Genotype frequencies for polymorphisms related to chemotherapy-induced nausea and vomiting in a Japanese population

Polymorphisms of 5-hydroxytryptamine receptor type 3B gene and clinical characteristics for vomiting after breast surgery in chinese han female population

WHAT IS KNOWN AND OBJECTIVE

The 5-hydroxytryptamine type 3B receptor (HTR3B) is involved in postoperative vomiting. We aimed to investigate whether genomic variations of rs1176744 and rs1672717 in HTR3B are associated with postoperative vomiting (POV) in the Chinese Han female population after surgery.

METHODS

Five hundred and sixty-eight female patients classified as ASA I-II undergoing breast surgery under standard general anaesthesia were enrolled in the study. Episodes of POV in the first 24 h after surgery were recorded. Targeted single nucleotide polymorphisms (SNPs) in the HTR3B gene were identified by genotyping using the SNPscan^TM technique. Univariate and multivariate analyses were conducted to investigate the association between SNPs and POV.

RESULTS

We eventually analysed 407 subjects undergoing breast surgery under general anaesthesia. Of these, 104(25.6%) patients suffered POV within 24 h after surgery. In the multivariate logistic regression analysis, we found that age≥50 years (p = 0.012) and longer duration of surgery (p = 0.019) were independent risk factors for POV. Simultaneously, in the dominant model of rs1672717, compared with the AA genotype, GG+GA carriers suffered more POV (OR=1.669, p = 0.038). However, the use of atropine reduced the incidence of POV in our study (p = 0.019).

WHAT IS NEW AND CONCLUSION

Our investigation demonstrated that polymorphism of rs1672717 (HTR3B) may be a genetic risk factor for developing POV.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT03705026.

Novel susceptibility genes were found in a targeted sequencing of stroke patients with or without depression in the Chinese Han population

BACKGROUND

Both stroke and depression are multi-factorial diseases, with both genetic and environmental factors likely to participate in their pathogenesis. Post stroke depression (PSD) is a common complication after stroke leading to poor functional outcome, increased physical disability and mortality. Although several genes have been associated with PSD, the genetic basis of PSD remains poorly understood.

METHOD

A 2-stage candidate gene study by targeted sequencing was conducted involving stroke patients with or without depression and health controls. In the discovery stage (121 PSD, 131 non-PSD and 639 HC), logistic regression was used to test associations respectively in PSD and non-PSD groups. In the replication stage (200 PSD, 218 non-PSD and 983 HC), 54 selected SNPs were again genotyped in an independent cohort. Fixed-effects inverse variance-weighted meta-analysis was used in the combined samples.

RESULTS

The study identified 2 novel genes associated with PSD [HTR3D (rs55674402, p = 0.002512, odds ratio (OR) = 0.7431); NEUROG3 (rs144643855, p = 0.00325, OR = 0.6523)] and 3 risk SNPs in one risk gene associated with non-PSD [PIK3C2B (rs17406271, p = 0.0006801, OR = 1.446; rs2271419, p = 0.0005836, OR = 1.497; rs2271420, p = 0.001031, OR = 1.431)] in the Chinese sample. NEUROG3 shows highest expression level in hippocampus. Functional enrichment analysis shows that susceptibility genes for PSD are mostly enriched in chemical synaptic transmission and regulation of lipid synthetic process.

LIMITATIONS

The sample size was not sufficient to reach a genome-wide p value level. To overcome this shortage, some unique strategies were applied during the selection of SNPs for replication. Secondly, the age, gender composition and depressive severity between two stages were not well-matched. Different sample sources should be blamed, and to minimizing the influence, gender was corrected as co-variant in logistic regression.

CONCLUSION

This study identified that HTR3D and NEUROG3 were linked with the susceptibility of PSD and PIK3C2B with stroke in the Chinese Han population. Further replication of these findings in a larger and better matched sample is warranted. Functional analysis suggests that the pathogenesis of PSD may be implicated in 5-HT synaptic transmission, neural plasticity and lipid metabolism, and therapeutic interventions targeting these pathways may be effective approaches for PSD treatment.

Pharmacogenetics of toxicity of 5-fluorouracil, doxorubicin and cyclophosphamide chemotherapy in breast cancer patients

The differences in patients' response to the same medication, toxicity included, are one of the major problems in breast cancer treatment. Chemotherapy toxicity makes a significant clinical problem due to decreased quality of life, prolongation of treatment and reinforcement of negative emotions associated with therapy. In this study we evaluated the genetic and clinical risk factors of FAC chemotherapy-related toxicities in the group of 324 breast cancer patients. Selected genes and their polymorphisms were involved in FAC drugs transport (ABCB1, ABCC2, ABCG2,SLC22A16), metabolism (ALDH3A1, CBR1, CYP1B1, CYP2C19, DPYD, GSTM1, GSTP1, GSTT1, MTHFR,TYMS), DNA damage recognition, repair and cell cycle control (ATM, ERCC1, ERCC2, TP53, XRCC1). The multifactorial risk models that combine genetic risk modifiers and clinical characteristics were constructed for 12 toxic symptoms. The majority of toxicities was dependent on the modifications in components of more than one pathway of FAC drugs, while the impact level of clinical factors was comparable to the genetic ones. For the carriers of multiple high risk factors the chance of developing given symptom was significantly elevated which proved the factor-dosage effect. We found the strongest associations between concurrent presence of clinical factors - overall and recurrent anemia, nephrotoxicity and early nausea and genetic polymorphisms in genes responsible for DNA repair, drugs metabolism and transport pathways. These results indicate the possibility of selection of the patients with expected high tolerance to FAC treatment and consequently with high chance of chemotherapy completion without the dose reduction, treatment delays and decline in the quality of life.