Epigenetic EGFR Gene Repression Confers Sensitivity to Therapeutic BRAFV600E Blockade in Colon Neuroendocrine Carcinomas

BRAF - a tumour-agnostic drug target with lineage-specific dependencies

In June 2022, the FDA granted Accelerated Approval to the BRAF inhibitor dabrafenib in combination with the MEK inhibitor trametinib for the treatment of adult and paediatric patients (≥6 years of age) with unresectable or metastatic BRAFV600E-mutant solid tumours, except for BRAFV600E-mutant colorectal cancers. The histology-agnostic approval of dabrafenib plus trametinib marks the culmination of two decades of research into the landscape of BRAF mutations in human cancers, the biochemical mechanisms underlying BRAF-mediated tumorigenesis, and the clinical development of selective RAF and MEK inhibitors. Although the majority of patients with BRAFV600E-mutant tumours derive clinical benefit from BRAF inhibitor-based combinations, resistance to treatment develops in most. In this Review, we describe the biochemical basis for oncogenic BRAF-induced activation of MAPK signalling and pan-cancer and lineage-specific mechanisms of intrinsic, adaptive and acquired resistance to BRAF inhibitors. We also discuss novel RAF inhibitors and drug combinations designed to delay the emergence of treatment resistance and/or expand the population of patients with BRAF-mutant cancers who benefit from molecularly targeted therapies.

Druggable growth dependencies and tumor evolution analysis in patient-derived organoids of neuroendocrine neoplasms from multiple body sites

Neuroendocrine neoplasms (NENs) comprise well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Treatment options for patients with NENs are limited, in part due to lack of accurate models. We establish patient-derived tumor organoids (PDTOs) from pulmonary NETs and derive PDTOs from an understudied subtype of NEC, large cell neuroendocrine carcinoma (LCNEC), arising from multiple body sites. PDTOs maintain the gene expression patterns, intra-tumoral heterogeneity, and evolutionary processes of parental tumors. Through hypothesis-driven drug sensitivity analyses, we identify ASCL1 as a potential biomarker for response of LCNEC to treatment with BCL-2 inhibitors. Additionally, we discover a dependency on EGF in pulmonary NET PDTOs. Consistent with these findings, we find that, in an independent cohort, approximately 50% of pulmonary NETs express EGFR. This study identifies an actionable vulnerability for a subset of pulmonary NETs, emphasizing the utility of these PDTO models.

Selection of Chemotherapy in Advanced Poorly Differentiated Extra-Pulmonary Neuroendocrine Carcinoma

Extra-pulmonary poorly differentiated neuroendocrine carcinoma is rare, and evidence for treatment has been limited. In this article, the evidence behind the cytotoxic chemotherapy choices used for metastatic or unresectable EP-PD-NEC is reviewed. In the first-line setting, etoposide and platinum chemotherapy or irinotecan and platinum have been demonstrated to be equivalent in a large phase III trial. Questions remain regarding the optimal number of cycles, mode of delivery, and the precise definition of platinum resistance in this setting. In the second-line setting, FOLFIRI has emerged as an option, with randomized phase 2 trials demonstrating modest, but significant, response rates. Beyond this, data are extremely limited, and several regimens have been used. Heterogeneity in biological behaviour is a major barrier to optimal EP-PD-NEC management. Available data support the potential role of the Ki-67 index as a predictive biomarker for chemotherapy response. A more personalised approach to management in future studies will be essential, and comprehensive multi-omic approaches are required to understand tumour somatic genetic changes in relation to their effects on the surrounding microenvironment.

Managing Metastatic Extrapulmonary Neuroendocrine Carcinoma After First-Line Treatment

PURPOSE OF REVIEW

Extrapulmonary neuroendocrine carcinoma (EP-NEC) is a rare, aggressive malignancy that can arise from any organ and frequently presents with distant metastases. Advanced disease has a poor prognosis with median overall survival (OS) rarely exceeding 1 year even with systemic therapy. The management paradigm of advanced/metastatic EP-NEC has been extrapolated from small cell lung cancer (SCLC) and commonly consists of 1st line therapy with etoposide and platinum (cisplatin or carboplatin), followed by alternative cytotoxic regimens at the time of progression. Only a minority of patients are able to receive 2nd line therapy, and cytotoxics derived from the SCLC paradigm such as topotecan or lurbinectedin have very limited activity. We aimed to evaluate emerging therapeutic options in the 2nd and later lines and survey potential future developments in this space.

