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. Author manuscript; available in PMC: 2017 Nov 1.
Published in final edited form as: Cancer Immunol Res. 2016 Oct 13;4(11):927–935. doi: 10.1158/2326-6066.CIR-16-0112

Table 4.

let-7a and let-7b expression in colorectal cancer tissue and survival

Cancer-specific mortality
Overall mortality
let-7 expression No. of cases No. of events Univariate HR (95% CI) Multivariate HRa (95% CI) No. of events Univariate HR (95% CI) Multivariate HRa (95% CI)
let-7a (n = 795)
 Q1 198 43 1 (reference) 1 (reference) 96 1 (reference) 1 (reference)
 Q2 199 57 1.38 (0.93–2.05) 1.38 (0.93–2.05) 120 1.28 (0.98–1.68) 1.34 (1.02–1.75)
 Q3 199 66 1.63 (1.13–2.45) 1.66 (1.48–3.25) 115 1.31 (1.00–1.71) 1.41 (1.08–1.86)
 Q4 199 76 1.97 (1.25–2.66) 1.82 (1.42–3.13) 114 1.35 (1.03–1.77) 1.39 (1.06–1.84)
Ptrendb 0.0002 0.001 0.04 0.02
let-7b (n = 792)
 Q1 198 52 1 (reference) 1 (reference) 109 1 (reference) 1 (reference)
 Q2 198 63 1.26 (0.87–1.82) 1.30 (0.90–1.88) 114 1.31 (0.87–1.47) 1.17 (0.90–1.52)
 Q3 198 70 1.45 (1.01–2.08) 1.53 (1.07–2.20) 114 1.08 (0.96–1.63) 1.26 (0.97–1.64)
 Q4 198 56 1.08 (0.74–1.58) 1.11 (0.76–1.62) 105 1.01 (0.77–1.32) 1.00 (0.77–1.32)
Ptrendb 0.53 0.44 0.76 0.84
a

The multivariate Cox regression model initially included sex, age, year of diagnosis, family history of colorectal cancer in parent or sibling, microsatellite instability, CpG island methylator phenotype, KRAS, BRAF, and PIK3CA mutations, and LINE-1 methylation level. A backward stepwise elimination with a threshold of P < 0.05 was used to select variables in the final models.

b

Ptrend was calculated by the linear trend test across the ordinal categories (first to fourth quartile) of let-7a or let-7b expression as a continuous variable in the Cox regression model for cancer-specific mortality and overall mortality. We adjusted two-sided α level to 0.012 (= 0.05/4) by simple Bonferroni correction.

CI, confidence interval; HR, hazard ratio; Q1 to Q4, quartile 1 (lowest) to quartile 4 (highest).