Table 2. Association of CDK18 protein expression with protein expression of the indicated DNA repair factor, cell cycle or apoptotic regulator within the Nottingham Tenovus breast cancer cohort.

Variable	CDK18 (cytoplasmic) Protein Expression		P- value
	Low N (%)	High N (%)
BRCA1
Absent	135 (20.8)	34 (16.3)	0.149
Normal	513 (79.2)	175 (83.7)
XRCC1
Low	117 (17.7)	27 (12.4)	0.065
High	543 (82.3)	191 (87.6)
FEN1
Low	469 (74.9)	134 (69.1)	0.107
High	157 (25.1)	60 (30.9)
SMUG1
Low	241 (39.6)	69 (35.4)	0.288
High	367 (60.4	126 (64.6)
APE1
Low	416 (54.6)	92 (36.7)	1.0 × 10–6
High	346 (45.4)	159 (63.3)
Pol β
Low	344 (43.2)	73 (27.2)	4.0 × 10–6
High	453 (56.8)	195 (72.8)
ATR
Low	521 (68.8)	152 (59.1)	0.005
High	236 (31.2)	105 (40.9)
ATM
Low	296 (52.9)	92 (51.4)	0.733
High	264 (47.1)	87 (48.6)
DNA-PKcs
Low	285 (39.3)	56 (23.6)	1.3 × 10–5
High	441 (60.7)	181 (76.4)
P16
Low	544 (88.0)	167 (81.5)	0.018
High	74 (12.0)	38 (18.5)
P21
Low	369 (55.8)	113 (56.5)	0.866
High	292 (44.2)	87 (43.5)
MIB1
Low	339 (45.9)	96 (39.3)	0.075
High	400 (54.1)	148 (60.7)
P53
Low expression	595 (79.4)	176 (75.5)	0.205
High expression	154 (20.6)	57 (24.5)
Bcl-2
Negative	309 (37.5)	84 (33.2)	0.214
Positive	515 (62.5)	169 (66.8)
TOP2A
Low	310 (49.1)	82 (36.9)	0.002
Overexpression	322 (50.9)	140 (63.1)
pChk1 (Nuclear)
Low	801 (87.5)	220 (74.3)	1.0 × 10–6
High	114 (12.5)	76 (25.7)
pChk1 (Cytoplasmic)
Low	314 (34.3)	72 (24.3)	0.001
High	601 (65.7)	224 (75.7)
Chk2
Low	335 (51.6)	70 (33.5)	5.0 × 10-6
High	314 (48.4)	139 (66.5)
Bax
Low	371 (70.3)	111 (66.1)	0.305
High	157 (29.7)	57 (33.9)
CDK1
Low	414 (72.9)	114 (61.6)	0.004
High	154 (27.1)	71 (38.4)
MDM2
Low	495 (78.0)	140 (71.1)	0.047
Overexpression	140 (22.0)	57 (28.9)