Decreased mitochondrial DNA content in posttreatment salivary rinses from head and neck cancer patients.
OBJECTIVE
Alterations in mitochondrial DNA (mtDNA) sequence and content have been described in human tissues and tumors in association with smoking exposure. We did quantitative PCR analysis of cytochrome c oxidase (Cox) I and Cox II genes to measure changes in mtDNA content in pretreatment and posttreatment salivary rinses obtained from 76 patients undergoing surgical resection for primary head and neck squamous cell carcinoma. We also examined the relationship between changes in mtDNA content and postoperative radiation therapy, smoking exposure, alcohol intake, and other clinical characteristics.


RESULTS
Overall, mtDNA content in posttreatment saliva was significantly decreased. The mean change for Cox I was -0.21 [95% confidence interval (95% CI), -0.44 to 0.01, P = 0.06] and for Cox II was -0.31 (95% CI, -0.55 to -0.08, P = 0.01). Patients in the radiation therapy group exhibited a significant decrease compared with the nonradiated group (P = 0.03 for Cox I; P = 0.05 for Cox II). In addition, significant decreases in Cox I (-0.71; 95% CI, -1.17 to -0.25, P = 0.005) and Cox II (-0.65; 95% CI, -1.17 to -0.13, P = 0.02) were found in never-smoking patients but not in former or current smokers.


CONCLUSIONS
Our data suggest that salivary mtDNA content is decreased in never smokers and in response to radiation therapy after primary surgical resection.
Department of Otolaryngology-Head and Neck Surgery, Head and Neck Cancer Division, Johns Hopkins Medical Institutions, Baltimore, MD 21287-0910, USA.
Wei-Wen
WW
Jiang
Eli
E
Rosenbaum
Elizabeth
E
Mambo
Marianna
M
Zahurak
Brett
B
Masayesva
Andre Lopes
AL
Carvalho
Shaoyu
S
Zhou
William H
WH
Westra
Anthony J
AJ
Alberg
David
D
Sidransky
Wayne
W
Koch
Joseph A
JA
Califano
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005720:Gamma Rays; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011182:Postoperative Care; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012463:Saliva / Q000378:metabolism*; D012907:Smoking / Q000009:adverse effects
D004272:DNA, Mitochondrial; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2