To evaluate the role of c-jun and c-myc proto-oncogenes in normal, hyperplastic and neoplastic endometrium in relation to estrogen receptor (ER) status and to investigate whether these genes can be related to other histopathological features of endometrial carcinoma, 32 endometrial carcinomas, 38 endometrial hyperplasias and 22 cyclic endometria (10 proliferative and 12 secretory) were evaluated histologically. Endometrial hyperplasia cases were classified as simple and complex hyperplasia without atypia, and atypical hyperplasia. Endometrial carcinoma cases were subtyped according to the International Society of Gynecological Pathologists. Modified FIGO system was used for both grading and staging. Immunohistochemical examination was performed using antibodies to ER-alpha, c-myc and c-jun with streptavidin-biotin-peroxidase technique. The mean percentage of ER-alpha positive cells changed cyclically during the menstrual cycle, and it was the highest (96%) and the lowest (31.6%) in proliferative and carcinomatous endometrium, respectively. There was a statistically significant difference between proliferative and secretory phases and proliferative and carcinomatous endometrium in relation to ER-alpha staining (p<0.05). There was also a statistically significant difference with respect to ERalpha reactivity between secretory phase and each hyperplastic group, as well as between the carcinoma group and each hyperplastic group (p<0.05). Although not significant, the mean percentage of c-myc expressing cells in the carcinoma group was higher (15.3%) than that of proliferative phase and hyperplastic groups. The mean percentage of c-jun positive cells in proliferative endometrium was slightly higher than in secretory endometrium, and it was the highest in atypical hyperplastic endometrium (28.3%), but there was no statistically significant difference between the groups. In carcinoma cases, a positive correlation was observed between c-jun positivity and tumor grade (p=0.027, r=0.3908), but such a correlation with c-myc was not found. A positive correlation was detected between ER-alpha and c-myc expression (p=0.038, r=0.3686). A progressive loss of ER seems to be correlated with increasing malignant transformation. C-myc expression might play a role in the development of endometrial carcinoma via ER. The association between c-jun and ER appears to be lost in endometrial carcinoma. The relationship between c-myc, c-jun and ER appears to be altered in endometrial carcinoma compared to that of menstrual endometrium.
Using double promoter expression systems is a promising approach to increase heterologous protein production. In this review, current double promoter expression systems for the production of recombinant proteins (r-proteins) by industrially important bacteria, Bacillus subtilis and Escherichia coli; and yeasts, Saccharomyces cerevisiae and Pichia pastoris, are discussed by assessing their potentials and drawbacks. Double promoter expression systems need to be designed to maintain a higher specific product formation rate within the production domain. While bacterial double promoter systems have been constructed as chimeric tandem promoters, yeast dual promoter systems have been developed as separate expression cassettes. To increase production and productivity, the optimal transcriptional activity should be justified either by simultaneously satisfying the requirements of both promoters, or by consecutively stimulating the changeover from one to another in a biphasic process or via successive-iterations. Thus, considering the dynamics of a fermentation process, double promoters can be classified according to their operational mechanisms, as: i) consecutively operating double promoter systems, and ii) simultaneously operating double promoter systems. Among these metabolic design strategies, extending the expression period with two promoters activated under different conditions, or enhancing the transcriptional activity with two promoters activated under similar conditions within the production domain, can be applied independently from the host. Novel studies with new insights, which aim a rational systematic design and construction of dual promoter expression vectors with tailored transcriptional activity, will empower r-protein production with enhanced production and productivity. Finally, the current state-of-the-art review emphasizes the advantages of double promoter systems along with the necessity for discovering new promoters for the development of more effective and adaptive processes to meet the increasing demand of r-protein industry.
On consecutive sections BCL2 and CgA positivity closely paralleled each other and a significant positive correlation was observed between CgA and BCL2 expression. These findings suggest a close association between BCL2 expression and neuroendocrine differentiation and indicate that BCL2 may be involved in neuroendocrine differentiation in addition to its role in protecting cells from apoptosis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.