Breath Test for Chemicals (Volatile Organic Compounds)

Background: \- Some types of cancer, like cancer of the esophagus, are difficult to detect at an early stage. A possible detection method involves collecting breath samples to look for chemicals that may be signs of cancer. However, more research is needed to determine how different chemicals appear in different breath samples. This study will involve healthy volunteers. Objectives: \- To study chemicals appearing in breath samples of healthy volunteers. Eligibility: \- Healthy volunteers between 30 and 60 years of age. Design: * Participants will fast overnight (midnight to morning) and then provide two breath samples taken 5 minutes apart. * Breath samples will be collected on days 1, 49, and 98 of the study

Background: Although breath tests are common for specific uses where the biomarker is highly concentrated (e .g. alcohol, urea for Helicobacter prylori infection), lower concentration compounds in the breath can also provide information on exogenous exposures and endogenous metabolic processes. Employing standardized collection techniques and high sensitivity measurement technologies have shown that breath profiles can accurately identify people with diseases such as breast cancer and lung cancer. Breath profiling technologies have great potential as non-invasive tools for diagnosis and risk stratification of precancerous disease as well as elucidation of the causes of cancer. Prior to using breath profiles for these purposes it is essential to assess how much of the breath profile and which parts of the breath profile are relatively stable over a period of time. Objectives: The primary objective of this pilot study is to assess the intra-individual variability of breath profiles sampled over a period of 98 days. Eligibility: DCEG volunteers aged 30-60 years, inclusive. Design: Pilot study. Five DCEG volunteers will be enrolled for this study. We will assess breath profiles sampled in duplicate at three time periods (days 1, 49 and 98). We will calculate a coefficients of variation (CV) to determine the proportion and parts of the breath profile which have values less than 10% when collected on the same day,49 days apart, and 98 days apart.