Table 1. HPV16 expression in peripheral blood and fresh tumor tissue samples of HNSCC in Southwest China and its association with clinicopathologic characteristics.

Variable	HPV (PB)		P-value	HPV (TS)		P-value
	Negative	Positive		Negative	Positive
Age			0.0101			0.0170
<60	60	29		60	25
≥60	89	18		81	14
Gender			0.897			0.804
Mae	84	27		80	23
Female	65	20		61	16
Smoking status			<0.001			0.0106
Current/former	86	10		74	11
Never	63	37		67	28
Alcohol use						0.0002
Positive	79	7	<0.001	77	8
Negative	70	40		64	31
Clinical Stage			0.422			0.978
I+II	63	23		69	19
III+IV	86	24		72	20
Tumor Localization			0.001			0.001
Mouth Floor	25	6		21	4
Tongue	69	17		61	15
Oropharyngeal	9	13		7	10
Buccal Mucosa	46	11		52	10
Pathological Stage			0.005			0.034
High	46	7		49	10
Middle Grade	63	10		51	9
Low Grade	40	30		41	20

Chi-square was reported to compare the difference between HPV status and clinical-pathological characteristics. Former/current smokers defined as >= one pack-year history of smoking. Positive alcohol use was defined as current alcohol use of >one drink per day for 1 year (12 oz of beer with 5% alcohol, 5 oz of wine with 12% to 15% alcohol, or 1 oz of liquor with 45% to 60% alcohol).