Table 2.
Clinical, pathological and molecular features of colorectal cancer according to PIK3CA mutation status
| Total
|
PIK3CA wild-type
|
PIK3CA mutation present
|
P (across all categories) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Only in exon 9
|
P (exon 9 vs. exon 20) | Only in exon 20
|
In both exon 9 and exon 20
|
|||||||||
| Feature | No. | No. | No. | No. | No. | |||||||
| Total No. | 1170 | 981 | 109 | 73 | 7 | |||||||
| Sex | 0.88 | 0.26 | ||||||||||
| Male, (HPFS) | 536 | 46% | 439 | 45% | 56 | 51% | 36 | 49% | 5 | 71% | ||
| Female, (NHS) | 634 | 54% | 542 | 55% | 53 | 49% | 37 | 51% | 2 | 29% | ||
| Mean age at diagnosis (years) ± SD | 68.7 ± 8.7 | 68.6 ± 8.7 | 69.4 ± 8.9 | 0.94 | 68.3 ± 9.0 | 75.6 ± 10.0 | 0.95 | |||||
| Year of diagnosis | 0.76 | 0.92 | ||||||||||
| Prior to 1997 | 501 | 43% | 424 | 43% | 43 | 39% | 31 | 43% | 3 | 43% | ||
| 1997 or after | 669 | 57% | 557 | 57% | 66 | 61% | 42 | 57% | 4 | 57% | ||
| Family history of colorectal cancer in first degree relatives | 0.19 | 0.030 | ||||||||||
| Absent | 951 | 81% | 804 | 82% | 90 | 83% | 54 | 74% | 3 | 43% | ||
| Present | 219 | 19% | 177 | 18% | 19 | 17% | 19 | 26% | 4 | 57% | ||
| Tumor location | 0.80 | 0.19 | ||||||||||
| Rectum | 258 | 22% | 230 | 24% | 17 | 16% | 10 | 14% | 1 | 14% | ||
| Distal colon | 359 | 31% | 300 | 31% | 32 | 29% | 25 | 34% | 2 | 29% | ||
| Proximal colon | 546 | 47% | 444 | 45% | 60 | 55% | 38 | 52% | 4 | 57% | ||
| Disease stage | 0.093 | 0.23 | ||||||||||
| I | 282 | 24% | 231 | 24% | 33 | 30% | 15 | 21% | 3 | 43% | ||
| II | 327 | 28% | 270 | 28% | 28 | 26% | 28 | 38% | 1 | 14% | ||
| III | 308 | 26% | 264 | 27% | 24 | 22% | 19 | 26% | 1 | 14% | ||
| IV | 151 | 13% | 124 | 13% | 15 | 14% | 10 | 14% | 2 | 29% | ||
| Unknown | 102 | 9% | 92 | 9% | 9 | 8% | 1 | 1% | 0 | 0 | ||
| Tumor grade | 0.067 | 0.27 | ||||||||||
| Low | 1052 | 91% | 880 | 90% | 102 | 94% | 63 | 86% | 7 | 100% | ||
| High | 111 | 9% | 95 | 10% | 6 | 6% | 10 | 14% | 0 | 0 | ||
| MSI status | 0.0007 | 0.0050 | ||||||||||
| MSI-low/MSS | 978 | 85% | 820 | 85% | 100 | 92% | 52 | 72% | 6 | 86% | ||
| MSI-high | 176 | 15% | 146 | 15% | 9 | 8% | 20 | 28% | 1 | 14% | ||
| CIMP status | 0.028 | 0.025 | ||||||||||
| CIMP-low/0 | 906 | 83% | 762 | 83% | 88 | 87% | 52 | 73% | 4 | 57% | ||
| CIMP-high | 187 | 17% | 152 | 17% | 13 | 13% | 19 | 27% | 3 | 43% | ||
| BRAF status | 0.030 | 0.15 | ||||||||||
| Wild-type | 993 | 85% | 831 | 85% | 99 | 91% | 57 | 79% | 6 | 86% | ||
| Mutant | 171 | 15% | 145 | 15% | 10 | 9% | 15 | 21% | 1 | 14% | ||
| KRAS status | 0.29 | 0.0001 | ||||||||||
| Wild-type | 747 | 64% | 659 | 67% | 48 | 44% | 38 | 53% | 2 | 29% | ||
| Mutant | 418 | 36% | 318 | 33% | 61 | 56% | 34 | 47% | 5 | 71% | ||
| Mean LINE-1 methylation level (%) ± SD | 62.8 ± 9.5 | 62.5 ±9.6 | 64.3±9.6 | 0.53 | 63.9±8.9 | 62.3±7.5 | 0.79 | |||||
| TP53 expression | 0.71 | 0.0080 | ||||||||||
| Negative | 520 | 57% | 422 | 55% | 56 | 72% | 39 | 68% | 3 | 60% | ||
| Positive | 385 | 43% | 343 | 44% | 22 | 28% | 18 | 32% | 2 | 40% | ||
The % number indicates the proportion of patients with a specific clinical, pathological or molecular feature among all patients, or patients with specific PIK3CA mutation status. CIMP, CpG island methylator phenotype; HPFS, Health Professionals Follow-Up Study; MSI, microsatellite instability; MSS, microsatellite stable; NHS, Nurses’ Health Study; SD, standard deviation.