Jana Halámková

Do polymorphisms and haplotypes of mismatch repair genes modulate risk of sporadic colorectal cancer

The Czech Republic presents one of the highest incidences of colorectal cancer in the world. We genotyped 10 single nucleotide polymorphisms in five DNA mismatch repair genes in 614 colorectal cancer cases and 614 matched controls from this country. The carriers of T-allele of the hMSH6-556G>T polymorphism were at increased risk of colorectal cancer (OR 1.29; 95% CI 1.02-1.62). The stratification of data showed that risk associated with the polymorphism was confined to rectal cancer (OR 1.42; 95% CI 1.03-1.95). The A-allele of the Ex1-145G>A polymorphism in the hMSH6 gene was associated with a decreased risk of colorectal cancer (OR 0.76; 95% CI 0.60-0.98). The C-allele of the IVS4-101G>C polymorphism in hMSH6 was associated with an increased risk of colon cancer (OR 1.34; 95% CI 1.03-1.74). The carriers of the variant allele for the polymorphism IVS9-1406C>T in hMLH1 exhibited a decreased risk of rectal cancer (OR 0.71; 95% CI 0.51-0.98). We observed a differential distribution of haplotypes based on three hMSH6 polymorphisms (-556G>T-Ex1-145G>A-IVS4-101G>C) in the cases and controls (global P=0.02). The TAG haplotype was associated with a decreased risk of colorectal cancer (OR 0.74; 95% CI 0.59-0.92), whereas the most frequent haplotype GGG was associated with increased risk of rectal cancer (OR 1.32; 95% CI 1.05-1.65). However, multiple hypotheses testing diminishes a statistical significance of above associations. Our data suggest a limited role for the investigated individual variants in mismatch repair genes for the susceptibility to the disease. The haplotypes covering hMSH6 gene may, however, be involved in risk modulation in this population.

Clinical relevance of uPA, uPAR, PAI 1 and PAI 2 tissue expression and plasma PAI 1 level in colorectal carcinoma patients.

BACKGROUND/AIMS Urokinase (uPA) is a serine protease, which together with uPAR, tPA, PAI 1 and PAI 2 forms the plasminogen activator system, a component of metastatic cascade contributing to the invasive growth and angiogenesis of malignant tumours. METHODOLOGY Both preceding therapy and after 6-8 weeks of the treatment, plasma PAI 1 levels (photometric microplate method on the ELISA) and uPA, uPAR, PAI 1 and PAI 2 tissue expression (immunohistochemical reaction) were analysed from 80 colorectal carcinoma patients. RESULTS Analysis showed higher pre-treatment plasma levels of PAI 1 in patients with advanced tumours, which decreased after surgery or the start of therapy (p=0.004); Patients with higher plasma level PAI 1 before (0.013) and after therapy (0.004) had significantly shorter survival. There was a higher expression of uPA (p<0.001), uPAR (p<0.001), PAI 1 (p=0.042) and PAI 2 (p<0.001) in advanced colorectal carcinoma. A relationship between PAI 2 (p=0.010) and uPAR (p=0.019) expression and survival was demonstrated. There is a correlation between pre-treatment plasma PAI 1 levels and PAI 2 (p=0.028) and uPAR (p=0.043) expression. CONCLUSIONS Immunohistochemical analysis of PAS in tumour tissue and plasma PAI 1 levels was found to be a useful prognostic factor in colorectal carcinoma patients. Plasma PAI 1 could be advantageous in evaluating the effectiveness of a mode of treatment.

MiR-215-5p is a tumor suppressor in colorectal cancer targeting EGFR ligand epiregulin and its transcriptional inducer HOXB9

Growing evidence suggests that microRNAs are involved in the development and progression of colorectal cancer (CRC). In the present study, deregulation and functioning of tumor-suppressive miR-215-5p was evaluated in CRC. In total, 448 tumor tissues and 325 paired adjacent healthy tissues collected from Czech and Spain cohorts of CRC patients have been used for miR-215-5p expression analyses. A series of in vitro experiments have been performed using transient transfection of miR-215-5p mimics into four CRC cell lines to identify specific cellular processes affected by miR-215-5p. Further, the effects of miR-215-5p on tumor growth were evaluated in vivo using NSG mice and stable cell line overexpressing miR-215-5p. Target mRNAs of miR-215-5p were tested using luciferase assay and western blot analyses. We found that miR-215-5p is significantly downregulated in tumor tissues compared with non-tumor adjacent tissues and its decreased levels correlate with the presence of lymph node metastases, tumor stage, and shorter overall survival in CRC patients. Overexpression of miR-215-5p significantly reduced proliferation, clonogenicity, and migration of CRC cells, lead to cell cycle arrest in G2/M phase and p53-dependent induction of apoptosis. The ability of miR-215-5p to inhibit tumor growth was confirmed in vivo. Finally, we confirmed epiregulin and HOXB9 to be the direct targets of miR-215-5p. As epiregulin is EGFR ligand and HOXB9 is its transcriptional inducer, we suggest that the main molecular link between miR-215-5p and CRC cells phenotypes presents the EGFR signaling pathway, which is one of the canonical pathogenic pathways in CRC.

