Evaluation of Splicing on X-box Binding Protein Transcript in Tissue Samples of Colorectal Cancer.

Background The genetic etiology of colorectal cancer (CRC) is the occurrence of mutation in the genes involved in signal transduction pathways including that of cellular responses to endoplasmic reticulum (ER) stress. This study examines alterations of pre-messenger ribonucleic acid (pre-mRNA) splicing in X-box binding protein (XBP) transcripts related to the ER stress pathway in CRC. Materials and methods In this study, samples were deparaffinized and underwent RNA extraction. A total of 30 synthesized complementary deoxyribonucleic acid (cDNA) templates from the extracted RNAs related to tumor and non-tumor CRC samples, collected over three years and containing pathological data, were subjected to semi-quantitative reverse transcriptase polymerase chain reaction (sqRT-PCR). These cDNA templates were amplified in reaction tubes with specific primers for both spliced and non-spliced isoforms of XBP. Results with P< .05 were considered statistically significant. Results Microscopic assessment represented lymphocyte-rich effusion in tumor samples. sqRT-PCR electrophoresis results showed spliced and non-spliced forms of XBP messenger RNA in the studied samples. In addition, our data showed there were more than 7.8 times the total number of spliced variants in the marginal tumor samples than in the tumor tissue samples (P<.05). Conclusion Alterations of expression in genes involved in stress signaling pathways in cancer have been identified previously. Our results showed an inverse relationship between XBP splicing and CRC tumor tissue, possibly lead to the inactivation of apoptosis in the downstream response to ER stress. However, we propose that the remaining genes in this pathway should undergo gene expression analysis using a greater number of samples.