Pancytopenia and Severe Gastrointestinal Toxicities Associated with 5-Fluorouracil in a Patient with Thymidylate Synthase (TYMS) Polymorphism

Alternative chemoradiotherapy in anal carcinoma patients with mutations in thymidylate synthase and dihydropyrimidine dehydrogenase genes

BACKGROUND

5-fluorouracil (5-FU) and mitomycin-C (MMC) with radiotherapy (RT) remain an established treatment for patients with anal cancer (AC). Genetic mutations in two major metabolizing enzymes for 5-FU; dihydropyrimidine dehydrogenase (DPYD and thymidylate synthetase (TYMS), have been associated with clinical response and toxicity. However, their place in the treatment of AC remains undetermined.

METHODS

We retrospectively reviewed 21 patients with AC, including T2-4, N0-1, M0 or T1-4, N2-3, and M0 treated between 2012 and 2018. All patients were treated with 5-FU 1,000 mg/m²/day via continuous intravenous (IV) infusion 1-4 and 29-32, MMC 10 mg/m² IV bolus days 1 and 29 plus RT. Patients who developed ⩾3 grade toxicities were tested for the DPYD and TYMS genes. Treatment was either modified with reduced doses or changed to MMC 10 mg/m² day 1 and 29 with cisplatin 25 mg/m²/week plus RT. Toxicities and responses were collected.

RESULTS

Six out of 21 patients who developed ⩾3 grade toxicities including pancytopenia, neutropenia, thrombocytopenia, mucositis, nausea, rash, and nephritis were found to have genetic mutations: TYMS 2RG/3RC (n = 2), 3RG/3RC (n = 1), 2R/2R (n = 2), TYMS 3'UTR del/Ins (n = 2), and DPYD c.2864A > T heterozygous (n = 1). Two patients received 5-FU at a 50% reduced dose on days 29-32; one patient refused to receive 5-FU (continued with MMC and RT); one patient received only radiation therapy due to persistent pancytopenia despite the use of growth factors; two patients received an alternative regimen consisting of MMC 10 mg/m² on day 29 with cisplatin (CDDP) 25 mg/m²/week plus RT; and two patients received cisplatin/MMC with RT from the beginning as they were prospectively detected to have TYMS abnormalities prior to dosing the chemotherapy. These patients tolerated treatment very well with only grade 2 toxicities. All the patients (4/4) on cisplatin/MMC achieved clinical complete response (cCR), while four patients (4/15) on 5-FU/MMC reached cCR at the first assessment. Radiological response showed complete response at the end of 24 weeks assessment.

CONCLUSIONS

Molecular testing for DPYD and TYMS genes can allow us to identify patients who are most likely to respond or face severe toxicity to 5-FU in a potentially curable cancer. Combining radiation with CDDP with MMC in patients with AC is feasible. A prospective study based on pharmacogenetic testing comparing MMC/cisplatin with MMC/5-FU is indicated in patients with AC.

Association of expression and genotypes of thymidylate synthase in non-small cell lung cancer patients with different clinicopathological characteristics

Objective

To explore the expression and genotypes of thymidylate synthase (TS) in patients of non-small cell lung cancer (NSCLC) with different clinicopathological characteristics.

Methods

The expression profiles of TS were examined by immunohistochemical staining and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) in 160 patients with NSCLC. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect TS-5′UTR tandem repeats, G/C nucleotide polymorphisms, and 3′UTR 6 bp deletion/insertion polymorphisms. The relationships between clinicopathological characteristics and TS expression or genotypes were investigated through χ 2 test. Kaplan–Meier survival analysis was used to analyze the association between TS expression and overall survival (OS) and disease-free survival (DFS) of NSCLC patients.

Results

The expression levels of TS protein and TS gene in NSCLC tissues were significantly higher than that in paracancerous tissues (P < 0.05). Furthermore, high expression of TS protein and 5′UTR polymorphism of TS gene showed significant correlation with differentiation, TNM stage, and lymph node metastases. The frequency of −6 bp/−6 bp genotypes in patients with NSCLC was 43.13% (69/160), which was higher than others. In addition, the rate of TS protein overexpression in NSCLC patients with 3R/3R was 79.79%, which was higher than others. Interestingly, high expression of TS protein predicted shorter DFS and OS and lower 3-year DFS rate and 3-year OS rate.