RECENT FINDINGS

After a long period of stagnation in treatment options and outcomes, more promising regimens are gradually being utilized in the 2nd line setting including systemic therapy combinations such as FOLFIRI, FOLFOX, modified FOLFIRINOX, CAPTEM, and, more recently, novel checkpoint inhibitors such as nivolumab and ipilimumab. Simultaneously, advances in the understanding of disease biology are helping to refine patient selection and identify commonalities between NEC and their sites of origin which may eventually lead to additional targeted therapy options. While many questions remain, contemporary developments give grounds for optimism that improved outcomes for EP-NEC will soon be within reach.

Potent molecular-targeted therapies for gastro-entero-pancreatic neuroendocrine carcinoma

Neuroendocrine neoplasms (NENs), which are characterized by neuroendocrine differentiation, can arise in various organs. NENs have been divided into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs) based on morphological differentiation, each of which has a distinct etiology, molecular profile, and clinicopathological features. While the majority of NECs originate in the pulmonary organs, extrapulmonary NECs occur most predominantly in the gastro-entero-pancreatic (GEP) system. Although platinum-based chemotherapy is the main therapeutic option for recurrent or metastatic GEP-NEC patients, the clinical benefits are limited and associated with a poor prognosis, indicating the clinically urgent need for effective therapeutic agents. The clinical development of molecular-targeted therapies has been hampered due to the rarity of GEP-NECs and the paucity of knowledge on their biology. In this review, we summarize the biology, current treatments, and molecular profiles of GEP-NECs based on the findings of pivotal comprehensive molecular analyses; we also highlight potent therapeutic targets for future precision medicine based on the most recent results of clinical trials.

Neuroendocrine Neoplasms: Genetics and Epigenetics

Neuroendocrine neoplasms (NENs) are a group of rare, heterogeneous tumors of neuroendocrine cell origin, affecting a range of different organs. The clinical management of NENs poses significant challenges, as tumors are often diagnosed at an advanced stage where overall survival remains poor with current treatment regimens. In addition, a host of complex and often unique molecular changes underpin the pathobiology of each NEN subtype. Exploitation of the unique genetic and epigenetic signatures driving each NEN subtype provides an opportunity to enhance the diagnosis, treatment, and monitoring of NEN in an emerging era of individualized medicine.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for digestive neuroendocrine carcinoma

This ENETS guidance paper, developed by a multidisciplinary working group, provides up-to-date and practical advice on the diagnosis and management of digestive neuroendocrine carcinoma, based on recent developments and study results. These recommendations aim to pave the road for more standardized care for our patients resulting in improved outcomes. Prognosis is generally poor for digestive NEC, most are advanced at diagnosis and median survival in metastatic disease is 11-12 months. Surgery can be of benefit for localized disease after extensive preoperative imaging. Carboplatin in combination with etoposide is recommended as first-line treatment for metastatic disease. Irinotecan with fluoropyrimidines has the best evidence as second-line treatment. Immunotherapy plays a minor role in biomarker-unselected patients. Molecular profiling if available is encouraged to identify new targets. More prospective clinical trials are highly needed to fulfil the unmet needs in this field, especially on new predictive and prognostic biomarkers and to improve survival of patients with advanced disease.

Future therapeutic strategies in the treatment of extrapulmonary neuroendocrine carcinoma: a review

