Int J Med Sci 2019; 16(8):1142-1148. doi:10.7150/ijms.34541 This issue
1. Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Ruijin er Road, Shanghai, 200025, China.
2. Department of Oncology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Ruijin er Road, Shanghai, 200025, China.
3. Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Ruijin er Road, Shanghai, 200025, China.
*These authors contributed equally to this manuscript and should be considered co-first authors
Background: The aims of this study were to investigate the expression pattern of CDK12 protein in gastric cancer, and to analyze the correlations of CDK12 expression between CD8+ cell density and CCL12 expression.
Methods: Eighty-six paired tumor and non-tumor samples were collected from patients who underwent radical surgery and had pathological confirmed gastric adenocarcinoma. Immunohistochemistry was used to assess CDK12 expression and CD8+ cell density. Expression of CDK12 and CCL21 mRNA was detected by quantitative reverse transcription-polymerase chain reaction.
Results: CDK12 expression in gastric tumor tissues was significantly higher than it in paired non-tumor tissues (P<0.001). High expression of CDK12 was identified in 43 cases (50%), and it was significantly correlated with Lauren's classification (diffuse type) and number of metastatic lymph nodes (≥15). High CDK12 protein level indicated a relative poorer overall survival than patients with CKD12 low expression, while it was not identified as an independent prognostic factor. Median number of CD8+ cells in tumor tissues was 51 (range: 0-292). Number of CD8+ cells was positively correlated with CDK12 expression score in tumor tissues (r=0.243, P=0.024). Positive correlation was also found between CDK12 and CCL21 mRNA expression (r=0.419, P=0.017).
Conclusion: High CDK12 expression was detected in gastric cancer which was correlated with malignant phenotypes and worse outcome. Positive correlations of CD8+ cell number and CCL21 mRNA expression with CDK12 level were identified.
Keywords: Gastric cancer, CDK12, lymph node metastasis, CD8+ cells, CCL21