Table 2.

The association between clinical characteristics of 425 OPC patients an HPV positive OPC defined by HPV PCR testing and p16 IHC staining

	HPV PCR			p16 IHC
	Negative	Positive	P value	Negative	Positive	P value
Age (years)
< 50	104 (72.7)	39 (27.3)	0.45	93 (71.5)	37 (28.5)	0.48
50–60	113 (72.9)	42 (27.1)		100 (69.9)	43 (30.1)
> 60	71 (66.4)	36 (33.6)		61 (64.2)	34 (35.8)
Gender
Male	271 (74.3)	94 (25.8)	< 0.01	241 (71.4)	92 (27.6)	< 0.01
Female	17 (42.5)	23 (57.5)		13 (37.1)	22 (62.9)
Cigarette smoking
Never	44 (50.6)	43 (49.4)	< 0.01	36 (48.0)	39 (52.0)	< 0.01
Ever	199 (77.1)	9 (22.9)		175 (75.1)	58 (24.9)
Alcohol drinking
Never	57 (49.1)	59 (50.9)	< 0.01	51 (49.0)	53 (51.0)	< 0.01
Ever	162 (80.6)	39 (19.4)		145 (78.4)	40 (21.6)
Betel quid chewing
Never	92 (54.4)	77 (45.6)	< 0.01	78 (51.7)	73 (48.3)	< 0.01
Ever	128 (85.9)	21 (14.1)		119 (86.2)	19 (13.8)
T classification
T1	58 (20.0)	27 (23.0)	< 0.01	46 (18.1)	32 (28.0)	< 0.01
T2	82 (27.8)	50 (42.7)		73 (28.7)	39 (34.2)
T3	37 (12.8)	17 (14.5)		33 (13.0)	20 (17.5)
T4	76 (26.4)	13 (11.1)		68 (26.8)	13 (11.4)
N classification
N0	82 (27.8)	17 (14.5)	< 0.01	71 (28.0)	17 (14.9)	< 0.01
N1	33 (11.4)	9 (7.7)		26 (10.2)	10 (8.8)
N2	111 (38.5)	72 (61.5)		98 (38.6)	65 (57.0)
N3	27 (9.3)	9 (7.7)		25 (9.8)	12 (10.5)
Overall stage
I	32 (11.1)	4 (3.4)	< 0.01	25 (9.8)	6 (5.2)	0.13
II	28 (9.7)	9 (7.7)		25 (9.8)	8 (7.0)
III	38 (13.1)	10 (8.5)		31 (12.2)	11 (9.6)
IV	155 (53.8)	84 (71.8)		139 (54.7)	79 (69.3)
Location
Tonsil	131 (59.5)	89 (40.5)	< 0.01	115 (57.5)	85 (42.5)	< 0.01
Tongue base	69 (82.1)	15 (17.9)		64 (80.0)	16 (20.0)
Soft palate	66 (91.7)	6 ( 8.3)		57 (90.5)	6 (9.5)
Unspecific	22 (75.9)	7 (24.1)		18 (72.0)	7 (28.0)