Table II.
Prevalence of MTHFR, TS and RFC1 polymorphisms in colorectal cancer cases and controls.
| Genotypes | Controls (n=514) | Cases (n=477) | AOR (95% CI)a | P-value |
|---|---|---|---|---|
| MTHFR 677C>T | ||||
| CC | 172 (33.5) | 159 (33.3) | 1.00 (reference) | |
| CT | 265 (51.6) | 248 (52.0) | 0.99 (0.75–1.33) | 0.971 |
| TT | 77 (15.0) | 70 (14.7) | 0.93 (0.62–1.40) | 0.736 |
| Dominant (CC vs. CT+TT) | 0.98 (0.74–1.29) | 0.882 | ||
| Recessive (CC+CT vs. TT) | 0.93 (0.65–1.34) | 0.708 | ||
| HWE P-value | 0.125 | 0.091 | ||
| MTHFR 1298A>C | ||||
| AA | 364 (70.8) | 336 (70.4) | 1.00 (reference) | |
| AC | 143 (27.8) | 125 (26.2) | 0.96 (0.72–1.29) | 0.784 |
| CC | 7 (1.4) | 16 (3.4) | 2.36 (0.94–5.97) | 0.069 |
| Dominant (AA vs. AC+CC) | 1.03 (0.77–1.37) | 0.846 | ||
| Recessive (AA+AC vs. CC) | 2.46 (0.98–6.20) | 0.056 | ||
| HWE P-value | 0.089 | 0.305 | ||
| TSER 2R/3R | ||||
| 3R3R | 357 (69.5) | 316 (66.2) | 1.00 (reference) | |
| 2R3R | 147 (28.6) | 148 (31.0) | 1.08 (0.81–1.44) | 0.579 |
| 2R2R | 10 (1.9) | 13 (2.7) | 1.63 (0.69–3.85) | 0.270 |
| Dominant (3R3R vs. 2R3R+2R2R) | 1.11 (0.84–1.47) | 0.443 | ||
| Recessive (3R3R+2R3R vs. 2R2R) | 1.56 (0.66–3.66) | 0.310 | ||
| HWE P-value | 0.248 | 0.379 | ||
| TS 1494 0bp/6bp | ||||
| 0bp0bp | 245 (47.7) | 250 (52.4) | 1.00 (reference) | |
| 0bp6bp | 225 (43.8) | 183 (38.4) | 0.80 (0.61–1.06) | 0.115 |
| 6bp6bp | 44 (8.6) | 44 (9.2) | 1.05 (0.66–1.68) | 0.840 |
| Dominant (0bp0bp vs. 0bp6bp+6bp6bp) | 0.84 (0.65–1.09) | 0.196 | ||
| Recessive (0bp0bp+0bp6bp vs. 6bp6bp) | 1.16 (0.74–1.82) | 0.516 | ||
| HWE P-value | 0.447 | 0.215 | ||
| RFC1 −43T>C | ||||
| TT | 108 (21.0) | 102 (21.4) | 1.00 (reference) | |
| TC | 266 (51.8) | 219 (45.9) | 0.88 (0.63–1.25) | 0.485 |
| CC | 140 (27.2) | 156 (32.7) | 1.18 (0.82–1.70) | 0.368 |
| Dominant (TT vs. TC+CC) | 0.99 (0.72–1.36) | 0.946 | ||
| Recessive (TT+TC vs. CC) | 1.28 (0.97–1.70) | 0.086 | ||
| HWE P-value | 0.376 | 0.127 | ||
| RFC1 80G>A | ||||
| GG | 103 (20.0) | 96 (20.1) | 1.00 (reference) | |
| GA | 242 (47.1) | 218 (45.7) | 0.98 (0.69–1.39) | 0.904 |
| AA | 169 (32.9) | 163 (34.2) | 1.05 (0.73–1.51) | 0.775 |
| Dominant (AA vs. AG+GG) | 1.01 (0.73–1.39) | 0.966 | ||
| Recessive (AA+AG vs. GG) | 1.05 (0.80–1.39) | 0.709 | ||
| HWE P-value | 0.334 | 0.140 | ||
| RFC1 696C>T | ||||
| CC | 110 (21.4) | 105 (22.0) | 1.00 (reference) | |
| CT | 262 (51.0) | 229 (48.0) | 0.97 (0.69–1.36) | 0.867 |
| TT | 142 (27.6) | 143 (30.0) | 1.07 (0.74–1.53) | 0.729 |
| Dominant (CC vs. CT+TT) | 1.00 (0.73–1.37) | 0.996 | ||
| Recessive (CC+CT vs. TT) | 1.09 (0.82–1.45) | 0.562 | ||
| HWE P-value | 0.595 | 0.462 |
a
Models adjusted for age, gender, hypertension and diabetes mellitus status. HWE, Hardy-Weinberg equilibrium; MTHFR, methylenetetrahydrofolate reductase; TS, thymidylate synthase; TSER, TS enhancer region; RFC1, reduced folate carrier 1; AOR, adjusted odds ratio; CI, confidence interval.