Conclusions

The expression levels of TS in NSCLC were significantly increased and may help to predict the prognosis of NSCLC, and high expression of TS protein and 5′UTR polymorphism of TS gene were significantly related to differentiation, TNM stage, and lymph node metastases.

Pharmacogenomic Markers of Methotrexate Response in the Consolidation Phase of Pediatric Acute Lymphoblastic Leukemia Treatment

Methotrexate (MTX) is one of the staples of pediatric acute lymphoblastic leukemia (ALL) treatment. MTX targets the folate metabolic pathway (FMP). Abnormal function of the enzymes in FMP, due to genetic aberrations, leads to adverse drug reactions. The aim of this study was to investigate variants in pharmacogenes involved in FMP and their association with MTX pharmacokinetics (MTX elimination profile) and toxicity in the consolidation therapy phase of pediatric ALL patients. Eleven variants in the thymidylate synthetase (TYMS), methylenetetrahydrofolate reductase (MTHFR), dihydrofolate reductase (DHFR), SLC19A1 and SLCO1B genes were analyzed in 148 patients, using PCR- and sequencing-based methodology. For the Serbian and European control groups, data on allele frequency distribution were extracted from in-house and public databases. Our results show that the A allele of SLC19A1 c.80 variant contributes to slow MTX elimination. Additionally, the AA genotype of the same variant is a predictor of MTX-related hepatotoxicity. Patients homozygous for TYMS 6bp deletion were more likely to experience gastrointestinal toxicity. No allele frequency dissimilarity was found for the analyzed variants between Serbian and European populations. Statistical modelling did not show a joint effect of analyzed variants. Our results indicate that SLC19A1 c.80 variant and TYMS 6bp deletion are the most promising pharmacogenomic markers of MTX response in pediatric ALL patients.

Expression of ERCC1 and TYMS in colorectal cancer patients and the predictive value of chemotherapy efficacy

The present study investigated the expression of excision repair cross-complementing gene 1 (ERCC1) and thymidylate synthase (TYMS) in patients with colorectal cancer and the predictive value of chemotherapy. Eighty patients with colorectal cancer chemotherapy admitted to Binzhou Medical University Hospital from June 2013 to June 2015 were randomly selected, and 80 cancer tissues and 68 adjacent tissues were taken for analysis. RT-qPCR was used to detect ERCC1 as well as the expression level of TYMS. The relationship of the expression level with the chemotherapy efficacy, clinical pathology and survival time in colorectal cancer patients receiving standard chemotherapy, was compared. The expression of ERCC1 and TYMS mRNA in cancer tissues was significantly higher than that in the adjacent tissues (P<0.05). There was no correlation between ERCC1 mRNA expression, TYMS mRNA and clinicopathological features of colorectal cancer (P>0.05). The predictive effect of ERCC1 on colorectal cancer chemotherapy was 0.919 (95% CI, 0.862–0.976), P<0.001. The AUC of TYMS for predicting the efficacy of chemotherapy on colon cancer was 0.831 (95% CI, 0.735–0.926), and both had higher predictive values. The expression levels of ERCC1 and TYMS mRNA in 80 patients with colorectal cancer were divided into the low and high expression groups. The 3-year survival rate of patients in the low expression group was significantly higher than that in the high expression group, and the difference between the two groups was statistically significant (P<0.05). ERCC1 and TYMS had a high predictive value for the efficacy of chemotherapy in patients with colorectal cancer, and patients with lower expression of ERCC1 and TYMS had improved 3-year survival rates than patients with higher expression. Therefore, for patients with colorectal cancer, ERCC1 and TYMS can be used as predictors of the efficacy of chemotherapy.

