Oral Epithelium as a Surrogate Tissue for Assessing Smoking-Induced Molecular Alterations in the Lungs

Manisha Bhutani; Ashutosh Kumar Pathak; You-Hong Fan; Diane D. Liu; J. Jack Lee; Hongli Tang; Jonathan M. Kurie; Rodolfo C. Morice; Edward S. Kim; Waun Ki Hong; Li Mao

doi:10.1158/1940-6207.CAPR-08-0058

DOI: 10.1158/1940-6207.CAPR-08-0058 Published June 2008

Article Figures & Data

Figures

Tables
Additional Files

Download figure
Open in new tab
Download powerpoint
Fig. 1
A flexible bronchoscope is inserted through the nose or mouth to examine the airways after i.v. sedation (bottom right). Bronchial brushings are taken from six predetermined sites (top right). Oral brushing using a cytologic brush is done (top left) by rubbing the inner side of the left cheek (bottom left). From Visual Art © 2008, The University of Texas, M. D. Anderson Cancer Center; with permission.

Table 1

Gene promoter methylation status at baseline using patient (combining six bronchial brush sites within each patient) as an analysis unit

Characteristic		*p16*				*FHIT*				*p16/FHIT*
		Bronchial		Oral		Bronchial		Oral		Bronchial		Oral
		M	U	M	U	M	U	M	U	M	U	M	U
No. patients (%)		74 (58.3)	53 (41.7)	24 (19.4)	100 (80.4)	50 (39.4)	77 (60.6)	19 (15.3)	105 (84.7)	98 (77.2)	29 (22.8)	39 (31.2)	86 (68.8)
Age (y), n (%)
<54	62 (48.8)	36 (58.1)	26 (41.9)	12 (20.3)	47 (79.7)	24 (38.7)	38 (61.3)	9 (15.3)	50 (84.7)	46 (74.2)	16 (25.8)	19 (31.7)	41 (68.3)
≥54	65 (51.2)	38 (58.5)	27 (41.5)	12 (18.5)	53 (81.5)	26 (40)	39 (60)	10 (15.4)	55 (84.6)	52 (80)	13 (20)	20 (30.8)	45 (69.2)
P		0.96		0.79		0.88		0.98		0.44		0.91
Sex, n (%)
F	58 (45.7)	39 (67.2)	19 (32.8)	12 (21.1)	45 (78.9)	25 (43.1)	33 (56.9)	10 (17.9)	46 (82.1)	49 (84.5)	9 (15.5)	20 (35.1)	37 (64.9)
M	69 (54.3)	35 (50.7)	34 (49.3)	12 (17.9)	55 (82.1)	25 (36.2)	44 (63.8)	9 (13.2)	59 (86.8)	49 (71)	20 (29)	19 (27.9)	49 (72.1)
P		0.06		0.66		0.43		0.48		0.07		0.39
Smoker, n (%)
Current	99 (78)	59 (59.6)	40 (40.4)	21 (21.9)	75 (78.1)	38 (38.4)	61 (61.6)	12 (12.5)	84 (87.5)	77 (77.8)	22 (22.2)	31 (32)	66 (68)
Former	28 (22)	15 (53.6)	13 (43.4)	3 (10.7)	25 (89.3)	12 (42.9)	16 (57.1)	7 (25)	21 (75)	21 (75)	7 (25)	8 (28.6)	20 (71.4)
P		0.56		0.28		0.67		0.11		0.76		0.73
Pack-years, n (%)
<30	36 (28.3)	12 (33.3)	24 (66.7)	3 (8.6)	32 (91.4)	14 (38.9)	22 (61.1)	6 (17.1)	29 (82.9)	20 (55.6)	16 (44.4)	9 (25)	27 (75)
30-40	32 (25.2)	23 (71.9)	9 (28.1)	6 (18.8)	26 (81.3)	15 (46.9)	17 (53.1)	4 (12.5)	28 (87.5)	29 (90.6)	3 (9.4)	9 (28.1)	23 (71.9)
41-50	24 (18.9)	15 (62.5)	9 (37.5)	5 (20.8)	19 (79.2)	8 (33.3)	16 (66.7)	6 (25)	18 (75)	19 (79.2)	5 (20.8)	10 (41.7)	14 (58.3)
≥50	35 (27.6)	24 (68.6)	11 (31.4)	10 (30.3)	23 (69.7)	13 (37.1)	22 (62.9)	3 (9.1)	30 (90.9)	30 (85.7)	5 (14.3)	11 (33.3)	22 (66.7)
P^*		0.0003		0.08		0.94		0.72		0.0003		0.34
Quit-years, n (%)
<1	99 (78)	59 (59.6)	40 (40.4)	21 (21.9)	75 (78.1)	38 (38.4)	61 (61.6)	12 (12.5)	84 (87.5)	77 (77.8)	22 (22.2)	31 (32)	66 (68)
1-10	18 (14.2)	9 (50)	9 (50)	3 (16.7)	15 (83.3)	9 (50)	9 (50)	6 (33.3)	12 (66.7)	14 (77.8)	4 (22.2	7 (38.9)	11 (61.1)
>10	10 (7.9)	6 (60)	4 (40)	0 (0)	10 (100)	3 (30)	7 (70)	1 (10)	9 (90)	7 (70)	3 (30)	1 (10)	9 (90)
P^†		1		0.21		0.74		1		0.69		0.17

