Table 2.
Clinical and molecular features of serrated lesions and non-serrated adenomas (tubular or tubulovillous adenoma) according to histological type n (%)
| Clinical or molecular feature | Total n |
Histological type |
P value | |||||
|
Serrated lesion |
Non-serrated adenoma |
|||||||
| HP | SSA without cytological dysplasia | SSA with cytological dysplasia | TSA without high-grade dysplasia (HGD) | Tubular adenoma without HGD | Tubulovillous adenoma without HGD | |||
| All cases | 416 | 115 | 120 | 10 | 91 | 77 | 3 | |
| Sex | ||||||||
| Male | 263 (63) | 78 (68) | 72 (60) | 5 (50) | 55 (60) | 50 (65) | 3 (100) | 0.36 |
| Female | 153 (37) | 37 (32) | 48 (40) | 5 (50) | 36 (40) | 27 (35) | 0 (0) | |
| Age (mean ± SD) | 60.3 ± 11.8 | 57.5 ± 12.1 | 57.2 ± 11.6 | 74.1 ± 4.7 | 60.9 ± 12.3 | 66.6 ± 11.4 | 66.0 ± 8.9 | < 0.0001 |
| Tumor size (mm) | 10.5 ± 5.4 | 9.3 ± 3.7 | 11.6 ± 5.4 | 12.3 ± 6.4 | 9.7 ± 4.7 | 10.9 ± 7.2 | 15.7 ± 13.2 | 0.0069 |
| (mean ± SD) | ||||||||
| Tumor location | ||||||||
| Rectum | 42 (10) | 15 (13) | 0 (0) | 0 (0) | 16 (18) | 10 (14) | 1 (33) | < 0.0001 |
| Distal colon | 127 (31) | 44 (39) | 17 (14) | 1 (10) | 39 (44) | 25 (34) | 1 (33) | |
| Proximal colon | 239 (59) | 54 (48) | 103 (86) | 9 (90) | 34 (38) | 38 (52) | 1 (33) | |
| BRAF mutation | ||||||||
| Wild-type | 183 (44) | 59 (51) | 16 (13) | 2 (20) | 28 (31) | 75 (97) | 3 (100) | < 0.0001 |
| Mutant | 231 (55) | 56 (49) | 104 (87) | 8 (80) | 61 (69) | 2 (2.6) | 0 (0) | |
| KRAS mutation | ||||||||
| Wild-type | 357 (87) | 92 (81) | 117 (98) | 10 (100) | 74 (83) | 62 (81) | 2 (67) | < 0.0001 |
| Mutant | 55 (13) | 21 (19) | 3 (2.5) | 0 (0) | 15 (17) | 15 (19) | 1 (33) | |
| PIK3CA mutation | ||||||||
| Wild-type | 406 (99) | 113 (99) | 117 (100) | 10 (100) | 89 (100) | 74 (99) | 3 (100) | 0.67 |
| Mutant | 2 (0.5) | 1 (0.9) | 0 (0) | 0 (0) | 0 (0) | 1 (1.3) | 0 (0) | |
| MSI status | ||||||||
| MSS/MSI-low | 408 (98) | 113 (98) | 119 (99) | 6 (60) | 90 (99) | 77 (100) | 3 (100) | 0.0004 |
| MSI-high | 8 (1.9) | 2 (1.7) | 1 (0.8) | 4 (40) | 1 (1.1) | 0 (0) | 0 (0) | |
| IGF2 DMR0 | 64.5 ± 17.2 | 61.9 ± 20.5 | 73.1 ± 12.3 | 69.0 ± 10.8 | 61.6 ± 19.6 | 58.9 ± 16.1 | 61.0 ± 7.1 | < 0.0001 |
| methylation level (mean ± SD) | ||||||||
| LINE-1 | 58.7 ± 5.0 | 58.6 ± 3.4 | 58.1 ± 5.4 | 58.3 ± 8.4 | 58.8 ± 4.7 | 59.4 ± 6.0 | 60.9 ± 1.4 | 0.59 |
| methylation level (mean ± SD) | ||||||||
Percentage indicates the proportion of patients of each histological type who met the criteria for a specific clinical or molecular feature. P values were calculated by analysis of variance for age, tumor size, methylation levels of IGF2 DMR0 and LINE-1 and by χ2 or Fisher’s exact test for all other variables. The P value for significance was adjusted by Bonferroni correction to 0.0050 (= 0.05/10). HGD: High-grade dysplasia; HP: Hyperplastic polyp; MSI: Microsatellite instability; MSS: Microsatellite stable; SSA: Sessile serrated adenoma; TSA: Traditional serrated adenoma; IGF2: Insulin-like growth factor 2.