Associations of Genetic Variations in MicroRNA Seed Regions With Acute Adverse Events and Survival in Patients With Rectal Cancer Receiving Postoperative Chemoradiation Therapy

mirSNPs as Potential Colorectal Cancer Biomarkers: A Systematic Review

Colorectal cancer (CRC) is the third most common neoplasm in the world and the second with the highest mortality rate. Single nucleotide polymorphisms (SNPs) in microRNA (miRNA) genes known as mirSNPs may be related to dysregulated miRNA expression in several neoplasms. This systematic review aims to investigate studies that investigate SNPs located in regions of miRNA genes that influence their expression and are associated with CRC, as well as their potential as biomarkers for the disease, based on the available literature. For this, searches were performed in public databases, including MEDLINE/PubMed, Embase, Web of Science, and Scopus. The rigorous review of the PRISMA 2020 guidelines and the methodological quality of these studies was assessed using the Newcastle-Ottawa scale and the Mixed Methods Assessment Tool. Of the 175 studies identified, 26 were considered eligible: 18 of them highlighted mirSNPs as potential biomarkers of risk and prognosis for CRC; 4 studies suggested a protective role; 1 study linked mirSNPs to treatment; 3 studies found no relevant evidence. These results highlight the importance of conducting further research on the topic, given the potential of these biomarkers to contribute to risk assessment, prognosis, and the development of therapeutic strategies for patients with CRC.

Polymorphism in the Hsa-miR-4274 seed region influences the expression of PEX5 and enhances radiotherapy resistance in colorectal cancer

Identifying biomarkers for predicting radiotherapy efficacy is crucial for optimizing personalized treatments. We previously reported that rs1553867776 in the miR-4274 seed region can predict survival in patients with rectal cancer receiving postoperative chemoradiation therapy. Hence, to investigate the molecular mechanism of the genetic variation and its impact on the radiosensitivity of colorectal cancer (CRC), in this study, bioinformatics analysis is combined with functional experiments to confirm peroxisomal biogenesis factor 5 (PEX5) as a direct target of miR-4274. The miR-4274 rs1553867776 variant influences the binding of miR-4274 and PEX5 mRNA, which subsequently regulates PEX5 protein expression. The interaction between PEX5 and Ku70 was verified by co-immunoprecipitation and immunofluorescence. A xenograft tumor model was established to validate the effects of miR-4274 and PEX5 on CRC progression and radiosensitivity in vivo. The overexpression of PEX5 enhances radiosensitivity by preventing Ku70 from entering the nucleus and reducing the repair of ionizing radiation (IR)-induced DNA damage by the Ku70/Ku80 complex in the nucleus. In addition, the enhanced expression of PEX5 is associated with increased IR-induced ferroptosis. Thus, targeting this mechanism might effectively increase the radiosensitivity of CRC. These findings offer novel insights into the mechanism of cancer radioresistance and have important implications for clinical radiotherapy.

Systemic inflammation score in locally advanced rectal cancer patients following total mesorectal excision

Objective

The objective of the study was to evaluate whether any association exists between systemic inflammation score (SIS) and adverse events (AEs) and survival of locally advanced rectal cancer patients treated with total mesorectal excision (TME) followed by adjuvant chemoradiotherapy.

Patients and methods

All of the 109 rectal cancer patients recruited between May 2008 and June 2015 were treated with TME followed by adjuvant chemoradiotherapy. The prognostic ability of SIS for overall survival (OS) was calculated by the receiver operating characteristic (ROC) curves.

Results

According to the classification of the SIS, 22 (20.2%), 59 (54.1%) and 28 (25.7%) patients were classified as a score of 2, 1 and 0, respectively. With an area under the curve (AUC) of 0.616, the SIS score of 1 was defined as the optimal cut-off value. Therefore, we divided the patients into the SIS-low group (SIS score of 1 or 0, n=87) and SIS-high group (SIS score of 2, n=22). Multivariate analysis indicated that SIS was associated with OS (HR 0.390, 95% CI 0.186–0.817, P=0.012). The 5-year OS rate in patients without adjuvant chemotherapy was lower than the patients with adjuvant chemotherapy (53.3% vs 75.8%, P=0.010). Multivariate analysis showed that adjuvant chemotherapy was associated with OS (HR 0.217, 95% CI 0.089–0.529, P=0.001). A marginal statistically significant difference was observed in terms of leukopenia during adjuvant chemoradiotherapy between the SIS-low group and the SIS-high group (P=0.05).

Conclusion

These results suggest that SIS might serve as an independent biomarker for predicting AEs and prognosis in locally advanced rectal cancer treated with TME followed by adjuvant chemoradiotherapy. Strengthening treatment may be administered to locally advanced rectal cancer with high SIS score obtained before adjuvant chemoradiotherapy.

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Associations of Genetic Variations in Mismatch Repair Genes MSH3 and PMS1 with Acute Adverse Events and Survival in Patients with Rectal Cancer Receiving Postoperative Chemoradiotherapy

Purpose

Mismatch repair (MMR) deficiency plays a critical role in rectal cancer. This study aimed to explore the associations between genetic variations in seven MMR genes and adverse events (AEs) and survival of patients with rectal cancer treated with postoperative chemoradiotherapy (CRT).

Materials and Methods

Fifty single nucleotide polymorphisms in seven MMR (MLH1, MLH3, MSH2, MSH3, MSH6, PMS1 and PMS2) genes were genotyped by Sequenom MassARRAY method in 365 patients with locally advanced rectal cancer receiving postoperative CRT. The associations between genotypes and AEs were measured by odds ratios and 95% confidence intervals (CIs) by unconditional logistic regression model. The associations between genetic variations and survival were computed by the hazard ratios and 95% CIs by Cox proportional regression model.

Results

The most common grade ≥ 2 AEs in those 365 patients, in decreasing order, were diarrhea (44.1%), leukopenia (29.6%), and dermatitis (18.9%). Except 38 cases missing, 61 patients (18.7%) died during the follow-up period. We found MSH3 rs12513549, rs33013 and rs6151627 significantly associated with the risk of grade ≥ 2 diarrhea. PMS1 rs1233255 had an impact on the occurrence of grade ≥2 dermatitis. Meanwhile, PMS1 rs4920657, rs5743030, and rs5743100 were associated with overall survival (OS) time of rectal cancer.

Conclusion

These results suggest that MSH3 and PMS1 polymorphisms may play important roles in AEs prediction and prognosis of rectal cancer patients receiving postoperative CRT, which can be potential genetic biomarkers for rectal cancer personalized treatment.