Table 2.

Clinical, pathologic, and molecular features according to tumor MIR21 expression in 538 colorectal cancer cases

Tumor MIR21 expression (quartile)
CharacteristicaTotal (N = 538)Q1 (lowest; n = 135)Q2 (second; n = 134)Q3 (third; n = 134)Q4 (highest; n = 135)Pb
Mean age ± SD, y67.6 ± 8.366.7 ± 8.267.2 ± 8.568.8 ± 8.167.5 ± 8.30.19
Sex0.044
 Men185 (34%)50 (37%)44 (33%)56 (42%)35 (26%)
 Women353 (66%)85 (63%)90 (67%)78 (58%)100 (74%)
Year of diagnosis0.006
 Prior to 1995201 (38%)63 (47%)55 (41%)42 (32%)41 (30%)
 1996–2000202 (38%)43 (32%)54 (40%)44 (34%)61 (45%)
 2001–2008131 (24%)28 (21%)25 (19%)45 (34%)33 (25%)
Family history of colorectal cancer in a first-degree relative0.21
 Absent422 (79%)105 (78%)111 (83%)96 (74%)110 (82%)
 Present109 (21%)29 (22%)22 (17%)34 (26%)24 (18%)
Tumor location0.30
 Cecum96 (18%)20 (15%)22 (17%)27 (20%)27 (20%)
 Ascending to transverse colon173 (32%)39 (29%)40 (30%)43 (32%)51 (38%)
 Splenic flexure to sigmoid149 (28%)39 (29%)44 (33%)31 (23%)35 (26%)
 Rectosigmoid and rectum117 (22%)36 (27%)27 (20%)33 (25%)21 (16%)
Disease stage0.009
 I110 (21%)37 (28%)29 (22%)23 (18%)21 (16%)
 II173 (34%)44 (34%)45 (35%)44 (35%)40 (31%)
 III164 (32%)31 (24%)44 (34%)48 (39%)41 (32%)
 IV67 (13%)18 (14%)11 (8.5%)10 (8.0%)28 (21%)
Tumor differentiation0.24
 Well to moderate486 (91%)121 (90%)127 (95%)119 (89%)119 (88%)
 Poor51 (9.5%)13 (9.7%)7 (5.2%)15 (11%)16 (12%)
MSI status0.26
 MSI-low/MSS440 (84%)114 (87%)115 (86%)107 (82%)104 (79%)
 MSI-high86 (16%)17 (13%)18 (14%)24 (18%)27 (21%)
MLH1 hypermethylation0.15
 Absent461 (87%)118 (89%)121 (91%)109 (83%)113 (85%)
 Present69 (13%)14 (11%)12 (9.0%)23 (17%)20 (15%)
CIMP status0.015
 Low/negative440 (83%)113 (86%)119 (89%)108 (82%)100 (75%)
 High90 (17%)19 (14%)14 (11%)24 (18%)33 (25%)
BRAF mutation0.003
 Wild-type444 (84%)120 (90%)116 (88%)110 (82%)98 (75%)
 Mutant86 (16%)13 (9.8%)16 (12%)24 (18%)33 (25%)
KRAS mutation0.11
 Wild-type311 (59%)76 (58%)67 (51%)88 (66%)80 (61%)
 Mutant216 (41%)55 (42%)64 (49%)46 (34%)51 (39%)
PIK3CA mutation0.86
 Wild-type408 (83%)99 (84%)104 (82%)105 (82%)100 (85%)
 Mutant82 (17%)19 (16%)23 (18%)23 (18%)17 (15%)
Mean LINE-1 methylation level (%) ± SD61.6 ± 9.661.6 ± 8.459.6 ± 10.462.1 ± 10.263.0 ± 9.10.032

Abbreviations: Q1 to Q4, quartile 1 to quartile 4.

  • aPercentage indicates the proportion of cases with a specific clinical, pathologic, or molecular feature in colorectal cancer cases with each tumor MIR21 expression. There were cases that had missing values for any of the characteristics except for age and sex.

  • bTo assess associations between the ordinal categories (first to fourth quartile) of tumor MIR21 expression and categorical data, the χ2 test was performed. To compare mean age and mean LINE-1 methylation levels, an ANOVA was performed. We adjusted the two-sided α level to 0.003 (= 0.05/14) by simple Bonferroni correction for multiple hypothesis testing.