Effect of DPYD, MTHFR, ABCB1, XRCC1, ERCC1 and GSTP1 on chemotherapy related toxicity in colorectal carcinoma

Gene polymorphism and prediction of toxicity to platinum-based chemotherapy in patients with gynecologic cancer

The relationship between single nucleotide polymorphisms (SNPs) at various loci and adverse drug reactions (ADRs) in patients with gynecologic cancer receiving platinum-based chemotherapy (PPCT) remains unexplored. This research aimed to investigate the correlation between SNPs at several loci (e.g., GSTP1 rs1695, MTHFR rs1801133, XPC rs2228001, TP53 rs1042522, and ERCC1 rs3212986) and ADRs in patients with gynecologic cancer receiving PPCT. A total of 244 patients with gynecologic cancer who received first-line PPCT were included in this retrospective study. Blood fluorescence quantitative polymerase chain reaction was used to detect genotypes. Logistic regression, Pearson's Chi-square test, and Fisher's exact test were used to explore the correlations between these SNPs and the occurrence of ADRs. The logistic regression results showed that different genotypes of the five genes had no statistical significance in the overall grade greater than or equal to 3 ADRs. The results of Pearson's Chi-square test showed the same results. On specific adverse reactions, we found that the rs1042522 GG genotype significantly increased the risk of grade greater than or equal to 3 leucopenia compared with the CG and the CC genotypes (p = 0.002). The rs1695 AG genotype showed higher correlation for grade greater than or equal to 3 neutropenia (p = 0.020). The rs2228001 CC genotype also had a higher risk for grade greater than or equal to 3 neutropenia (p = 0.003). This study found that whereas the overall grade greater than or equal to 3 adverse reactions in patients with gynecologic cancer receiving PPCT were not associated with SNPs, specific SNPs (rs1042522 GG, rs1695 AG, and rs2228001 CC) were linked to higher risks of leucopenia and neutropenia, indicating their potential as predictors of hematotoxicity in PPCT-treated patients with gynecologic cancer.

Influence of Single-Nucleotide Polymorphisms on Clinical Outcomes of Capecitabine-Based Chemotherapy in Colorectal Cancer Patients: A Systematic Review

The aim of this systematic review was to provide a comprehensive overview of the literature published in the last decade on the association of single-nucleotide polymorphisms in genes involved in the pharmacodynamic and pharmacokinetic pathways of capecitabine with treatment outcomes among colorectal cancer patients. A systematic search of the literature published in the last 10 years was carried out in two databases (Medline and Scopus) using keywords related to the objective. Quality assessment of the studies included was performed using an assessment tool derived from the Strengthening the Reporting of Genetic Association (STREGA) statement. Thirteen studies were included in this systematic review. Genes involved in bioactivation, metabolism, transport, mechanism of action of capecitabine, DNA repair, and folate cycle were associated with toxicity. Meanwhile, genes related to DNA repair were associated with therapy effectiveness. This systematic review reveals that several SNPs other than the four DPYD variants that are screened in clinical practice could have an impact on treatment outcomes. These findings suggest the identification of future predictive biomarkers of effectiveness and toxicity in colorectal cancer patients treated with capecitabine. However, the evidence is sparse and requires further validation.

Exosome-Transmitted miR-506-3p Inhibits Colorectal Cancer Cell Malignancy via Regulating GSTP1

Exosome-mediated microRNA transfer has been shown to regulate cancer progression. However, the involvement of exosomal-miR-506-3p in colorectal cancer (CRC) is unknown. The goal of the research was to study into the role of exosomal-miR-506-3p in CRC. Using a qRT-PCR experiment, it was observed that CRC tissues had lower levels of miR-506-3p than non-tumor tissues. It was observed that miR-506-3p inhibited the proliferation, regulates apoptosis, and cell cycle of HT29 and SW480 cells as compared to control groups. Dual luciferase reporter assay results showed that GSTP1 was the downstream target molecule of miR-506-3p, which was consistent with the database prediction. Furthermore, FHC cells transfected with miR-506-3p could transfer miR-506-3p to SW480 cells, limiting cell growth and inducing cell death. We discovered a unique regulatory mechanism in which exosome-mediated transfer of miR-506-3p reduces proliferation and induces apoptosis in CRC through negative regulation of GSTP1, implying that exosome-mediated delivery of miR-506-3p provides fresh insight into CRC diagnostics and treatment.

