Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

Table 2 The ABCB1, ABCC2 and ABCG2 mRNA levels in intestinal tissue from patients with adenomas and colorectal cancer and healthy individuals

	Unaffected tissue	P value1	Adenomas/carcinomas	P value1	P value2	Ref.
ABCB1						[13]
Healthy individuals	0.012 ± 0.008
Mild/moderate dysplasia cases	0.009 ± 0.004	NS	0.005 ± 0.004	< 0.050	< 0.001
Severe dysplasia cases	0.009 ± 0.030	NS	0.003 ± 0.002	< 0.050	< 0.001
Cancer patients	0.009 ± 0.014 (distant)	< 0.05	0.003 ± 0.005	< 0.001	< 0.001
	0.007 ± 0.009 (adjacent)	< 0.05			< 0.010
ABCC2						[14]
Healthy individuals	5.35 ± 3.24
Mild moderate dysplasia cases	4.62 ± 4.79	0.081	6.68 ± 6.77	0.87	0.037
Severe dysplasia cases	6.66 ± 8.47	0.880	10.18 ± 11.52	0.27	0.240
Cancer patients	28.06 ± 68.84 (distant)	0.036	87.50 ± 270.21	0.0046	0.0037
	11.44 ± 25.58 (adjacent)	0.690			< 0.0001
ABCG2						[14]
Healthy individuals	718.06 ± 761.24
Mild moderate dysplasia	732.85 ± 2305.28	0.550	56.02 ± 118.42	< 0.0001	< 0.0001
Severe dysplasia	448.02 ± 195.34	0.840	76.31 ± 102.63	< 0.0001	< 0.0001
Cancer patients	6679 ± 58353 (distant)	0.080	98.41 ± 476.36	< 0.0001	< 0.0001
	1302 ± 10090 (adjacent)	0.011			< 0.0001

¹P values for comparison of the expression levels in tissue from healthy individuals adjusted for age and gender. Samples were available for 18 healthy controls, 88-94 patients with mild/moderate dysplasia, 12 with severe dysplacia, and 121-122 patients with CRC;

²P value for the comparison of the expression levels in morphologically unaffected and affected tissue from the same individual using Paired Student’s t-test. All values are mean ± SD. ABCB1 mRNA levels are normalised to the β-actin mRNA level. ABCC2 and ABCG2 mRNA levels are normalised to 18S RNA levels. Matching samples were available from ABCG2: 66-75 cases with mild-moderate dysplasia, 11 cases with severe dysplasia, and 63-80 and 66-99 CRC cases (distant unaffected tissue, and adjacent unaffected tissue, respectively). NS: Not significant.