Table 4. PD-L1 expression in peripheral blood of OSCC patients related to histomorphological parameters (T-, N-, L-, Pn-status, grading).

		n	mean ∆CT	SD	p-value	AUC	FC	COP	No. of cases	+	-	% pos. cases	p-value χ2 test
PD-L1_4 tissue		78			< 0.001	0.83	3.19	7.99	78	41	37		< 0.001
controls		35	8.82	1.11					35	6	29	17.1%
patients		43	7.15	1.59					43	35	8	81.4%
PD-L1_4 blood		75			0.165	nd	nd	nd	nd	nd	nd	nd	nd
controls		31	7.17	1.40
patients		44	6.90	1.24
PD-L1_2 tissue		74			< 0.001	0.76	3.18	10.37	74	40	34		< 0.001
controls		31	10.92	1.45					31	8	23	25.8%
patients		43	9.25	1.94					43	32	11	74.4%
PD-L1_2 blood		75			0.287	nd	nd	nd	nd	nd	nd	nd	nd
controls		31	7.10	1.33
patients		44	6.92	1.21

Association between the PD-L1 mRNA expression rates in peripheral blood samples of OSCC patients and histomorphological parameters (T-, N-, L-, Pn-status, grading). Data for PD-L1 splicing variants 1 and 4 (PD-L1_4) and splicing variants 1 and 2 (PD-L1_2) are given. The mean ΔCT value (mean), standard deviation (SD) and the p-value provided by the Mann-Whitney U test are shown. Higher ΔCT values indicate lower PD-L1 mRNA expression. Regarding the N-status, area under the curve (AUC), fold-change FC and cut-off point (COP) values are given. Based on their ΔCT value related to the COP, the cases were determined as positive (+) and negative (-). The percentage of positive tested cases (% pos. cases) in the N0 and N+ group is presented. A Statistical analysis was carried out by the Chi-square test (χ² test). Fold-change (FC) of PD-L1 mRNA expression was determined by the ΔΔCT method comparing the average ΔCT values of the two groups. nd: not determined.