Hallmarks of RET and Co-occuring Genomic Alterations in RET-aberrant Cancers

The ESMO Tumour-Agnostic Classifier and Screener (ETAC-S): a tool for assessing tumour-agnostic potential of molecularly guided therapies and for steering drug development

BACKGROUND

Advances in precision oncology led to approval of tumour-agnostic molecularly guided treatment options (MGTOs). The minimum requirements for claiming tumour-agnostic potential remain elusive.

METHODS

The European Society for Medical Oncology (ESMO) Precision Medicine Working Group (PMWG) coordinated a project to optimise tumour-agnostic drug development. International experts examined and summarised the publicly available data used for regulatory assessment of the tumour-agnostic indications approved by the US Food and Drug Administration and/or the European Medicines Agency as of December 2023. Different scenarios of minimum objective response rate (ORR), number of tumour types investigated, and number of evaluable patients per tumour type were assessed for developing a screening tool for tumour-agnostic potential. This tool was tested using the tumour-agnostic indications approved during the first half of 2024. A taxonomy for MGTOs and a framework for tumour-agnostic drug development were conceptualised.

RESULTS

Each tumour-agnostic indication had data establishing objective response in at least one out of five patients (ORR ≥ 20%) in two-thirds (≥4) of the investigated tumour types, with at least five evaluable patients in each tumour type. These minimum requirements were met by tested indications and may serve as a screening tool for tumour-agnostic potential, requiring further validation. We propose a conceptual taxonomy classifying MGTOs based on the therapeutic effect obtained by targeting a driver molecular aberration across tumours and its modulation by tumour-specific biology: tumour-agnostic, tumour-modulated, or tumour-restricted. The presence of biology-informed mechanistic rationale, early regulatory advice, and adequate trial design demonstrating signs of biology-driven tumour-agnostic activity, followed by confirmatory evidence, should be the principles for tumour-agnostic drug development.

CONCLUSION

The ESMO Tumour-Agnostic Classifier (ETAC) focuses on the interplay of targeted driver molecular aberration and tumour-specific biology modulating the therapeutic effect of MGTOs. We propose minimum requirements to screen for tumour-agnostic potential (ETAC-S) as part of tumour-agnostic drug development. Definition of ETAC cut-offs is warranted.

The Eμ-Ret mouse is a novel model of hyperdiploid B-cell acute lymphoblastic leukemia

The presence of supernumerary chromosomes is the only abnormality shared by all patients diagnosed with high-hyperdiploid B cell acute lymphoblastic leukemia (HD-ALL). Despite being the most frequently diagnosed pediatric leukemia, the lack of clonal molecular lesions and complete absence of appropriate experimental models have impeded the elucidation of HD-ALL leukemogenesis. Here, we report that for 23 leukemia samples isolated from moribund Eμ-Ret mice, all were characterized by non-random chromosomal gains, involving combinations of trisomy 9, 12, 14, 15, and 17. With a median gain of three chromosomes, leukemia emerged after a prolonged latency from a preleukemic B cell precursor cell population displaying more diverse aneuploidy. Transition from preleukemia to overt disease in Eμ-Ret mice is associated with acquisition of heterogeneous genomic abnormalities affecting the expression of genes implicated in pediatric B-ALL. The development of abnormal centrosomes in parallel with aneuploidy renders both preleukemic and leukemic cells sensitive to inhibitors of centrosome clustering, enabling targeted in vivo depletion of leukemia-propagating cells. This study reveals the Eμ-Ret mouse to be a novel tool for investigating HD-ALL leukemogenesis, including supervision and selection of preleukemic aneuploid clones by the immune system and identification of vulnerabilities that could be targeted to prevent relapse.

