RET Mutations Research Articles

Metastatic medullary thyroid carcinoma: a new way forward.

Medullary thyroid carcinoma (MTC) is a rare malignancy comprising 1–2% of all thyroid cancers in the United States. Approximately 20% of cases are familial, secondary to a germline RET mutation, while the remaining 80% are sporadic and also harbour a somatic RET mutation in more than half of all cases. Up to 15–20% of patients will present with distant metastatic disease, and retrospective series report a 10-year survival of 10–40% from time of first metastasis. Historically, systemic therapies for metastatic MTC have been limited, and cytotoxic chemotherapy has demonstrated poor objective response rates. However, in the last decade, targeted therapies, particularly multitargeted tyrosine kinase inhibitors (TKIs), have demonstrated prolonged progression-free survival in advanced and progressive MTC. Both cabozantinib and vandetanib have been approved as first-line treatment options in many countries; nevertheless, their use is limited by high toxicity rates and dose reductions are often necessary. New generation TKIs, such as selpercatinib or pralsetinib, that exhibit selective activity against RET, have recently been approved as a second-line treatment option, and they exhibit a more favourable side-effect profile. Peptide receptor radionuclide therapy or immune checkpoint inhibitors may also constitute potential therapeutic options in specific clinical settings. In this review, we aim to present all current therapeutic options available for patients with progressive MTC, as well as new or as yet experimental treatments.

Preoperative serum calcitonin may improve initial surgery for medullary thyroid cancer in patients with indeterminate cytology.

BackgroundMedullary thyroid cancer (MTC) is rare, with poorer outcomes than differentiated thyroid cancer. We aimed to identify areas for improvement in the pre‐operative evaluation of patients with possible MTC in a high‐volume endocrine surgery unit in accordance with current practice guidelines. We hypothesised that the selective use of serum calcitonin (sCT) as a biomarker for possible MTC could guide the extent of initial surgical management.MethodsWe recruited MTC patients between 2000 and 2020 from the Monash University Endocrine Surgery Unit database. Demographics, tumour characteristics, pre‐operative evaluation, operative management, and outcomes were analysed.ResultsOf 1454 thyroid cancer patients, 43 (3%) had MTC. Pre‐operatively, 36 (84%) patients with MTC confirmed on cytology (28, 65%), elevated sCT (6, 14%) or RET mutation (2, 4%). Of these 36 patients, 31 (86%) had optimal extent of thyroidectomy and lymph node dissection (LND). Five (14%) had less than total thyroidectomy due to nerve injury. Thirty‐four patients had compartmental LND. In the 12 (27%) patients with indeterminate or non‐diagnostic cytology, 5 had elevated sCT and were managed as above. None of the remaining seven had LND, thus potentially suboptimal surgery.ConclusionOur findings reflect the rarity of MTC, and the challenges of pre‐operative diagnosis. The addition of sCT may improve surgical planning in patients with indeterminate cytology.

The efficacy and prognostic factors of immunotherapy in advanced non-small cell lung cancer patients with different driver gene mutations

