Inhibition of the angiotensin II type 2 receptor AT2R is a novel therapeutic strategy for glioblastoma.

Glioblastoma (GBM) is an aggressive malignant primary brain tumor with limited therapeutic options. We show that the angiotensin II (AngII) type 2 receptor (AT2R) is a therapeutic target for GBM and that AngII, endogenously produced in GBM cells, promotes proliferation through AT2R. We repurposed EMA401, an AT2R antagonist originally developed as a peripherally restricted analgesic, for GBM and showed that it inhibits the proliferation of AT2R-expressing GBM spheroids and blocks their invasiveness and angiogenic capacity. The crystal structure of AT2R bound to EMA401 was determined and revealed the receptor to be in an active-like conformation with helix-VIII blocking G-protein or ß-arrestin recruitment. The architecture and interactions of EMA401 in AT2R differ drastically from complexes of AT2R with other relevant compounds. To enhance central nervous system (CNS) penetration of EMA401, we exploited the crystal structure to design an angiopep-2-tethered EMA401 derivative, A3E. A3E exhibited enhanced CNS penetration, leading to reduced tumor volume, inhibition of proliferation, and increased levels of apoptosis in an orthotopic xenograft model of GBM.

Expression and subcellular localization of the bromodomain-containing protein 7 is a prognostic biomarker in breast cancer.

Bromodomain-containing protein 7 (BRD7) is a member of the bromodomain-containing protein family. Previous studies suggest that BRD7 is predominantly localized in the nucleus, wherein it functions as a transcriptional regulator. Several lines of evidence imply a tumour suppressor function for BRD7. However, the importance of BRD7 in the pathogenesis of breast cancer is not well understood. We have investigated the expression, CpG island methylation and subcellular localization of BRD7 in breast cancer cell lines and clinical cases and thereby assessed its prognostic significance by correlating with clinical-pathological features and time-dependent clinical outcomes. We show that nuclear exclusion of BRD7 occurs commonly in breast cancer and is strongly associated with cases expressing wild-type p53. Moreover, clinical outcomes are significantly less favourable in cases with nuclear exclusion or loss of expression than those in which there is nuclear expression of BRD7. Methylation of the CpG island of BRD7 increases in breast cancer relative to normal breast tissue, but there is not an obvious correlation between methylation and reduced expression or between methylation and clinical outcomes. Overall, our results suggest that nuclear exclusion, rather than transcriptional silencing, is a common mechanism by which the tumour suppressor function of wild-type p53 is inhibited in breast cancer, and show that BRD7 is a promising candidate biomarker in breast cancer.

MicroRNAs role as potential biomarkers and key regulators in melanoma.

Malignant melanoma (MM) is a highly aggressive skin cancer with high incidence worldwide. It originates from melanocytes and is characterized by invasion, early metastasis and despite the use of new drugs it is still characterized by high mortality. Since an early diagnosis determines a better prognosis, it is important to explore novel prognostic markers in the management of patients with MM. microRNAs (miRNAs) are small (∼22 nucleotides) single-stranded non-coding RNAs that negatively regulate the expression of more than 60% of human genes.miRNAs alterations are involved in several cancers, including MM, where a differential expression for some of them has been reported between healthy controls and MM patients. Moreover, since miRNAs are stable and easily detectable in body fluids, they might be considered as robust candidate biomarkers useful to identify risk of MM, to diagnose an early lesion and/or an early metastatic disease. This review highlights the importance of miRNAs as risk factors, prognostic factors and their role as molecular regulator in the development and progression of MM. © 2016 Wiley Periodicals, Inc.

Elevated basal antibody-dependent cell-mediated cytotoxicity (ADCC) and high epidermal growth factor receptor (EGFR) expression predict favourable outcome in patients with locally advanced head and neck cancer treated with cetuximab and radiotherapy.