Neuroendocrine neoplasms (NENs) are rare malignancies arising most commonly in the gastrointestinal and bronchopulmonary systems. Neuroendocrine carcinomas (NECs) are a subgroup of NENs characterised by aggressive tumour biology, poor differentiation and dismal prognosis. Most NEC primary lesions arise in the pulmonary system. However, a small proportion arise outside of the lung and are termed extrapulmonary (EP)-, poorly differentiated (PD)-NECs. Patients with local or locoregional disease may benefit from surgical excision; however, this is often not an option, due to late presentation. To date, treatment has mirrored that of small-cell lung cancer, with platinum-etoposide forming the basis of first-line treatment. There is a lack of consensus in relation to the most effective second-line treatment option. Low incidence, an absence of representative preclinical models and a lack of understanding of the tumour microenvironment all present challenges to drug development in this disease group. However, progress made in elucidating the mutational landscape of EP-PD-NEC and the observations made in several clinical trials are paving the way towards improving outcomes for these patients. The optimisation and strategic delivery of chemotherapeutic interventions according to tumour characteristics and the utilisation of targeted and immune therapies in clinical studies have yielded mixed results. Targeted therapies that complement specific genetic aberrations are under investigation, including AURKA inhibitors in those with MYCN amplifications, BRAF inhibitors in those with BRAFV600E mutations and EGFR suppression, and Ataxia Telangiectasia and Rad3-related inhibitors in patients with ATM mutations. Immune checkpoint inhibitors (ICIs) have conferred promising results in several clinical trials, particularly with dual ICIs and in combination with targeted therapy or chemotherapy. However, further prospective investigations are required to elucidate the impact of programmed cell death ligand 1 expression, tumour mutational burden and microsatellite instability on response. This review aims to explore the most recent developments in the treatment of EP-PD-NEC and contribute towards the requirement for clinical guidance founded on prospective evidence.

Acquired resistance to BRAF inhibitors is mediated by BRAF splicing variants in BRAF V600E mutation-positive colorectal neuroendocrine carcinoma

Neuroendocrine carcinomas (NECs), a poorly differentiated subtype of neuroendocrine neoplasms, are aggressive and have a poor prognosis. Colorectal neuroendocrine carcinomas (CRC-NECs) are observed in about 0.6% of all patients with CRC. Interestingly, patients with CRC-NECs show higher frequencies of BRAF mutation than typical CRC. BRAF V600E mutation-positive CRC-NECs were shown to be sensitive to BRAF inhibitors and now are treated by BRAF inhibitors. Similar to the other BRAF V600E mutated cancers, resistances against BRAF inhibitors have been observed, but the resistance mechanisms are still unclear. In this study, we established BRAF V600E mutated CRC-NEC cell line directly from surgical specimens and experimentally obtained BRAF inhibitor dabrafenib resistant cell lines. The resistant cells are revealed to express at least three types of BRAF splicing variants harboring V600E-mutation, and contribute to RAF/MEK/ERK pathway activation. In these cells, MEK and ERK inhibitors but not dabrafenib significantly suppressed cell growth and survival. Thus, in BRAF V600E mutation-positive CRC-NECs, BRAF splicing variants activate the RAF/MEK/ERK pathway and contribute to acquire BRAF inhibitor resistance. Hence, MEK or ERK are potential therapeutic targets to overcome BRAF resistance.

Expanding Therapeutic Opportunities for Extrapulmonary Neuroendocrine Carcinoma

Poorly differentiated neuroendocrine carcinomas (PD-NEC) are rare cancers garnering interest as they become more commonly encountered in the clinic. This is due to improved diagnostic methods and the increasingly observed phenomenon of "NE lineage plasticity," whereby nonneuroendocrine (non-NE) epithelial cancers transition to aggressive NE phenotypes after targeted treatment. Effective treatment options for patients with PD-NEC are challenging for several reasons. This includes a lack of targetable, recurrent molecular drivers, a paucity of patient-relevant preclinical models to study biology and test novel therapeutics, and the absence of validated biomarkers to guide clinical management. Although advances have been made pertaining to molecular subtyping of small cell lung cancer (SCLC), a PD-NEC of lung origin, extrapulmonary (EP)-PD-NECs remain understudied. This review will address emerging SCLC-like, same-organ non-NE cancer-like and tumor-type-agnostic biological vulnerabilities of EP-PD-NECs, with the potential for therapeutic exploitation. The hypotheses surrounding the origin of these cancers and how "NE lineage plasticity" can be leveraged for therapeutic purposes are discussed. SCLC is herein proposed as a paradigm for supporting progress toward precision medicine in EP-PD-NECs. The aim of this review is to provide a thorough portrait of the current knowledge of EP-PD-NEC biology, with a view to informing new avenues for research and future therapeutic opportunities in these cancers of unmet need.

