Table 3. Distribution of PD-1 expression rates in cancer cells and lymphocytes according to stages.

	Stage I		Stage II		Stage III		p
	n	%	n	%	n	%
Squamous cell carcinoma
PD-1 expression on cancer cells	8	32.0	6	46.2	9	39.1	0.68
PD-1 expression on lymphocytes	11	44.0	8	61.5	12	52.2	0.58
Adenocarcinoma
PD-1 expression on cancer cells	10	32.3	7	41.2	12	63.2	0.09
PD-1 expression on lymphocytes	11	35.5	9	52.9	15	78.9	0.012
LCC
PD-1 expression on cancer cells	1	4.2	6	30.0	3	15.8	0.065
PD-1 expression on lymphocytes	13	54.2	11	55.0	11	57.9	0.97
Overall
PD-1 expression on cancer cells	19	23.8	19	38.0	24	39.3	0.091
PD-1 expression on lymphocytes	35	43.8	28	56.0	38	62.3	0.080
PD-1: Programmed death 1.