Objective: To explore the efficacy and prognostic factors of immunotherapy in advanced non-small cell lung cancer (NSCLC) patients with different driver gene mutations. Methods: Medical records of advanced NSCLC patients who harbored driver gene mutations (EGFR, KRAS, ALK and etc.) and received PD-1 inhibitors in Henan Cancer Hospital from April 2016 to May 2021 were collected. Treatment patterns, progression free survival (PFS), overall survival (OS) and prognostic factors of patients with driver gene mutations were estimated. Results: A total of 120 patients were included. There were 70 males and 50 females, with a median age [M(Q1,Q3)] of 57 (50, 65) years. Of these, 52 patients harbored KRAS mutations, 42 patients harbored EGFR mutations, 16 patients harbored ERBB2 mutations, 5 patients harbored MET mutations or amplifications, 5 patients harbored ROS-1 mutations, 2 patients harbored BRAF mutations, and the last 2 patients harbored ALK and RET mutations, respectively. The PFS and OS [M (95%CI)] were 6.4 (5.1-7.8) and 31.2 (22.0-40.3) months in 120 participated patients. Patients with KRAS mutations showed the greatest survival benefit from Immune checkpoint inhibitors (ICIs) with the PFS of 9.7 (4.8-14.6) months and OS of 31.2 (19.4-50.6) months. They mostly received the first-line (34.6%, 18/52) and second-line (38.5%, 20/52) ICIs. The PFS and OS of EGFR mutant patients were 3.9 (1.8-6.1) months and 18.0 (12.1-23.8) months, respectively. They tended to receive ICIs after resistance to EGFR-tyrosine kinase inhibitors (TKIs), and the proportion of second-, third-, fourth or further-line drugs was 38.1% (16/42), 11.9% (5/42), and 47.6% (20/42), respectively. PD-L1 expression level (negative vs ≥50% positive: HR=3.710, 95%CI: 1.372-10.031, P=0.010; 1%-49% positive vs ≥50% positive: HR=2.738, 95%CI: 0.841-8.912, P=0.094), age (every additional year: HR=0.957, 95%CI: 0.933-0.982, P=0.001) and different driver mutations status (EGFR vs KRAS: HR=2.676, 95%CI: 1.317-5.436, P=0.006; ERBB2 vs KRAS: HR=3.411, 95%CI: 1.493-7.792, P=0.004; other mutations vs KRAS: HR=0.727, 95%CI: 0.322-1.643, P=0.444) were prognostic factors for PFS. While PD-L1 expression level (negative vs ≥50% positive: HR=2.305, 95%CI: 0.748-7.103, P=0.146; 1%-49% positive vs ≥50% positive: HR=1.286, 95%CI: 0.337-4.913, P=0.713), and treatment lines of ICIs (first-line vs ≥ third-line: HR=0.322, 95%CI: 0.114-0.914, P=0.033; second-line vs ≥ third-line: HR=0.375, 95%CI: 0.178-0.789, P=0.010) were prognostic factors for OS. Conclusions: KRAS mutant NSCLC patients mostly receive ICIs at the front line, and have best survival benefits from immunotherapy. While EGFR mutant NSCLC patients tend to receive ICIs at the back line, and obtain reasonable survival benefits. PD-L1 expression level, age, and different driver mutations status are prognostic factors for PFS, and PD-L1 expression level and treatment lines of ICIs are prognostic factors for OS.

SDHB knockout and succinate accumulation are insufficient for tumorigenesis but dual SDHB/NF1 loss yields SDHx-like pheochromocytomas.

SUMMARYInherited pathogenic succinate dehydrogenase (SDHx) gene mutations cause the hereditary pheochromocytoma and paraganglioma tumor syndrome. Syndromic tumors exhibit elevated succinate, an oncometabolite that is proposed to drive tumorigenesis via DNA and histone hypermethylation, mitochondrial expansion, and pseudohypoxia-related gene expression. To interrogate this prevailing model, we disrupt mouse adrenal medulla SDHB expression, which recapitulates several key molecular features of human SDHx tumors, including succinate accumulation but not 5hmC loss, HIF accumulation, or tumorigenesis. By contrast, concomitant SDHB and the neurofibromin 1 tumor suppressor disruption yields SDHx-like pheochromocytomas. Unexpectedly, in vivo depletion of the 2-oxoglutarate (2-OG) dioxygenase cofactor ascorbate reduces SDHB-deficient cell survival, indicating that SDHx loss may be better tolerated by tissues with high antioxidant capacity. Contrary to the prevailing oncometabolite model, succinate accumulation and 2-OG-dependent dioxygenase inhibition are insufficient for mouse pheochromocytoma tumorigenesis, which requires additional growth-regulatory pathway activation.