If it's a target, it's a pan-cancer target: Tissue is not the issue

Cancer is traditionally diagnosed and treated on the basis of its organ of origin (e.g., lung or colon cancer). However, organ-of-origin diagnostics does not reveal the underlying oncogenic drivers. Fortunately, molecular diagnostics have advanced at a breathtaking pace, and it is increasingly apparent that cancer is a disease of the genome. Hence, we now have multiple genomic biomarker-based, tissue-agnostic Food and Drug Administration approvals for both gene- and immune-targeted therapies (larotrectinib/entrectinib, for NTRK fusions; selpercatinib, RET fusions; dabrafenib plus trametinib, BRAFV600E mutations; pembrolizumab/dostarlimab, microsatellite instability; and pembrolizumab for high tumor mutational burden; pemigatinib is also approved for FGFR1-rearranged myeloid/lymphoid neoplasms). There are emerging targets as well, including but not limited to ALK, BRCA and/or homologous repair deficiency, ERBB2 (HER2), IDH1/2, KIT, KRASG12C, NRG1, and VHL. Many tissue-agnostic approvals center on rare/ultra-rare biomarkers (often < 1 % of cancers), necessitating screening hundreds of tumors to find a single one harboring the cognate molecular alteration. Approval has generally been based on small single-arm studies (<30-100 patients) with high response rates (>30 % to > 75 %) of remarkable durability. Because of biomarker rarity, single-gene testing is not practical; next generation sequencing of hundreds of genes must be performed to obtain timely answers. Resistance to biomarker-driven therapeutics is often due to secondary mutations or co-driver gene defects; studies are now addressing the need for customized drug combinations matched to the complex molecular alteration portfolio in each tumor. Future investigation should expand tissue-agnostic therapeutics to encompass both hematologic and solid malignancies and include biomarkers beyond those that are DNA-based.

Response to immune checkpoint inhibitor combination therapy in metastatic RET-mutated lung cancer from real-world retrospective data

BACKGROUND

The impact of immune checkpoint inhibitors (ICIs) based treatments on non-small cell lung cancers (NSCLCs) with RET fusions remains poorly understood.

METHODS

We screened patients with RET fusions at the First Affiliated Hospital of Zhengzhou University and included those who were treated with ICIs based regimens for further analysis. We evaluated clinical indicators including objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS).

RESULTS

A total of 232 patients with RET fusions were included in the study. Of these, 129 patients had their programmed death-ligand 1 (PDL1) expression levels tested, with 22 patients (17.8%) having a PDL1 level greater than or equal to 50%. Additionally, tumor mutational burden (TMB) status was evaluated in 35 patients, with the majority (30/35, 85.8%) having a TMB of less than 10 mutations per megabase. Out of the 38 patients treated with ICI based regimens, the median PFS was 5 months (95% confidence interval [CI]: 2.4-7.6 months) and the median OS was 19 months (95% CI: 9.7-28.3 months) at the time of data analysis. Stratification based on treatment lines did not show any significant differences in OS (18 vs. 19 months, p = 0.63) and PFS (6 vs. 5 months, p = 0.86). The ORR for patients treated with ICIs was 26.3%. Furthermore, no significant differences were found for PFS (p = 0.27) and OS (p = 0.75) between patients with positive and negative PDL1 expression. Additionally, there was no significant difference in PD-L1 levels (p = 0.10) between patients who achieved objective response and those who did not.

CONCLUSIONS

Patients with RET fusion positive NSCLCs may not benefit from ICI based regimens and therefore should not be treated with ICIs in clinical practice.

A network map of GDNF/RET signaling pathway in physiological and pathological conditions

Glial cell line-derived neurotrophic factor (GDNF) signals through a multi-component receptor system predominantly consisting of glycosyl-phosphatidylinositol-anchored GDNF family receptor alpha-1 (GFRα1) and the Rearranged during transfection (RET) receptor tyrosine kinase. GDNF/RET signaling is vital to the central and peripheral nervous system, kidney morphogenesis, and spermatogenesis. In addition, the dysregulation of the GDNF/RET signaling has been implicated in the pathogenesis of cancers. Despite the extensive research on GDNF/RET signaling, a molecular network of reactions induced by GDNF reported across the published literature. However, a comprehensive GDNF/RET pathway resource is currently unavailable. We describe an integrated signaling pathway reaction map of GDNF/RET consisting of 1151 molecular reactions. These include information pertaining to 52 molecular association events, 70 enzyme catalysis events, 36 activation/inhibition events, 22 translocation events, 856 gene regulation events, and 115 protein-level expression events induced by GDNF in diverse cell types. We developed a comprehensive GDNF/RET signaling network map based on these molecular reactions. The pathway map was made accessible through WikiPathways database ( https://www.wikipathways.org/index.php/Pathway:WP5143 ). Biocuration and development of gene regulatory network map of GDNF/RET signaling pathway.

