Normal tissue | Tumour tissue | |||||||
---|---|---|---|---|---|---|---|---|
Frequency (No positive/ total No (%)) | Concentration1-a (μmol O6-MedG/ mol dG) | Frequency (No positive/ total No (%)) | Concentrationa(μmol O6-MedG/ mol dG) | |||||
Proximal colon1-b | 4/16 (25) | 0.021 (0.003)1 2 3 | 9/15 (60) | 0.044 (0.030) | ||||
Sigmoid colon | 11/21 (52) | 0.044 (0.025)c 1 3 | 6/19 (32) | 0.050 (0.050) | ||||
Rectum | 12/25 (48) | 0.042 (0.020)2 | 15/24 (63) | 0.046 (0.048) |
↵1-a Levels inO 6-MedG containing samples.
↵1-b Tumours of the caecum, hepatic flexure, and transverse colon.
1-c Levels are 0.126 (0.27) μmolO 6-MedG/mol dG if positive outlier is included.
Alkylation levels in normal DNA from the proximal colon were lower than those in normal DNA from the sigmoid colon (1p=0.04, Mann-Whitney U test) or rectum (2p=0.03 Mann-Whitney U test). Inclusion of the positive outlier result did not alter the results (3p=0.05, Mann-Whitney U test).