Mechanisms of resistance to anti-epidermal growth factor receptor inhibitors in metastatic colorectal cancer

The prognosis of patients with metastatic colorectal cancer (mCRC) remain poor despite the impressive improvement of treatments observed over the last 20 years that led to an increase in median overall survival from 6 mo, with the only best supportive care, to approximately 30 mo with the introduction of active chemotherapy drugs and targeted agents. The monoclonal antibodies (moAbs) cetuximab and panitumumab, directed against the epidermal growth factor receptor (EGFR), undoubtedly represent a major step forward in the treatment of mCRC, given the relevant efficacy in terms of progression-free survival, overall survival, response rate, and quality of life observed in several phase III clinical trials among different lines of treatment. However, the anti-EGFR moAbs were shown only to be effective in a subset of patients. For instance, KRAS and NRAS mutations have been identified as biomarkers of resistance to these drugs, improving the selection of patients who might derive a benefit from these treatments. Nevertheless, several other alterations might affect the response to these drugs, and unfortunately, even the responders eventually become resistant by developing secondary (or acquired) resistance in approximately 13-18 mo. Several studies highlighted that the landscape of responsible alterations of both primary and acquired resistance to anti-EGFR drugs biochemically converge into MEK-ERK and PIK3CA-AKT pathways. In this review, we describe the currently known mechanisms of primary and acquired resistance to anti-EGFR moAbs together with the various strategies evaluated to prevent, overcame or revert them.

Cardiorespiratory fitness measured with cardiopulmonary exercise testing and mortality in patients with cardiovascular disease:A systematic review and meta-analysis

Background Cardiorespiratory fitness(CRF)is inversely associated with mortality in apparently healthy subjects and in some clinical populations,but evidence for the association between CRF and all-cause and/or cardiovascular disease(CVD)mortality in patients with established CVD is lacking.This study aimed to quantify this association.Methods We searched for prospective cohort studies that measured CRF with cardiopulmonary exercise testing in patients with CVD and that examined all-cause and CVD mortality with at least 6 months of follow-up.Pooled hazard ratios(HRs)were calculated using random-effect inverse-variance analyses.Results Data were obtained from 21 studies and included 159,352 patients diagnosed with CVD(38.1%female).Pooled HRs for all-cause and CVD mortality comparing the highest vs.lowest category of CRF were 0.42(95%confidence interval(95%CI):0.28–0.61)and 0.27(95%CI:0.16–0.48),respectively.Pooled HRs per 1 metabolic equivalent(1-MET)increment were significant for all-cause mortality(HR=0.81;95%CI:0.74–0.88)but not for CVD mortality(HR=0.75;95%CI:0.48–1.18).Coronary artery disease patients with high CRF had a lower risk of all-cause mortality(HR=0.32;95%CI:0.26–0.41)than did their unfit counterparts.Each 1-MET increase was associated with lower all-cause mortality risk among coronary artery disease patients(HR=0.83;95%CI:0.76–0.91)but not lower among those with heart failure(HR=0.69;95%CI:0.36–1.32).Conclusion A better CRF was associated with lower risk of all-cause mortality and CVD.This study supports the use of CRF as a powerful predictor of mortality in this population.

miR-99a-5p modulates doxorubicin resistance via the COX-2/ABCG2 axis in triple-negative breast cancer: from the discovery to in vivo studies

Dear Editor,Breast cancer(BC)is the most commonly diagnosed cancer and the fifth cause of cancer-related death worldwide[1].Despite the advances in BC targeted therapies,cytotoxic chemotherapy is still widely used[2].However,around 20%-30%of BC patients develop metastasis after treatment as a consequence of drug resistance[3].In this context,microRNAs have emerged as potential therapeutic targets to overcome therapy resistance[4].Therefore,we aimed to elucidate the molecular mechanisms underlying resistance to doxorubicin,one of the most effective chemotherapeutic agents used in BC.Methods are detailed in Supplementary Materials.

Maintenance with single agent bevacizumab fails to improve disease-control in metastatic colorectal cancer

The availability of biologicals,such as anti-EFGR and anti-VEGF antibodies in combination with chemotherapy(ChT),has improved prognosis of metastatic colorectal cancer(mCRC).However,the administration of drug combinations for a prolonged time implies an increased rate of toxicities,which is why some strategies to de-escalate treatment intensity have been studied.