Expression Of Apoptosis Inhibitor, Survivin And Its Relationship With Expression Of Bcl-2 And Bax In Laryngeal Carcinoma

Tumor is still one of unsolvable problems. To reveal pathogenesy of tumor can help to direct early tumor diagnosis and specific therapy. So research of tumor pathogenesy has become more and more important. The morbidity of Laryngocarcinoma is second only to nasopharyngeal carcinoma and nasal cavity carcinoma. Recently, this morbidity has been evidently increasing. Although much research had been done, pathogenesy of tumor has been uncertain. Laryngocarcinoma formation is a process containing a few oncogenes , anti-oncogenes and multiple stages. On the one hand, oncogenes activation, anti-oncogenes deletion or mutation lead to tumor cell excess proliferation; on the other hand, it may be the result that inhibitors of apoptosis aberrantly prolongs tumor cell viability . There is a delicate balance between cell proliferation and apoptotic, which are two important factors in maintenance of cell and tissue homeostasis. If the regulation factors change, tumor formation and growth should be effected. So far, several apoptosis inhibitors such as bcl-2 family and inhibitors of apoptosis family (IAPs),have been identificated.IAP proteins were discovered in baculoviruses and are typically characterized by 2-3 baculovirus IAP repeats (BIR) and a RING finger motif. These proteins suppress apoptosis through direct caspase and pro-caspase inhibition, (primarily caspase 3 and 7). Recently, the cancer field has become greatly excited by the discovery of Survivin, one of the IAPs, that functions in vertebrates to regulate both cell proliferation and apoptosis. Survivin contains a single BIR and lacks a carboxyl-terminal RING finger. Although undetectable in terminally differentiated adult tissues, survivin is present during fetal development and in most transformed cell lines and cancers tested to date. Even more importantly, survivin expression appears to be homogenous within the tumor environment, a feature unusual in a disease characterized by spontaneous mutation. Expression of survivin was observed in the cytoplasm, and at specifical stage of the cell cycle-G2/M. Furthermore, survivin has a natural antisense strand, effector cell protease receptor-1(EPR-1),so regulation of transcriptions of these two complementations can modulate apoptosis.bcl-2 is the firstly found apoptosis regulation gene, and its mechanism of action may be concerned with a few factors such as Ca2+ dependent endonuclease, anti-oxyradical, control of cell signaling and so on. bcl-2 has several homologizations, and these proteins interact to promote or inhibite apoptosis. Bcl-2 play a part in apoptosis inhibition induced by many factors.To identify the role of apoptosis inhibition induced by overexpression of survivin and its relationship to bcl-2 and bax in Laryngocarcinoma pathogenesis, immunohistochemical staining of survivin,bcl-2 and bax by using the monoclonal or multiclonnal antibody were performed by the standard streptavidin-peroxidase (SP) technique for the 64 paraffin sections which included 10 polyp of cord as control, and 54 Laryngocarcinoma. Overexpression of survivin(70.4%), bcl-2(75.9%) and bax(61.1%) were observed in Laryngocarcinoma. No immunoreactivity of survivin and bcl-2 were seen in the polyp of cord while positive rate of bax is 30.0% . The positive rate of survivin was related to the clinical stage, the histological grade and the cervical lymphatic metastasis of the tumor, and not to patients' age, sex, tumor size or clinical classification. The positive rate of bcl-2 was related to the clinical stage, the histological grade and the cervical lymphatic metastasis of the tumor. Moreover, there was the correlation between survivin and bcl-2, and not between survivin and bax.Our studies demonstrated that the action of apoptotic inhibition of survivin may participate in the onset and progression of laryngeal carcinoma. Survivin could become a new diagnostic , prognostic and therapeutic marker in laryngeal carcinoma. The overexpression of bcl-2 is the essential event in the early stage of laryngeal carcinoma becau...