in gastroenterological cancer: Evaluation of measurement methods using quantitative polymerase chain reaction and a literature review.

The human microbiome , which primarily inhabits the oral cavity, causes periodontal disease and has also been implicated in the development of colorectal cancer. However, whether is present in other gastroenterological cancer tissues remains to be elucidated. The present study evaluated whether quantitative polymerase chain reaction (qPCR) assays were able to detect DNA and measure the quantity of DNA in esophageal, gastric, pancreatic and liver cancer tissues. The accuracy of the qPCR assay was determined from a calibration curve using DNA extracted from cells from the oral cavity. Formalin-fixed paraffin-embedded (FFPE) tumor tissues from 20 patients with gastroenterological [esophageal (squamous cell carcinoma), gastric, colorectal, pancreatic and liver] cancer and 20 matched normal tissues were evaluated for DNA content. The cycle threshold values in the qPCR assay for and solute carrier organic anion transporter family member 2A1 (reference sample) decreased linearly with the quantity of input DNA (>0.99). The detection rate in esophageal, gastric and colorectal cancer tissues were 20% (4/20), 10% (2/20) and 45% (9/20), respectively. was not detected in liver and pancreatic cancer tissues. The qPCR results from the frozen and FFPE tissues were consistent. Notably, was detected at a higher level in superficial areas compared with the invasive areas. in esophageal, gastric and colorectal cancer tissues was evaluated by qPCR using FFPE tissues. may be involved in the development of esophageal, gastric and colorectal cancer.