Polymorphisms in TYMS for Prediction of Capecitabine-Induced Hand-Foot Syndrome in Chinese Patients with Colorectal Cancer

The Association Between Thymidylate Synthase Gene Polymorphisms and the Risk of Ischemic Stroke in Chinese Han Population

Family history of hypertension, smoking, diabetes and alcohol consumption and atherosclerotic plaque were identified as common risk factors in IS. We aimed at investigating the relationship between Thymidylate Synthase (TS) gene polymorphisms and ischemic stroke (IS).This case-control research selected and genotyped three single nucleotide polymorphisms (SNPs)of TS( rs699517, rs2790, and rs151264360) with Sanger sequencing in Chinese Han population. We also adopted logistic regression analysis in genetic models for calculating odds ratios and 95% confidence intervals. Genotype-Tissue Expression(GTEx) database analyzed the tissue-specific expression and TS polymorphisms. The ischemic stroke patients showed higher low-density lipoprotein cholesterol and total homocysteine (tHcy). It was found that patients with the TT genotype of rs699517 and GG genotype of rs2790 had larger degrees of tHcy than those with CC + CT genotypes and AA + AG genotypes, respectively. The genotype distribution of the three SNPs did not deviate from Hardy-Weinberg equilibrium (HWE). Haplotype analysis showed that T-G-del was the major haplotype in IS, and C-A-ins was the major haplotype in controls. GTEx database indicated that the rs699517 and rs2790 increased the expression of TS in healthy human and associated with TS expression level in a single tissue. In conclusion: This study has shown that TS rs699517 and rs2790 were significantly related to ischemic stroke patients.

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.

Predicting drug response and toxicity in metastatic colorectal cancer: the role of germline markers

INTRODUCTION

Despite the introduction of targeted agents leading to therapeutic advances, clinical management of patients with metastatic colorectal cancer (mCRC) is still challenged by significant interindividual variability in treatment outcomes, both in terms of toxicity and therapy efficacy. The study of germline genetic variants could help to personalize and optimize therapeutic approaches in mCRC.

AREAS COVERED

A systematic review of pharmacogenetic studies in mCRC patients published on PubMed between 2011 and 2021, evaluating the role of germline variants as predictive markers of toxicity and efficacy of drugs currently approved for treatment of mCRC, was perfomed.

EXPERT OPINION

Despite the large amount of pharmacogenetic data published to date, only a few genetic markers (i.e., DPYD and UGT1A1 variants) reached the clinical practice, mainly to prevent the toxic effects of chemotherapy. The large heterogeneity of available studies represents the major limitation in comparing results and identifying potential markers for clinical use, the role of which remains exploratory in most cases. However, the available published findings are an important starting point for future investigations. They highlighted new promising pharmacogenetic markers within the network of inflammatory and immune response signaling. In addition, the emerging role of previously overlooked rare variants has been pointed out.

DNA damage repair-related gene signature predicts prognosis and indicates immune cell infiltration landscape in skin cutaneous melanoma

BACKGROUND

DNA damage repair plays an important role in the onset and progression of cancers and its resistance to treatment therapy. This study aims to assess the prognostic potential of DNA damage repair markers in skin cutaneous melanoma (SKCM).

METHOD

In this study, we have analyzed the gene expression profiles being downloaded from TCGA, GTEx, and GEO databases. We sequentially used univariate and LASSO Cox regression analyses to screen DNA repair genes associated with prognosis. Then, we have conducted a multivariate regression analysis to construct the prognostic profile of DNA repair-related genes (DRRGs). The risk coefficient is used to calculate the risk scores and divide the patients into two cohorts. Additionally, we validated our prognosis model on an external cohort as well as evaluated the link between immune response and the DRRGs prognostic profiles. The risk signature is compared to immune cell infiltration, chemotherapy, and immune checkpoint inhibitors (ICIs) treatment.

RESULTS

An analysis using LASSO-Cox stepwise regression established a prognostic signature consisting of twelve DRRGs with strong predictive ability. Disease-specific survival (DSS) is found to be lower among high-risk patients group as compared to low-risk patients. The signature may be employed as an independent prognostic predictor after controlling for clinicopathological factors, as demonstrated by validation on one external GSE65904 cohort. A strong correlation is also found between the risk score and the immune microenvironment, along with the infiltrating immune cells, and ICIs key molecules. The gene enrichment analysis results indicate a wide range of biological activities and pathways to be exhibited by high-risk groups. Furthermore, Cisplatin exhibited a considerable response sensitivity in low-risk groups as opposed to the high-risk incidents, while docetaxel exhibited a considerable response sensitivity in high-risk groups.

CONCLUSIONS

Our findings provide a thorough investigation of DRRGs to develop an DSS-related prognostic indicator which may be useful in forecasting SKCM progression and enabling more enhanced clinical benefits from immunotherapy.

DPYD Exome, mRNA Expression and Uracil Levels in Early Severe Toxicity to Fluoropyrimidines: An Extreme Phenotype Approach

Dihydropyrimidine dehydrogenase deficiency is a major cause of severe fluoropyrimidine-induced toxicity and could lead to interruption of chemotherapy or life-threatening adverse reactions. This study aimed to characterize the DPYD exon sequence, mRNA expression and in vivo DPD activity by plasma uracil concentration. It was carried out in two groups of patients with extreme phenotypes (toxicity versus control) newly treated with a fluoropyrimidine, during the first three cycles of treatment. A novel nonsense gene variant (c.2197insA) was most likely responsible for fluoropyrimidine-induced toxicity in one patient, while neither DPYD mRNA expression nor plasma uracil concentration was globally associated with early toxicity. Our present work may help improve pharmacogenetic testing to avoid severe and undesirable adverse reactions to fluoropyrimidine treatment and it also supports the idea of looking beyond DPYD.