Expression of CD163 in gastric cancer and its clinical significance
Authors: CHENG Hongjun , ZHU Chenglou , Jichun MA , PAN Zhiang , Da Ming-xu 
Published: February 2023

Abstract
Background Scavenger receptor cysteine-rich type 1 protein M130 (CD163) is a marker protein on the surface of M2-associated macrophages (TAMs). CD163 is closely related to the occurrence and prognosis of cardiovascular and cerebrovascular diseases, inflammation, and malignant tumors. To detect the expression of CD163 in gastric cancer (GC) tissues and adjacent normal tissues, and explore the relationship between its expression differences and clinicopathological characteristics and prognosis of patients.
Methods 1. The expression of CD163 mRNA in 22 pairs of GC tissues and adjacent tissues was detected by qPCR. 2. The expression status of CD163 in 60 cases of GC tissues and adjacent tissues was detected by immunohistochemistry. Statistical methods were used to analyze the expression of CD163 and the clinicopathological characteristics of GC patients (gender, age, tumor size, tumor location, degree of differentiation, depth of invasion, lymph node metastasis, distant metastasis, TNM stage). 3. Kaplan-Meier survival analysis was used to analyze the relationship between the expression of CD163 and the prognosis and survival of patients. COX regression analysis was used to predict risk factors.
Results 1. The expression level of CD163 mRNA in GC tissue was up-regulated, which was significantly higher than that in adjacent tissue, and the difference was statistically significant (P<0.05). 2. The CD163 was mainly expressed in the subepithelial connective tissue and the front stroma of tumor infiltration, and it was yellowish-brown or tan. The positive expression rate of CD163 in GC tissues was 51.7% (31/60), while the positive expression rate in adjacent tissues was only 21.7% (13/60). The positive expression rate of CD163 in GC tissues was significantly higher than that in adjacent tissues (P<0.05). 3. The expression level of CD163 was positively correlated with tumor size, degree of tissue differentiation, depth of tumor invasion, lymph node metastasis, and TNM staging（P＜0.05）, but was not associated with patient gender, age, tumor location, and whether there was distant metastasis, and the difference was not statistically significant ( P>0.05). 4. Kaplan-Meier survival analysis showed that the average survival time of GC patients in the high CD163 expression group was 29.73 ± 2.51 months, while the average survival time in the low expression group was 48.80 ±2.68 months, there was a statistically significant difference between the two groups (P<0.05). 5. Through COX regression analysis, the results showed that: in univariate analysis, tumor size（HR：2.30，95% CI：1.23-4.34）, degree of tissue differentiation（HR：2.52，95% CI：1.32-4.83）, lymph node metastasis （HR：3.13，95% CI：1.43-6.83）, distant metastasis（HR：4.98，95% CI：1.94-12.80）, TNM stage（HR：3.49，95% CI：1.60-7.61）, CD163 expression level （HR：3.99，95% CI：2.00-7.97）was related to the prognosis of GC patients, and the difference was statistically significant (P < 0.05); while gender, age, tumor location, depth of invasion and the risk of not affecting the prognosis of GC patients factor (P>0.05). In multivariate analysis, a CD163 expression level（HR：4.68，95% CI：1.71-12.77）showed a close correlation with poor prognosis of GC patients, with differences There was statistical significance (P<0.05); however, age, gender, and tumor size, tumor location, degree of tissue differentiation, depth of invasion, lymph node metastasis, distant metastasis, and TNM stage could not be used as risk factors for the prognosis of GC patients (P>0.05).
Conclusion CD163 is highly expressed in GC tissues, plays an important role in the occurrence and development of tumors, and is closely related to the prognosis of GC patients. It is expected to become an important biomarker and potential molecular therapeutic target for GC prognosis evaluation.