A synchronous medullary and papillary thyroid carcinoma

<p>The synchronous occurrence of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) is rare (<1%). The medullary component determines the prognosis. A 31-year-old female with no relevant personal or family cancer history presented with swelling on the right side of the neck. A fine-needle aspiration biopsy was positive for MTC and PTC. Mass sequencing of 322 genes associated with cancer came back negative. The histopathological examination revealed synchronous MTC and PTC with thymic and bilateral lymph node metastasis. The patient underwent total thyroidectomy with bilateral radical neck dissection (II-V), central dissection, and mediastinal dissection including the thymus. The extent of surgery is determined by MTC and the analysis of RET and BRAF mutations. Post-operative treatment must include monitoring for specific markers (calcitonin and thyroglobulin, respectively, for MTC and PTC). Based on histopathological results and recurrent PTC, TSH suppression and iodine-131 therapy should be considered. Recurrent MTC must be treated with new targeted therapies.</p>

Diagnostic characteristics, treatment patterns, and clinical outcomes for patients with advanced/metastatic medullary thyroid cancer

BackgroundMedullary thyroid cancer (MTC) accounts for approximately 1.6% of new cases of thyroid cancer. The objective of this study was to describe patient characteristics, biomarker testing, treatment patterns, and clinical outcomes among patients with advanced/metastatic MTC in a real-world setting in the United States and to identify potential gaps in the care of these patients.MethodsSelected oncologists retrospectively reviewed medical records of patients aged ≥ 12 years diagnosed with advanced MTC. Patients must have initiated ≥ 1 line of systemic treatment for advanced/metastatic MTC between January 2013–December 2018 to be eligible. Patient characteristics, biomarker testing, and treatment patterns were summarized descriptively; progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method.ResultsThe 203 patients included in this study had a mean (SD) age of 52.2 (10.4) years; mean (SD) duration of follow-up from start of first-line treatment was 24.5 (16.0) months. Most patients (82.8%) were initially diagnosed with stage IVA, IVB, or IVC disease. Among all patients, 121 (59.6%) had testing for RET mutations, of whom 37.2% had RET-mutant MTC. The RET-mutation type was reported for 28 patients; the most common mutations reported were M918T (64.3%) and C634R (32.1%). Of the 203 patients, 75.9% received only one line of systemic treatment for advanced disease, and 36% were still undergoing first-line therapy at the time of data extraction. Cabozantinib (30.0%), vandetanib (30.0%), sorafenib (17.2%), and lenvatinib (4.9%) were the most common first-line treatments. Among 49 patients who received second-line treatment, most received cabozantinib (22.4%), vandetanib (20.4%), lenvatinib (12.2%), or sunitinib (12.2%). Median PFS (95% confidence interval [CI]) from start of first- and second-line treatments was 26.6 months (20.8–60.8) and 15.3 months (6.6-not estimable [NE]), respectively. Median OS from initiation of first- and second-line treatment was 63.8 months (46.3-NE) and 22.4 months (12.4-NE), respectively.ConclusionsFor the treatment of advanced/metastatic MTC, no specific preference of sequencing systemic agents was observed in the first- and second-line settings. Considering the recent approval of selective RET inhibitors for patients with RET-mutant MTC, future research should investigate how treatment patterns evolve for these patients.

Surgical aspects and controversies in the management of medullary thyroid cancer.

Medullary thyroid cancer (MTC) accounts for only 4% of thyroid carcinomas but 15% of thyroid cancer deaths. MTC is a tumour of the calcitonin secreting parafollicular C cells in the thyroid which can occur sporadically or be hereditary in multiple endocrine neoplasias type 2 syndromes due to germline RET mutations. Sporadic forms of MTC can also be caused by mutations in the RET protooncogene. MTC commonly presents in a late stage, with 70% of patients presenting with local nodal metastasis. Currently, the only curative treatment for MTC is surgical removal. The aim of this paper is to describe the current guidelines and progressions of the surgical management of MTC and to highlight up-and-coming chemotherapies. A database literature review was completed utilizing PubMed to cumulate the extant literature, screening for most recent guidelines and publications regarding the management of MTC. Current guidelines were described by the American Thyroid Association in 2015. Controversial publications continue to present supporting evidence for varying degrees of thyroidectomy and neck dissections. Recently, researchers have been exploring non-surgical options including external beam radiotherapy and multikinase inhibitors such as vandetanib and cabozantinib for the treatment of MTC. Surgical management of MTC remains controversial and varies significantly dependent on the extent of disease. Chemotherapeutic options have undetermined effects on survival to date.