BACKGROUND: Antibody-dependent cell-mediated cytotoxicity (ADCC) may contribute to the antitumor activity of cetuximab. However, the extent of this contribution is unclear. In this study, we investigated the impact of baseline ADCC on the outcome of patients with locally advanced squamous cell carcinoma treated with cetuximab and radiotherapy. METHODS: We determined baseline ADCC in 28 patients treated with cetuximab and radiotherapy and in 15 patients treated with chemoradiation. We linked the values observed with complete response and with overall survival. We also considered the role of epidermal growth factor receptor (EGFR) expression and studied the combined effect of EGFR and ADCC. RESULTS: We observed a wide range of baseline values of ADCC. Complete response did not correlate with either ADCC or EGFR expression. However, when ADCC and EGFR were considered together using a mixed score, they significantly correlated with achieving a complete response (p = 0.04). High baseline ADCC significantly correlated with outcome compared to low (p = 0.03), but not in patients treated without cetuximab. Patients showing high baseline levels of both ADCC and EGFR3+ achieved the best outcome compared to the others (p = 0.02). CONCLUSIONS: In this study, patients treated with cetuximab and radiotherapy, showing high baseline of both ADCC and EGFR3+, have significant higher probability of achieving a complete response and a long overall survival compared to the others.

Schedule-dependent interaction between temsirolimus and cetuximab in head and neck cancer: a preclinical study.

Aberrant epidermal growth factor receptor (EGFR) signaling is associated with tumor growth in head and neck squamous cell carcinoma (HNSCC) and is a major focus of targeted therapy. The phosphatidylinositol-3-kinase/AKT/mammalian target of the rapamycin (PI3K/AKT/mTOR) signaling pathway is frequently mutated in HNSCC and is involved in disease progression and resistance to EGFR inhibitors. The aim of this study was to assess the antiproliferative effects of mTOR inhibition (temsirolimus) combined with the anti-EGFR monoclonal antibody cetuximab, administered according to different combination schedules. Antiproliferative effects of the combination of temsirolimus and cetuximab were determined on the representative HNSCC CAL33 cell line (PI3KCA H1047R mutated and K-RAS wild-type). In addition, key proteins related to the EGFR pathway (pEGFR/EGFR, pAKT/AKT) and the mTOR pathway (p-p70S6K1, p4E-BP1) were determined to explain the cytotoxic effects. Temsirolimus and cetuximab showed a synergistic effect when administered in combination. Supra-additive effect was lost when the two drugs were administered sequentially, irrespective of which drug was administered first. Synergistic effect of the combination was corroborated by a marked downregulation of pEGFR, significant downregulation of pAKT expression, and a marked diminution of p70S6K1 and p4E-BP1 expression. Our study demonstrated a synergistic effect of temsirolimus and cetuximab administered in combination, well illustrated by a simultaneous blockade of intracellular signaling pathways regulating cell proliferation and survival. These results establish the notion of a schedule dependency for the combined treatment, which can be of importance at the clinical level.

The effect of paclitaxel and nab-paclitaxel in combination with anti-angiogenic therapy in breast cancer cell lines.

Taxanes represent a treatment of choice for metastatic breast cancer. Their combination with bevacizumab improved response rate and progression-free survival. We studied in vitro the effect on cell survival of the combination of either paclitaxel or nab-paclitaxel with bevacizumab and we investigated the biological factors involved in the response to treatments. We used two breast cancer cell lines, MCF7 (ER+/HER2-) and MDA-MB-231 (ER-/HER2-), co-cultured with or without HUVEC cells. We analysed cell survival by MTT test, VEGF secretion by ELISA and VEGFR, SPARC, MDR1 expression by western blot. Doses of both taxanes causing a 50 % growth inhibition were higher in MCF7 than MDA-MB-231, suggesting that taxanes are more effective in ER- cell lines. When both cell lines were grown as single culture, the combination bevacizumab+paclitaxel showed a similar anti-proliferative effect compared to paclitaxel alone. The association bevacizumab+nab-paclitaxel was more effective than nab-paclitaxel alone. An increased anti-proliferative effect of bevacizumab+paclitaxel was observed when MDA-MB-231 cells were cultured with HUVEC. We detected an induction of VEGF secretion when MDA-MB-231 cells were treated with either taxanes. Paclitaxel caused a reduction of VEGF in MCF7. SPARC resulted up-regulated in both cell lines treated with bevacizumab+nab-paclitaxel. Nab-paclitaxel seems to play an important role in inhibiting tumor proliferation through albumin-SPARC bound in association with bevacizumab compared to taxanes alone in both breast cancer cells. The addition of bevacizumab to paclitaxel increased its activity only in ER- cells. This difference might be due to their ER status.

