VEGF gene promoter polymorphisms and risk of VTE in chemotherapy-treated cancer patients

A Clinical-Genetic Risk Score for Predicting Cancer-Associated Venous Thromboembolism: A Development and Validation Study Involving Two Independent Prospective Cohorts

PURPOSE

Venous thromboembolism (VTE) is a leading cause of death among patients with cancer. The Khorana score was developed for assessing the risk of VTE in outpatients with cancer receiving chemotherapy, but its accuracy in identifying patients at high risk has been questioned. The aim of this study was to develop and validate a clinical-genetic score that improves the assessment of VTE risk in oncology outpatients within 6 months of diagnosis.

METHODS

The new score was developed using the data of 364 outpatients belonging to the Spanish ONCOTHROMB 12-01 population. In this cohort, clinical data associated with the risk of VTE were collected at the time of diagnosis, including the Khorana score. These patients were also genotyped for the 51 genetic variants known to be associated with VTE. Multivariate logistic regression was performed to determine the weight of each genetic and clinical variable in relation to VTE risk, allowing a clinical-genetic risk score (the ONCOTHROMB score) to be developed. The Khorana and the ONCOTHROMB scores were then compared via the area under the receiver operating characteristic curve (AUC), calibration, and the number of patients needed to treat. The new score was then validated in a study of 263 patients in the Vienna Cancer and Thrombosis Study population.

RESULTS

Nine genetic variants, tumor site, TNM stage, and a body mass index of > 25 kg/m2 were found to be associated with VTE and were used to build the ONCOTHROMB score, which better predicted the overall risk of VTE than did the Khorana score (AUC, 0.781 v 0.580; P < .001). Similar AUC results were recorded in the validation study the Vienna Cancer and Thrombosis Study cohort involving patients with the same type of tumor (AUC for the ONCOTHROMB score v the Khorana score: 0.686 v 0.577; P < .001) and with all type of tumors (AUC for the ONCOTHROMB score v the Khorana score: 0.720 v 0.561; P < .0001).

CONCLUSION

The ONCOTHROMB score for VTE risk in outpatients with cancer, which takes into account both clinical and genetic variables, better identifies patients who might benefit from primary thromboprophylaxis than does the Khorana score.

Vascular endothelial growth factor and the risk of venous thromboembolism: a genetic correlation and two-sample Mendelian randomization study

Background

The relationship between vascular endothelial growth factor (VEGF) and the risk of venous thromboembolism (VTE) has always been one of the concerns in the medical field. However, the causal inferences from published observational studies on this issue may be affected by confounders or reverse causality. We performed a two-sample bidirectional Mendelian randomization (MR) to infer the associations between VEGF and VTE.

Methods

Summary statistics from genome-wide association studies (GWAS) for VEGF and VTE were obtained from published meta-analysis studies and the FinnGen consortium, respectively. Independent genetic variables significantly associated with exposure were selected as instrumental variables. Linkage disequilibrium score regression (LDSC) and five robust MR analytical approaches were conducted to estimate the genetic correlations and causal inference. The MR-Egger intercept, Cochran’s Q, and MR pleiotropy residual sum and outlier (MR-PRESSO) were performed to evaluate the horizontal pleiotropy, heterogeneities, and stability of these genetic variants on outcomes. Notably, replication analyses were performed using different subgroups of VTE.

Results

LDSC failed to identify genetic correlations between VEGF and VTE. Based on 9 SNPs, the circulating VEGF level was positively related to the risk of VTE using inverse variance weighting (IVW) method (odds ratio (OR) = 1.064, 95% confidence interval (CI), 1.009–1.122). Reverse MR analyses showed that genetic liability for VTE was not associated with increased VEGF level (β = -0.021, 95% CI, -0.087-0.045). Pleiotropy-robust methods indicated no bias in any estimates.

Conclusions

Our findings failed to detect coheritability between VEGF and VTE. The suggestive positive effect of the higher VEGF level on the VTE risk may have clinical implications, suggesting that VEGF as a possible predictor and therapeutic target for VTE prevention need to be further warranted.

Impact of hereditary thrombophilia on cancer-associated thrombosis, tumour susceptibility and progression: A review of existing evidence

Venous thromboembolism (VTE) is a cardiovascular disorder frequently diagnosed among cancer patients. Aside from being common, VTE severely deteriorates the prognosis of these patients as they face a higher risk of morbidity and mortality, which makes clinical tools able to identify the patients more prompt to thrombogenesis very attractive. Over the years, several genetic polymorphisms have been linked with VTE susceptibility in the general population. However, their clinical usefulness as predictive biomarkers for cancer-related VTE is yet unclear. Furthermore, as a two-way association between cancer and VTE is well-recognized, with haemostatic components fuelling tumour progression, haemostatic gene polymorphisms constitute potential cancer predictive and/or prognostic biomarkers as well. Thus, in this article, we review the existing evidence on the role of these polymorphisms on cancer-related VTE and their impact on cancer onset and progression. Despite the promising findings, the existing studies had inconsistent results most likely due to their limited statistical power and population heterogeneity. Future studies are therefore required to clarify the role of these polymorphisms in setting of malignancy.

Prognostic Factors for Venous Thromboembolism in Patients with Solid Tumours on Systemic Therapy: A Systematic Review

Background  Patients undergoing systemic cancer therapy are susceptible to developing venous thromboembolism (VTE). The most pertinent prognostic factors for VTE remain unclear. This systematic review aims to summarize prognostic factors associated with VTE in this population.