Molecular Characterization and Prognostication of Large Cell Neuroendocrine Carcinoma and Large Cell Carcinoma.

PurposeLarge cell neuroendocrine carcinoma (LCNEC) and classic large cell carcinoma (LCC) are two distinct entities with different histological and biological characteristics. However, the mutational profiles and the clinical behavior of the two subtypes of lung cancer remain to be explored.Patients and MethodsPathological diagnoses of all screened patients were finally confirmed by three or four experienced pathologists. Patients with uncertain pathological diagnoses were excluded. Finally, we genetically profiled ten patients with LCNEC and seven with LCC. ALL patients were subjected to next-generation sequencing (NGS) test, which included nine patients sequenced with a 139-gene panel and eight patients with a 425-gene panel. Including only intersected mutations from these two panels, survival analysis was further conducted.ResultsBoth LCNEC and LCC showed high prevalence in male patients, with no clear association with smoking history. Potential targetable mutations in KRAS and RET were detected in the study cohort. However, LCNEC and LCC showed distinct mutational profiles with an enrichment of RB1/TP53 co-mutations in a subset of LCNEC patients. SMARCA4 and KEAP1 mutations were exclusively found in LCC patients, and RICTOR, BRAF, ROS1 and TET2 mutations were only detected in LCNEC. LCC patients in the cohort had shorter survival compared to LCNEC patients (p=0.006). Survival analysis revealed an association between SMARCA4 mutations and poor outcome in the study cohort and in the LCC subset. Mutations in BRAF were associated with a trend of increased survival in the study cohort, as well as in the LCNEC subset. Finally, TET2 mutations were associated with poor outcome in the LCNEC cohort.ConclusionLCC and LCNEC were both heterogeneous diseases with limited treatment options. Our study identified potential targetable mutations and prognostic biomarkers that might provide more therapeutic options and improve individualized patient care.

Distribution of RET proto‐oncogene variants in children with appendicitis

BackgroundIn addition to patient‐related systemic factors directing the immune response, the pathomechanisms of appendicitis (AP) might also include insufficient drainage leading to inflammation caused by decreased peristalsis. Genetic predisposition accounts for 30%–50% of AP. M. Hirschsprung (HSCR), also characterized by disturbed peristalsis, is associated with variants in the RET proto‐oncogene. We thus hypothesized that RET variants contribute to the etiology of AP.MethodsDNA from paraffin‐embedded appendices and clinical data of 264 children were analyzed for the RET c.135A>G variant (rs1800858, NC_000010.11:g.43100520A>G). In 46 patients with gangrenous or perforated AP (GAP), peripheral blood DNA was used for RET sequencing.ResultsGermline mutations were found in 13% of GAP, whereas no RET mutations were found in controls besides the benign variant p.Tyr791Phe (NC_000010.11:g.43118460A>T). In GAP, the polymorphic G‐allele in rs2435352 (NC_000010.11:g.43105241A>G) in intron 4 was underrepresented (p = 0.0317).ConclusionOur results suggest an impact of the RET proto‐oncogene in the etiology of AP. Mutations were similar to patients with HSCR but no clinical features of HSCR were observed. The pathological phenotypes in both populations might thus represent a multigenic etiology including RET germline mutations with phenotypic heterogeneity and incomplete penetrance.

Multicenter real-world data of patients harboring rare mutations other than EGFR or ALK in advanced or metastatic non-small cell lung cancer.

