ObjectiveEarly detection and early treatment are of vital importance to the successful treatment of various cancers. The development of a novel screening method that is as economical and non-invasive as the faecal occult blood test (FOBT) for early detection of colorectal cancer (CRC) is needed. A study was undertaken using canine scent detection to determine whether odour material can become an effective tool in CRC screening.DesignExhaled breath and watery stool samples were obtained from patients with CRC and from healthy controls prior to colonoscopy. Each test group consisted of one sample from a patient with CRC and four control samples from volunteers without cancer. These five samples were randomly and separately placed into five boxes. A Labrador retriever specially trained in scent detection of cancer and a handler cooperated in the tests. The dog first smelled a standard breath sample from a patient with CRC, then smelled each sample station and sat down in front of the station in which a cancer scent was detected.Results33 and 37 groups of breath and watery stool samples, respectively, were tested. Among patients with CRC and controls, the sensitivity of canine scent detection of breath samples compared with conventional diagnosis by colonoscopy was 0.91 and the specificity was 0.99. The sensitivity of canine scent detection of stool samples was 0.97 and the specificity was 0.99. The accuracy of canine scent detection was high even for early cancer. Canine scent detection was not confounded by current smoking, benign colorectal disease or inflammatory disease.ConclusionsThis study shows that a specific cancer scent does indeed exist and that cancer-specific chemical compounds may be circulating throughout the body. These odour materials may become effective tools in CRC screening. In the future, studies designed to identify cancer-specific volatile organic compounds will be important for the development of new methods for early detection of CRC.

Early detection and treatment are of vital importance to the successful eradication of various cancers, and development of economical and non-invasive novel cancer screening systems is critical. Previous reports using canine scent detection demonstrated the existence of cancer-specific odours. However, it is difficult to introduce canine scent recognition into clinical practice because of the need to maintain accuracy. In this study, we developed a Nematode Scent Detection Test (NSDT) using Caenorhabditis elegans to provide a novel highly accurate cancer detection system that is economical, painless, rapid and convenient. We demonstrated wild-type C. elegans displayed attractive chemotaxis towards human cancer cell secretions, cancer tissues and urine from cancer patients but avoided control urine; in parallel, the response of the olfactory neurons of C. elegans to the urine from cancer patients was significantly stronger than to control urine. In contrast, G protein α mutants and olfactory neurons-ablated animals were not attracted to cancer patient urine, suggesting that C. elegans senses odours in urine. We tested 242 samples to measure the performance of the NSDT, and found the sensitivity was 95.8%; this is markedly higher than that of other existing tumour markers. Furthermore, the specificity was 95.0%. Importantly, this test was able to diagnose various cancer types tested at the early stage (stage 0 or 1). To conclude, C. elegans scent-based analyses might provide a new strategy to detect and study disease-associated scents.

Zoonotic transmission of hepatitis E virus (HEV) from captured wild deer or boars to humans has been suggested. Antibody to HEV was detected in 9% of 35 wild boars and 2% of 117 wild deer tested, and a presumably indigenous HEV of genotype 3 was isolated from a boar in Japan.Hepatitis E virus (HEV), the causative agent of hepatitis E, is an important human pathogen (4,18,21). The genome of HEV is approximately 7.2 kb in size and contains three open reading frames (ORF1, ORF2, and ORF3) (18). Although only one serotype has been recognized, extensive genomic diversity has been noted among HEV isolates, and HEV sequences have tentatively been classified into four genotypes (genotypes 1 to 4) (20). Transmission of HEV occurs primarily by the fecal-oral route through contaminated water supplies in developing countries (18). In addition, increasing evidence has indicated that hepatitis E is a zoonosis (4, 8, 10-13, 15, 16, 21, 24, 29). It has recently been suggested that zoonotic foodborne transmission of HEV from domestic pigs, wild boars, or wild deer to humans plays an important role in the occurrence of cryptic hepatitis E in Japan, where people have distinctive habits of ingesting raw fish (sushi or sashimi) and, less frequently, uncooked or undercooked meat (including the liver and colon or intestine of animals) (9,23,24,29). The first animal strain of HEV to be isolated and characterized was a swine HEV from a pig in the United States in 1997 (10). Since then, many swine HEV isolates, which exhibit extensive genetic heterogeneity, have been identified worldwide and shown to be genetically closely related to strains of human HEV (1,3,5,6,16,17,(25)(26)(27)30). In previous studies, a high prevalence of the swine immunoglobulin G (IgG) class of antibody to HEV (anti-HEV) was found among 2-to 6-month-old Japanese pigs (58% or 1,448 of 2,500) (22), and a pair of Japanese swine and human HEV isolates of genotype 4 with 99% identity over the entire genome were identified (15). In addition, a certain proportion of packaged raw pig livers for sale in stores as food (1.9% or 7 of 363) were contaminated with HEV, which had high nucleotide sequence identity, up to 100%, with the HEV isolates recovered from Japanese patients with hepatitis E who had ingested undercooked pig liver before disease onset (29). As for HEV from wild boars, although Chandler et al. (1)

The development of postoperative complications is an independent disease-specific poor prognostic factor after curative resection for patients with less-advanced esophageal squamous cell carcinoma.