Expression of H3K27me3 in Tibetan Patients with Gastric Cancer and Its Significance

Objective  To investigate the expression and its significance of H3K27me3 in Tibetan patients with gastric cancer.  Methods  Clinical and pathological data were retrospectively collected from Tibetan patients with gastric cancer in the Tibet Autonomous Region People's Hospital from August 2019 to August 2021 and Tibetan non-gastric cancer patients during the same period. The expression of H3K27me3 in gastric cancer tissues, corresponding adjacent normal gastric mucosa and normal gastric mucosa of Tibetan patients with non-gastric cancer tissues was detected by immunohistochemical method, and the differences of H3K27me3 expression between gastric cancer patients with different clinical and pathological characteristics was compared.  Results  A total of 54 Tibetan gastric cancer patients and 55 Tibetan non-gastric cancer patients who met the inclusion and exclusion criteria were enrolled. H3K27me3 was localized in the nucleus, and the nucleus showed brownish-yellow granular staining when positively expressed. The high expression rate of H3K27me3 in gastric cancer tissues was significantly higher than that in adjacent normal gastric mucosa tissue[64.8%(35/54) vs. 29.6%(16/54), P < 0.001]and normal gastric mucosal tissue of Tibetan patients with non-gastric cancer[64.8%(35/54) vs. 34.5%(19/55), P=0.002], and the high expression rate of H3K27me3 in the adjacent normal gastric mucosa tissue was not significantly different from that in normal gastric mucosal tissue of Tibetan patients with non-gastric cancer(P=0.683). H3K27me3 expression in gastric cancer tissues was not related to gender, age, degree of differentiation, depth of invasion, maximum tumor size, Lauren's classification, lymph node metastasis, vascular and nerve invasion and TNM stage.  Conclusions  H3K27me3 is highly expressed in gastric cancer tissues of Tibetan people in Tibet. There is no significant difference in H3K27me3 positive expression cells in adjacent tissues and normal gastric mucosa. The significance of H3K27me3 in Tibetan patients with gastric cancer is uncertain and requires further investigations