Table IV.
Molecular characterization of lesions from patients with SPP-FHP/CRC, stratified by preferential location of the lesions in each patient.
| Molecular characterization | Preferential location of lesions
|
p-value | |
|---|---|---|---|
| Proximal/whole-colon | Distal colon | ||
| Total Wnt gene mutations | 14/26 (54%) | 4/20 (20%) | 0.02b |
| Total RAS/RAF gene mutations | 12/30 (40%) | 18/20 (90%) | 3.7×10−4b |
| BRAF gene mutations | 7/30 (23%) | 12/20 (60%) | 0.0089 (χ2 test) |
| KRAS gene mutations | 5/32 (16%) | 6/20 (30%) | NS |
| MSIa | 15/26 (58%) | 2/15 (13%) | 0.0059b |
| MMR gene methylation and/or LOH of D2S123 | 17/18 (94%) | 0/11 | 3.0×10−7b |
| MGMT gene methylation | 19/29 (65%) | 7/17 (41%) | NS |
| LOH of MGMT locus | 16/23 (70%) | 1/14 (7%) | 2.2×10−4b |
a
Except for one lesion, microsatellite instability (MSI), either microsatellite instability-low (MSI-L) or microsatellite instability-high (MSI-H), was detected only in dinucleotide microsatellite markers.
b
Fisher's exact test (two-sided). SPP, serrated polyposis; CRC, colorectal cancer; SPP-FHP/CRC, SPP associated with a family history of SPP and/or polyps/CRC (multiple or diagnosed at a young age) in first-degree relatives; MMR, mismatch repair; LOH, loss of heterozygosity; MGMT, O-6-methylguanine-DNA methyltransferase. Statistically significant values are shown in bold. NS, non-significant (p>0.05).