Potential Biomarkers of Skin Melanoma Resistance to Targeted Therapy—Present State and Perspectives

Simple Summary

Around 5–10% of advanced melanoma patients progress early on anti-BRAF targeted therapy and 20–30% respond only with the stabilization of the disease. Presumably, these patients could benefit more from first-line immunotherapy. Resistance to BRAF/MEK inhibitors is generated by genetic and non-genetic factors inherent to a tumor or acquired during therapy. Some of them are well documented as a cause of treatment failure. They are potential predictive markers that could improve patients’ selection for both standard and also alternative therapy as some of them have therapeutic potential. Here, a summary of the most promising predictive and therapeutic targets is presented. This up-to-date knowledge may be useful for further study on implementing more accurate genetic/molecular tests in melanoma treatment.

Abstract

Melanoma is the most aggressive skin cancer, the number of which is increasing worldwide every year. It is completely curable in its early stage and fatal when spread to distant organs. In addition to new therapeutic strategies, biomarkers are an important element in the successful fight against this cancer. At present, biomarkers are mainly used in diagnostics. Some biological indicators also allow the estimation of the patient’s prognosis. Still, predictive markers are underrepresented in clinics. Currently, the only such indicator is the presence of the V600E mutation in the BRAF gene in cancer cells, which qualifies the patient for therapy with inhibitors of the MAPK pathway. The identification of response markers is particularly important given primary and acquired resistance to targeted therapies. Reliable predictive tests would enable the selection of patients who would have the best chance of benefiting from treatment. Here, up-to-date knowledge about the most promising genetic and non-genetic resistance-related factors is described. These are alterations in MAPK, PI3K/AKT, and RB signaling pathways, e.g., due to mutations in NRAS, RAC1, MAP2K1, MAP2K2, and NF1, but also other changes activating these pathways, such as the overexpression of HGF or EGFR. Most of them are also potential therapeutic targets and this issue is also addressed here.

Clinicopathological and molecular profile of grade 3 gastroenteropancreatic neuroendocrine neoplasms

The 2019 Word Health Organization (WHO) subclassified grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) into neuroendocrine carcinoma (NEC) or tumours (G3 NET) based on morphology and proliferation. Yet, few data exist on molecular profiles for G3 NEN. We compared clinicopathological and molecular characteristics of these two groups. We retrospectively reviewed consecutive G3 GEP NEN patients and had their tumour tissues reviewed, reclassified as per the WHO 2019, and analyzed by a next-generation sequencing (NGS) panel. Between 2000 and 2019, 43 patients had pathology revision: 29 (67%) were NEC and 14 (33%) were G3 NET, with a 23% change in diagnosis. Median overal survival for G3 NET and NEC patients was 55.6 and 11.9 months, respectively (hazard ratio = 2.78 [95% confidence interval = 1.09-7.11], p = .042), which was confirmed by an adjusted analysis (hazard ratio = 2.90 NEC vs. G3 NET; p = .03). NGS was performed in 32 cases: 21 NEC and 11 G3 NET. Mutations in RB1 and PTEN were exclusively encountered in NEC. Median tumour mutational burden was 5 (0-67) mutations per megabase in NEC and 4.5 (0-9) among G3 NET. Microsatellite instability was found in 3 (14.3%) NEC cases. In conclusion, pathology revision is essential to estimate prognosis and therapeutic plan. G3 GEP NEN generally harbour low tumor mutation burden and fewer actionable mutations, but 14% of NEC cases were microsatellite unstable and could benefit from immune checkpoint inhibitors.

Efficacy of BRAF inhibitor and anti-EGFR antibody in colorectal neuroendocrine carcinoma

Neuroendocrine neoplasms of the colon and rectum are colorectal epithelial neoplasms with neuroendocrine differentiation. A platinum regimen used for small cell lung cancer is the currently recommended chemotherapy for gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs), regardless of the organ. The BRAF V600E mutation has been recently reported as a druggable driver mutation in colorectal NECs. In BRAF V600E mutant colorectal cancer, a combination of BRAF inhibitor and anti-epidermal growth factor receptor (EGFR) antibody, with or without a MEK inhibitor, is recommended. Here, we report the case of 77-year-old man who had lymph node recurrence after surgery for primary ascending colonic NEC. Two cytotoxic regimens, cisplatin plus irinotecan and modified FOLFOX6, were administered as first- and second-line chemotherapies with no remarkable response observed. At this point, genetic analysis confirmed the tumor harbored a BRAF V600E mutation. Thus, a regimen of BRAF inhibitor plus anti-EGFR antibody was administered. After commencing this regimen, carcinoembryonic antigen levels decreased within normal range, and there was dramatic shrinkage of the lymph node metastases observed by chest and abdominal computed tomography scans. To our knowledge, this is the first reported case of a colorectal NEC responding to a BRAF inhibitor and anti-EGFR antibody.

