Role of ABCG2 expression driven by cisplatin in platinum-containing chemotherapy for gastric cancer

Table 1 Characteristics of patients according to increased expression times of ABCG2 mRNA by terciles n (%)

Clinical pathological parameters	Total cohort	ABCG2 mRNA expression times			P value
		≤0.71 (n = 40)	0.71-1.8 (n = 23)	≥1.8 (n =1 5)
Age (yr)					0.123
Median	59	58	61	59
Range	27-81	27-79	28-81	30-80
Gender					0.269
Female	19 (24.4)	10 (24.8)	6 (28.0)	3 (19.0)
Male	59 (75.6)	30 (75.2)	17 (72.0)	12 (81.0)
Performance status					0.556
0-1	70 (89.7)	36 (88.8)	20 (85.0)	14 (91.0)
2	8 (10.3)	4 (11.2)	3 (15.0)	1 (9.0)
Histological grad					0.106
Differentiated	39 (50.0)	19 (48.0)	12 (51.0)	8 (52.3)
Undifferentiated	39 (50.0)	21 (52.0)	11 (49.0)	7 (47.7)
Stage					0.170
IIIA	24 (30.8)	12 (29.0)	7 (31.0)	5 (33.0)
IIIB	24 (30.8)	13 (32.1)	7 (30.0)	4 (28.0)
IV	30 (38.5)	15 (38.9)	9 (39.0)	6 (39.0)
Chemotherapeutic regimen					0.322
Cisplatin + fluoropyrimidine	18 (23.1)	9 (23.1)	6 (26.9)	3 (21.4)
Cisplatin + docetaxel	11 (14.1)	6 (15.4)	3 (14.6)	2 (13.8)
Cisplatin + paclitaxel	10 (12.8)	5 (12.8)	3 (15.1)	2 (14.3)
Cisplatin + capecitabine	19 (24.4)	7 (32.1)	7 (30.5)	5 (35.8)
Cisplatin + S-1	20 (25.6)	13 (16.7)	4 (12.8)	3 (14.7)

Table 2 Univariate analysis of median overall survival and hazard ratios for risk of mortality according to clinical parameters

Clinical pathological parameters	Overall survival		Risk of mortality
	Month (95%CI)	P value	HR (95%CI)	P value
Performance status		0.012
0-1	14.4 (10.8-17.0)		1.00 (referent)
2	7.6 (2.5-13.7)		3.26 (0.96-16.46)	0.041
Histological grade		0.062
Differentiated	15.5 (8.2-22.5)		1.00 (referent)
Undifferentiated	10.9 (4.5-17.3)		4.95 (0.92-18.6)	0.122
Tumor-node-metastasis stage		0.001
IIIA	19.3 (16.9-21.7)		0.87 (0.51-9.76)	< 0.001
IIIB	13.0 (7.8-18.2)		0.92 (0.81-2.15)	0.102
IV	7.2 (4.4-10.0)		1.00 (referent)
Chemotherapeutic regimen		0.536
Cisplatin + fluoropyrimidine	10.7 (5.1-16.3)		1.00 (referent)
Cisplatin + docetaxel	13.2 (7.0-19.4)		0.84 (0.76-1.79)	0.073
Cisplatin + paclitaxel	12.6 (6.4-18.9)		0.91 (0.85-2.41)	0.145
Cisplatin + capecitabine	11.3 (5.6-18.0)		0.98 (0.90-3.26)	0.210
Cisplatin + S-1	12.0 (6.1-17.9)		0.95 (0.89-2.84)	0.179
ABCG2 mRNA expression times		0.031
≤ 0.71	14.2 (9.7-18.6)		0.71 (0.43-0.96)	< 0.001
0.71-1.8	11.4 (6.3-16.5)		0.94 (0.76-1.52)	0.083
≥ 1.8	9.0 (6.4-11.6)		1.00 (referent)