Abbreviations: M, methylated; U, unmethylated.

↵*Comparing methylation between the groups <30 and ≥30 pack-years.
↵^†Comparing methylation between the groups <10 and ≥10 quit-years.

Table 2
Association between oral methylation status and bronchial methylation status
Bronchial Oral
p16 FHIT p16/FHIT
U M U M U M
U 49^* 2 76 1 27 2
M 51 22 29 18 59 37
P^† 0.0002 <0.0001 0.001
↵*Data are expressed as number of patients.
↵^†Fisher's exact test.

Table 3

Correlation between oral methylation status and bronchial methylation index

	Bronchial methylation index
	Oral	n	Mean ± SD, median (range)	P^*
Baseline
p16	U	100	0.18 ± 0.22, 0.17 (0-0.83)	<0.0001
p16	M	24	0.47 ± 0.30, 0.50 (0-1.00)
FHIT	U	105	0.10 ± 0.20, 0.00 (0-1.00)	<0.0001
FHIT	M	19	0.50 ± 0.29, 0.50 (0-1.00)
p16/FHIT	U	86	0.27 ± 0.26, 0.17 (0-1.00)	<0.0001
p16/FHIT	M	39	0.53 ± 0.29, 0.50 (0-1.00)
3 mo
p16	U	89	0.14 ± 0.21, 0.00 (0-1.00)	<0.0001
p16	M	36	0.39 ± 0.29, 0.33 (0-1.00)
FHIT	U	113	0.08 ± 0.18, 0.00 (0-1.00)	<0.0001
FHIT	M	14	0.57 ± 0.28, 0.67 (0.17-1.00)
p16/FHIT	U	83	0.21 ± 0.24, 0.17 (0-1.00)	<0.0001
p16/FHIT	M	44	0.50 ± 0.31, 0.50 (0-1.00)

↵*Wilcoxon's rank-sum test comparing bronchial brush methylation index between oral brush methylation groups.

Table 4

Comparison of modulation of promoter methylation status between oral and bronchial epithelia after 3-mo intervention

Oral baseline/3 mo	n	Bronchial methylation index (baseline/3 mo)
Oral baseline/3 mo	n	Mean ± SD, median (range)	P^*
p16
M/M	7	−0.16 ± 0.19, −0.17 (−0.5-0)	0.003
M/U	16	−0.15 ± 0.40, −0.17 (−0.67-0.67)
U/M	28	0.16 ± 0.34, 0.17 (−0.50-1.00)
U/U	71	−0.05 ± 0.28, 0 (−0.83-0.67)
FHIT
M/M	3	−0.11 ± 0.25, −0.17 (−0.33-0.17)	<0.0001
M/U	16	−0.46 ± 0.30, −0.50 (−0.83-0)
U/M	10	0.42 ± 0.33, 0.42 (−0.17-1.00)
U/U	95	0.01 ± 0.22, 0 (−0.50-1.00)
p16/FHIT
M/M	16	−0.06 ± 0.37, −0.17 (−0.83-0.67)	0.007
M/U	23	−0.22 ± 0.38, −0.33 (−0.83-0.50)
U/M	27	0.16 ± 0.37, 0.17 (−0.50-1.00)
U/U	59	−0.05 ± 0.31, 0 (−0.83-0.50)