The molecular characteristics of high-grade gastroenteropancreatic neuroendocrine neoplasms

High-grade (HG) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) are rare but have a very poor prognosis and represent a severely understudied class of tumours. Molecular data for HG GEP-NEN are limited, and treatment strategies for the carcinoma subgroup (HG GEP-NEC) are extrapolated from small-cell lung cancer (SCLC). After pathological re-evaluation, we analysed DNA from tumours and matched blood samples from 181 HG GEP-NEN patients; 152 neuroendocrine carcinomas (NEC) and 29 neuroendocrine tumours (NET G3). Based on the sequencing of 360 cancer-related genes, we assessed mutations and copy number alterations (CNA). For NEC, frequently mutated genes were TP53 (64%), APC (28%), KRAS (22%) and BRAF (20%). RB1 was only mutated in 14%, but CNAs affecting RB1 were seen in 34%. Other frequent copy number losses were ARID1A (35%), ESR1 (25%) and ATM (31%). Frequent amplifications/gains were found in MYC (51%) and KDM5A (45%). While these molecular features had limited similarities with SCLC, we found potentially targetable alterations in 66% of the NEC samples. Mutations and CNA varied according to primary tumour site with BRAF mutations mainly seen in colon (49%), and FBXW7 mutations mainly seen in rectal cancers (25%). Eight out of 152 (5.3%) NEC were microsatellite instable (MSI). NET G3 had frequent mutations in MEN1 (21%), ATRX (17%), DAXX, SETD2 and TP53 (each 14%). We show molecular differences in HG GEP-NEN, related to morphological differentiation and site of origin. Limited similarities to SCLC and a high fraction of targetable alterations indicate a high potential for better-personalized treatments.

Drug resistance in colorectal cancer: An epigenetic overview

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Despite significant progress that has been made in therapies against CRC over the past decades, drug resistance is still a major limitation in CRC treatment. Numerous investigations have unequivocally shown that epigenetic regulation plays an important role in CRC drug resistance because of the high rate of epigenetic alterations in multiple genes during cancer development or drug treatment. Furthermore, the reversibility of epigenetic alterations provides novel therapeutic strategies to overcome drug resistance using small molecules, which can target non-coding RNAs or reverse histone modification and DNA methylation. In this review, we discuss epigenetic regulation in CRC drug resistance and the possible role of preventing or reversing CRC drug resistance using epigenetic therapy in CRC treatment.

Chemotherapy in NEN: still has a role?

Neuroendocrine neoplasms (NENs) comprise a broad spectrum of tumors with widely variable biological and clinical behavior. Primary tumor site, extent of disease, tumor differentiation and expression of so matostatin receptors, proliferation and growth rates are the major prognostic factors that determine the therapeutic strategy. Treatment options for advanced disease have considerably expanded in recent years, particularly for well differentiated tumors (NETs). Novel drugs approved over the past decade in this context include somatostatin analogues and ¹⁷⁷Lu-oxodotreotide for somatostatin-receptor-positive gastroenteropancreatic (GEP) NETs, sunitinib for pancreatic NETs (P-NETs), and everolimus for P-NETs and non-functioning lung or gastrointestinal NETs. Nevertheless, chemotherapy remains an essential component of the treatment armamentarium of patients with NENs, particularly of patients with P-NETs or those with bulky, symptomatic or rapidly progressive tumors (generally G3 or high-G2 NENs). In this manuscript we will comprehensively review available evidence related to the use of chemotherapy in lung and GEP NENs and will critically discuss its role in the treatment algorithm of this family of neoplasms.

Is the Morphological Subtype of Extra-Pulmonary Neuroendocrine Carcinoma Clinically Relevant?

