Dihydropyrimidine dehydrogenases and cytidine-deaminase gene polymorphisms as outcome predictors in resected gastric cancer patients treated with fluoropyrimidine adjuvant chemotherapy

Tailored therapy in patients treated with fluoropyrimidines: focus on the role of dihydropyrimidine dehydrogenase

Fluoropyrimidines are widely used in the treatment of solid tumors, mainly gastrointestinal, head and neck and breast cancer. Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme for catabolism of 5-FU and it is encoded by DPYD gene. To date, many known polymorphisms cause DPD deficiency and subsequent increase of 5-FU toxicity. In addition, reduced inactivation of 5-FU could lead to increased 5-FU intracellular concentration and augmented efficacy of this drugs. Therefore DPD expression, particularly intratumoral, has been investigated as predictive and prognostic marker in 5-FU treated patients. There also seems to be a tendency to support the correlation between DPD expression and response/survival in patients treated with fluoropyrimidine even if definitive conclusions cannot be drawn considering that some studies are conflicting. Therefore, the debate on intratumoral DPD expression as a potential predictor and prognostic marker in patients treated with fluoropyrimidines is still open. Four DPD-polymorphisms are the most relevant for their frequency in population and clinical relevance. Many studies demonstrate that treating a carrier of one of these polymorphisms with a full dose of fluoropyrimidine can expose patient to a severe, even life-threatening, toxicity. Severe toxicity is reduced if this kind of patients received a dose-adjustment after being genotyped. CPIC (Clinical Pharmacogenetics Implementation Consortium) is an International Consortium creating guidelines for facilitating use of pharmacogenetic tests for patient care and helps clinicians ensuring a safer drug delivery to the patient. Using predictive DPD deficiency tests in patients receiving 5FU-based chemotherapy, in particular for colorectal cancer, has proven to be a cost-effective strategy.

Somatic mutation of DNAH genes implicated higher chemotherapy response rate in gastric adenocarcinoma patients

Background

The dynein axonemal heavy chain (DNAH) family of genes encode the dynein axonemal heavy chain, which is involved in cell motility. Genomic variations of DNAH family members have been frequently reported in diverse kinds of malignant tumors. In this study, we analyzed the genomic database to evaluate the mutation status of DNAH genes in gastric adenocarcinoma and further identified the significance of mutant DNAH genes as effective molecular biomarkers for predicting chemotherapy response in gastric cancer patients.

Methods

We analyzed the clinical and genomic data of gastric cancer patients published in The Cancer Genome Atlas (TCGA) project. Data on chemotherapy response, overall survival (OS) and chemotherapy-free survival were retrieved. Then, we verified the results via targeted sequencing of gastric cancer patients with similar clinical characteristics but different chemotherapeutic outcomes.

Results

In total, 132 gastric adenocarcinoma patients undergoing chemotherapy treatment from TCGA were included in our study. Somatic mutations in all 13 members of the DNAH family of genes were associated with different chemotherapy responses. Compared with patients with wild-type DNAH genes (n = 59), a significantly higher proportion of those with mutations in DNAH genes (n = 73) (55.9% vs 80.8%) responded to chemotherapy (P = 0.002). Moreover, DNAH mutations were correlated with significantly better OS (P = 0.027), chemotherapy-free survival (P = 0.027), fluoropyrimidine-free survival (P = 0.048) and platinum-free survival (P = 0.014). DNAH mutation status was an independent risk factor for OS (P = 0.015), chemotherapy-free survival (P = 0.015) and platinum-free survival (P = 0.011). We identified somatic mutations in 27 (42.2%) of the 64 stage III gastric adenocarcinoma patients receiving fluoropyrimidine-based chemotherapy by targeted exon sequencing with strict screening conditions. In our own cohort, a significantly higher proportion of patients (n = 32) with DNAH mutations than patients with wild-type DNAH genes (n = 32) had a good prognosis (OS > 48 months) (70.4% vs 35.1%) (P = 0.005).