The significance of tissue-agnostic biomarkers in solid tumors: the more the merrier?

INTRODUCTION

To date, several emerging biomarkers have gained considerable interest in the field of predictive molecular oncology. The advent of precision medicine has led to the development of innovative drugs targeting rare molecular pathways independently from histology, defined as tissue-agnostic drugs.

AREAS COVERED

Although there is a lot of promise for this new tissue-agnostic model in the oncological scenario, crucial issues from both the diagnostic and therapeutic standpoint are emerging. This review aims to critically examine the role of tissue-agnostic biomarkers in different solid tumors, focusing on the prevalence and methods of detection of agnostic biomarkers together with drug approvals to guide clinicians in this evolving landscape.

EXPERT OPINION

To strengthen the framework for tissue-agnostic approvals, the dialogue between regulatory, industrial, and academic parties should be intensified. Critical questions include the development of an efficient network system that can overcome the heterogeneity of patients' inclusion criteria along with the increasingly difficult interpretation of next-generation sequencing (NGS) profiling technologies. Cost-effectiveness and risk-benefit studies are needed in the national context considering the modalities of access to diagnostic tests and reimbursement of treatments.

Clinical Characteristics and Responses to Immune Checkpoint Inhibitors in RET-Aberrant Digestive Tract Tumours

BACKGROUND

RET plays an oncogenic role, and its aberrations are potentially actionable. However, they have seldom been reported in tumours other than lung or thyroid cancers. The correlation of RET aberrations with clinical characteristics, co-occurring aberrations, and responses to immune checkpoint inhibitors (ICPi) have not been explored in digestive tract tumours.

OBJECTIVES

The aim of the study was to elucidate the clinical characteristics, frequently co-altered genes, and treatment responses in RET-aberrant digestive tract tumours.

PATIENTS AND METHODS

We retrospectively evaluated patients with digestive tract cancers for RET-aberrant tumours via FoundationOne CDx tumour-based selected genome sequencing from Jan 2016 to Jan 2021.

RESULTS

In a median follow-up time of 51 months, a total of 453 patients were analysed. RET-aberrant tumours accounted for 4.4% in the studied population (n = 20), and 1.1% had an oncogenic fusion (n = 5). APC, KRAS, TP53, MSH6 and STK11 were the differentially co-altered genes (all false discovery rates <0.05). The presence of RET aberrations alone was not a significant prognostic factor. Eleven patients with RET-aberrant tumours received ICPi-based treatment and none achieved an objective response. In contrast, 47 patients with non-aberrant tumours received ICPi treatment and had an objective response rate of 27.7% and a significantly longer treatment duration (6.2 vs 2.8 months, p = 0.0008).

CONCLUSIONS

Albeit rarely, RET aberrations can be found in digestive tract tumours. Patients with RET-aberrant tumours have a blunted response to ICPi and a comparable prognosis as compared with RET-wild type tumours. Together, these results provide insights into this rare but potentially actionable target in digestive tract tumours.

Precision oncology with selective RET inhibitor selpercatinib in RET-rearranged cancers

Rearranged during transfection (RET) is a protooncogene that encodes for receptor tyrosine kinase with downstream effects on multiple cellular pathways. Activating RET alterations can occur and lead to uncontrolled cellular proliferation as a hallmark of cancer development. Oncogenic RET fusions are present in nearly 2% of patients with non-small cell lung cancer (NSCLC), 10-20% of patients with thyroid cancer, and <1% across the pan-cancer spectrum. In addition, RET mutations are drivers in 60% of sporadic medullary thyroid cancers and 99% of hereditary thyroid cancers. The discovery, rapid clinical translation, and trials leading to FDA approvals of selective RET inhibitors, selpercatinib and pralsetinib, have revolutionized the field of RET precision therapy. In this article, we review the current status on the use of the selective RET inhibitor, selpercatinib, in RET fusion-positive tumors: NSCLC, thyroid cancers, and the more recent tissue-agnostic activity leading to FDA approval.