Treatment effect of buparlisib, cetuximab and irradiation in wild-type or PI3KCA-mutated head and neck cancer cell lines.

Introduction In complement to anti-EGFR therapy, the targeting of PI3K/AKT/mTOR signaling pathway is of particular interest in the management of Head and Neck Squamous Cell Carcinoma (HNSCC). Here, we assess the effects of PI3K inhibition combined with anti-EGFR monoclonal antibody cetuximab and/or irradiation (RT). Material and methods Anti-proliferative effects of the combination of buparlisib (a specific PI3K inhibitor), cetuximab and RT was determined in two HNSCC cell lines (CAL33, PI3KCA H1047R-mutated and CAL27, PI3KCA wild-type). We examined biochemical factors related to proliferation, apoptosis (caspases), DNA repair (ERCC1, XRCC1) and the PI3K pathway (pEGFR/EGFR, pAKT/AKT, p-p70, p4EBP1). Results The best synergistic combined treatment in inhibiting cell proliferation was sequence 2 (cetuximab followed by buparlisib) in both cell lines. Addition of RT increased sequence 2 anti-proliferative effect only in CAL27. Data on protein expression indicated a possible activation of mTORC2 complex and caspases proteins in CAL27 not seen in CAL33. In CAL33, the synergistic anti-proliferative effect of the two drugs may derive from the higher sensitivity of mutated cells to PI3K targeting. Conclusions Our study demonstrates a synergistic effect of cetuximab followed by buparlisib in both PI3KCA wild-type and mutated cells, even with different intracellular signaling cross-talk depending on mutational status.

Role of IL-8 induced angiogenesis in uveal melanoma.

Introduction Uveal melanoma (UM) is a highly vascularised tumour generally treated with radiotherapy (RT). A recent preclinical study from our group [1] demonstrated that RT-associated anti-angiogenic therapy has more than additive effects on cell growth, by modulating vascular endothelial growth factor (VEGF) levels. The pro-angiogenic interleukin-8 (IL-8) is highly expressed in both tumour and endothelial cells and is associated with resistance to VEGF-targeted therapies in various tumour types. The aim of this study is to investigate IL-8 release in response to the anti-angiogenic drug bevacizumab (AV) and RT given alone and in combination. Material and methods The human ocular melanoma cells (OCM-1) and human umbilical vein endothelial cells (HUVEC) were grown in transwell plates. AV was administered at a 2,500 µg/ml dose and cells were irradiated with a 6 Gy dose. IL-8 concentrations were determined by ELISA assay. Protein expression was detected by western blot. Results AV alone or in combination with RT reduces VEGF levels in both cell lines when co-cultured; unexpectedly, RT alone did not increase VEGF levels. In transwell plate AV alone lowered IL-8 secretion in both cell lines. This inhibitory effect was reduced when co-cultured cells are treated with AV + RT, suggesting that RT-induced VEGF may reactivate IL-8 secretion, enhancing an alternative pathway to sustain tumour angiogenesis. Conclusions These data indicate that the UM microenvironment, beside VEGF, can activate IL-8 signalling as an alternative pro-angiogenic pathway.

Combination of bevacizumab and irradiation on uveal melanoma: an in vitro and in vivo preclinical study.