Conclusions

Dynein axonemal heavy chain gene mutations contribute positively to chemotherapy sensitivity in gastric cancer patients.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1867-6) contains supplementary material, which is available to authorized users.

Early disease relapse in a patient with colorectal cancer who harbors genetic variants of DPYD, TYMS, MTHFR and DHFR after treatment with 5-fluorouracil-based chemotherapy

Background Early relapse in colorectal cancer (CRC) after curative resection is mainly attributed to the key determinants such as tumor histology, stage, lymphovascular invasion, and the response to chemotherapy. Case presentation Interindividual variability in the efficacy of adjuvant chemotherapy between patients receiving the same treatment may be ascribed to the patients' genetic profile. In this report, we highlight a clinical case of a patient with stage II CRC who relapsed within a short period after starting adjuvant chemotherapy and was later found to have multiple genetic polymorphisms in the DPYD, TYMS, MTHFR, and DHFR genes. Conclusions Based on the clinical data of the patient and the key role of these genes in 5-fluorouracil pathway, we hypothesize that these variants may contribute to the drug response and early relapse in CRC.

Operable gastro-oesophageal junctional adenocarcinoma: Where to next?

Oesophageal junctional adenocarcinoma is a challenging and increasingly common disease. Optimisation of pre-operative staging and consolidation of surgery in large volume centres have improved outcomes, however the preferred adjunctive treatment approach remains a matter of debate. This review examines the benefits of neoadjuvant, peri-operative, and post-operative chemotherapy and chemoradiotherapy in this setting in an attempt to reach an evidence based conclusion. Recent findings relating to the molecular characterisation of oesophagogastric cancer and their impact on therapeutics are explored, in addition to the potential benefits of fluoro-deoxyglucose positron emission tomography (FDG-PET) directed therapy. Finally, efforts to decrease the incidence of junctional adenocarcinoma using early intervention in Barrett’s oesophagus are discussed, including the roles of screening, endoscopic mucosal resection, ablative therapies and chemoprevention.

Gastric cancer pharmacogenetics: progress or old tripe?

Gastric cancer remains the second most frequent cause of cancer-related mortality. While surgery is traditionally the initial treatment for early-stage disease, the addition of chemotherapy has been shown to significantly increase overall survival and progression-free survival in advanced and metastatic stages of disease. However, despite the incorporation of newer chemotherapies and regimens into gastric cancer clinical trials, the response rate and median overall survival for treated patients has not significantly improved throughout the years; therefore, newer therapeutic approaches to improve upon the medication selection process are warranted. Treatment and dose selection based on patient factors, such as genetic variation, may provide a more rational and potentially more powerful means of personalizing chemotherapy. This review provides an update on the current status of pharmacogenetic studies regarding germline DNA mutations that may alter response to chemotherapeutic agents used to treat gastric cancer, including perspectives on clinical translation and future work.

Paclitaxel and cetuximab combination efficiency after the failure of a platinum-based chemotherapy in recurrent/metastatic head and neck squamous cell carcinoma

The addition of cetuximab (CTX) to the combination of cisplatin and 5-fluorouracil increases the overall survival (OS) in recurrent/metastatic head and neck squamous cell carcinoma. Only a few patients are eligible for this treatment because of its toxicity. The combination of CTX and paclitaxel (TXL) could be included in sequential treatment strategies. Patients were treated with CTX (400/250 mg/m) and TXL (60-80 mg/m) weekly until disease progression or unacceptable toxicity. Efficacy and safety outcomes were determined retrospectively. A total of 42 patients were included in this analysis. The overall response rate was 38% [95% confidence interval (CI); 23-53%]. The disease control rate with TXL and CTX combination was 74%. Seven (17%) patients progressed before the first evaluation. The median progression-free survival was 3.9 months [95% CI; 3.1-4.7 months] and the median OS was 7.6 months [95% CI; 5.3-9.9 months]. Neurotoxicity and skin rash were the most frequent grade≥2 toxicities, reported in 17 and 12% of patients, respectively. Previous chemotherapy seems to be associated with a lower response rate and progression-free survival but not with the OS. The combination of CTX and TXL was an active and well-tolerated treatment in this series of patients with a poor prognosis and who were mostly symptomatic.

