| Inhibitor of apoptosis proteins (IAPs) are very important anit-apoptosis factors. The common structure characteristics of this family are the one or more than one tandem IAP repeated sequences on the N terminus and the ring finger structure on the C terminus. The universal property of tumor cell is anti apoptosis. IAP family is a kind of apoptosis regulator which is more and more respected by the scientists. There are 8 members in the IAP family and Livin is a new one. Livin consists of one BIR domain and one RING finger domain. It can block many apoptosis pathways by inhibiting the activity of caspase 3,7 and 9 etc al. The expression of Livin in normal tissues is low or deficient, while high in human malignant tumor cell lines and most of the melanin cell lines, which indicates that Livin may play some roles during the formation and development of tumor. Livin-αis absent in normal urinary bladder tissue but highly expressed in urinary bladder caner cell, which suggests that it could be a marker to predict the tendency of tumor recurrence. Nowadays, it was found that the expression of Livin was overloaded in gastrointestinal tumors, such as gastric cancer, intestinal cancer, pancreatic cancer and hepatic cancer. Yagihashi and his colleagues indicated that Livin was highly expressed in gastrointestinal cancer patients, and has some relationship with human gastrointestinal cancer formation. Hofimann and his copartners found that Livin has the anti-apoptosis activity during the development of non-small cell lung cancer. All these results indicate that the high expression of Livin has close relationship with the formation of malignant cancers. The further investigation on Livin may have important significance for us to understand the formation, development, therapy and prevention of tumors.Esophageal cancer is a common life-threatening malignant disease. The therapy of esophageal cancer is still challenging. Nowadays, the expression of Livin in esophageal cancer has not been reported both in China and aboard. Therefore, the further investigation on Livin must have some significance.Materials and Methods40 esophageal squamous carcinoma tissues were analyzed by reverse transcription polymerase chain reaction (PT-PCR) and Western Blot, using normal tissues as control, to detect the expression of Livin at both mRNA and protein level. Data was statistically analyzed using SPSS 11.5 software. Two samples and multiple samples comparison were analyzed with x~2 test. The densities of bands were analyzed with Scion Image software, which was statistically analyzed using t-test to compare the difference of two groups.Results1. The results of RT-PCR show that the expression rate of Livin mRNA in 40 esophageal squamous carcinoma tissues is 65%, while only 5% in normal esophageal tissues. There is significant difference between this two group (P<0.01).2. The mRNA of Livinαandβare expressed simultaneously, and with the same amount.3. The differences of Livin mRNA expression among different genders, ages and cancer tissue states (differentiation, invasion and nodal metastasis) have no statistical significance.4. The results of Western Blot show that the expression of Livin protein is positive in Livin mRNA positively expressed esophageal squamous cancer tissues, while positively expressed in only 2 normal esophageal tissues, and the expression of Livina andβare simultaneous, which is identical to the results of RT-PCR. Conclusions1. Livin, an inhibitor of apoptosis, correlates with the formation and development of esophageal squamous cancer by inhibiting the apoptosis of cells.2. The highly expressed Livin in esophageal squamous cancer tissue may act as a molecular marker for esophageal tumors, which may provides a new way for the diagnosis and therapy of esophageal cancers.
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