BackgroundStudies on the application of targeted therapies for patients with non‐small cell lung cancer (NSCLC) who harbor rare genetic mutations are ongoing. In the present study, we investigated the real‐world data of NSCLC patients who harbor rare mutations.MethodsWe retrospectively analyzed patients with advanced or metastatic nonsquamous NSCLC aged >20 years with confirmed rare mutations (BRAF, ROS1, MET, RET, HER2, FGFR, and NTRK) from January 2015 to September 2020 at nine tertiary hospitals. In addition, we validated the lung cancer PCR panel kit in patients with confirmed mutations by NGS.ResultsAmong 118 patients included, 88 received platinum‐based chemotherapy as first‐line chemotherapy. The progression‐free survival of patients with BRAF, ERBB2, MET, RET, and ROS1 mutations was 10.9 months (95% confidence interval [CI]: 1.3–20.5), 5.3 months (95% CI: 3.0–7.5), 7.2 months (95% CI: 3.6–10.9), 11.4 months (95% CI: 9.2–13.6), and 10.0 months (95% CI: 3.7–16.4) respectively (p = 0.041). The median overall survival (OS) was not reached in patients with ROS1 mutations; however, in BRAF, ERBB2, MET, and RET mutant patients, median OS was 14.1 months (95% CI: 10.1–14.1), 34.5 months (95% CI: 13.2–36.9), 22.7 months (95% CI: 1.7–24.0), and 29.8 months (95% CI: 28.9–61.3), respectively (p = 0.006). Of the 27 tissue samples, 26 (96.3%) showed the same PCR panel kit result with NGS.ConclusionsFirst‐line platinum‐based chemotherapy showed durable benefit in patients with advanced or metastatic nonsquamous NSCLC harboring rare genetic mutation other than EGFR or ALK.

Abstract P06-02: Discovery of TAS0953/HM06, a novel next generation RET-specific inhibitor capable of inhibiting RET solvent front mutations

Abstract RET gene fusions are oncogenic drivers in multiple tumor types and are estimated to be present in 1% to 2% of non-squamous non-small cell lung cancers (NSCLCs). Although the first-generation selective RET inhibitors selpercatinib and pralsetinib show clinical antitumor activity in NSCLCs, acquired resistances driven by RET solvent front mutation (G810R/S/C) have emerged. In such cases, no other treatment options are currently available for these patients after relapse with selpercatinib or pralsetinib. TAS0953/HM06, a novel adenosine triphosphate-competitive and highly selective RET inhibitor, is a next-generation RET inhibitor that may overcome solvent front mutant resistance. We performed a panel test of 254 kinases and found that 23-nM TAS0953/HM06 displayed only RET inhibition as plotted over 50% inhibited kinases. TAS0953/HM06 potently inhibits recombinant wild-type (WT) RET at sub-nanomolar concentrations that are similar to the IC50 values of selpercatinib and pralsetinib in WT RET. We investigated the cellular potencies against RET WT fusions and RET mutations, including the gatekeeper mutations V804L/M and selpercatinib- or pralsetinib-resistant mutations G810R/S, in engineered BA/F3 cells. TAS0953/HM06 inhibited the growth of the RET fusion overexpressed in Ba/F3 cells, including both the V804M/L and G810R/S RET mutations and WT RET. In addition, we examined the crystal structure of the RET kinase domain complexed with an analogue of TAS0953/HM06. X-ray crystal structures of the complex revealed that the analogue has unique binding mode to RET respect to selpercatinib and pralsetinib: it does not fill the space in the direction of the side chain of G810, suggesting that TAS0953/HM06 effectively circumvents steric hindrance from solvent front substitutions. This feature likely contributes to the ability of TAS0953/HM06 to maintain its biological potency in G810 mutations. Finally, we evaluated the antitumor activity of various doses of TAS0953/HM06 in xenograft tumor model derived from Ba/F3 cells from mice expressing WT or G810R KIF5B-RET (these mice show resistance to selpercatinib and pralsetinib). A Doses as low as of 10 mg/kg twice a day, TAS0953/HM06 were able to significantly inhibit tumor growth and phospho-RET. Taken together, the results show that, in addition to its selective high potency against WT RET, TAS0953/HM06 shows significant potency against G810R solvent front mutation which is highly resistant to selpercatinib and pralsetinib, in vitro and in vivo. Therefore, TAS0953/HM06 might represent a new therapeutic option for patients with RET mutations, including those resistant to 1st generation selective RET inhibitors. The safety and efficacy of TAS0953/HM06 are currently being investigated in a phase 1/2 clinical trials (NCT04683250). Citation Format: Isao Miyazaki, Keiji Ishida, Masanori Kato, Tatsuya Suzuki, Hidenori Fujita, Shuichi Ohkubo, Yoshikazu Iwasawa. Discovery of TAS0953/HM06, a novel next generation RET-specific inhibitor capable of inhibiting RET solvent front mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P06-02.