Design, synthesis and pharmacological evaluation of 2,3-dihydrobenzofuran IRAK4 inhibitors for the treatment of diffuse large B-cell lymphoma

Interleukin-1 receptor associated kinase 4 (IRAK4) is a critical mediator of MYD88 L265P-induced NF-κB activation, indicating it is a promising therapeutic target for diffuse large B-cell lymphoma (DLBCL). Herein we report the discovery of a series of 2,3-dihydrobenzofuran IRAK4 inhibitors through structure-based drug design. The representative compound 22 exhibited strong IRAK4 inhibitory potency (IRAK4 IC₅₀ = 8.7 nM), favorable kinase selectivity and high antiproliferative activity against the MYD88 L265P DLBCL cell line (OCI-LY10 IC₅₀ = 0.248 μM). Compound 22 also exhibited the ability to inhibit the activation of IRAK4 signaling pathway and induce apoptosis in MYD88 L265P DLBCL cell line. In combination with Bruton's tyrosine kinase (BTK) inhibitor ibrutinib, 22 showed enhanced apoptosis-inducing effect and antiproliferative potency. The most advanced compound 22 in this inhibitor series holds promise for further development into efficacious and selective IRAK4 inhibitors for the treatment of DLBCL.

Complete response to alectinib in ALK-fusion metastatic salivary ductal carcinoma

The advent of next-generation sequencing (NGS) has allowed for the identification of novel therapeutic targets for patients with uncommon cancers. It is well known that fusion translocations are potent driver of cancer pathogenesis and can render tumors exquisitely sensitive to matching targeted therapies. Here we describe a patient with ALK-fusion positive widely metastatic salivary ductal carcinoma, who achieved a durable complete response from alectinib, a potent and specific ALK tyrosine kinase inhibitor. This case serves as another reminder that ALK-fusions can be targeted regardless of histology and can afford patients dramatic and durable benefit. It also emphasizes the need for insurance coverage for such beneficial therapies. While ALK fusions are exceedingly rare in salivary ductal carcinoma, the presence of multiple other targetable aberrations supports the recommendation for universal NGS testing for such tumors.

Progress and challenges in RET-targeted cancer therapy

The rearranged during transfection (RET) is a receptor protein tyrosine kinase. Oncogenic RET fusions or mutations are found most often in non-small cell lung cancer (NSCLC) and in thyroid cancer, but also increasingly in various types of cancers at low rates. In the last few years, two potent and selective RET protein tyrosine kinase inhibitors (TKIs), pralsetinib (BLU-667) and selpercatinib (LOXO-292, LY3527723) were developed and received regulatory approval. Although pralsetinib and selpercatinib gave high overall response rates (ORRs), < 10% of patients achieved a complete response (CR). The RET TKI-tolerated residual tumors inevitably develop resistance by secondary target mutations, acquired alternative oncogenes, or MET amplification. RET G810 mutations located at the kinase solvent front site were identified as the major on-target mechanism of acquired resistance to both selpercatinib and pralsetinib. Several next-generation of RET TKIs capable of inhibiting the selpercatinib/pralsetinib-resistant RET mutants have progressed to clinical trials. However, it is likely that new TKI-adapted RET mutations will emerge to cause resistance to these next-generation of RET TKIs. Solving the problem requires a better understanding of the multiple mechanisms that support the RET TKI-tolerated persisters to identify a converging point of vulnerability to devise an effective co-treatment to eliminate the residual tumors.

Receptor tyrosine kinase inhibitors in cancer

Targeted therapy is a new cancer treatment approach, involving drugs that particularly target specific proteins in cancer cells, such as receptor tyrosine kinases (RTKs) which are involved in promoting growth and proliferation, Therefore inhibiting these proteins could impede cancer progression. An understanding of RTKs and the relevant signaling cascades, has enabled the development of many targeted drug therapies employing RTK inhibitors (RTKIs) some of which have entered clinical application. Here we discuss RTK structures, activation mechanisms and functions. Moreover, we cover the potential effects of combination drug therapy (including chemotherapy or immunotherapy agents with one RTKI or multiple RTKIs) especially for drug resistant cancers.

