Overexpression of the M2 isoform of pyruvate kinase is an adverse prognostic factor for signet ring cell gastric cancer

Table 1 Correlation between the M2 isoform of pyruvate kinase expression and clinicopathologic characteristics of gastric cancer patients n (%)

Characteristics		M2 isoform of pyruvate kinase expression
	Total (n = 368)	Negative (n = 224)	Positive (n = 144)	P
Median follow-up (70.6 mo)
Relapse	143 (39.0)
Death	138 (37.7)
Adjuvantchemotherapy	243 (66.0)
Age (yr)				0.027
≤ 60	230	150 (65.2)	80 (34.8)
> 60	138	74 (53.6)	64 (46.4)
Gender				0.263
Male	222	130 (58.6)	92 (41.4)
Female	146	94 (64.4)	52 (35.6)
AJCC 7th stage				0.811
I	105	67 (63.8)	38 (36.2)
II	89	51 (57.3)	38 (42.7)
III	172	105 (61.0)	67 (39.0)
IV	2	1 (50.0)	1 (50.0)
T stage				0.009
T1	94	62 (65.9)	32 (34.1)
T2	42	30 (71.4)	12 (28.6)
T3	87	40 (45.9)	47 (54.1)
T4	145	92 (63.4)	53 (36.6)
N stage				0.086
N0	131	80 (61.1)	51 (38.9)
N1	62	33 (53.2)	29 (46.8)
N2	69	37 (53.6)	32 (46.4)
N3	106	74 (69.8)	32 (30.2)
Histology				< 0.001
Welldifferentiatedadenocarcinoma	22	8 (36.4)	14 (63.6)
Moderatelydifferentiatedadenocarcinoma	96	39 (40.6)	57 (59.4)
Poorlydifferentiatedadenocarcinoma	143	91 (63.6)	52 (36.4)
Signetringcellcarcinoma	79	65 (82.3)	14 (17.7)

AJCC: American Joint Committee on Cancer; T: Tumor; N: Node.

Table 2 Prognosis analysis of recurrence-free survival and overall survival of total patients (n = 366)

Characteristics	RFS		OS
	HR (95% CI)	P value	HR (95% CI)	P value
Age (yr)
≤ 60
> 60	1.12 (0.80-1.57)	0.488	1.16 (0.83-1.64)	0.373
Gender
M
F	1.18 (0.85-1.65)	0.315	1.09 (0.78-1.53)	0.600
PKM2
Negative
Positive	0.93 (0.66-1.32)	0.713	0.92 (0.65-1.30)	0.637
T stage
T1/2/3
T4	6.12 (4.25-8.81)	< 0.001	5.04 (3.51-7.22)	< 0.001
N stage
N0/1/2
N3	6.02 (4.29-8.46)	< 0.001	5.64 (4.01-7.95)	< 0.001
Stage
I/II
III	8.42 (5.48-12.94)	< 0.001	6.70 (4.41-10.16)	< 0.001

RFS: Recurrence-free survival; OS: Overall survival; HR: Hazard ratio; PKM2: The M2 isoform of pyruvate kinase; T: Tumor; N: Node; 95% CI: 95% confidence interval.

Table 3 Univariate and multivariate analysis of overall survival in signet ring cell carcinoma (n = 79)

Characteristics	Groups	HR (95% CI)	P value
Univariate analysis
Age (yr)	> 60 vs ≤ 60	1.11 (0.52-2.37)	0.785
Gender	F vs M	1.08 (0.56-2.07)	0.817
PKM2	Positive vs negative	2.13 (1.02-4.44)	0.042
T stage	T4 vs T1/2/3	6.25 (3.03-12.85)	< 0.001
N stage	N3 vs N0/1/2	5.70 (2.90-11.22)	< 0.001
Stage	III vsI/II	6.84 (2.83-16.53)	< 0.001
Multivariate analysis
PKM2	Positive vs negative	2.12 (1.02-4.42)	0.044
Stage	III vsI/II	6.84 (2.83-16.55)	< 0.001

HR: Hazard ratio; PKM2: The M2 isoform of pyruvate kinase; 95% CI: 95% confidence interval; F: Female; M: Male; T: Tumor; N: Node.