Proteasome inhibitors restore the STAT1 pathway and enhance the expression of MHC class I on human colon cancer cells

Table 1 Patient clinical characteristics

Characteristic	All patients (%)^a	Tumor STAT1 ≧ 1% (%)^a	Tumor STAT1 < 1% (%)^a	p-value
All	60 (100%)	32 (53.3%)^b	28 (46.7%)^b
Gender
Female	31 (51.7%)	16 (50.0%)	15 (53.6%)	0.782
Male	29 (48.3%)	16 (50.0%)	13 (46.4%)
Age (years)
Median (Range)	59.8 (36–84)	54.6 (38–85)	62.5 (36–81)
Age ≤ 65 years	42 (70.0%)	23 (71.9%)	19 (67.9%)	0.735
Age > 65 years	18 (30.0%)	9 (28.1%)	9 (32.1%)
Primary site
Right-sided^c	22 (36.7%)	11 (34.4%)	11 (39.3%)	0.694
Left-sided^d	38 (63.3%)	21 (65.6%)	17 (60.7%)
Initial stage
I–III	4 (6.7%)	4 (12.5%)	0 (0%)	0.156
IV	56 (93.3%)	28 (87.5%)	28 (100%)
Mutation status
Wild type	26 (43.3%)	16 (50%)	10 (35.7%)	0.516
RAS mutant	25 (41.7%)	12 (37.5%)	13 (46.4%)
BRAF mutant	6 (10.0%)	3 (9.4%)	3 (10.7%)
MSI-H	4 (6.7%)	1 (3.1%)	3 (10.7%)
Tumor PD-L1
< 1%	27 (45.0%)	7 (21.9%)	20 (71.4%)	< 0.001^e
≧1%	33 (55.0%)	25 (78.1%)	8 (28.6%)
Non-tumor PD-L1
< 1%	48 (80.0%)	22 (68.8%)	26 (92.9%)	0.020^e
≧1%	12 (20.0%)	10 (31.2%)	2 (7.1%)
Tumor MHC-1
< 50%	12 (20.0%)	0 (0.0%)	12 (42.9%)	< 0.001^e
≧50%	48 (80.0%)	32 (100.0%)	16 (57.1%)
Non-tumor MHC-1
< 50%	20 (33.3%)	6 (18.7%)	14 (50.0%)	0.010^e
≧50%	40 (66.7%)	26 (81.3%)	14 (50.0%)
Non-tumor CD4, CD8
Both < 1% CD4 or CD8 ≧1%	34 (56.7%) 26 (43.3%)	11 (34.4%) 21 (65.6%)	23 (82.1%) 5 (17.9%)	< 0.001^e

^aPercentage from subgroup analysis. ^bPercentage is based on all 60 cases. ^cIncluding the cecum, ascending colon, and transverse colon. ^dIncluding the splenic flexure, descending colon, sigmoid colon, and rectum. ^ep < 0.05

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