Table 3.
Clinical, Pathological, and Molecular Characteristics of Colorectal Cancer Cases According to the Amount of pks+ E. coli DNA in Colorectal Cancer Tissue
| Characteristic* | All cases (N = 1175) | Amount of pks+ E. coli DNA in colorectal cancer tissue | P value† | ||
|---|---|---|---|---|---|
| Negative (N = 1064) | Low (N = 55) | High (N = 56) | |||
| Sex | 0.28 | ||||
| Female (NHS) | 656 (56%) | 588 (55%) | 31 (56%) | 37 (66%) | |
| Male (HPFS) | 519 (44%) | 476 (45%) | 24 (44%) | 19 (34%) | |
| Mean age ± SD (years) | 69.0 ± 8.8 | 68.9 ± 8.8 | 69.6 ± 10.0 | 69.9 ± 8.1 | 0.61 |
| Year of diagnosis | 0.09 | ||||
| 1995 or before | 399 (34%) | 371 (35%) | 12 (22%) | 16 (29%) | |
| 1996–2000 | 375 (32%) | 333 (31%) | 18 (33%) | 24 (43%) | |
| 2001–2008 | 401 (34%) | 360 (34%) | 25 (45%) | 16 (29%) | |
| Family history of colorectal cancer in first-degree relative(s) | 0.17 | ||||
| Absent | 935 (80%) | 854 (81%) | 42 (76%) | 39 (71%) | |
| Present | 235 (20%) | 206 (19%) | 13 (24%) | 16 (29%) | |
| Tumor location | 0.70 | ||||
| Cecum | 202 (17%) | 182 (17%) | 11 (20%) | 9 (16%) | |
| Ascending to transverse | 364 (31%) | 334 (32%) | 16 (29%) | 14 (25%) | |
| Descending to sigmoid | 355 (30%) | 314 (30%) | 19 (35%) | 22 (39%) | |
| Rectum | 249 (21%) | 229 (22%) | 9 (16%) | 11 (20%) | |
| AJCC disease stage | 0.008 | ||||
| I | 262 (24%) | 230 (23%) | 12 (24%) | 20 (42%) | |
| II | 354 (33%) | 319 (32%) | 19 (37%) | 16 (33%) | |
| III | 311 (29%) | 288 (29%) | 14 (27%) | 9 (19%) | |
| IV | 157 (14%) | 148 (15%) | 6 (12%) | 3 (6.3%) | |
| Tumor size ± SD (cm) | 4.4 ± 2.0 | 4.4 ± 2.0 | 4.7 ± 2.0 | 4.5 ± 2.1 | 0.39 |
| Tumor differentiation | 0.42 | ||||
| Well to moderate | 1053 (90%) | 954 (90%) | 47 (85%) | 52 (93%) | |
| Poor | 118 (10%) | 106 (10%) | 8 (15%) | 4 (7.1%) | |
| MSI status | 0.49 | ||||
| Non-MSI-high | 947 (83%) | 860 (83%) | 40 (78%) | 47 (87%) | |
| MSI-high | 188 (17%) | 170 (17%) | 11 (22%) | 7 (13%) | |
| CIMP status | 0.63 | ||||
| Low/negative | 885 (82%) | 803 (82%) | 36 (82%) | 46 (87%) | |
| High | 197 (18%) | 182 (18%) | 8 (18%) | 7 (13%) | |
| Mean LINE-1 methylation level ± SD | 63.0 ± 9.8 | 63.0 ± 9.8 | 63.4 ± 11.5 | 63.5 ± 7.2 | 0.88 |
| KRAS mutation | 0.50 | ||||
| Wild-type | 645 (59%) | 586 (59%) | 30 (64%) | 29 (53%) | |
| Mutant | 443 (41%) | 400 (41%) | 17 (36%) | 26 (47%) | |
| BRAF mutation | 0.55 | ||||
| Wild-type | 942 (84%) | 852 (84%) | 41 (82%) | 49 (89%) | |
| Mutant | 177 (16%) | 162 (16%) | 9 (18%) | 6 (11%) | |
| PIK3CA mutation | 0.51 | ||||
| Wild-type | 878 (84%) | 795 (84%) | 39 (85%) | 44 (90%) | |
| Mutant | 168 (16%) | 156 (16%) | 7 (15%) | 5 (10%) | |
Percentage indicates the proportion of patients with a specific clinical, pathological, or molecular characteristic among all patients or in strata of the amount of pks+ E. coli DNA in colorectal cancer tissue.
To assess associations between the categories (negative, low, and high) of pks+ E. coli DNA in colorectal cancer tissue and categorical data, the chi-square test was performed. To compare age, and LINE-1 methylation level, an analysis of variance was performed. To compare AJCC disease stage, Spearman analysis was performed.
Abbreviations: AJCC, American Joint Committee on Cancer; CIMP, CpG island methylator phenotype; HPFS, Health Professionals Follow-up Study; LINE-1, long-interspersed nucleotide element-1; MSI, microsatellite instability; NHS, Nurses’ Health Study; SD, standard deviation.