Increased EZH2 expression during the adenoma‑carcinoma sequence in colorectal cancer

  • Authors:
    • Mayuko Ohuchi
    • Yasuo Sakamoto
    • Ryuma Tokunaga
    • Yuki Kiyozumi
    • Kenichi Nakamura
    • Daisuke Izumi
    • Keisuke Kosumi
    • Kazuto Harada
    • Junji Kurashige
    • Masaaki Iwatsuki
    • Yoshifumi Baba
    • Yuji Miyamoto
    • Naoya Yoshida
    • Takashi Shono
    • Hideaki Naoe
    • Yutaka Sasaki
    • Hideo Baba
  • View Affiliations

  • Published online on: July 31, 2018     https://doi.org/10.3892/ol.2018.9240
  • Pages: 5275-5281
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Abstract

The adenoma‑carcinoma sequence, the sequential mutation and deletion of various genes by which colorectal cancer progresses, is a well‑established and accepted concept of colorectal cancer carcinogenesis. Proteins of the polycomb repressive complex 2 (PRC2) function as transcriptional repressors by trimethylating histone H3 at lysine 27; the activity of this complex is essential for cell proliferation and differentiation. The histone methyltransferase enhancer of zeste homolog 2 (EZH2), an essential component of PRC2, is associated with the transcriptional repression of tumor suppressor genes. EZH2 expression has previously been reported to increase with the progression of pancreatic intraductal papillary mucinous neoplasm. Thus, we hypothesized that EZH2 expression also increases during the adenoma‑carcinoma sequence of colorectal cancer. The present study investigated changes in EZH2 expression during the colorectal adenoma‑carcinoma sequence. A total of 47 patients with colorectal adenoma, 20 patients with carcinoma in adenoma and 43 patients with colorectal carcinoma who underwent surgical or endoscopic resection were enrolled in this study. Non‑cancerous tissue from the clinical specimens was also examined. The association between EZH2 expression, pathology and expression of tumor suppressor genes during colorectal carcinogenesis were analyzed. Each specimen was immunohistochemically stained for EZH2, proliferation marker protein Ki‑67 (Ki‑67), cyclin‑dependent kinase inhibitor (CDKN) 1A (p21), CDKN1B (p27) and CDKN2A (p16). Total RNA was extracted from formalin‑fixed paraffin‑embedded blocks and reverse transcription‑quantitative polymerase chain reaction analysis of these genes was performed. Ki‑67 and EZH2 expression scores increased significantly during the progression of normal mucosa to adenoma and carcinoma (P=0.009), and EZH2 expression score was positively associated with Ki‑67 expression score (P=0.02). Conversely, p21 mRNA and protein expression decreased significantly, whereas expression of p27 and p16 did not change significantly. During the carcinogenesis sequence from normal mucosa to adenoma and carcinoma, EZH2 expression increased and p21 expression decreased significantly. EZH2 may therefore contribute to the development of colorectal cancer from adenoma via suppression of p21.
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October-2018
Volume 16 Issue 4

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Spandidos Publications style
Ohuchi M, Sakamoto Y, Tokunaga R, Kiyozumi Y, Nakamura K, Izumi D, Kosumi K, Harada K, Kurashige J, Iwatsuki M, Iwatsuki M, et al: Increased EZH2 expression during the adenoma‑carcinoma sequence in colorectal cancer. Oncol Lett 16: 5275-5281, 2018.
APA
Ohuchi, M., Sakamoto, Y., Tokunaga, R., Kiyozumi, Y., Nakamura, K., Izumi, D. ... Baba, H. (2018). Increased EZH2 expression during the adenoma‑carcinoma sequence in colorectal cancer. Oncology Letters, 16, 5275-5281. https://doi.org/10.3892/ol.2018.9240
MLA
Ohuchi, M., Sakamoto, Y., Tokunaga, R., Kiyozumi, Y., Nakamura, K., Izumi, D., Kosumi, K., Harada, K., Kurashige, J., Iwatsuki, M., Baba, Y., Miyamoto, Y., Yoshida, N., Shono, T., Naoe, H., Sasaki, Y., Baba, H."Increased EZH2 expression during the adenoma‑carcinoma sequence in colorectal cancer". Oncology Letters 16.4 (2018): 5275-5281.
Chicago
Ohuchi, M., Sakamoto, Y., Tokunaga, R., Kiyozumi, Y., Nakamura, K., Izumi, D., Kosumi, K., Harada, K., Kurashige, J., Iwatsuki, M., Baba, Y., Miyamoto, Y., Yoshida, N., Shono, T., Naoe, H., Sasaki, Y., Baba, H."Increased EZH2 expression during the adenoma‑carcinoma sequence in colorectal cancer". Oncology Letters 16, no. 4 (2018): 5275-5281. https://doi.org/10.3892/ol.2018.9240