Evolution of the Targeted Therapy Landscape for Cholangiocarcinoma: Is Cholangiocarcinoma the 'NSCLC' of GI Oncology?

In the past two decades, molecular targeted therapy has revolutionized the treatment landscape of several malignancies. Lethal malignancies such as non-small cell lung cancer (NSCLC) have become a model for precision-matched immune- and gene-targeted therapies. Multiple small subgroups of NSCLC defined by their genomic aberrations are now recognized; remarkably, taken together, almost 70% of NSCLCs now have a druggable anomaly. Cholangiocarcinoma (CCA) is a rare tumor with a poor prognosis. Novel molecular alterations have been recently identified in patients with CCA, and the potential for targeted therapy is being realized. In 2019, a fibroblast growth factor receptor 2 (FGFR2) inhibitor, pemigatinib, was the first approved targeted therapy for patients with locally advanced or metastatic intrahepatic CCA who had FGFR2 gene fusions or rearrangement. More regulatory approvals for matched targeted therapies as second-line or subsequent treatments in advanced CCA followed, including additional drugs that target FGFR2 gene fusion/rearrangement. Recent tumor-agnostic approvals include (but are not limited to) drugs that target mutations/rearrangements in the following genes and are hence applicable to CCA: isocitrate dehydrogenase 1 (IDH1); neurotrophic tropomyosin-receptor kinase (NTRK); the V600E mutation of the BRAF gene (BRAFV600E); and high tumor mutational burden, high microsatellite instability, and gene mismatch repair-deficient (TMB-H/MSI-H/dMMR) tumors. Ongoing trials investigate HER2, RET, and non-BRAFV600E mutations in CCA and improvements in the efficacy and safety of new targeted treatments. This review aims to present the current status of molecularly matched targeted therapy for advanced CCA.

The Glycosylated N-Terminal Domain of MUC1 Is Involved in Chemoresistance by Modulating Drug Permeation Across the Plasma Membrane

Mucin 1 (MUC1) is aberrantly expressed in various cancers and implicated in cancer progression and chemoresistance. Although the C-terminal cytoplasmic tail of MUC1 is involved in signal transduction, promoting chemoresistance, the role of the extracellular MUC1 domain [N-terminal glycosylated domain (NG)-MUC1] remains unclear. In this study, we generated stable MCF7 cell lines expressing MUC1 and cytoplasmic tail-deficient MUC1 (MUC1ΔCT) and show that NG-MUC1 is involved in drug resistance by modulating the transmembrane permeation of various compounds without cytoplasmic tail signaling. Heterologous expression of MUC1ΔCT increased cell survival in treating anticancer drugs (such as 5-fluorouracil, cisplatin, doxorubicin, and paclitaxel), in particular by causing an approximately 150-fold increase in the IC₅₀ of paclitaxel, a lipophilic drug, compared with the control [5-fluorouracil (7-fold), cisplatin (3-fold), and doxorubicin (18-fold)]. The uptake studies revealed that accumulations of paclitaxel and Hoechst 33342, a membrane-permeable nuclear staining dye, were reduced to 51% and 45%, respectively, in cells expressing MUC1ΔCT via ABCB1/P-gp-independent mechanisms. Such alterations in chemoresistance and cellular accumulation were not observed in MUC13-expressing cells. Furthermore, we found that MUC1 and MUC1ΔCT increased the cell-adhered water volume by 2.6- and 2.7-fold, respectively, suggesting the presence of a water layer on the cell surface created by NG-MUC1. Taken together, these results suggest that NG-MUC1 acts as a hydrophilic barrier element against anticancer drugs and contributes to chemoresistance by limiting the membrane permeation of lipophilic drugs. Our findings could help better the understanding of the molecular basis of drug resistance in cancer chemotherapy. SIGNIFICANCE STATEMENT: Membrane-bound mucin (MUC1), aberrantly expressed in various cancers, is implicated in cancer progression and chemoresistance. Although the MUC1 cytoplasmic tail is involved in proliferation-promoting signal transduction thereby leading to chemoresistance, the significance of the extracellular domain remains unclear. This study clarifies the role of the glycosylated extracellular domain as a hydrophilic barrier element to limit the cellular uptake of lipophilic anticancer drugs. These findings could help better the understanding of the molecular basis of MUC1 and drug resistance in cancer chemotherapy.

