NDRG2 gene copy number is not altered in colorectal carcinoma

Table 1 Mean values of normalised levels of NDRG2 mRNA in colorectal cancer cell lines and healthy colonic tissue

Sample	mRNA level
DLD-1 cell line	0
LoVo cell line	0.005
SW-480 cell line	0.001
Control human colona	0.034 ± 0.009

All samples were analysed in technical triplicates and normalised to β-actin mRNA levels.

^aPreviously published data for the mean ± standard deviation for 15 individuals[3].

Table 2 ddCt values and corresponding copy numbers for the NDRG2 and MYC genes in colorectal cancer cell lines

Cell line	NDRG2 - 5’ end		NDRG2 - 3’ end		MYC
	ddCt ± SD	Copy number	ddCt ± SD	Copy number	ddCt ± SD	Copy number
LoVo	1.23 ± 0.47	2	1.12 ± 0.51	2	0.91 ± 0.31	2
DLD-1	1.04 ± 0.23	2	1.08 ± 0.50	2	0.74 ± 0.22	Loss
SW-480	1.04 ± 0.26	2	0.94 ± 0.44	2	4.88 ± 0.30	Gain

Copy number loss is defined as ddCt < 0.75 and a gain is defined as ddCt > 1.25. ddCt: Delta delta Ct; SD: Standard deviation.

Table 3 Alteration in copy numbers for the NDRG2 and MYC genes in colorectal tissue

Colorectal tissue	Number of samples	Loss ddCt < 0.75	Unaltered ddCt 0.75-1.25	Gain ddCt > 1.25	Normal vs CRC
NDRG2 - 5’ end
Normal	8	1	7	0
CRC	40	2	29	9	P = 0.194a
NDRG2 - 3’ end
Normal	8	0	8	0
CRC	40	2	32	6	P = 0.470a
MYC
Normal	8	0	7	1
CRC	40	4	19	17	P = 0.135b

^aP value for comparison of ddCt values (supplementary table S2) in normal and CRC samples using an unpaired two-tailed t test;

^bP value for comparison of ddCt values (supplementary table S2) in normal and CRC samples using a Mann-Whitney test. ddCt: Delta delta Ct.