Prospective study of serum cysteine levels and oesophageal and gastric cancers in China.
BACKGROUND
Cancers of the upper gastrointestinal tract remain a significant cause of morbidity and mortality. Cysteine, known to be involved in a myriad of immuno-modulatory, anti-oxidant, and anti-carcinogenic pathways, has not been investigated in the aetiology of oesophageal or gastric cancers. To examine the relationship between serum cysteine concentration and risk of these cancers we conducted a nested case-cohort study within the General Population Nutrition Intervention Trial in Linxian, China.


METHODS
498 oesophageal squamous cell carcinomas (OSCCs) and 255 gastric cardia adenocarcinomas (GCAs) were matched by age and sex to 947 individuals from the wider cohort. We calculated HRs and 95% CIs using the case-cohort estimator for the Cox proportional hazards models, stratified on age and sex, with adjustment for potential confounders.


RESULTS
Higher concentrations of serum cysteine were significantly associated with a lower risk of both OSCC and GCA. For those in the highest quartile of serum cysteine, compared to those in the lowest, the multivariate HRs were 0.70 for OSCC (95% CI 0.51 to 0.98) and 0.59 for GCA (95% CI 0.38 to 0.91). These associations were dose dependent (p for trend=0.006 and 0.008, respectively). These inverse associations were not significantly modified by other risk factors, with the exception of age, where a stronger association was noted among persons in the older age strata.


CONCLUSIONS
Higher serum concentrations of cysteine were associated with a significantly reduced risk of OSCC and GCA. Cysteine should be further investigated for its potential as a chemopreventive agent for upper gastrointestinal cancers.
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA. murphygw@mail.nih.gov
Gwen
G
Murphy
Jin-Hu
JH
Fan
Steven D
SD
Mark
Sanford M
SM
Dawsey
Jacob
J
Selhub
Jianbing
J
Wang
Philip R
PR
Taylor
You-Lin
YL
Qiao
Christian C
CC
Abnet
D000230:Adenocarcinoma / Q000097:blood* / Q000209:etiology; D000328:Adult; D000367:Age Factors; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood*; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000209:etiology; D002299:Cardia; D003545:Cysteine / Q000097:blood*; D004812:Epidemiologic Methods; D004938:Esophageal Neoplasms / Q000097:blood* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects / Q000097:blood; D013274:Stomach Neoplasms / Q000097:blood* / Q000209:etiology
D014408:Biomarkers, Tumor; D003545:Cysteine
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