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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., Competing Interests: The authors have declared that no competing interests exist.

Background The nucleotide excision repair (NER) system is one of the most important deoxyribonucleic acid (DNA) repair mechanisms and is critical for chemotherapy resistance. We conducted the present study to investigate the association between two polymorphisms of excision of repair cross-complementing group 1 (ERCC1), the key component of the NER pathway, and the clinicopathological features of patients with non-small cell lung cancer (NSCLC). Methods A total of 38 patients with confirmed NSCLC were included in our study. DNA was extracted from peripheral blood. ERCC1 rs3212986 (8092) and rs11615 (118) were genotyped using molecular assays including polymerase chain reaction (PCR) with restriction fragment length polymorphism (by MboII and HpyCH4 enzymes) and sequencing. Results The PCR results indicated the correct performance of the genomics extraction and molecular protocols. The distribution of C/C, C/A and A/A genotypes at position 8092 was 42.10%, 47.36%, and 10.52% respectively (P=0.03). Multivariate regression analysis showed that there was a significant correlation between C8092A (rs3212986) polymorphism and metastasis, grade of the tumor, and response to treatment. Individuals carrying the rs3212986 CA genotype and A allele had a significantly worse response to the treatment. Also, the correlation between alteration at this genomics location and patients with NSCLC who used to smoke cigarettes was positive. However, no significant association was detected between rs11615 C118>T polymorphism and demographic characteristics of patients with NSCLC. Conclusion We concluded that in lung cancer patients there is a relationship between tumor stage and rs3212986C>A polymorphism., Competing Interests: The authors have declared that no competing interests exist.