title: Screening miRNAs for early diagnosis of colorectal cancer by small RNA deep sequencing and evaluation in a Chinese patient population.
abstract: OBJECTIVE
  This study aims to screen microRNAs (miRNAs), for an early diagnosis of colorectal cancer, by deep sequencing and evaluation of total miRNAs using clinical samples from a Chinese patient population.
  
  
  METHODS
  Total small RNAs from normal colonic mucosa, colonic adenomas, and colorectal cancer tissues were prepared for miRNA analysis by deep sequencing. The sequencing data were then analyzed by bioinformatics for candidate diagnostic miRNAs, which were further validated for their up- or downregulation status.
  
  
  RESULTS
  Comparison of cancer tissues with normal mucosa identified 99 upregulated and 90 downregulated miRNAs. Comparison of adenomas and normal mucosa found 114 upregulated and 107 downregulated miRNAs. Comparison of cancer and adenoma tissues found 70 upregulated and 27 downregulated miRNAs. Selected up- and downregulated miRNAs were validated for their expressions in 12 cases of patients with cancer and polyps. Specifically, for the upregulated miRNAs, miR-18a-5p and miR-21-3p were significantly upregulated in adenomas and cancer tissues, compared with the normal mucosa; miR-135b-5p, miR-17-5p, miR-182-5p, miR-200a-5p, and miR-200c-3p were significantly upregulated in cancer tissues compared to the normal mucosa, but their differential expression was not significant in adenoma tissues when compared with the normal mucosa. miR-183-5p and miR-96-5p were significantly upregulated in adenoma tissues when compared with normal mucosa, but these differences were not significant in cancer tissues when compared to normal mucosa. For the downregulated miRNAs, miR-133a-3p was significantly downregulated in both adenoma and cancer tissues when compared to normal mucosa; miR-204-5p, miR-125b-5p, miR-139-5p, miR-100-5p, and miR-30a-5p were significantly downregulated in cancer tissues compared to the normal mucosa, but their differential expression was not significant in adenoma tissue compared to normal mucosa.
  
  
  CONCLUSIONS
  The findings of this study show that a number of miRNAs might be important in the diagnosis and prognosis of colorectal cancer in Chinese patients using the method of small RNA deep sequencing. Upregulation of miR-18a-5p and miR-21-3p or downregulation of miR-133a-3p in adenoma and cancer tissues may serve as an index for early screening of colorectal cancer. Other miRNAs, such as miR-135b-5p, miR-17-5p, miR-182-5p, miR-200a-5p, miR-200c-3p, miR-183-5p, and miR-96-5p, which were either up- or downregulated, in cancer tissues, but not in adenoma tissues, have limited significance in early diagnosis. Further study is needed to determine a screening index with diagnostic value.
authors.affiliation: National Center of Colorectal Surgery, The Third Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China; Graduate School of Nanjing University of Traditional Chinese Medicine, Nanjing, People's Republic of China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: National Center of Colorectal Surgery, The Third Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China; Department of General Surgery, Peking University International Hospital, Beijing, People's Republic of China.
authors.forename: Heiying
authors.initials: H
authors.lastname: Jin
authors.affiliation: National Center of Colorectal Surgery, The Third Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.
authors.forename: Shuiming
authors.initials: S
authors.lastname: Wang
authors.affiliation: National Center of Colorectal Surgery, The Third Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Tang
authors.affiliation: Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA.
authors.forename: Guiliang
authors.initials: G
authors.lastname: Tang
keywords: colorectal adenoma; colorectal cancer; deep sequencing; miRNA