Extra-pulmonary neuroendocrine carcinomas (EP-NECs) are lethal cancers with limited treatment options. Identification of contributing factors to the observed heterogeneity of clinical outcomes within the EP-NEC family is warranted, to enable identification of effective treatments. A multicentre retrospective study investigated potential differences in "real-world" treatment/survival outcomes between small-cell (SC) versus (vs.) non-SC EP-NECs. One-hundred and seventy patients were included: 77 (45.3%) had SC EP-NECs and 93 (54.7%) had non-SC EP-NECs. Compared to the SC subgroup, the non-SC subgroup had the following features: (1) a lower mean Ki-67 index (69.3% vs. 78.7%; p = 0.002); (2) a lower proportion of cases with a Ki-67 index of ≥55% (73.9% vs. 88.7%; p = 0.025); (3) reduced sensitivity to first-line platinum/etoposide (objective response rate: 31.6% vs. 55.1%, p = 0.015; and disease control rate; 59.7% vs. 79.6%, p = 0.027); (4) worse progression-free survival (PFS) (adjusted-HR = 1.615, p = 0.016) and overall survival (OS) (adjusted-HR = 1.640, p = 0.015) in the advanced setting. Within the advanced EP-NEC cohort, subgroups according to morphological subtype and Ki-67 index (<55% vs. ≥55%) had significantly different PFS (adjusted-p = 0.021) and OS (adjusted-p = 0.051), with the non-SC subgroup with a Ki-67 index of <55% and non-SC subgroup with a Ki-67 index of ≥55% showing the best and worst outcomes, respectively. To conclude, the morphological subtype of EP-NEC provides complementary information to the Ki-67 index and may aid identification of patients who could benefit from alternative first-line treatment strategies to platinum/etoposide.

FOLFIRINEC: a randomized phase II trial of mFOLFIRINOX vs platinum-etoposide for metastatic neuroendocrine carcinoma of gastroenteropancreatic or unknown origin

BACKGROUND

Poorly differentiated neuroendocrine carcinomas (NEC) are rare diseases with a poor prognosis. Platinum-etoposide (PE) has been the recommended first-line treatment for decades. FOLFIRINEC (NCT04325425) is a national multicenter randomized phase II study which aims to challenge this standard regimen.

METHODS

The primary objective is to compare the median progression-free survival (PFS) under mFOLFIRINOX versus PE. The secondary objectives are to evaluate the objective response rates (ORR), median overall survival (OS), safety and quality of life. The associated real-time translational study will establish a molecular profile for each patient enrolled.

MAIN INCLUSION CRITERIA ARE

NEC of gastroenteropancreatic (GEP) or unknown origin, metastatic and RECIST 1.1 evaluable disease, tumor sample available and no contraindication to chemotherapy. Patients will be randomized 1:1 between PE every 21 days for 6-8 cycles and mFOLFIRINOX every 14 days for up to 12 cycles and stratified according to center, performance status, Ki67 and pathological subtype. This trial will randomize 218 patients (24 months of follow-up) to have 80% power to detect an improvement of the median PFS from 5 months under PE to 7.5 months under mFOLFIRINOX (HR of 0.67, α =5%, two-sided). An intermediate analysis is planned at 50% of events. Recruitment started on October 20, 2020.

Systemic Treatment of Gastroenteropancreatic Neuroendocrine Carcinoma

OPINION STATEMENT

Treatment recommendations for advanced gastroenteropancreatic neuroendocrine carcinomas (GEP-NEC) are based on uncontrolled, mainly retrospective data. Chemotherapy can offer palliative relief, but long-lasting complete responses or cures are rare. The European Neuroendocrine Tumour Society (ENETS) and European Society for Medical Oncology (ESMO) recommend platinum-based chemotherapy as first-line treatment. This has been the golden standard since the late 1980s and has been evaluated in mostly retrospective clinical studies. However, progression is inevitable for most patients. Unfortunately, data on effective second-line treatment options are scant, and ENETS and ESMO recommendations propose fluorouracil- or temozolomide-based chemotherapy schedules. As such, there is a huge unmet need for improved care. Improved knowledge on GEP-NEC biology may provide a pathway towards more effective interventions including chemotherapy, targeted gene therapy, peptide receptor radionuclide therapy, as well as immune checkpoint inhibitors. The review summarises this current state of the art as well as the most promising developments for systemic therapy in GEP-NEC patients.

