Table 4.
Inverse probability weighting-adjusted ordinal logistic regression analysis to assess the association of the combination of PIK3CA mutation and PTEN expression (predictor) with CD274 (PD-L1) expression (outcome)
| Characteristic | CD274 (PD-L1) expression For one category increase in three ordinal CD274 categories |
|||
|---|---|---|---|---|
| Univariable OR (95% CI)* |
P value | Multivariable OR (95% CI)*† |
P value | |
| Combination of PIK3CA mutation and PTEN expression | ||||
| PIK3CA wild-type/PTEN intact (N = 123) | 1 (referent) | 1 (referent) | ||
| PIK3CA mutant/PTEN intact (N = 24) | 1.49 (0.59–3.77) | 0.40 | 1.56 (0.63–3.86) | 0.33 |
| PIK3CA wild-type/PTEN lost (N = 204) | 1.97 (1.23–3.16) | 0.005 | 1.90 (1.19–3.06) | 0.008 |
| PIK3CA mutant/PTEN lost (N = 33) | 3.53 (1.55–8.07) | 0.003 | 3.70 (1.68–8.19) | 0.001 |
| MSI status | ||||
| Non-MSI-high (N = 322) | 1 (referent) | 1 (referent) | ||
| MSI-high (N = 63) | 0.35 (0.21–0.61) | <0.001 | 0.35 (0.20–0.62) | <0.001 |
* IPW was applied to reduce selection bias due to the availability of tumor tissue.
†The multivariable ordinal logistic regression model initially included sex, age, year of diagnosis, tumor differentiation, disease stage, family history of colorectal cancer, tumor location, microsatellite instability, CpG island methylator phenotype, long-interspersed nucleotide element-1 methylation level, KRAS mutation and BRAF mutation. A backward elimination with a threshold P of 0.05 was used to select variables for the final models.
Abbreviations: CI, confidence interval; IPW, inverse probability weighting; MSI, microsatellite instability; OR, odds ratio; PD-L1, programmed cell death 1 ligand 1.