TABLE 2.

Methylation of the LCR and E6 gene of HPV-16 in clinical samples from Brazil and New Mexico^a

Site(s)	Sample type (total no.)	No. of samples showing:		% of amplifiable samples with methylation
		Methylation	No methylation
Brazil	Asymptomatic (14)	8	6	57.1
	CIN I (3)	0	3	0
	Invasive cancer (16)	2	14	12.5
New Mexico	Asymptomatic (11)	5	6	45.4
	CIN I (10)	3	7	30
	CIN III (10)	2	8	20
	Invasive cancer (17)	0	17	0
Bothb	Asymptomatic (25)	13	12	52
	CIN I and III (23)	5	18	21.7
	Invasive cancer (33)	2	31	6.1

^aCpG methylation was determined by cleavage of the DNA preparations with the restriction enzyme McrBC and subsequent PCR amplification of a genomic segment of HPV-16 corresponding to the promoter and E6 gene as shown in Fig. 3.

^bData from both cohorts were combined, results with CIN I and CIN III were united into one group of precursor lesions, and DNA preparations that could not be amplified were omitted.