Current Treatment Strategies and Future Directions for Extrapulmonary Neuroendocrine Carcinomas: A Review

Importance

Patients with extrapulmonary neuroendocrine carcinomas (EPNECs) receive essentially the same treatment as those with small cell lung cancer (SCLC) despite differences in origin, clinical course, and survival. This SCLC-based approach is attributable to the rarity of EPNECs, which impedes the use of randomized clinical trials. However, neuroendocrine carcinomas are becoming more common because of the increasing use of systemic cancer therapy for adenocarcinomas. This treatment can transdifferentiate certain adenocarcinomas into neuroendocrine carcinomas. In addition, the treatment landscape for SCLC is slowly changing, potentially impacting the treatment paradigms for EPNECs.

Observations

New information on tumorigenesis of EPNECs from different origins, either as a primary malignant tumor or after neuroendocrine differentiation from adenocarcinomas, demonstrates their biological similarity. Activated molecular pathways that appear to underlie the development of EPNECs are potentially targetable, and some of these targets, such as poly(adenosine diphosphate-ribose) polymerase, Wee1, and Aurora A kinase, are currently under investigation. Immune checkpoint inhibitors (ICIs) already constituted a new treatment modality for patients with SCLC and produced some promising results in patients with EPNECs.

Conclusions and Relevance

Although only moderately effective, the introduction of ICIs signifies the first new option in systemic treatment of SCLC in decades. To prove the value of ICIs and other new drugs for patients with EPNECs, these patients should be included in clinical trials independent of the primary tumor site. Furthermore, to optimize clinical decision-making for patients with EPNECs, experts from the neuroendocrine tumor board should collaborate with members from tumor site-specific boards, which will require patient referral to a center with EPNEC expertise.

Use of DNA methylation profiling in translational oncology

DNA methylation is a highly regulated process that has a critical role in human development and homeostatic control of the cell. The number of genes affected by anomalous DNA methylation in cancer-associated pathways is swiftly accelerating and with the advancement of molecular technologies, new layers of complexity are opening up and refining our strategies to combat cancer. DNA methylation profiling is an essential facet to understanding malignant transformation and is becoming an increasingly important tool for cancer diagnosis, prognosis and therapy monitoring. In this review, the role of DNA methylation in normal cellular function is discussed, as well as how epigenetic aberrations override normal cellular cues that lead to tumor initiation and propagation. The review also focuses on the latest advancements in DNA methylation profiling as a biomarker for early cancer detection, predicting patient clinical outcomes and responses to treatment and provides new insights into epigenetic-based therapy in clinical oncology.

Rectal neuroendocrine carcinoma: case report of a rare entity and perspective review of promising agents

Neuroendocrine neoplasms (NENs) comprise a heterogeneous group of tumours, which can be classified into neuroendocrine tumours (NETs), neuroendocrine carcinomas (NECs) and mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs). To date, there is no consensus regarding the optimal therapy, which usually depends on the primary location and classification, according to morphological features of differentiation and proliferation rates. Nevertheless, multidisciplinary strategies combining medical treatments and locoregional strategies have yielded better efficacy results. Here, we report the case of a patient diagnosed with a nonfunctional rectal NECs with metastatic widespread to pelvic lymph nodes and bilateral lung metastases. The patient received three cycles of platinum-etoposide, concomitantly with palliative radiotherapy. Although CT scan after three cycles showed a significant partial response, there was an early fatal progression only 3 months after having stopped systemic therapy. As formerly described in the literature, this case highlights the aggressive behaviour of NECs, rare tumours that often present in advanced stages at diagnosis. Lately, new insights into the molecular biology of NECs have unveiled the possibility of using novel drugs, such as targeted agents or immunotherapy, in molecularly selected subgroups of patients. In this review, we discuss the current management of this rare entity and provide an overview of the most relevant molecular findings, whilst illustrating the potential value that prescreening panels can offer, searching for actionable targets (MSI/dMMR, PD-L1, BRAF^v600E) to guide therapy with promising agents that could fill a void in this disease.