[Feasibility of genetic polymorphisms analysis using genomic DNA obtained from human buccal cells].
OBJECTIVE
Using DNA samples obtained from buccal cells for genetic polymorphism analysis in molecular epidemiological studies has been repeatedly reported, but whether DNA from food remnants in mouth influences the result is still concerned. This study was to compare genetic polymorphisms of buccal cell DNA with those of buffy coat DNA, and with plant and animal DNA from foods to rule out the possibility of interference from food remnants, to improve technique of buccal cell collection and elevate DNA yield.


METHODS
Buccal cells were collected from mouthwash (40 ml/case) of 62 subjects, and fixed with isopropyl alcohol; buffy coats of peripheral blood were collected from 30 of these subjects. Common foods (rice, greengrocery, soybean, apple, pork, beef, chicken, and duck) were also collected. DNA of all samples was extracted by chloroform-phenol method. NAT2, GSTM1, GSTT1, CYP1A1, and CYP2E1 genetic polymorphisms were assayed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Alu (human mutual DNA sequence) was also tested.


RESULTS
DNA yield of 62 individual mouthwash samples was (135.15+/-64.30) microg (22.36-330.70 microg); 30 individual mouthwash samples contained 75%-95% oral epithelial cells with DNA yield of (143.44+/-61.64) microg (51.01-283.58 microg). DNA yield of 30 buffy coat samples was (91.19+/-38.01) microg (30.83-178.63 microg). Electrophoresis showed that all 62 buccal cell samples and 30 buffy coat samples contained DNA fragments in high molecular weight; beta-globin, Alu, NAT2, GSTM1, GSTT1, CYP1A1, and CYP2E1 gene fragments were successfully amplified from 61 buccal cells samples and 30 buffy coat samples, which showed no difference between the 2 kinds of samples from individual collections; these gene fragments were not amplified from all food DNA samples.


CONCLUSIONS
The majority of DNA from mouthwash is human-origin. A little amount of food remnants would not influence the measurements of genetic polymorphisms. The genetic polymorphisms show no difference between buccal cell samples and buffy coat samples.
Cheng
Jia-Rong
JR
Department of Epidemiology, Shanghai Cancer Institute, Cancer Research Institute, Shanghai Jiaotong University, Shanghai, 200032 PR China. jiarongcheng@163.com
Guan
Sai-Fang
SF
Wang
Xue-Li
XL
Han
Li-Hua
LH
Gao
Yu-Tang
YT
D000368:Aged; D020087:Alu Elements / Q000235:genetics; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000302:isolation & purification; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015342:DNA Probes; D016021:Epidemiologic Studies; D005787:Gene Frequency; D015894:Genome, Human; D005982:Glutathione Transferase / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008297:Male; D009061:Mouth Mucosa / Q000166:cytology*; D009067:Mouthwashes / Q000032:analysis; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length
D001191:Arylamine N-Acetyltransferase; D004247:DNA; D015342:DNA Probes; D005982:Glutathione Transferase; D009067:Mouthwashes; C478900:NAT2 protein, human