Expressions and correlations of interleukin-6, tumorassociated macrophages and lymphangiogenesis in the tissues of gastric cancer

Objective:To explore the expressions of interleukin-6 (IL-6), tumorassociated macrophages (TAMs) and lymphangiogenesis in the tissues of gastric cancer, and their correlation with the clinicopathological factors and prognosis of patients.
Methods:The clinical data of 40 patients with gastric cancer who were admitted to the Southwest Hospital from September 2012 to September 2013 were retrospectively analyzed. The surgical specimens from stomach tissues were collected. The expressions of IL-6, TAMs specific antigen (CD68) and lymphatic vessel specific protein (D2-40) in the tumor tissues and adjacent normal tissues were observed by immunohistochemical double staining technique. The correlations among the expressions of CD68 and D2-40, clinicopathological factors and prognosis of patients. The followup was carried out on the patients till July 2014. The measurement data with normal distribution were presented as ±s and analyzed by the t test, and the correlation analysis was conducted.  The relationship between the expressions of  IL-6, CD68 and D2-40 and the clinicopathological factors was analyzed by the t test and the ANOVA. The survival curve was drawn by the KaplanMeier method and the survival analysis was done using the Logrank test.
Results:The expressions of IL-6, CD68 and D2-40 were located at the cytoplasm of tumor cells and adjacent normal cells. The number of cells with positive expressions of IL-6, CD68 and D2-40 and positive coexpression of IL-6 and CD68 were 48.0±10.3, 26.0±5.5, 7.6±3.8, 11.4±2.1 in the tumor tissues and 11.1±2.3, 5.9±1.6, 2.5±1.2, 2.1±0.7 in the adjacent normal tissues, respectively, showing significant differences  (t=22.021, 22.105, 8.103, 21.893, P<0.05). There were significant positive correlations among the number of cells with positive expressions of IL-6, CD68 and D2-40 and positive coexpression of IL-6 and CD68 in the tumor tissues (r=0.941, 0.776, 0.781, P<0.05). There was a significant positive correlation in the number of cells with positive expression between CD68 and D2-40 (r=0.840, P<0.05). The number of cells with positive expressions of IL-6, CD68 and D2-40 and positive coexpression of IL-6 and CD68 in the patients with gastric cancer of stage Ⅰ-Ⅱ were 38.6±5.3, 21.0±2.2, 4.7±1.6 and 9.7±1.2, respectively, which were significantly different from 57.3±2.6, 31.1±1.9, 10.6±2.9 and 13.1±1.3 in the patients with gastric cancer of stage Ⅲ-Ⅳ (t=-14.169,-15.509,-8.149,-8.509, P<0.05). The number of cells with positive expressions of IL-6, CD68 and D2-40 and positive coexpression of IL-6 and CD68 in the patients with infiltrative depth of stage T1-T2 were 41.5±12.2, 22.2±5.1, 5.5±2.6 and 9.7±1.8, respectively, which were significantly different from 50.1±8.8, 27.3±5.1, 8.3±3.9 and 12.0±1.9 in the patients with infiltrative depth of stage T3-T4 (t=-2.435,-2.770,-2.212,-3.236, P<0.05). The number of cells with positive expressions of IL-6, CD68 and D2-40 and positive coexpression of IL-6 and CD68 in the patients without lymph node metastases were 39.2±6.7, 21.3±3.0, 5.2±3.3 and 9.8±1.4, respectively, which were significantly different from 55.2±6.4, 29.9±3.8, 9.6±2.9 and 12.7±1.6 in the patients with lymph node metastases (t=-7.722,-7.838,-4.581,-5.756, P<0.05). All the 40 patients were followed up for 6-22 months with a median time of 18 months. The 1year cumulative survival rate in the 20 patients with high expression of IL-6 was 70.0%, which was significantly different from 90.0% in the 20 patients with low expression of IL-6 (χ²=4.410, P<0.05). The 1year cumulative survival rate in the 20 patients with high expression of CD68 was 70.0%, which was significant different from 90.0% in the 20 patients with low expression of CD68 (χ²=4.075, P<0.05). The 1year cumulative survival rate in the 20 patients with high expression of D2-40 was 65.0%, which was significantly different from 95.0% in the 20 patients with low expression of D2-40 (χ²=4.705, P<0.05). The 1year cumulative survival rate in the 20 patients with high coexpression of IL-6 and CD68 was 70.0%, which was significantly different from 90.0% in the 20 patients with low coexpression of IL-6 and CD68 (χ²=4.152, P<0.05).
Conclusions:There are high expressions of IL-6, TAMs and lymphangiogenesis in the tissues of gastric cancer, and positive correlations among expressions of IL-6, TAMs and lymphangiogenesis. The expressions of IL-6, TAMs and lymphangiogenesis in the tissues of gastric cancer are significantly correlated with the progression of gastric cancer and prognosis of paitents.