Polo-like kinase 1 expression is a prognostic factor in human colon cancer

Table 1 Overall expression of PLK1 in colon carcinoma as well as distribution of PLK1 expression in the study population, n (%)

Characteristics		All cases	PLK1negative	PLK1positive	P
All cases		153	51 (33.3)	102 (66.7)
Age (yr)
	≤65 yr	74 (48.4)	28 (37.8)	46 (62.2)	0.3041
	>65 yr	79 (51.6)	23 (29.1)	56(70.9)
Dukes stage
	A	35 (22.9)	20 (57.1)	15 (42.9)
	B	55 (35.9)	19 (34.5)	36 (65.5)	<0.0012
	C	50 (32.7)	10 (20)	40 (80)
	D	13 (8.5)	2 (15.4)	11 (84.6)
Tumor stage
	T1	10 (6.5)	9 (90)	1 (10)
	T2	36 (23.5)	14 (38.9)	22 (61.1)	0.0012
	T3	96 (62.7)	24 (25)	72 (75)
	T4	11 (7.3)	4 (36.4)	7 (63.6)
Nodal status
	N0	91 (59.5)	38 (41.8)	53 (58.2)
	N1	30 (19.6)	4 (13.3)	26 (86.7)	0.0492
	N2	32 (20.9)	9 (28.1)	23 (71.9
State of distant metastasis
	Mx	140 (91.5)	49 (35)	91 (65)	0.2211
	M1	13 (8.5)	2(15.4)	11 (84.6)
Grade
	G1	6 (3.9)	2 (33.3)	4 (66.7)
	G2	123 (80.4)	43 (35)	80 (65)	0.4232
	G3	24 (15.7)	6 (25)	18 (75)

¹Fisher’s exact test,

²χ ² test for trends.

Table 2 Correlation of PLK1 expression and selected tumor param-eters with patient prognosis

		Cases	Events	Mean survival(mo)	Standard error	Log-ranktest P
Age (yr)	≤65 yr	74	13	76.59	3.42	0.0142
	>65 yr	79	29	57.94	3.51
Dukes stage	A	35	4	70.27	3.18	<0.0001
	B	55	5	83.89	2.67
	C	50	23	48.26	4.28
	D	13	10	22.96	6.6
Tumor stage	T1	10	0	Not reached	–	0.0006
	T2	36	8	74.08	5.06
	T3	96	27	63.84	3.06
	T4	11	7	27	7.22
Nodal status	N0	91	11	81.93	2.34	<0.0001
	N1	30	10	55.94	5.17
	N2	32	21	28.74	3.97
Metastasis	Mx	140	32	73.19	2.68	<0.0001
	M1	13	10	22.96	6.6
Grade	G1	6	0	Not reached	–	0.0007
	G2	123	29	72.61	2.9
	G3	24	13	33.37	4.68
PLK1	Negative	51	7	74.13	2.9	0.006
(all cases)	Positive	102	35	63.75	3.66
PLK1	Negative	49	5	76.36	2.52
(locoregional disease)	Positive	91	27	67.77	3.66	0.0119

Table 3 Multivariate survival analysis for all cases (n = 153)

	RR	95%CI	P
Age (yr)
per yr	1.040	1.008–1.072	0.013
Tumor stage
T1/T2	1.000
T3/T4	1.061	0.466–2.413	0.888
Nodal status
Per positive node	1.116	1.037–1.201	0.003
Metastasis
Mx	1.000
M1	3.223	1.202–8.643	0.02
Grade
G1/G2	1.000
G3	2.773	1.382–5.564	0.004
PLK1 expression
Negative	1.000
Positive	2.067	0.890–4.800	0.091

Table 4 Multivariate survival analysis for the subgroup of patients without distant metastasis (n = 140)

	RR	95%CI	P
Age (yr)
per yr	1.044	1.009–1.079	0.013
Tumor stage
T1/T2	1.000
T3/T4	0.898	0.365–2.206	0.814
Nodal status
Per positive node	1.231	1.125–1.348	<0.001
Grade
G1/G2	1.000
G3	2.614	1.172–5.829	0.019
PLK1 expression
Negative	1.000
Positive	3.306	1.214–9.002	0.019