Methods  MEDLINE, Embase, and CENTRAL databases were searched for observational or randomized studies that used multivariable analysis adjusted for tumor type and/or metastatic disease to model the risk of VTE. Adjusted effect estimates for each prognostic factor were collected for all of the included studies. Risk of bias was assessed using the Quality in Prognostic Factor Studies (QUIPS) tool.

Results  From 5,988 search results, 15 eligible studies and 42 prognostic factors were identified. A total of 8,554 patients of whom 456 (5.33%) developed VTE were included. Fourteen studies had a high risk of bias and one study had a moderate risk. The most commonly reported prognostic factors include age, gender, tumor site, metastasis, performance status, and systemic therapy type. Poor performance status and the use of platinum-based chemotherapy compounds were associated with an increased risk of VTE across the majority of studies. The evidence to suggest that the other prognostic factors identified were associated with VTE development was inconclusive. Several individual studies identified novel biomarkers for VTE. Heterogeneity in statistical methods and prognostic factor definitions across studies precluded meta-analysis.

Conclusion  Overall, many prognostic factors were identified; however, the evidence for association with development of VTE for most of the factors is inconclusive. Findings were limited by high heterogeneity and risk of bias in the included studies.

Prognostic Factors for Venous Thromboembolism in Patients with Solid Tumours on Systemic Therapy: A Systematic Review

Background  Patients undergoing systemic cancer therapy are susceptible to developing venous thromboembolism (VTE). The most pertinent prognostic factors for VTE remain unclear. This systematic review aims to summarize prognostic factors associated with VTE in this population. Methods  MEDLINE, Embase, and CENTRAL databases were searched for observational or randomized studies that used multivariable analysis adjusted for tumor type and/or metastatic disease to model the risk of VTE. Adjusted effect estimates for each prognostic factor were collected for all of the included studies. Risk of bias was assessed using the Quality in Prognostic Factor Studies (QUIPS) tool. Results  From 5,988 search results, 15 eligible studies and 42 prognostic factors were identified. A total of 8,554 patients of whom 456 (5.33%) developed VTE were included. Fourteen studies had a high risk of bias and one study had a moderate risk. The most commonly reported prognostic factors include age, gender, tumor site, metastasis, performance status, and systemic therapy type. Poor performance status and the use of platinum-based chemotherapy compounds were associated with an increased risk of VTE across the majority of studies. The evidence to suggest that the other prognostic factors identified were associated with VTE development was inconclusive. Several individual studies identified novel biomarkers for VTE. Heterogeneity in statistical methods and prognostic factor definitions across studies precluded meta-analysis. Conclusion  Overall, many prognostic factors were identified; however, the evidence for association with development of VTE for most of the factors is inconclusive. Findings were limited by high heterogeneity and risk of bias in the included studies.

Cancer-associated thrombosis: The search for the holy grail continues

Cancer patients have an increased risk of developing venous thromboembolism (VTE), a condition that is associated with increased morbidity and mortality. Although risk assessment tools have been developed, it is still very challenging to predict which cancer patients will suffer from VTE. The scope of this review is to summarize and discuss studies focusing on the link between genetic alterations and risk of cancer-associated thrombosis (CAT). Thus far, classical risk factors that contribute to VTE have been tried as risk factors of CAT, with low success. In support, hypercoagulant plasma profiles in patients with CAT differ from those with only VTE, indicating other risk factors that contribute to VTE in cancer. As germline mutations do not significantly contribute to elevated risk of VTE, somatic mutations in tumors may significantly associate with and contribute to CAT. As it is very time-consuming to investigate each and every mutation, an unbiased approach is warranted. In this light we discuss our own recent unbiased proof-of-principle study using RNA sequencing in isolated colorectal cancer cells. Our work has uncovered candidate genes that associate with VTE in colorectal cancer, and these gene profiles associated with VTE more significantly than classical parameters such as platelet counts, D-dimer, and P-selectin levels. Genes associated with VTE could be linked to pathways being involved in coagulation, inflammation and methionine degradation. We conclude that tumor cell-specific gene expression profiles and/or mutational status has superior potential as predictors of VTE in cancer patients.

Role of VEGFA gene polymorphisms in colorectal cancer patients who treated with bevacizumab

Objectives

This study aimed to explore the effects of vascular endothelial growth factor A (VEGFA) gene polymorphisms (rs699947 and rs833061) on Bevacizumab (BEV) treatment in colorectal cancer (CRC) patients.

Methods

125 CRC cases receiving BEV plus FOLFIRI treatment were recruited in this study. VEGFA polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Correlation of VEGFA gene polymorphisms with the response rate and progression free survival (PFS) was evaluated. Multivariate analyses were performed to estimate the effects of VEGFA polymorphisms on the therapeutic effects of BEV treatment in CRC patients.

Results

Rs699947 variants did not show significant association with BEV treatment. For rs833061 analysis, TT and TC genotype carriers had significantly higher ORR (objective response rate) than CC carriers (P=0.048 and P=0.021, respectively). Moreover, TT carriers underwent a well DCR (disease control rate) compared to CC carriers (P=0.002). PFS time also showed obvious correlation with rs833061 polymorphism (log rank test, P=0.002). Multivariate analyses demonstrated that TT and TC genotypes of rs833061 polymorphism were significantly correlated with enhanced therapeutic effects and prolonged PFS in CRC patients.

Conclusion

VEGFA rs833061 polymorphism is significantly associated with the therapeutic efficiency of bevacizumab in CRC patients.