Evaluation of antibody-dependent cell-mediatedcy totoxicity activity and cetuximab response in KRAS wildtype metastatic colorectal cancer patients

AIM:To investigate the prognostic role of invariant natural killer T(iNKT) cells and antibody-dependent cell-mediated cytotoxicity(ADCC) in wild type KRAS metastatic colorectal cancer(mC RC) patients treated with cetuximab.METHODS: Forty-one KRAS wt mC RC patients,treated with cetuximab and irinotecan-based chemotherapy in Ⅱ and Ⅲ lines were analyzed. Genotyping of single nucleotide polymorphism(SNP)s in the FCGR2A,FCGR3A and in the 3' untranslated regions of KRAS and mutational analysis for KRAS,BRAF and NRAS genes was determined either by sequencing or allelic discrimination assays. Enriched NK cells were obtained from lymphoprepperipheral blood mononuclear cell and iN KT cells were defined by co-expression of CD3,TCRVα24,TCRVβ11. ADCC was evaluated as ex vivo NK-dependent activity,measuring lactate dehydrogenase release.RESULTS: At basal,mCRC patients performing ADCC activity above the median level(71%) showed an improved overall survival(OS) compared to patients with ADCC below(median 16 vs 8 mo;P=0.026). We did not find any significant correlation of iN KT cells with OS(P=0.19),albeit we observed a trend to a longer survival after 10 mo in patients with iN KT above median basal level(0.382 cells/microliter). Correlation of OS and progression-free survival(PFS) with interesting SNPs involved in ADCC ability revealed not to be significant. Patients carrying alleles both with A in FCGR2 A and TT in FCGR3A presented a trend of longer PFS(median 9 vs 5 mo;P=0.064). Chemotherapy impacted both iN KT cells and ADCC activity. Their prognostic values get lost when we analysed them after 2 and 4 mo of treatment.CONCLUSION: Our results suggest a link between iN KT cells,basal ADCC activity,genotypes in FCGR2A and FCGR3A,and efficacy of cetuximab in KRAS wt mC RC patients.

Prognostic and predictive biomarkers in metastatic colorectal cancer anti-EGFR therapy

AIM: To reviewing genetic and epigenetic make-up of metastatic colorectal cancers(m CRCs) addicted to epidermal growth factor receptor(EGFR) signalling.METHODS: The present study summarizes the potential value of prognostic and predictive biomarkers in selecting m CRC patients treated with anti-EGFR therapy. A meta-analysis was performed using a systematic search of Pub Med, Medline and Web of Science to identify eligible papers until March 21 st, 2016 using these following terms: ‘‘colorectal cancer'', "predictive biomarkers' ', "anti-EGFR therapy", "KRAS", "NRAS'', "PIK3CA", "TP53", "PTEN", ‘‘EGFR", "MET", "HER2", "epiregulin", "amphiregulin", "prognostic biomarkers", "BRAF", "miR NA" and "antibody-dependent cell-mediated cytotoxicity(ADCC) activity". Two investigators independently evaluated and extracted data from each identified studies based on selected criteria of inclusion and exclusion. RESULTS: The introduction of agents targeting EGFR such as cetuximab and panitumumab increased overall survival of mC RCs. Nevertheless, it has firstly became evident that response rates to cetuximab regimens in unselected patient populations were typically lower than 30%. Clinical data confirmed the predictive value of RAS mutations for resistance to cetuximab and panitumumab leading to the license of these monoclonal antibodies exclusively for the management of patients with RAS-wild type colorectal cancers. So far the identification of predictive biomarkers have generated interesting, though preliminary and, at times, conflicting data on the importance of tumour mR NA levels of EGFR ligands, of activating mutations in other genes such as NRAS and PIK3 CA. The prognostic value of selected micro RNAs level and ADCC activity is under investigation, while the prognostic impact of BRAF status remains controversial.CONCLUSION: This review focuses on the personalized treatment of m CRC and discusses the potential of new prognostic and predictive biomarkers in selecting patients treated with anti-EGFR therapy.

