Background: Recently the serine/threonine kinase Akt has been a focus of interest because of its activity to inhibit apoptosis. Akt is classified in three specific isoforms (Akt1, Akt2, and Akt3) and suggested the relation with carcinogenesis. For example, there are some reports that Akt1 is activated and amplified in gastric cancer, prostatic cancer, and breast cancer. Akt2 and Akt3 are also reported in ovarian cancer, pancreatic cancer and in malignant melanoma, respectively. The aim of this study is to investigate the expression of Akt1, -2 and -3, and MDM2 and p53 in esophageal squamous cell carcinoma. In addition, we evaluated the correlation between mRNA level of each genes and clinico-pathological factors (histological type of tumor, depth, lymph node metastasis and stage). Materials and Method: We analyzed the expression of isoforms Akt1, -2, -3, MDM2 and p53 in tumor and normal mucosa by real-time quantitative RT-PCR studies. Frozen samples of esophageal squamous cell carcinoma were derived from 17 patients. The patients were not treated with pre-operative chemotherapy and radiotherapy. Result: The relative mRNA level of Akt1 in the tumor compared with normal mucosa ranged from 0.68 to 4.11 arbitrary unit (AU). In 15 of 17 cases (88.2%), relative mRNA levels of Akt1 in tumors are higher than those of normal tissues. In the same way, relative mRNA levels of Akt2, -3, mdm2 and p53 in the tumors ranged from 0.22 to 2.14, 0.09 to 4.05, 0.46 to 3.99 and 0.04 to 1.93 AU, respectively. The incidences of higher mRNA levels in tumors were 50.0% of Akt2, 44.4% of Akt3 and 60.0% of MDM2, respectively. In these cases, the mRNA level of Akt1 in tumor was significantly higher than that of normal mucosa ( P<0.0001 ), but there was no statistical correlation between each genes and clinico-pathological factors. Conclusion: In this study, high expression of Akt1 may play an important role during development of esophageal squamous cell carcinoma.
[Proc Amer Assoc Cancer Res, Volume 46, 2005]