Expression and significance of the lysine-specific demethylase 1 in gastric cancer tissues

Abstract

Objective To investigate the expressions and relationship between lysine-specific demethylase 1 (LSD1) and E-cadherin protein in gastric cancer tissues and adjacent normal tissues, and the correlation with the clinicopathological features and prognosis of patients with gastric cancer. Methods The case-control study was adopted. The gastric cancer tissues and adjacent normal tissues were collected by surgical resection from 80 patients with gastric cancer who were admitted to the Xiangya Hospital of Central South University from June 2008 to June 2009. Expressions of LSD1 and E-cadherin protein were detected by immunohistochemistry (IHC). The follow-up of telephone interview was performed to detect survival of patients till June 2015. Relationships between the expressions of LSD1 and E-cadherin protein and clinicopathological features or prognosis of patients were analyzed. Comparison of count data and correlation were analyzed by the chi-square test and Spearman rank correlation analysis. Survival curve was drawn using the Kaplan-Meier method, and survival analysis was done using the Log-rank test. Results Expressions of LSD1 in cancer tissues and adjacent normal tissues were located at the cell nucleus. The positive expression rate of LSD1 was 67.5%(54/80) and 43.8%(35/80) in cancer tissues and adjacent normal tissues, respectively, with a significant difference (χ2=9.141, P<0.05). Expressions of E-cadherin protein in cancer tissues and adjacent normal tissues were located at the cell membrane and cytoplasm. The positive expression rate of E-cadherin was 63.8%(51/80) and 81.3%(65/80) in cancer tissues and adjacent normal tissues, respectively, with a significant difference (χ2=6.140, P<0.05). The positive expression rate of LSD1 was 83.3%(25/30), 76.0%(19/25) and 40.0%(10/25) in the low-, moderate- and high-differentiated tumors, 37.5%(6/16), 72.7%(16/22), 71.9%(23/32) and 90.0%(9/10) in the Ⅰ, Ⅱ, Ⅲ and Ⅳ stages of TNM stage, 36.4%(4/11) and 72.5%(50/69) in patients without and with lymph node metastasis, respectively, showing significant differences (χ2=12.870, 9.425, 4.111, P<0.05). The positive expression rate of E-cadherin protein was 53.3%(16/30), 56.0% (14/25) and 84.0%(21/25) in the low-, moderate- and high-differentiated tumors, 75.0%(12/16), 63.6%(14/22), 71.9%(23/32) and 20.0% (2/10) in the Ⅰ, Ⅱ, Ⅲ and Ⅳ stages of TNM stage, 100.0%(11/11)and 58.0%(40/69) in patients without and with lymph node metastasis, 70.0%(49/70) and 20.0%(2/10) in patients without and with distant metastasis, respectively, showing significant differences (χ2=6.494, 10.073, 5.547, 7.426, P<0.05). There was a negative correlation in expressions between LSD1 and E-cadherin protein (r=-0.355, P<0.05). The survival time and 5-year overall survival rate of patients with positive and negative expressions of LSD1 were (36.9±2.5)months and 31.1%, (47.4±3.4)months and 56.0%, respectively, showing a significant difference (χ2=4.550, P<0.05). The survival time and 5-year overall survival rate of the patients with positive and negative expressions of E-cadherin protein were (44.0±2.5)months and 46.7%, (32.6±3.5)months and 24.9%, respectively, showing a significant difference (χ2=7.306, P<0.05). Conclusions Positive expression of LSD1 in gastric cancer tissues is higher than that in adjacent normal tissues. There are increased expression of LSD1 and reduced expression of E-cadherin protein in low-differentiated gastric cancer tissues and high TNM stage, showing a negative correlation between them. Positive expression of LSD1 and negative expression of E-cadherin protein may indicate a poor prognosis. Key words: Gastric neoplasms; Epigenetic; Lysine-specific demethylase 1; E-cadherin protein; Prognosis