Drugging Hijacked Kinase Pathways in Pediatric Oncology: Opportunities and Current Scenario

Childhood cancer is considered rare, corresponding to ~3% of all malignant neoplasms in the human population. The World Health Organization (WHO) reports a universal occurrence of more than 15 cases per 100,000 inhabitants around the globe, and despite improvements in diagnosis, treatment and supportive care, one child dies of cancer every 3 min. Consequently, more efficient, selective and affordable therapeutics are still needed in order to improve outcomes and avoid long-term sequelae. Alterations in kinases' functionality is a trademark of cancer and the concept of exploiting them as drug targets has burgeoned in academia and in the pharmaceutical industry of the 21st century. Consequently, an increasing plethora of inhibitors has emerged. In the present study, the expression patterns of a selected group of kinases (including tyrosine receptors, members of the PI3K/AKT/mTOR and MAPK pathways, coordinators of cell cycle progression, and chromosome segregation) and their correlation with clinical outcomes in pediatric solid tumors were accessed through the R2: Genomics Analysis and Visualization Platform and by a thorough search of published literature. To further illustrate the importance of kinase dysregulation in the pathophysiology of pediatric cancer, we analyzed the vulnerability of different cancer cell lines against their inhibition through the Cancer Dependency Map portal, and performed a search for kinase-targeted compounds with approval and clinical applicability through the CanSAR knowledgebase. Finally, we provide a detailed literature review of a considerable set of small molecules that mitigate kinase activity under experimental testing and clinical trials for the treatment of pediatric tumors, while discuss critical challenges that must be overcome before translation into clinical options, including the absence of compounds designed specifically for childhood tumors which often show differential mutational burdens, intrinsic and acquired resistance, lack of selectivity and adverse effects on a growing organism.

RET aberrant cancers and RET inhibitor therapies: Current state-of-the-art and future perspectives

Precision oncology informed by genomic information has evolved in leaps and bounds over the last decade. Although non-small cell lung cancer (NSCLC) has moved to center-stage as the poster child of precision oncology, multiple targetable genomic alterations have been identified in various cancer types. RET alterations occur in roughly 2% of all human cancers. The role of RET as oncogenic driver was initially identified in 1985 after the discovery that transfection with human lymphoma DNA transforms NIH-3T3 fibroblasts. Germline RET mutations are causative of multiple endocrine neoplasia type 2 syndrome, and RET fusions are found in 10-20% of papillary thyroid cases and are detected in most patients with advanced sporadic medullary thyroid cancer. RET fusions are oncogenic drivers in 2% of Non-small cell lung cancer. Rapid translation and regulatory approval of selective RET inhibitors, selpercatinib and pralsetinib, have opened up the field of RET precision oncology. This review provides an update on RET precision oncology from bench to bedside and back. We explore the impact of selective RET inhibitor in patients with advanced NSCLC, thyroid cancer, and other cancers in a tissue-agnostic fashion, resistance mechanisms, and future directions.

Exceptional response to neoadjuvant targeted therapy with the selective RET inhibitor selpercatinib in RET-fusion-associated sarcoma

With the increasing use of next-generation sequencing, highly effective targeted therapies have been emerging as treatment options for several cancer types. Recurrent gene-fusions have been recognized in sarcomas; however, options for targeted therapy remain scarce. Here, we describe a case of a sarcoma, associated with a RET::TRIM33-fusion gene with an exceptional response to a neoadjuvant therapy with the selective RET inhibitor selpercatinib. Resected tumor revealed subtotal histopathologic response. This is the first report of successful targeted therapy with selpercatinib in RET-fusion-associated sarcomas. As new targeted therapies are under development, similar treatment options may become available for sarcoma patients.

