3.2 Comparison of high and low PD-L1 expression associated with
clinical parameters
This study showed that high expression of PD-L1 in TCs was correlated
with femal patients (OR,0.68; 95% CI: [0.56, 0.82]; P
<0.001). Meta-analysis of twenty-three studies contrasting the
smokers to non-smokers revealed that high PD-L1 expression in TCs was
associated with non-smoker (OR, 0.62; 95% CI: [0.48, 0.79]; P
<0.001). High expression of PD-L1 in TCs was observed in
non-drinkers (OR, 0.69; 95% CI: [0.49, 0.98]; P =0.037)
(Fig.2 ). However, the consequent meta-analysis suggested that
the statistically significant association was disappeared between the
expression of PD-L1 in TILs involving gender, smoking and drinking (Supplemental File 2 ).
There were no significant differences between the expression of PD-L1 in
TCs and age, T status, M status, grade, or anatomical location.
(Supplemental Fig.S3-S7) . Thirty studies were selected to
identify whether the N status was associated with PD-L1 expression. The
results showed that N+ patients were more likely to have high expression
of PD-L1 when compared to N0 patients (OR, 1.34; 95% CI: [1.03,
1.74]; P =0.027)(Supplemental Fig.S8) .Tumor stages were
grouped as stage I/II and stage III/IV that were used to assess the
discrepancy in comparison of high/low expression. Seventeen studies were
ultimately enrolled in meta-analysis. The result showed that patients
with stage III/IV had high PD-L1 expression (OR, 1.41; 95% CI: [1.04,
1.90]; P =0.028)(Supplemental Fig.S9) . The significance was
also observed in the association of high PD-L1 expression in TCs with
high levels of PD-1 (OR,33.57; 95% CI: [2.08, 542.52]; P =0.024),
and CD8+ (OR,5.03; 95% CI: [1.23, 20.50]; P
=0.022)(Supplemental Fig.S10) . No significant association was
found between PD-L1 expression on TILs and any clinicopathological
variables (Supplemental File 2 ).