine, syndecan-3 protein expression and perineural invasion in pancreatic cancer

Protein	PNI			P value
	0	1	2
MK (+) (n = 26)	3	10	13	0.018
MK (-) (n = 16)	7	7	2
Syndecan-3 (+) (n = 24)	2	9	13	0.031
Syndecan-3 (-) (n = 18)	7	7	4

Perineural invasion was scored as follows: 0, perineural invasion was difficult to find, with less than one occurrence per slide; 1, perineural invasion was easy to find, with two to four occurrences per slide; and 2, perineural invasion was easy to find, with more than four occurrences per slide or intraneural invasion. PN: Perineural invasion; MK: Midkine.