The influence of gemcitabine pathway polymorphisms on treatment outcome in patients with malignant mesothelioma

OBJECTIVE

Identification of biomarkers that could predict gemcitabine efficacy and toxicity is a key issue in the development of individualized therapy. The aim of our study was to evaluate the influence of gemcitabine pathway polymorphisms on treatment outcome in patients with malignant mesothelioma (MM).

METHODS

In total, 107 patients with MM, treated with gemcitabine-platinum chemotherapy, were genotyped for 11 polymorphisms in deoxycytidine kinase, ribonucleotide reductase M1 (RRM1), and cytidine deaminase genes using KASPar assays. Binary logistic regression was used to evaluate the influence of selected polymorphisms on tumor response and occurrence of treatment-related toxicity, while their influence on survival was estimated by Cox proportional hazards model. A haplotype analysis was carried out to assess the combined effect of RRM1 polymorphisms.

RESULTS

Deoxycytidine kinase and cytidine deaminase polymorphisms did not influence treatment outcome in patients with MM. In multivariable analysis, RRM1 2927A>C polymorphism significantly decreased overall survival probability [hazard ratio (HR)=2.02; 95% confidence interval (CI)=1.11-3.65; P=0.021]. Two promoter polymorphisms, RRM1 -524T>C and -37C>A, decreased the odds of nausea/vomiting grade≥2 occurrence [odds ratio (OR)=0.25; 95% CI=0.10-0.60; P=0.002 and OR=0.26; 95% CI=0.11-0.63; P=0.003, respectively]. RRM1 TTCCA haplotype was associated with worse tumor response (OR=16.67; 95% CI=2.38-100.00; P=0.004) and worse overall survival (HR=2.97; 95% CI=1.46-6.06; P=0.003) compared with the most frequent TTCAA haplotype, while TCACA haplotype influenced nausea/vomiting grade≥2 occurrence (OR=0.27; 95% CI=0.12-0.60; P=0.001).

CONCLUSION

RRM1 polymorphisms as well as haplotypes showed an association with gemcitabine treatment efficacy and toxicity; therefore, they should be validated as potential markers for the prediction of clinical outcome in patients with MM.

5-Fluorouracil pharmacogenomics: still rocking after all these years?

The 5-fluorouracil (5-FU) metabolic pathway is mainly dependent on the activity of several intracellular enzymes. Among them, four in particular; thymidylate synthase, methylenetetrahydrofolate reductase, dihydropyrimidine dehydrogenase and thymidine phosphorylase are considered the key points in determining sensitivity or resistance to this drug. These enzymes are needed to metabolize the drug in its active form (thymidylate phosphorylase) or to drop the concentration of the active drug in the cell (dihydropyrimidine dehydrogenase) or both (thymidylate synthase and methylenetetrahydrofolate reductase). Several different studies have tried to investigate the relationship between the presence of mutations in these enzymes and a reduced/improved activity of treatment based on 5-FU or its derivatives. In this article, we will focus on the often contradictory results of these studies.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Toward molecularly selected chemotherapy for advanced gastric cancer: state of the art and future perspectives

In the last few years therapeutic options for gastric cancer patients have slowly, but constantly expanded following the introduction of both new chemotherapy agents and innovative indications for treatment. Along with the medical therapy also our knowledge of the molecular mechanisms underlying this disease has progressively improved. However although the available treatment options have undoubtedly increased no clear definitive indications can be made for a standard chemotherapy regimen and we are still unable to accurately select the appropriate treatment for the appropriate patient. Many molecular determinants of response/toxicity to chemotherapy agents have been identified, but only few of them seem to possess the necessary potential for a subsequent application in the clinical practice. Some of these factors have also been indicated as a therapeutic target for a novel class of anti-cancer compounds. This systematic review will analyse available data about these factors with the aim to constitute a starting point for future research.