From the morphological point of view, the dysplasia-carcinoma sequence is the most plausible carcinogenic pathway for gallbladder cancer, a process which would require a period of approximately 10 years.
Gallbladder cancer (GC) is considered a rare disease associated with a poor prognosis. Unfortunately, the low number of cases makes the performance of trials addressing the role of adjuvant, neoadjuvant, and/or palliative therapy difficult. For a long time, the majority of trials were 5-fluorouracil (5 FU)-based, and results were uniformly poor. Since the introduction of Gemcitabine, response rates of approximately 30% have been observed through the use of this drug and new approaches have been tested. In this sense, drugs such as Cisplatin and Capecitabine have been employed concurrently with gemcitabine and/or radiation. Since a recurrence pattern is both distant and local, chernoradiation seems a logical option to deal with the disease. However, at the present time, the lack of valid and scientific evidence means that most of the recommendations originate from trials dealing with other tumors, such as pancreas cancer and biliary tract cancer (BTC). The aforementioned treatment alternatives warrant further evaluation focusing on GC.
Teneurins are a family of highly conserved pair-rule proteins involved in morphogenesis and development of the central nervous system. Their function in adult tissues and in disease is largely unknown. Recent evidence suggests a role for dysregulated expression of Teneurins in human tumors, but systematic investigations are missing. Here, we investigated Teneurin-2 and Teneurin-4 expression in various cancer cell lines and in ovarian tumor tissues. Teneurin-2 and Teneurin-4 were expressed in most of the breast cancer cell lines tested. Teneurin-4 was also detected in ovarian cancer cell lines, and throughout ovarian tumors and normal ovary tissue. Ovarian tumors with low Teneurin-4 expression showed less differentiated phenotypes and these patients had shorter mean overall survival. Similarly, Teneurin-2 expression correlated with overall survival as well, especially in patients with serous tumors. In the various cell lines, 5-Aza-cytidine-induced changes in DNA methylation did not alter expression of Teneurin-2 and Teneurin-4, despite the existence of predicted CpG islands in both genes. Interestingly, however, we found evidence for the control of Teneurin-2 expression by the oncogenic growth factor FGF8. Furthermore, we identified multiple transcript splicing variants for Teneurin-2 and Teneurin-4, indicating complex gene expression patterns in malignant cells. Finally, downregulation of Teneurin-4 expression using siRNA caused a cell-type dependent increase in proliferation and resistance to cisplatin. Altogether, our data suggest that low Teneurin-4 expression provides a growth advantage to cancer cells and marks an undifferentiated state characterized by increased drug resistance and clinical aggressiveness. We conclude that Teneurin-2 and Teneurin-4 expression levels could be of prognostic value in ovarian cancer.
Background: Gallbladder cancer (GBC) is an uncommon neoplasm in the United States, but one with high mortality rates.This malignancy remains largely understudied at the molecular level such that few targeted therapies or predictive biomarkers exist. Experimental Design: We built the first series of serial analysis of gene expression (SAGE) libraries from GBC and nonneoplastic gallbladder mucosa, composed of 21-bp long-SAGE tags. SAGE libraries were generated from three stage-matched GBC patients (representing Hispanic/ Latino, Native American, and Caucasian ethnicities, respectively) and one histologically alithiasic gallbladder. Real-time quantitative PCR was done on microdissected epithelium from five matched GBC and corresponding nonneoplastic gallbladder mucosa. Immunohistochemical analysis was done on a panel of 182 archival GBC in high-throughput tissue microarray format. Results: SAGE tags corresponding to connective tissue growth factor (CTGF) transcripts were identified as differentially overexpressed in all pairwise comparisons of GBC (P < 0.001). Realtime quantitative PCR confirmed significant overexpression of CTGF transcripts in microdissected primary GBC (P < 0.05), but not in metastatic GBC, compared with nonneoplastic gallbladder epithelium. By immunohistochemistry, 66 of 182 (36%) GBC had high CTGF antigen labeling, which was significantly associated with better survival on univariate analysis (P = 0.0069, log-rank test). Conclusions: An unbiased analysis of the GBC transcriptome by SAGE has identified CTGF expression as a predictive biomarker of favorable prognosis in this malignancy. The SAGE libraries from GBC and nonneoplastic gallbladder mucosa are publicly available at the Cancer Genome Anatomy Project web site and should facilitate much needed research into this lethal neoplasm.
The use of therapies targeted according to the detection of specific molecular alterations is in the early stages of evaluation and could represent a significant advance in the treatment of a large number of patients from developing countries.
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