Capecitabine-induced enterocolitis: a case report and pharmacogenetic profile

Capecitabine is a widely-used antineoplastic drug, a prodrug to 5-fluorouracil which commonly induces gastrointestinal toxicity. Enterocolitis, as a rarely recognized gastrointestinal adverse effect (AE) of capecitabine, is potentially severe and usually results in antitumor treatment withdrawal. For the better management of severe AEs, pharmacogenetics is one promising field. Herein, we describe a case of capecitabine-induced enterocolitis presenting with severe diarrhea in order to improve recognition by clinicians. Moreover, we conduct a pharmacogenetic profile of the patient and review the current studies of gene polymorphisms of 5-fluorouracil-related diarrhea, hoping to offer a reference for further clinical pharmacogenetic practice in predicting capecitabine AEs showing diarrhea as the main symptom.

Concomitant Administration of Capecitabine and Folate Supplements: Need to Encourage Medication Reconciliation

Hand-Foot syndrome (HFS) and diarrhoea are dose-limiting Adverse Drug Reactions (ADRs) of capecitabine-based chemotherapy. Four polymorphisms in the dihydropyrimidine dehydrogenase (DPYD) gene, encoding the DPD enzyme responsible for the metabolism of fluoropyrimidines, such as capecitabine, are strongly associated with severe ADRs, and their screening should be performed before starting treatment. Moreover, capecitabine-related toxicity may worsen due to drug-drug and drug-supplement interactions. Here we investigated factors responsible for severe HFS and diarrhoea presented by two patients, non-carriers of the recommended DPYD single nucleotide polymorphisms (SNPs) but carriers of other genetic variants suggested to increase the risk of capecitabine-related ADRs. Through careful therapy recognition, we demonstrated that, unbeknownst to the oncologists, the patients were taking folic acid during the treatment with capecitabine at a dosage higher than 2000 mg/m2, which is the maximum tolerated dose when folate is administered. To resolve the ADRs, the therapy had to be drastically changed. In one case, dose reduction of capecitabine and discontinuation of lipid-lowering agents were carried out. In the other case, discontinuation of capecitabine and folic acid and capecitabine re-administration were performed after a month. Genetic and environmental factors should be considered good predictors of severe capecitabine-related toxicity. Medication reconciliation should be encouraged to avoid the harmful consequences of inappropriate treatments.

Introducing a simple and cost-effective RT-PCR protocol for detection of DPYD*2A polymorphism: the first study in Kurdish population

PURPOSE

Fluoropyrimidines, the major chemotherapeutic agents in various malignancies treatment, are metabolized by dihydropyrimidine dehydrogenase (DPD). DPD deficiency can lead to severe and sometimes fatal toxicity. In the present study, we developed a simple protocol to detect the DPYD*2A variant. Common side effects in patients treated with these drugs were also evaluated in a Kurdish population.

METHOD

We established a reverse-transcriptase polymerase chain reaction (RT-PCR) technique for detection of DPYD*2A. Sanger sequencing was used to confirm the results. 121 Kurdish patients receiving fluoropyrimidine derivatives were enrolled, and clinical information regarding the dosage and toxicity was analyzed.

RESULTS

Our RT-PCR method was able to detect one patient with heterozygous state for DPYD*2A (0.8%). The most observed adverse drug reactions were tingling, nausea, and hair loss. The frequency of patients with the toxicity of grade 3 or worse was 6.6%.

CONCLUSION

This was the first study that detect DPYD*2A polymorphism in the Kurdish population. Our method was successfully able to detect the DPYD*2A variant and, due to its simplicity and cost-effectiveness, it may be considered as an alternative to the current methods, especially in developing countries. Our detected polymorphism rate at 0.8% is comparable with other studies. Despite the low rate of DPYD*2A polymorphism, pharmacogenetics assessment before beginning the treatment process is highly recommended due to its association with a high risk of severe toxicity.

[Clinical significance of tumor chemosensitivity assay in patients with head and neck cancer]

