Expression profiling of gastric cancer samples by oligonucleotide microarray analysis reveals low degree of intra-tumor variability

Table 1 Clinical data and histopathological features of gastric cancers included in the study

Tumor number	Age/Sex	Site	Lauren	TNM
1	72/Female	Antrum	Intestinal	T2 N2 G3
2	78/Male	Body	Intestinal	T2 N1 G2
3	81/Male	Antrum	Intestinal	T2 N1 G2
4	75/Female	Antrum	Intestinal	T2 N0 G3
5	76/Male	Cardia	Intestinal	T2 N2 G3
6	76/Male	Cardia	Intestinal	T2 N0 G3

Table 2 RNA and hybridization quality control parameters

Extraction/Tumor number	A260/280ratio	GAPDH CT	Present calls (%)	GAPDH 3’5’ ratio
A/1	2.18	15.86	52.5	1.08
B/1	2.18	15.7	52.3	1.26
A/2	2.09	15.8	49.2	0.89
B/2	2.07	15.6	54.4	1.19
A/3	2.1	15.2	53.5	1.09
B/3	2.1	15.2	52.5	1.08
A/4	2.07	15.5	48.8	0.99
B/4	2.08	15.2	49.8	0.96
A/5	2.15	16.07	51.7	1.95
B/5	2.24	16.15	54.7	1.46
A/6	2.19	16.08	42.9	1.58
B/6	2.13	16.2	45.9	1.34

Table 3 Comparison results for all tumor samples analyzed

Comparison	Pairwise correlation coefficient	Percentage of “total change"
Tumor 1, extraction A vs B	0.96	1.07
Tumor 2, extraction A vs B	0.91	2.65
Tumor 3, extraction A vs B	0.99	0.08
Tumor 4, extraction A vs B	0.96	0.55
Tumor 5, extraction A vs B	0.94	1.28
Tumor 6, extraction A vs B	0.95	0.39

Tumor no. 3 was used to evaluate experimental variability.