Table 1.
Clinical and molecular features of colon cancer according to COX-2 expression.
| Clinical or molecular feature | All cases | COX-2 negative | COX-2 positive | P value |
|---|---|---|---|---|
| Total N | 662 | 114 | 548 | |
| Sex | 0.59 | |||
| Male (HPFS) | 287 (43%) | 52 (46%) | 235 (43%) | |
| Female (NHS) | 375 (57%) | 62 (54%) | 313 (57%) | |
| Mean age ± SD | 66.5 ± 8.3 | 66.8 ± 7.4 | 66.5 ± 8.4 | 0.69 |
| Year of diagnosis | 0.05 | |||
| Prior to 1990 | 101 (15%) | 17 (15%) | 84 (15%) | |
| 1990 to 1999 | 482 (73%) | 91 (80%) | 391 (71%) | |
| 2000 to 2002 | 79 (12%) | 6 (5.3%) | 73 (13%) | |
| Tumor location^ | 0.005 | |||
| Proximal | 434 (59%) | 80 (71%) | 305 (56%) | |
| Distal | 297 (41%) | 33 (29%) | 236 (44%) | |
| Tumor stage | 0.77 | |||
| I | 136 (21%) | 25 (22%) | 111 (20%) | |
| IIA | 207 (31%) | 40 (35%) | 167 (30%) | |
| IIB | 20 (3.0%) | 1 (0.9%) | 19 (3.5%) | |
| IIIA | 21 (3.2%) | 2 (1.8%) | 19 (3.5%) | |
| IIIB | 88 (13%) | 13 (11%) | 75 (14%) | |
| IIIC | 55 (8.3%) | 13 (11%) | 42 (7.7%) | |
| IV | 86 (13%) | 15 (13%) | 71 (13%) | |
| Unknown | 49 (7.4%) | 5 (4.4%) | 44 (8.0%) | |
| Tumor grade | 0.0003 | |||
| Low | 585 (89%) | 90 (79%) | 495 (91%) | |
| High | 74 (11%) | 24 (21%) | 50 (9.2%) | |
| p53* | <0.0001 | |||
| (-) | 404 (61%) | 91 (81%) | 313 (58%) | |
| (+) | 253 (39%) | 22 (19%) | 231 (42%) | |
| MSI | 0.0009 | |||
| MSI-low/MSS | 521 (81%) | 77 (69%) | 446 (84%) | |
| MSI-high | 121 (19%) | 33 (31%) | 88 (16%) | |
| CIMP | 0.004 | |||
| CIMP-0 | 277 (42%) | 32 (28%) | 245 (45%) | |
| CIMP-low | 257 (39%) | 53 (46%) | 204 (37%) | |
| CIMP-high | 128 (19%) | 29 (25%) | 99 (18%) | |
| KRAS mutation | 0.55 | |||
| (-) | 411 (64%) | 68 (61%) | 343 (64%) | |
| (+) | 234 (36%) | 43 (39%) | 191 (36%) | |
| BRAF mutation | 0.24 | |||
| (-) | 525 (83%) | 85 (79%) | 440 (84%) | |
| (+) | 105 (17%) | 22 (21%) | 83 (16%) |
(%) indicates the proportion of tumors with a specific clinical or molecular feature in a given COX-2 subtype.
^
Proximal colon includes cecum to transverse colon, and distal colon includes splenic flexure to sigmoid colon.
*
p53 status was determined by immunohistochemistry.
CIMP, CpG island methylator phenotype; COX-2, cyclooxygenase-2 (PTGS2); HPFS, Health Professionals Follow-up Study; MSI, microsatellite instability; MSS, microsatellite stable; NHS, Nurses' Health Study; SD, standard deviation.