MicroRNAs as outcome predictors in patients with metastatic colorectal cancer treated with bevacizumab in combination with FOLFOX

Bevacizumab is a humanized anti-vascular endothelial growth factor monoclonal antibody, used in combination with a oxaliplatin-based chemotherapy in the treatment of metastatic colorectal cancer (mCRC). The aim of the present study was to identify microRNA (miRNA)-based predictive biomarkers of therapy response in order to avoid unnecessary and costly therapy to non-responding patients. High-throughput miRNA microarray profiling (Affymetrix miRNA array) was performed on a discovery cohort of patients with mCRC. The discovery cohort was (n=20) divided into either responding (n=10) or non-responding (n=10) groups of bevacizumab/5-flourouracil, leucovorin, oxaliplatin (FOLFOX) treatment according to Response Evaluation Criteria in Solid Tumors criteria. Validation of candidate miRNAs was performed on an independent cohort of 41 patients with mCRC using quantitative reverse transcription polymerase chain reaction. Normalized data were subjected to receiver operating characteristic and Kaplan-Meier analyses. In total, 67 miRNAs were identified to be differentially expressed when miRNA expression was compared between responding and non-responding patients to bevacizumab/FOLFOX treatment (P<0.05). A total of 7 miRNAs were chosen for independent validation, which confirmed significantly higher expression of miR-92b-3p, miR-3156-5p, miR-10a-5p and miR-125a-5p (P<0.005) in tumor tissue of responding patients compared with non-reponding patients. Using the combination of miRNAs, the present study identified responders to the therapy with sensitivity 82% and specificity 64% (area under the curve = 0.8015). In conclusion, 4 predictive miRNAs associated with progression-free survival (PFS) were identified in patients with mCRC treated with bevacizumab/FOLFOX. Following further independent validations, detection of these miRNA may enable identification of patients with mCRC who may potentially benefit from the therapy.

Efficacy of bevacizumab and chemotherapy in the first-line treatment of metastatic colorectal cancer: broadening KRAS-focused clinical view.

BackgroundThe aim of the present retrospective study was to analyze clinical outcome and risk factors associated with treatment outcomes according to KRAS status in patient with metastatic colorectal cancer (mCRC) treated with bevacizumab (bev) plus chemotherapy in the first-line setting.MethodsWe performed observational study on 1622 patients with mCRC treated with bev plus oxaliplatin- or irinotecan-based chemotherapy, and correlated treatment outcomes with KRAS mutation status. The primary endpoint was progression-free survival (PFS) and additionally overall survival (OS). Adverse events of bevacizumab and risk factors including location of metastases were evaluated.ResultsMutation in KRAS was present in 40.6% of mCRC cases. The median PFS in patients with wild-type KRAS (wtKRAS) vs mutant KRAS was 11.5 vs 11.4 months, respectively. The median OS was 30.7 vs 28.4 months (p = 0.312). Patients with KRAS mutation had lung metastases more frequently than wtKRAS individuals (32.0% vs 23.8%; p = 0.001). We observed no difference in clinical outcome between hepatic and extrahepatic metastatic disease.ConclusionKRAS mutation does not interfere with clinical benefit from first-line treatment with bevacizumab plus chemotherapy in mCRC patients.

Current Recommendations for the Prevention and Treatment of Venous Thromboembolism in Cancer Patients

About 20% of patients suffer from venous thromboembolism (VTE) during oncology disease. Active cancer, along with cancer therapy, increases the risk of VTE, especially in the first 6 months after diagnosis. Most often VTE accompanies haematological malignancies and CNS tumours, and gastrointestinal, breast, lung, ovary and uterine cancer. The presence of distant metastases, together with the implantation of a central venous catheter, increases the risk even more. A cancer patient also has a 2-5× higher risk of recurrence of VTE during anticoagulant therapy than patients without a malignancy, as well as a 2-6× higher risk of serious bleeding. Thromboembolic disease is also an independent prognostic factor for death in patients with malignant tumours. Management of VTE is a part of everyday oncological practice, and oncologists should be aware of the basic recommendations regarding individual medical procedures and the clinical situations that may occur in cancer patients. They should also be able to adequately treat VTE when it occurs. It is necessary to consider some specificity during prophylaxis, diagnostics and treatment of venous thromboembolism in cancer care. The International Initiative on Thrombosis and Cancer (ITAC-CME) has created a mobile application based on international guidelines for the prevention and treatment of venous thromboembolism. It is a simple schematic algorithm for making decisions, and it helps in choosing the best therapeutic strategy and supports the judicious and appropriate use of anticoagulants for prophylaxis and treatment of VTE in cancer patients. This text contains a summary of the recommendations applicable in routine clinical practice.Key words: venous thromboembolism - cancer - central venous catheter thrombosis - guidelines This work was supported by Czech Ministry of Health - RVO (MMCI, 00209805). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 1. 8. 2016Accepted: 26. 10. 2016.