BACKGROUND: Radiotherapy (RT) is the standard treatment for uveal melanoma. However it can cause damage to the retina and optic nerve. This study examined the in vitro and in vivo effects of the anti-VEGF monoclonal antibody bevacizumab associated with radiotherapy (RT) on tumor growth and tumor proliferation and vasculature on OCM-1 human uveal melanoma cell line. METHODS: The anti-proliferative effects of bevacizumab, RT and their combination were tested both in vitro (OCM-1 cells co-cultured with HUVEC cells in Transwell plates) and in vivo (OCM-1 tumor xenografts in nude mice). In addition, treatment effects in vitro on VEGF secretion, as well as treatment effects in vivo on tumor proliferation (Ki67 labelling), tumor vasculature (VEGFR2 labelling) and VEGF tumoral concentration were analyzed. RESULTS: Bevacizumab given alone had a significant impact on tumor growth in vivo (and moderate effects in vitro). The bevacizumab-RT combination had additive effects in vitro (tumor cell proliferation) and in vivo (tumor growth), which translated into a significant decrease in Ki67 expression, VEGFR2 labelling and VEGF tumoral content. CONCLUSIONS: The bevacizumab-RT combination could be a promising clinical option to explore for the management of human uveal melanoma, since it may allow RT dose reduction without loss of antitumor efficacy.

Differential molecular mechanism of docetaxel-octreotide combined treatment according to the docetaxel-resistance status in PC3 prostate cancer cells.

To examine the effect and the molecular mechanisms of the combined treatment of the somatostatin (SST) analogue octreotide with docetaxel: analysis of proliferation, apoptosis and migration in the human prostate cancer cell line PC3, either sensitive (PC3wt) or made resistant to docetaxel (PC3R). We examined the effect of the two drugs individually or in combination on cell proliferation and migration by analysis of apoptosis and cell cycle proteins. The role of octreotide in modulating P-glycoprotein function was examined together with the modulation of SST receptors type 2 and 5 (SSTR2 and SSTR5). We observed an enhanced effect of docetaxel and octreotide given in combination or in sequence compared with either agent alone; this result was particularly evident when docetaxel was given before octreotide in PC3wt and when the two drugs were given together in PC3R cells. In contrast to lanreotide, our data indicate that octreotide does not act as a P-glycoprotein inhibitor in PC3R cells. A role of docetaxel and combined treatment in regulating SSTR2, SSTR5, proliferation and apoptosis gene expression is suggested as the possible mechanism for the enhanced effect observed. In addition, an evaluation of the effect of the combined treatment on cellular migration was examined, showing a moderate loss of invasive properties in PC3R cells. The present results confirm that SST analogues may be combined with docetaxel to increase the antitumour effect in patients with advanced prostate carcinoma.

The Role of Cytokinome in the HNSCC Tumor Microenvironment: A Narrative Review and Our Experience.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer. In locally advanced (LA) HNSCC, a multidisciplinary approach consisting of surgery followed by chemoradiation (CRT) or definitive CRT is the mainstay of treatment. In recurrent metastatic (R/M), HNSCC immune checkpoint inhibitors (ICIs) with or without chemotherapy represent the new first-line option. However, cancer will recur in about two out of five patients with LA HNSCC. If progression occurs within six months from platin-radiotherapy treatment, anti-programmed cell death-1 (PD-1) may be prescribed. Otherwise, immunotherapy with or without chemotherapy might be considered if PD-L1 is expressed. Despite several improvements in the outcome of patients with R/M HNSCC, overall survival (OS) remains dismal, equaling a median of 14 months. In-depth knowledge of the tumor microenvironment (TME) would be required to change the course of this complex disease. In recent years, many predictive and prognostic biomarkers have been studied in the HNSCC TME, but none of them alone can select the best candidates for response to ICIs or targeted therapy (e.g., Cetuximab). The presence of cytokines indicates an immune response that might occur, among other things, after tumor antigen recognition, viral and bacterial infection, and physic damage. An immune response against HNSCC results in the production of some cytokines that induce a pro-inflammatory response and attract cells, such as neutrophils, macrophages, and T cell effectors, to enhance the innate and adaptive anti-tumor response. We revised the role of a group of cytokines as biomarkers for treatment response in HNSCC.

Circulating Cytokines in Metastatic Breast Cancer Patients Select Different Prognostic Groups and Patients Who Might Benefit from Treatment beyond Progression.

