Epigenome-wide discovery and evaluation of leukocyte DNA methylation markers for the detection of colorectal cancer in a screening setting

Table 1 Study population characteristics

	Cases	Controls
BLITZ population
Sex (m/f)	38/19	1,978/2,521
Mean age ± SD	67 ± 7	62 ± 7
Smoking (never/ever)	25/32	2,313/2,175/11^a
Stage (Tis/I/II/III/IV)	4/19/6/19/3/6^a	—
Screening setting (plate A)
Study	BLITZ	BLITZ
Sex (m/f)	30/16	29/17
Mean age ± SD	67 ± 7	67 ± 7
Smoking (never/ever)	21/25	25/21
Stage (Tis/I/II/III/IV)	2/15/5/16/3/6^a	—
Cell proportions			\|Δ\|
Granulocytes	54.9 ± 12.8	48.7 ± 14.9	6.2
Monocytes	7.2 ± 1.9	7.6 ± 2.8	0.4
Natural killer cells	11.7 ± 5.2	13.3 ± 5.8	1.7
CD8+ T cells	3.5 ± 4.1	4.4 ± 3.8	0.9
CD4+ T cells	16.7 ± 7.7	19.1 ± 9.5	2.3
B lymphocytes	5.9 ± 2.8	6.8 ± 3.9	0.9
(Difference in mean LC is not significant, p-value 0.29)^c
Clinical setting (plates B and C)
Study	DACHS⁺	BLITZ
Sex (m/f)	57/36	57/37
Mean age ± SD	65 ± 8	65 ± 8
Smoking (never/ever)	43/50	47/47
Stage (Tis/I/II/III/IV)	4/28/41/29/22/1^a	—
Neoadj. therapy (none/rad./chemo./comb.)^b	60/12/2/19	—
Cell proportions			\|Δ\|
Granulocytes	64.9 ± 12.8	52.3 ± 12.6	12.6
Monocytes	9.3 ± 3.8	7.8 ± 2.7	1.5
Natural killer cells	7.2 ± 4.3	11.1 ± 5.2	3.9
CD8+ T cells	2.0 ± 2.9	3.5 ± 3.9	1.5
CD4+ T cells	12.6 ± 7.1	19.4 ± 7.8	6.9
B lymphocytes	4.0 ± 2.6	5.9 ± 2.9	1.9
(Difference in mean LC is significant, p-value 3.9 × 10⁻¹¹)^c

Study population characteristics stratified by plate. Subjects who smoked regularly more than 1 year of their life were defined as ever smokers. |Δ| gives the absolute difference in average leukocyte proportions between cases and controls
^aMissing values
^bNeoadjuvant therapy (none/radiation/chemotherapy/combination of radiation and chemotherapy)
^cAs cell proportions are compositional data, differences between cases and controls should not be tested for individual cell types, but for the composition as a whole. The isometric log-ratio transformation was applied and differences were tested using multivariate analysis of variance (MANOVA) as described in [25]

ISSN: 1868-7083