The density of CD8+ tumour-infiltrating T lymphocytes in rectal cancer cells and its relationship with the clinicopathological characteristics and prognosis of patients

Abstract

Abstract Objective:To explore the relationship between CD8+ tumor infiltrating T lymphocyte density and clinicopathological features and prognosis of patients with rectal cancer. Methods:For immunohistochemistry, paraffin-embedded TMA samples were cut into 4-μm sections. CD8 (ZA-0508, ZSGBBIO) Specific procedure: Tissue sections were baked, dewaxed and rehydrated. Endogenous peroxides were closed by incubating at 37°C for 15 minutes with a methanolic solution of 3% hydrogen peroxide. Antigen repair is then carried out by autoclaving in EDTA antigen repair solution (pH=8) for approximately 10 minutes. Sections were incubated with primary antibody for approximately 1.5 hours at 37°C. After washing, tissue sections were treated with HRPRABBIT/MOUSE secondary antibody (K5007, 20029103, Dako) for 30 minutes at room temperature. Sections were immunostained with diaminobenzidine tetrahydrochloride (DAB, K5007, 20019193, Dako) and restained with hematoxylin. Results:CD8+ TILS were expressed in rectal cancer tissues in T lymphocytes, which were localised to the cell membrane (Figure 1 ). The relationship between the density of CD8+ TILs in rectal cancer tissues and the clinicopathological characteristics of patients, low density group and high density group, there was no statistically significant difference (P>0.05) in terms of age, gender, type of surgery and size of the mass, and there was a statistically significant difference (P<0.05) when comparing the depth of infiltration and lymph node metastasis, as shown in Table 1. For survival analysis, Kaplan-Meier analysis showed that patients with high density CD8+ TILS had a better prognosis than those with low density CD8+ TILS. Figure 2. Multi-factor Cox regression analysis with prognosis as the dependent variable (Table 2 for variable assignment) showed that low density CD8+ TILs was an independent risk factor for poor prognosis in patients with rectal cancer (p<0.05), see Table 3. Conclusion:This study illustrates that CD8 expression can be used as an indicator of prognosis in rectal cancer patients, and also provides more effective guidance for immunotherapy in rectal cancer patients at a later stage.