Table 2. Patients' characteristics and correlation/association of PD-L1 DNA promoter methylation (mPD-L1) with clinicopathological parameters in the training (n = 498, Probe cg19724470) and validation cohort (n = 299). mPD-L1 was dichotomized according to the respective optimized cut-off (mPD-L1_low vs. mPD-L1_high).

	Training Cohort								Validation Cohort
	All patients	[%]	Median mPD-L1 [%]	mPD-L1low	[%]	mPD-L1high	[%]	p-value	All patients	[%]	Median mPD-L1 [%]	mPD-L1low	[%]	mPD-L1high	[%]	p-value
Patients [n]	498	100.0	36.3	397	79.7	101	20.3		299	100.0	0.49	197	65.9	102	34.1
Patients with follow-up [n]	410
Mean follow-up [months]	22								66
Median follow-up [months]	16								63
Age [years]
Mean	61
Median	61
≤60	224	45.0	33.6	184	36.9	40	8.0		75	25.1	0.42	60	20.1	15	5.0
>60	274	55.0	38.0	213	42.8	61	12.2		223	74.6	0.54	136	45.5	87	29.1
Unknown	0	0.0						0.028*	1	0.3						0.10*
Tumor category
pT2	188	37.8	32.0	164	32.9	24	4.8		205	68.6	0.41	147	49.2	58	19.4
pT3	303	60.8	40.5	228	45.8	75	15.1		94	31.4	0.80	50	16.7	44	14.7
Unknown	7	1.4						<0.001*	1	0.3						0.010*
ISUP grading group (Gleason)
1 (<7)	45	9.0	27.4	40	8.0	5	1.0		166	55.5	0.34	123	41.1	43	14.4
2 (3+4)	147	29.5	33.4	127	25.5	20	4.0		54	18.1	0.85	29	9.7	25	8.4
3 (4+3)	101	20.3	37.4	84	16.9	17	3.4		24	8.0	0.35	17	5.7	7	2.3
4 (=8)	64	12.9	34.9	46	9.2	18	3.6		37	12.4	0.82	21	7.0	16	5.4
5 (>8)	141	28.3	41.2	100	20.1	41	8.2		16	5.4	1.52	5	1.7	11	3.7
Unknown	0	0.0						0.001†	2	0.7						0.001†
Surgical margin
R0	316	63.5	33.8	267	53.6	49	9.8		197	65.9	0.47	132	44.1	65	22.7
R1	152	30.5	40.7	109	21.9	43	8.6		98	32.8	0.61	61	20.4	37	12.4
Unknown	30	6.0						0.013*	4	1.3						0.14*
Nodal category
pN0	346	69.5	36.5	274	55.0	72	14.5		278	93.0	0.49	185	61.9	93	31.1
pN1	79	15.9	36.4	61	12.2	18	3.6		20	6.7	0.48	11	3.7	9	3.0
Unknown	73	14.7						0.88*	1	0.3						0.90*
Pre-surgical PSA [ng/ml]
0-4	53	10.6	29.8	48	9.6	5	1.0		27	9.0	0.77	16	5.4	11	3.7
4-10	286	57.4	35.2	229	46.0	57	11.4		173	57.9	0.42	121	40.5	52	17.4
>10	156	31.3	40.5	118	23.7	38	7.6		86	28.8	0.61	52	17.4	34	11.4
Unknown	3	0.6						0.11†	13	4.3						0.72†
ERG#
Negative	178	35.7	34.4	146	29.3	32	6.4		145	48.5	0.57	94	31.4	51	17.1
Positive	152	30.5	40.6	121	24.3	31	6.2		65	21.7	0.88	35	11.7	30	10.0
Unknown	168	33.7						0.022*	89	29.8						0.19*
AR score§
Negative	166	33.3	36.6	136	27.3	30	6.0		83	27.8	0.33	54	18.1	29	9.7
Positive	167	33.5	37.7	134	26.9	33	6.6		81	27.1	0.71	54	18.1	27	9.0
Unknown	165	33.1						0.79*	136	45.5						0.24*

^*Mann-Whitney U test (Wilcoxon Rank-sum test)

^†Kruskal-Wallis test

^#Training cohort: ERG fusion (as adopted from [34]); validation cohort: nuclear ERG protein expression (as previously published in [35])

^§Training cohort: AR activity score (as adopted from [34]); validation cohort: AR protein expression (as previously published in [35])