Co-expression Of Survivin And HTERT In Colorectal Carcinogenesis And The Relationship With C-myc

Background and objectives: colorectal carcinoma is one of the common digestive carcinoma. Owning to the change of environment and diet structure, the rate of its incidence has increased during the past two decade in China . The colorectal mucosa cells are regulated by the coordinated balance of cell proliferation and apoptosis to maintain colorectal normal homeostasis . survivin belongs to the family of genes which inhibit apoptosis, and human telomerase reverse transcriptase (hTERT) accounts for the immortal status of cells. Both genes are expressed in malignancies selectively and control major steps in cancer development, indefinite tumor-cell growth and cell division.survivin, a novel member of the inhibitor of apoptosis protein(IAP) gene family, is expressed in proliferating cells such as fetal tissues and various malignancies, survivin has been shown to inhibit effector cell death proteases caspase-3, caspase-7 and block the programmed cell death . survivin is up-regulated during the G 2/M phase of the cell cycle and associates with microtubules of the mitotic spindle at the beginning of mitosis to inhibit apoptosis and promote proliferation.Telomerase, another factor, is associated with cell immortality, and consequent accumulation of malignant genetic property. hTERT parallels with the level of telomerase enzyme activity, to synthesize telomeric DNA and stablize chromosomal ends, with exception of embryonic and stem cells but reactived in all human cancers.Some studies show that survivin may depend on the functions of c-myc to promote cell transformation, c-myc can induce the expression of hTERT. The regulation and relationship between them remain unclear. In order to investigate theco-experssion of survivin and hTERT in colorectal carcinogenesis and the relationship with c-myc and clinicopathological parameters, also to provide theoretical basis of preventing and treating maliganant tumor centring on survivin and hTERT, an immunohistochemical streptavidin-peroxidase (SP) method was used to examine the expression of the three kinds of protein.Materials and methods: (1) Fourity-nine surgically resected colorectal adenocarcioma samples , 25 adenoma samples and 12 normal colorectal mucosa samples which were adjacent to carcinoma mucosa, were all confirmed pathologically All the tissues were fixed in 10% neutral formalin and embedded in paraffin. (2) SP immunohistochemistry technique was used to detect the expression of survivin ,hTERT and c-myc . (3) The data was analyzed by statistical software SPSS10.0. ^-test was used to analyze the difference between groups, and spearman grade correlation test was used to analyze the correlation . A difference was considered significant if P<0.05 .Results: In normal mucosa no stain of survivin was observed ,the positive rate was 0%; in colorectal adenoma , the positive rate of survivin was 32.0%; in colorectal carcinoma, survivin stain was heterogeneous , the positive rate was 65.3%, at the cellular level , survivin stain was predominantly cytoplasmic, and minimal nuclear reacting was observed. There were significant difference between three groups(P<0.05). hTERT were weak stained in few normal basal crypt epithelial cells, the positive rate was 8.3%; the positive rate in adenoma was 36.0%,no significant difference compared with normal group(P>0.05).The expression of hTERT in mostly tumor cells with cytoplasmic and nuclear stain ,the positive rates was 85.7%, was significantly higher than adenoma group(P<0.05). The positive rate of c-myc was 0%,20.0%,53.1% respecitively in normal group, adenoma group and tumor group, there were significant difference between three groups(P<0.05).2. According to the degree of differentiation of colorectal carcinoma, 49 cases were divided into highly differentiated group and moderately-poorly differentiated group. The positive rates of survivin wre 58.3% and 72.0%. The positive rates of hTERT were 79.17% and 92.0%. There were no significant difference (F>0.05) between the differentiation and the expression of survivin and hTERT...