An integrative pan cancer analysis of RET aberrations and their potential clinical implications

RET (rearranged during transfection), encoding a tyrosine kinase receptor, is a novel therapeutic target for cancers. The aberrations of RET are commonly found in cancers. Here, we profiled a comprehensive genomic landscape of RET mutations, copy number variants (CNVs), co-occurrence of RET and its mRNA expression and methylation levels in pan cancer, paving the way to the development of new RET-targeted therapies in clinic. Analysis of RET somatic mutations, CNVs, co-occurrence, mRNA expression and methylation were performed among 32 cancer types from The Cancer Genome Atlas (TCGA) dataset covering a total of 10,953 patients with 10,967 samples. RET aberrations were found in 3.0% of diverse cancers. The top two RET-altered tumors were skin cutaneous melanoma (SKCM) and uterine corpus endometrial carcinoma (UCEC) with dominant mutations in the other and PKinase_Tyr domains. RET-G823E and RET-S891L were most commonly found in SKCM and UCEC. Thyroid carcinoma (THCA) demonstrated the highest rate of coiled-coil domain containing 6 (CCDC6)-RET fusions, which constitutively activate RET kinase. Two FDA-approved RET inhibitors—pralsetinib and selpercatinib have been implied for the treatment of patients with RET S891L mutant UCEC and the treatment of patients with metastatic RET-fusion positive THCA and non-small cell lung cancer (NSCLC) at therapeutic level 1. We also identified four RET M918T-altered cases in patients with pheochromocytoma and paraganglioma (PCPG), which may induce drug resistance against multikinase inhibitors. Next, 273 co-occurring aberrations, most frequently in Notch signaling, TGF-β pathway, cell cycle, and Ras-Raf-MEK-Erk/JNK signaling, were uncovered among 311 RET altered cases. TP53 mutations (162 patients) leads to the most significant co-occurrence associated with RET aberrations. Furthermore, the RET expression was found most significantly increased in breast invasive carcinoma (BRCA) and neck squamous cell carcinoma (HNSC), as compared to their corresponding normal tissues. At last, patients with higher expression and sequence variant frequency have a worse prognosis, such as sarcoma patients. This work provided a profound and comprehensive analysis of RET and co-occurred alterations, RET mRNA expression and the clinical significance in pan cancer, offering new insights into targeted therapy for patients with RET anomalies.

[Targeted treatment of non-small cell lung cancer]

Non-small cell lung cancer (NSCLC) has made a remarkable development in recent decades with respect to its perception. In the late 1990s it was the "problem child" as the main cause of cancer with increasing tendencies, especially in women and with a pronounced stigmatization. It is now the role model as a biologically rational targeted treatment based on molecular dependencies of the tumor with a vast improvement of the traditionally poor survival times. Molecular tumor boards have long followed the NSCLC example in the assessment of targeted treatment approaches for other tumor entities. This review article gives an overview of the current possibilities for targeted treatment of NSCLC, which nowadays are applicable for nearly one third of all patients with NSCLC.

Sporadic Medullary Thyroid Carcinoma: Towards a Precision Medicine

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignant tumor originating from parafollicular C-cells producing calcitonin. Most of cases (75%) are sporadic while the remaining (25%) are hereditary. In these latter cases medullary thyroid carcinoma can be associated (multiple endocrine neoplasia type IIA and IIB) or not (familial medullary thyroid carcinoma), with other endocrine diseases such as pheochromocytoma and/or hyperparathyroidism. RET gene point mutation is the main molecular alteration involved in MTC tumorigenesis, both in sporadic and in hereditary cases. Total thyroidectomy with prophylactic/therapeutic central compartment lymph nodes dissection is the initial treatment of choice. Further treatments are needed according to tumor burden and rate of progression. Surgical treatments and local therapies are advocated in the case of single or few local or distant metastasis and slow rate of progression. Conversely, systemic treatments should be initiated in cases with large metastatic and rapidly progressive disease. In this review, we discuss the details of systemic treatments in advanced and metastatic sporadic MTC, focusing on multikinase inhibitors, both those already used in clinical practice and under investigation, and on emerging treatments such as highly selective RET inhibitors and radionuclide therapy.