Uridine triacetate for severe 5-fluorouracil toxicity in a patient with thymidylate synthase gene variation: Potential pharmacogenomic implications

Adverse drug reactions can be unpredictable. However, pharmacogenomic testing can help identify patients who may be more susceptible to the toxic effects of certain drugs. Genetic variations in the dihydropyrimidine dehydrogenase and thymidylate synthase genes have been shown to increase the risk of 5-fluorouracil toxicity. 5-Fluorouracil toxicity can be life threatening. Fortunately, there is treatment available for 5-fluorouracil toxicity, called uridine triacetate. Although, the indications for its use limit its administration to within 96 h of receiving 5-fluorouracil, we report a case of effective therapy in a patient started on uridine triacetate beyond the recommended 96 h, who was found to carry a thymidylate synthase gene variation but no dihydropyrimidine dehydrogenase mutations. This provides important implications for pharmacogenomic testing.

Thymidylate synthase predicts poor response to pemetrexed chemotherapy in patients with advanced breast cancer

Pemetrexed is a candidate chemotherapy regimen for anthracycline- and taxane-pretreated advanced breast cancer. However, to the best of our knowledge, no efficient treatment efficacy biomarkers have been identified. In the present study, the potential correlation between thymidylate synthase (TYMS) expression and clinical response to pemetrexed was examined in advanced breast cancer. A retrospective collection was performed by using 77 advanced breast cancer subjects, who received at least three cycles of pemetrexed treatment in the Second Hospital of Shandong University hospital. TYMS expression was detected using immunohistopathological staining. The correlations between TYMS and therapeutic efficacies of different chemotherapy treatment were analyzed. The objective response rate (ORR) and disease control was 31.17 and 64.94%, respectively. Immunohistochemical staining demonstrated that TYMS expression was observed in the cytoplasm and nuclei of breast cancer cells. High TYMS expression was observed in 32 specimens. Elevated TYMS expression was correlated with higher histological grade and lymph node metastasis (P<0.05). Furthermore, significantly higher TYMS expression was observed in treatment-resistant patients than response ones (P<0.05). Patients with low expression level of TYMS exhibit significantly higher ORR. Cox regression analysis indicated that elevated TYMS expression was a detrimental factor for pemetrexed treatment for advanced breast cancer patients. The present results suggested that TYMS expression levels predicts therapeutic sensitivity of pemetrexed chemotherapy in advanced breast cancer, indicating that it may be a useful biomarker to choose chemotherapy regimens.

Network Pharmacology-Based Approach to Investigate the Mechanisms of Hedyotis diffusa Willd. in the Treatment of Gastric Cancer

BACKGROUND

Hedyotis diffusa Willd. (HDW) is one of the renowned herbs often used in the treatment of gastric cancer (GC). However, its curative mechanism has not been fully elucidated.

OBJECTIVE

To systematically investigate the mechanisms of HDW in GC.

METHODS

A network pharmacology approach mainly comprising target prediction, network construction, and module analysis was adopted in this study.

RESULTS

A total of 353 targets of the 32 bioactive compounds in HDW were obtained. The network analysis showed that CA isoenzymes, p53, PIK3CA, CDK2, P27Kip1, cyclin D1, cyclin B1, cyclin A2, AKT1, BCL2, MAPK1, and VEGFA were identified as key targets of HDW in the treatment of GC. The functional enrichment analysis indicated that HDW probably produced the therapeutic effects against GC by synergistically regulating many biological pathways, such as nucleotide excision repair, apoptosis, cell cycle, PI3K/AKT/mTOR signaling pathway, VEGF signaling pathway, and Ras signaling pathway.

CONCLUSIONS

This study holistically illuminates the fact that the pharmacological mechanisms of HDW in GC might be strongly associated with its synergic modulation of apoptosis, cell cycle, differentiation, proliferation, migration, invasion, and angiogenesis.

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.

