Midkine promotes perineural invasion in human pancreatic cancer

Table 1 Associations between midkine, syndecan-3 protein expression and clinicopathologic factors in pancreatic cancers n (%)

Factor	Midkine positive cases	Syndecan-3 positive cases
Age (yr)
> 60 (n = 26)	17 (65.4)	17 (65.4)
≤ 60 (n = 16)	9 (56.3)	7 (43.8)
Sex
Female (n = 16)	12 (75.0)	10 (62.5)
Male (n = 26)	14 (53.8)	14 (53.8)
CA19-9 (n = 42)
>37 U/mL (n = 24)	16 (66.7)	12 (50.0)
≤ 37 U/mL (n = 18)	12 (66.7)	10 (55.6)
Histological grade
I (n = 5)	4 (80.0)	2 (40.0)
II (n = 22)	16 (72.7)	15 (68.2)
III (n = 15)	7 (46.7)	7 (46.7)
Tumor size
T ≤ 2 cm (n = 10)	4 (40.0)	3 (30.0)a
2 cm < T ≤ 5 cm (n = 24)	14 (58.3)	15 (62.5)a
T > 5 cm (n = 8)	8 (100.0)	7 (87.5)a
Lymph node metastasis
Negative (n = 17)	7 (41.2)a	7 (41.2)
Positive (n = 25)	19 (76.0)a	17 (68.0)
Distant metastasis
Negative (n = 36)	21 (58.3)	19 (52.8)
Positive (n = 6)	5 (83.3)	5 (83.3)
TNM grade
I + II (n = 21)	9 (42.9)b	10 (47.6)
III (n = 16)	13 (81.3)b	10 (62.5)
IV (n = 5)	5 (100.0)b	5 (100.0)

^aP < 0.05,

^bP < 0.01 vs negative cases.

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.