Cancer induces immune suppression to overcome its recognition and eradication by the immune system. Cytokines are messengers able to modulate immune response or suppression. There is great interest in the evaluation of their changes during treatment in order to identify their relationship with clinical outcome. We evaluated 18 cytokines in breast cancer patients treated with eribulin before starting treatment (T0) and after four courses of therapy (T1). Longitudinal modifications were considered and cytokine clusters through PCA and HCPC correlated to patients' outcomes were identified. Forty-one metastatic breast cancer patients and fifteen healthy volunteers were included. After clustering, we identified at T0 six patient clusters with different risk of relapse and death. At T1, only four clusters were identified, and three of them accounted for thirty-eight of forty-one patients, suggesting a possible role of treatment in reducing heterogeneity. The cluster with the best survival at T1 was characterized by low levels of IL-4, IL-6, IL-8, IL-10, CCL-2, CCL-4, and TGF-ß. The cluster showing the worst survival encompassed high levels of IL-4, IL-6, IL-8, IL-10, CCL-2, and IFN-γ. A subgroup of patients with short progression-free survival (PFS) and long overall survival (OS) was comprised in the cluster characterized by low levels of CCL-2, IL-6, IL-8, IL-10, and IL-12 at T0. Our data support the prognostic significance of longitudinal serum cytokine analysis. This approach may help identify patients for whom early treatment stop avoids needless toxicity or might justify treatment beyond early progression. Further investigations are required to validate this hypothesis.

A perspective on diet, epigenetics and complex diseases: where is the field headed next?

Dietary factors can regulate epigenetic processes during life, modulating the intracellular pools of metabolites necessary for epigenetic reactions and regulating the activity of epigenetic enzymes. Their effects are strong during the prenatal life, when epigenetic patterns are written, allowing organogenesis. However, interactions between diet and the epigenome continue throughout life and likely contribute to the onset and progression of various complex diseases. Here, we review the contribution of dietary factors to the epigenetic changes observed in complex diseases and suggest future steps to better address this issue, focusing on neurobehavioral, neuropsychiatric and neurodegenerative disorders, cardiovascular diseases, obesity and Type 2 diabetes, cancer and inflammatory skin diseases.

Loss of reelin expression in breast cancer is epigenetically controlled and associated with poor prognosis.

Reelin is a secreted, signaling protein associated with neuronal cell positioning and migration. Recently, reelin was found to be epigenetically silenced in gastric and pancreatic cancers in which down-regulation was associated with increased migratory ability and reduced survival. Here we analyzed reelin expression by immunohistochemistry in 17 normal breast tissue samples from reduction mammoplasties and in two independent tissue microarrays of 136 and more than 2000 breast cancer biopsy samples, respectively. Results were analyzed with regard to clinical parameters, including BRE (Bloom, Richardson, Elston) grade, nodal status, estrogen receptor and HER2 status, and overall survival. Reelin was expressed in the luminal epithelium and myoepithelium of the normal human breast but not in cancerous breasts. Loss of reelin protein expression correlated significantly with decreased survival (P=0.01) and positive lymph node status (P<0.001). By measuring reelin expression and promoter methylation status in 39 primary breast tumors, as well as in breast cancer-derived cell lines before and after decitabine treatment, we established that reelin expression levels correlated inversely with promoter methylation status, whereas demethylation increased reelin mRNA expression in vitro. Reelin overexpression in MDA-MB231 cells, as well as incubation with recombinant reelin, suppressed cell migration, invadopodia formation, and invasiveness in vitro. We conclude that reelin may play an important role in controlling invasiveness and metastatic potential of breast cancer cells and that its expression is controlled by promoter methylation.

Further Understanding of the Immune Microenvironment in Head and Neck Squamous Cell Carcinoma: Implications for Prognosis.

PURPOSE: We aimed to review the literature on the tumor microenvironment as a key player in tumor growth and anti-cancer treatment responses in head and neck cancer. PATIENTS AND METHODS: We reviewed the recent literature on this topic, using the following research words: "tumor microenvironment" and "head and neck cancer or neoplasm or head and neck squamous cell carcinoma" and "immune cells" and "stromal cells". A search was conducted on the PubMed website and reports from international meetings, presentations and abstracts. RESULTS: The tumor microenvironment is a complex network in which myeloid cells, tumoral cells, growth factors and cytokines are involved in angiogenesis, the extracellular matrix and epithelial-to-mesenchymal transition. CONCLUSION: Immune resistance and rapid tumor growth depend on immunosuppressive and pro-tumoral environments. Further investigations to classify and adequately treat patients with head and neck cancer are required.