Pharmacogenomics DNA Biomarkers in Colorectal Cancer: Current Update

Colorectal cancer (CRC) remains as one of the most common cause of worldwide cancer morbidity and mortality. Improvements in surgical modalities and adjuvant chemotherapy have increased the cure rates in early stage disease, but a significant portion of the patients will develop recurrence or advanced disease. The efficacy of chemotherapy of recurrence and advanced CRC has improved significantly over the last decade. Previously, the historical drug 5-fluorouracil was used as single chemotherapeutic agent. Now with the addition of other drugs such as capecitabine, irinotecan, oxaliplatin, bevacizumab, cetuximab, panitumumab, vemurafenib, and dabrafenib, the median survival of patients with advanced CRC has significantly improved from less than a year to the current standard of almost 2 years. However, the side effects of systemic therapy such as toxicity may cause fatal complications and have a major consequences on the patients' quality of life. Hence, there is an urgent need for key biomarkers which will enable the selection of optimal drug singly or in combination for an individual patient. The application of personalized therapy based on DNA testing could aid the clinicians in providing the most effective chemotherapy agents and dose modifications for each patient. Yet, some of the current findings are controversial and the evidences are conflicting. This review aims at summarizing the current state of knowledge about germline pharmacogenomics DNA variants that are currently used to guide therapeutic decisions and variants that have the potential to be clinically useful in the future. In addition, current updates on germline variants conferring treatment sensitivity, drug resistance to existing chemotherapy agents and variants affecting prognosis and survival will also be emphasized. Different alteration in the same gene might confer resistance or enhanced sensitivity; and while most of other published reviews generally stated only the gene name and codon location, we will specifically discuss the exact variants to offer more accurate information in this mini review.

Comparative efficacy and safety of Chinese herbal injections combined with the FOLFOX regimen for treating gastric cancer in China: a network meta-analysis

Background

Chinese herbal injections (CHIs) have been proven beneficial to patients with gastric cancer for improving clinical efficacy and relieving adverse reactions (ADRs) of chemotherapy. A network meta-analysis (NMA) was conducted in this study to assess the comparative efficacy and safety of CHIs combined with FOLFOX regimen for treating gastric cancer.

Results

A total of 2316 records were searched, and 81 eligible RCTs involving 15 types of CHIs and 5978 patients were included in the NMA. The results showed that patients who received Shengqifuzheng+ FOLFOX, Compound kushen+ FOLFOX, Huachansu+ FOLFOX, Astragalus+ FOLFOX, Kangai+ FOLFOX, and Lentinan injection + FOLFOX could significantly improve clinical efficacy than using FOLFOX single, and their odds ratios (OR) and 95% confidence intervals (CI)s were 1.57 (1.19,2.09), 2.12 (1.62,2.78),1.72 (1.08,2.80), 3.06 (1.01,8.99), 2.01 (1.52,2.70), and 1.99 (1.20,3.38) respectively. Furthermore, the therapy of Aidi+ FOLFOX, Shenqifuzheng+ FOLFOX, Compound Kushen+ FOLFOX, Huachansu+ FOLFOX, Astragalus polysaccharides+ FOLFOX, Kangai+ FOLFOX, Ginseng polysaccharide+ FOLFOX, Lentinan+ FOLFOX, Xiaoaiping+ FOLFOX, and Shenmai injection + FOLFOX could also achieve a higher performance status compared with FOLFOX regimen alone. Similarly, patients who received CHIs combine with FOLFOX regimen were associated with a significantly decrease the incidence of leucopenia, gastrointestinal reaction and hepatic dysfunction. Cluster analysis demonstrated that Astragalus polysaccharides+ FOLFOX, and Kangai+ FOLFOX seemed optimal therapies in improving clinical efficacy and performance status; Astragalus polysaccharides+ FOLFOX was superior in reducing leucopenia and gastrointestinal reaction; Disodium Cantharidinate and Vitamin B6+ FOLFOX was associated with favorable effects in reducing gastrointestinal reaction and hepatic dysfunction. By contrary, receiving FOLFOX regimen single was proved to rank the worst for these outcomes.

Materials and Methods

A comprehensive literature search was performed in several electronic databases to identify randomized controlled trial (RCTs) regarding CHIs for gastric cancer until January 10, 2017. The quality assessment was accomplished according to the Cochrane risk of bias tool and the methodological section of the CONSORT statement. And a random-effects model NMA was utilized to compare different CHIs combined with FOLFOX regimen with regard to efficacy and safety. Data were analyzed using STATA 12.0 and Win-BUGS 1.4 software.

Conclusions

The results of this NMA suggested that among 15 types of CHIs, Astragalus polysaccharides injection combined with FOLFOX regimen seemed optimal for patients with gastric cancer in improving clinical efficacy and performance status, and relieving ADRs. However, our findings should be confirmed by more prospectively designed, large-sample and multi-center RCTs.