Objective:To evaluate the clinical significance of OncoDrug-Seq™ tumor gene detection in patients with head and neck malignancies. Methods:A retrospective analysis of 338 patients with locally advanced or unresectable head and neck malignancies admitted to the Department of Otorhinolaryngology Head and Neck Surgery, Chinese PLA General Hospital from April 2011 to February 2021. Among them, 301 patients were pathologically diagnosed as squamous cell carcinoma, 37 cases were non-squamous cell carcinoma. All patients underwent OncoDrug-Seq™ gene detection, combined with the test results and the treatment response after induction chemotherapy to evaluate whether to change the chemotherapy regimen, and to calculate the accuracy of the gene detection and the survival rate of the patient. Results:Among 301 patients with head and neck squamous cell carcinoma, the results of the drug sensitivity test were compared with the actual clinical response, the true positive rate（TP）, true negative rate（TN）, positive predictive value（PPV）, negative predictive value（NPV） and total predictive accuracy rates were 85.37%, 65.45%, 91.70%, 50.00% and 81.73%, respectively. For patients who changed chemotherapy regimen（TN+FP） and did not change（TP+FN）, the 5-year progression-free survival（PFS） was 63.45% and 80.58%（P<0.05）, respectively, the 5-year overall survival（OS） was 54.18% and 84.74%（P<0.05）. Among 37 patients with non-squamous cell carcinoma, the TP, TN, PPV, NPV and total predictive accuracy rates were 88.46%, 72.73%, 88.46%, 72.73%, and 83.78%, respectively. The 5-year PFS of the patients who changed（TN+FP） and did not change the treatment regimen（TP+FN） were 68.57% and 56.00%, and the 5-year OS was 69.26% and 48.72%, the difference was not statistically significant. Conclusion:OncoDrug-Seq™ testing has certain significance in guiding clinicians to formulate personalized chemotherapy regimens. Timely replacement of the treatment plan can enable the patient to obtain a more ideal curative effect. Compared with patients with squamous cell carcinoma, patients with non-squamous cell carcinoma can obtain greater survival benefit from this testing. However, there are still some deviations in the accuracy of the test results compared with the actual clinical situation. Therefore, the decision should be made based on the test results in combination with the clinical reality.

The base excision repair process: comparison between higher and lower eukaryotes

The base excision repair (BER) pathway is essential for maintaining the stability of DNA in all organisms and defects in this process are associated with life-threatening diseases. It is involved in removing specific types of DNA lesions that are induced by both exogenous and endogenous genotoxic substances. BER is a multi-step mechanism that is often initiated by the removal of a damaged base leading to a genotoxic intermediate that is further processed before the reinsertion of the correct nucleotide and the restoration of the genome to a stable structure. Studies in human and yeast cells, as well as fruit fly and nematode worms, have played important roles in identifying the components of this conserved DNA repair pathway that maintains the integrity of the eukaryotic genome. This review will focus on the components of base excision repair, namely, the DNA glycosylases, the apurinic/apyrimidinic endonucleases, the DNA polymerase, and the ligases, as well as other protein cofactors. Functional insights into these conserved proteins will be provided from humans, Saccharomyces cerevisiae, Drosophila melanogaster, and Caenorhabditis elegans, and the implications of genetic polymorphisms and knockouts of the corresponding genes.

The Association Between the XRCC1 Arg399Gln Polymorphism and the Risk of Head and Neck Cancer: An Updated Meta-Analysis Including 14586 Subjects

BACKGROUND

Accumulated evidence shows that DNA repair gene X-ray repair cross complementing group 1 (XRCC1) may determine individual susceptibility to head and neck cancer (HNC) as a major DNA repair gene. However, the results from previous studies have been conflictive and inconsistent. In order to more accurately estimate and integrate the association between XRCC1 Arg399Gln polymorphism and HNC risk, we conducted a meta-analysis including 14586 subjects.

METHODS

In this meta-analysis, literatures were collected up until September 15, 2020 through multifarious retrieval strategies by searching through electronic databases of PubMed, Cochrane Library, EMBASE, Medline, Web of Science and CNKI. The association between the XRCC1 Arg399Gln polymorphism and HNC was analyzed through calculating summary odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Thirty-one studies consisting of 6025 cases and 8561 controls were identified and analyzed. No significant association between XRCC1 Arg399Gln polymorphisms and HNC risk was found under the allelic (OR = 0.94, 95% CI: 0.82-1.07, P = 0.35), homozygous (OR = 0.99, 95% CI: 0.81-1.21, P = 0.91), heterozygous (OR = 1.01, 95% CI: 0.90-1.13, P = 0.91), dominant (OR = 1.05, 95% CI: 0.85-1.29, P = 0.67) or recessive (OR = 0.93, 95% CI: 0.80-1.08, P = 0.35) genetic models in the overall comparison. In addition, subgroup analyses according to tumor site also displayed no significant association between XRCC1 Arg399Gln polymorphisms and HNC risk. However, subgroup analyses based on ethnicity indicated that HNC risk was significantly related to Arg399Gln genetic heterozygous model (OR = 1.21, 95%CI: 1.04-1.42, P = 0.02) and dominant model (OR = 1.27, 95%CI: 1.02-1.60, P = 0.04) in Caucasians populations.

CONCLUSION

The results from this meta-analysis suggest that the XRCC1 Arg399Gln variants (Arg/Gln and Arg/Arg+Arg/Gln) may contribute to high HNC risk among Caucasians. Further well-designed studies and larger sample sizes are needed to validate our findings.