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-ß, 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-α basal 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-ß, 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-ß and TNF-α negatively 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.

Exploratory analysis of circulating cytokines in patients with metastatic breast cancer treated with eribulin: the TRANSERI-GONO (Gruppo Oncologico del Nord Ovest) study.

BACKGROUND: Anticancer drugs can interact with the tumour microenvironment and their effects could be exploited to favour anticancer immune response. Eribulin contributes to tumour vasculature remodelling and transforming growth factor ß (TGF-ß) modulation in experimental models and in humans. We performed a prospective, translational, exploratory analysis of the levels of circulating cytokines at different time points in patients with metastatic breast cancer treated with eribulin. METHODS: TGF-ß, tumour necrosis factor α, vascular endothelial growth factor, IL-6, IL-8, IL-10, IL-21 and C-C motif chemokine ligand-2 levels were assessed in peripheral blood samples obtained from seven healthy volunteers and 41 patients at baseline (T0), after four cycles of eribulin (T1) and at disease progression (TPD). Baseline values and longitudinal changes in cytokine levels were then related to clinical outcome. RESULTS: In the 41 patients, high IL-6 and IL-8 (above the median) at T0 significantly correlated with worse survival. At T1, IL-21 significantly decreased in patients with TPD within the fourth course of treatment, compared with patients without progression. TGF-ß and IL-8 above the median and IL-21 below the median at T1 significantly correlates with worse progression free survival (PFS). Patients exhibiting an increase of TGF-ß or a decline of IL-21 between T0 and T1 showed a significantly worse PFS. Multivariate Cox regression analysis showed that only plasma TGF-ß changes at T1 correlated with survival. At TPD, TGF-ß significantly increased in all patients. CONCLUSIONS: We observed a significant correlation between TGF-ß decline during eribulin treatment and outcome in patients with metastatic breast cancer. Altogether, our data suggest that eribulin treatment might interfere with the tumour microenvironment.

DNA Methylation in the Diagnosis of Monogenic Diseases.

DNA methylation in the human genome is largely programmed and shaped by transcription factor binding and interaction between DNA methyltransferases and histone marks during gamete and embryo development. Normal methylation profiles can be modified at single or multiple loci, more frequently as consequences of genetic variants acting in cis or in trans, or in some cases stochastically or through interaction with environmental factors. For many developmental disorders, specific methylation patterns or signatures can be detected in blood DNA. The recent use of high-throughput assays investigating the whole genome has largely increased the number of diseases for which DNA methylation analysis provides information for their diagnosis. Here, we review the methylation abnormalities that have been associated with mono/oligogenic diseases, their relationship with genotype and phenotype and relevance for diagnosis, as well as the limitations in their use and interpretation of results.

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.

Long noncoding RNAs as regulators of cancer immunity.

Long noncoding RNAs (lncRNAs) are increasingly known to be important in cancer as they directly interact with the cell cycle, proliferation pathways and microbiome balance. Moreover, lncRNAs regulate the immune system: they do not directly encode proteins of innate or adaptive immunity, but regulate immune cell differentiation and function, such as dendritic cell activity, T cell ratio and metabolism. The result of this complex interaction is that lncRNAs regulate cancer processes through a complex multimodal system involving immunity, metabolism and infection. The possible functions of lncRNAs and their roles in the regulation of cancer immunity will be reported and discussed in the present review. Recent studies showed their function as regulators in the tumour microenvironment (TME), epithelial-mesenchymal transition, microbiota, metabolism and immune cell differentiation. However, there is not much knowledge regarding their roles in cancer immunity regulation. Thus, the main aim of this review is to describe lncRNAs that have specifically been associated with immunity, the immune cycle and the TME.