Overexpression And High Activation Of AKT And The Clinical Significance In Human Gastric Cancer And Colorectal Cancer

Objective:AKT is a family of serine/threonine protein kinase that plays an important role in tumorigenesis. AKT2, isoform 2 of AKT, is especially associated with the developments of kinds of human cancers. This study was designed to investigate the expressions of AKT2 and Phospho-Akt (p-Akt) and their clinical significances in samples of sporadic gastric cancer (GA) and colorectal cancer (CA). In addition, to clarify the difference of the immunohistochemical reactivity between samples from the same patient collected by endoscopies and surgery.Methods:The expression of AKT2 and p-Akt was detected by immunohistochemistry (IHC) in paraffin-embedded tumor samples (including small diagnostic biopsies collected by endoscopy and surgically resected specimens) from 38 GA patients, 45 CA patients and 40 nonmalignant human gastrointestinal tissues collected by endoscopy and their clinical significances were evaluated.Results: The prevalence of AKT2 overexpression in GA and CA were 39.5% and 68.9% respectively. CA had a significantly higher prevalence of AKT2 overexpression than did GA (P<0.01). Significant differences in the prevalence of AKT2 overexpression were both observed between GA or CA and nonmalignant gastric or colorectal tissues (P<0.01, P<0.01). Overexpression of AKT2 in GA had a positive correlation with lymph node metastases (P<0.05) and TNM stage (P<0.01). The prevalence of p-Akt overexpression in GA and CA were 84.2% and 88.9% respectively. Significant differences in the prevalence of p-Akt overexpression were both observed between GA or CA and benign gastric or colonic tissues (P < 0.01, P < 0.01). The immunohistochemical reactivity between samples collected by endoscopy and surgery was not all at equal. Especially immunohistochemistry of p-Akt showed significantly weaker staining in most surgically resected specimens than in biopsies collected by endoscopy.Conclusion:Overexpression of AKT2, high activation of AKT is important in development and progression of GA and CA. AKT2 overexpression in GA may promote lymph node metastasis and progression of the disease. Detection p-Akt in surgically resected specimens can not reflect the true AKT activity level of tissues in vivo, because it degrades quickly during the considerable time from blocking the tumors blood supply to fixing the sample.