Table 2. Difference of PD-L1 protein expression in LUADs and LUSCs.

Histological type	Variable	p value	ρ value
LUSC
	Tumor (T)	0.049	0.187*
	Region lymph node (N)	0.001	0.323**
	Clinical stage	0.003	0.278**
LUAD
	Sex	0.003	−0.116**
	Smoking history	0.035	0.118*
	Differentiation	0.000	−0.200**
	Tumor maximum diameter	0.001	0.195*
	Tumor (T)	0.002	0.184**
	Region lymph node (N)	0.000	0.337**
	Metastasis (M)	0.000	0.324**
	Clinical stage	0.000	0.361**

Note: ρ refers to Spearman coefficient. ρ value greater than zero means a positive correlation and less than zero means a negative correlation.