Table 2

Total and human DNA yields (μg/two cytobrushes or μg/one 10-ml mouthwash sample) from phase 2^a of the study by method of collection

Method of collection	N	Spectrophotometry			Hybridization
				Total DNA yield	A_{260 nm}:A_{280 nm}	Human DNA yield
				Median (range)	Median (range)	Median (range)
Cytobrushes	28	13.5^b (2.0–38.2)	1.8 (1.6–2.0)	1.6^c (0.11–7.7)
Mouthwash	25	38.7^b (11.9–124.2)	1.8 (1.7–1.9)	16.6^c (1.55–140.3)

^a Samples were collected from women participating in the WHS and extracted by phenol-chloroform.
^b P < 0.001, cytobrush versus mouthwash, Wilcoxon’s rank-sum test.
^c P < 0.001, cytobrush versus mouthwash, Wilcoxon’s rank-sum test.