Prognostic impact of membranous ATP-binding cassette Sub-family G member 2 expression in patients with colorectal carcinoma after surgical resection

Figures & data

Table 1. Characteristics of the patient population and tumors

Characteristic	Total group
N	234
Age (mean ± SD, years)	62.2 ± 11.6
Men (%)	130 (55.6)
Overall survival (mean ± SD, months)	84.20 ± 57.0
Site (N, %) Cecum	12 (5.1)
Ascending colon	37 (15.9)
Transverse colon	10 (4.3)
Descending colon	2 (0.9)
Sigmoid and rectum	173 (74.4)
Differentiation, Grade 1/2 (N, %)	200 (85.5)
T stage (N, %): 1, 2, 3, 4	2 (0.9), 50 (21.4), 141 (60.3), 41 (17.5)
Lymph node invasion (yes, %)	121 (51.7)
Distal metastasis (yes, %)	49 (20.9)
TNM stage (N, %)
I	43 (18.4)
II	60 (25.6)
III	82 (35.0)
IV	49 (20.9)
Curative resection (yes, %)	196 (83.8)
Adjuvant chemotherapy (yes, %)	207 (88.5)
Cytoplasmic ABCG2 expression (yes, %)	182 (77.8)
Membranous ABCG2 expression (yes, %)	144 (61.5)

Table 2. ABCG2 expression and clinicopathologic features

	Composite score
Characteristics	MCS ≤ 4	MCS > 4	P value	CCS ≤ 4	CCS > 4	P value
N	128	106		104	130
Age (mean ± SD, years)	62.3 ± 12.0	62.1 ± 11.2		61.0 ± 12.7	63.2 ± 10.7
Men (N, %)	75 (58.6)	55 (51.9)	0.355	64 (61.5)	66 (50.8)	0.113
Survival time (mean ± SD, months)
Overall	119.5 ± 8.0	131.2 ± 7.6	0.042^*	124.7 ± 8.6	132.2 ± 8.0	0.704
Disease-specific	130.5 ± 8.1	146.2 ± 7.1	0.01^*	138.0 ± 8.6	145.3 ± 7.9	0.748
Differentiation, Grade 1/2 (N, %)	103 (80.5)	97 (91.5)	0.017^*	80 (76.9)	120 (92.3)	0.001^*
Curative resection, yes (N, %)	105 (82.0)	91 (85.8)	0.479	85 (81.7)	111 (85.4)	0.479
Chemotherapy, yes (N, %)	111 (86.7)	96 (90.6)	0.415	92 (88.5)	115 (88.5)	1.000
TNM Stage (N, %)			0.840			0.742
I	26 (20.3)	17 (16.0)		16 (15.4)	27 (20.8)
II	31 (24.2)	29 (27.4)		27 (26.0)	33 (25.4)
III	44 (34.4)	38 (35.8)		39 (37.5)	43 (33.1)
IV	27 (21.1)	22 (20.8)		22 (21.2)	27 (20.8)
Site (N, %)			0.398			0.438
Cecum	5 (3.9)	7 (6.6)		3 (2.9)	9 (6.9)
Ascending colon	19 (14.8)	18 (17.0)		15 (14.4)	22 (16.9)
Transverse colon	7 (5.5)	3 (2.8)		5 (4.8)	5 (3.8)
Descending colon	2 (1.6)	0 (0.0)		1 (1.0)	1 (0.8)
Sigmoid colon and rectum	95 (74.2)	78 (73.6)		80 (76.9)	93 (71.5)

MCS, membranous composite score; CCS, Cytoplasmic composite score; SD: Standard deviation

* P < 0.05

Figure 1. Immunohistochemical staining of ABCG2 in human colorectal cancer. Representative tissue sections show low (A) and high (B) expression of ABCG2. (All × 400).

Figure 2. Overall and disease-specific survival according to ABCG2 expression, (A) membranous ABCG2 expression and overall survival, (B) membranous ABCG2 expression and disease-specific survival, (C) Cytoplasmic ABCG2 expression and overall survival, (D) Cytoplasmic ABCG2 expression and disease-specific survival.

Table 3. Multivariate analysis for patient survival

(A) Overall survival
Risk factor	OR (95% CI)	P value
Age	1.029 (1.010–1.047)	.002
Differentiation, grade 1/2	0.996 (0.581–1.707)	.989
Curative resection, yes	0.197 (0.099–0.389)	.000
Chemotherapy, yes	0.281 (0.158–0.502)	.000
TNM stage I
II	1.734 (0.785–3.829)	.173
III	3.388 (1.632–7.033)	.001
IV	5.172 (2.030–13.175)	.001
ABCG2 expression (MCS > 4)	0.624 (0.411–0.948)	.027
(B) Disease-specific survival
Risk factor	OR (95% CI)	P value
Age	1.019 (1.000–1.039)	.054
Differentiation, grade 1/2	0.833 (0.466–1.489)	.538
Curative resection, yes	0.194 (0.095–0.398)	.000
Chemotherapy, yes	0.305 (0.154–0.606)	.001
TNM stage I
II	2.43 (0.788–7.486)	.122
III	4.57 (1.586–13.150)	.005
IV	8.74 (2.581–29.606)	.000
ABCG2 expression (MCS > 4)	0.46 (0.285–0.741)	.001

MCS, membranous composite score

Figure 3. Overall and disease-specific survival from different cancer stages, according to membranous ABCG2 expression. MCS, membranous composite score. (A) Membranous ABCG2 expression and overall survival, stage I, (B) membranous ABCG2 expression and disease-specific survival, stage I, (C) membranous ABCG2 expression and overall survival, stage II and III, (D) membranous ABCG2 expression and disease-specific survival, stage II and III, (E) membranous ABCG2 expression and overall survival, stage IV, (F) membranous ABCG2 expression and disease-specific survival, stage IV.