Circulating cytokines and outcome in metastatic colorectal cancer patients treated with regorafenib

BACKGROUND Regorafenib is an oral small-molecule multikinase inhibitor approved in third or later line of treatment for patients with metastatic colorectal cancer(mCRC).Regorafenib has shown significant benefits in overall survival and progression free survival in two phase III trials compared to placebo in patients with mCRC who had progressed on previous therapy.AIM To identify an immune profile that might specifically correlate with the outcome in patients treated with regorafenib.METHODS Blood samples were collected from 17 patients before treatment with regorafenib and from 6 healthy volunteers.The proteins evaluated(TNF-α,TGF-β,VEGF,CCL-2,CCL-4,and CCL-5)were selected on the basis of their roles in angiogenesis and colorectal cancer pathogenesis.RESULTS We found that TNF-αbasal level was significantly higher in mCRC patients compared to healthy individuals.Non Responder(NR)patients showing progression of disease(n=12)had higher basal level of TGF-β,TNF-α,VEGF,CCL-2 and CCL-5 compared to Responder(R)patients(complete response CR,n=1;partial response PR,n=1;Stable Disease SD,n=3).On the contrary,plasma basal level of CCL-4 was higher in R compared to NR patients.High values of TGF-βand TNF-αnegatively correlated with progression free survival.CONCLUSION These results suggest a cytokine signature potentially able to discriminate between R and NR patients to treatment with regorafenib.

Epigenetics and DNA methylation in cancer

Epigenetic is the study of those alterations regulating gene expression without altering DNA sequence and inherited by transmission through cell division. Mutational and epimutational events that alterate cellular growth and division are combined in carcinogenesis. Advances in genome and epigenome-wide analysis identify DNA hypomethylation,hypermethylation of tumor suppressor genes,aberrant histone modifications and/or specific mi RNA expression profiles to contribute to tumor initiation and progression. The major challenge for cancer researchers is to enlighten the complex relationship between the epigenetic and genetic machinery in order tooptimize combined therapies,reducing chemoresistance and minimizing adverse effects in cancer patients. In this review we will cover many distinct aspects of epigenetic phenomenon. Firstly,we will globally explain the most common epigenetic events and their effects on gene expression regulation. Secondly,we will review the evidence of the correlation between epigenetics and cancer progression,focusing in particular on the effect of aberrant hypo- and hyper-methylation. We will also consider the main methods currently used for methylation analysis,covering both locus-specific technologies and genome-wide analysis. Finally,we will discuss the introduction of novel epigenetic drugs in combination with conventional treatments in order to develop more effective cancer therapies. Such information could help in understanding the important role of epigenetics in cancer.

Methylated PLK2 is a prognostic biomarker in taxane-treated breast cancers

Background:In search of potential biomarkers of drug responsiveness the tumour suppressor PLK2 has been identified as a mediator of taxane sensitivity in some tumour types,based on its role of G2M checkpoint regulation.Objective:The current study set out to evaluate PLK2 methylation in breast cancer treated with neo-adjuvant chemotherapy including a taxane,as a biomarker of disease progression.Methods:Silencing of PLK2 in MCF-7 cells followed by taxane treatment was assessed using apoptotic readout for proof of principle.DNA was extracted from 64 cases of diagnostic surgical FFPE sections.Using pyrosequencing,levels of PLK2 promoter methylation were measured.Results:Silencing of PLK2 resulted in a significantly reduced apoptotic response following paclitaxel treatment(compared with scramble transfected controls).An association with higher levels of CpG island promoter methylation was seen for those cases with a progression-free survival(PFS)of less than 12 months.Kaplan-Meier analysis showed there was an association between overall survival(OS)and level of methylation(p=.06).Conclusions:Thus,based on data obtained from this pilot study,further larger studies evaluating the utility of PLK2 methylation as a potential predictive biomarker in breast cancer are warranted.

RET in breast cancer:pathogenic implications and mechanisms of drug resistance

Initiation,progression,outcome and sensibility to therapies in breast cancer(BC),the most frequent cancer in women,are driven by somatic and germline mutations.Although the effectiveness of hormonal therapies is well-founded,it is prescribed for cancers which express steroid hormone receptors,such as estrogen receptor(ER).RET is a proto-oncogene encoding a transmembrane tyrosine kinase receptor that is activated by one of its four ligands(GDNF,neurturin,artemin or persephin)and one of its coreceptors(Gfrα1-4).Loss-of-function mutations in RET are responsible for Hirschsprung disease,while gain-of-function mutations for multiple endocrine neoplasia type 2.In addition,deregulation of its intracellular signaling,due to mutations,gene rearrangements,overexpression or transcriptional upregulation,can cause several neuroendocrine and epithelial tumors.In BC,amplification of receptor tyrosine kinases,such as ERBB2,EGFR,IGFR and FGFR1,and/or their upregulation contribute to cancer initiation and progression.RET can also have an important role in BC,but only in the subset of ER-positive(ER+)tumors,where it is found overexpressed.Targeting the RET pathway and shedding light on molecular basis of the resistance to hormone therapy may lead to new therapies in ER+BC,improving treatment outcome and preventing tumor-related events.Thus,here,we review the state of the art of RET biology in BC and agents targeting RET tested in the clinical trials and discuss the specificity of the still available RET inhibitors and the molecular mechanisms underlying the BC resistance to endocrine therapy.