Anticancer drug resistance: An update and perspective.

Driver mutations promote initiation and progression of cancer. Pharmacological treatment can inhibit the action of the mutant protein; however, drug resistance almost invariably emerges. Multiple studies revealed that cancer drug resistance is based upon a plethora of distinct mechanisms. Drug resistance mutations can occur in the same protein or in different proteins; as well as in the same pathway or in parallel pathways, bypassing the intercepted signaling. The dilemma that the clinical oncologist is facing is that not all the genomic alterations as well as alterations in the tumor microenvironment that facilitate cancer cell proliferation are known, and neither are the alterations that are likely to promote metastasis. For example, the common KRasG12C driver mutation emerges in different cancers. Most occur in NSCLC, but some occur, albeit to a lower extent, in colorectal cancer and pancreatic ductal carcinoma. The responses to KRasG12C inhibitors are variable and fall into three categories, (i) new point mutations in KRas, or multiple copies of KRAS G12C which lead to higher expression level of the mutant protein; (ii) mutations in genes other than KRAS; (iii) original cancer transitioning to other cancer(s). Resistance to adagrasib, an experimental antitumor agent exerting its cytotoxic effect as a covalent inhibitor of the G12C KRas, indicated that half of the cases present multiple KRas mutations as well as allele amplification. Redundant or parallel pathways included MET amplification; emerging driver mutations in NRAS, BRAF, MAP2K1, and RET; gene fusion events in ALK, RET, BRAF, RAF1, and FGFR3; and loss-of-function mutations in NF1 and PTEN tumor suppressors. In the current review we discuss the molecular mechanisms underlying drug resistance while focusing on those emerging to common targeted cancer drivers. We also address questions of why cancers with a common driver mutation are unlikely to evolve a common drug resistance mechanism, and whether one can predict the likely mechanisms that the tumor cell may develop. These vastly important and tantalizing questions in drug discovery, and broadly in precision medicine, are the focus of our present review. We end with our perspective, which calls for target combinations to be selected and prioritized with the help of the emerging massive compute power which enables artificial intelligence, and the increased gathering of data to overcome its insatiable needs.

What's New in Molecular Targeted Therapies for Thyroid Cancer?

Thyroid cancer refers to various cancers arising from thyroid gland. Differentiated thyroid cancers (DTCs) include papillary, follicular, and Hurthle cell carcinomas and represent cancers retain normal thyroid functions such as iodine uptake. Radioactive iodine (RAI) is generally used for upfront treatment of metastatic DTCs, but RAI refractory DTCs remain to be clinical challenges. Sorafenib and lenvatinib were approved for the treatment of RAI refractory DTCs and more recently, genomics-based targeted therapies have been developed for NTRK and RET gene fusion-positive DTCs. Poorly differentiated and anaplastic thyroid cancers (ATCs) are extremely challenging diseases with aggressive courses. BRAF/MEK inhibition has been proven to be highly effective in BRAF V600E mutation-positive ATCs and immune checkpoint inhibitors have shown promising activities. Medullary thyroid cancers, which arise from parafollicular cells of thyroid, represent a unique subset of thyroid cancer and mainly driven by RET mutation. In addition to vandetanib and cabozantinib, highly specific RET inhibitors such as selpercatinib and pralsetinib have demonstrated impressive activity and are in clinical use.

The correlation between the expression of ATF4 and procalcitonin combined with the detection of RET mutation and the pathological stage and clinical prognosis of medullary thyroid carcinoma.

To explore the correlation between the activating transcription factor 4 (ATF4) and procalcitonin (PCT) expressions combined with RET mutation and the pathological staging and clinical prognosis of sporadic medullary thyroid carcinoma (SMTC). Fifty cases (tumor tissue) of SMTC diagnosed by clinicopathology were collected and the patients with nodular goiter were selected as normal control. The RET mutation site was analyzed by detection kit and expressions of PCT and ATF4 in SMTC were analyzed by Western blot and immunohistochemistry. Multiple linear regression was used to analyze the correlation of risk factors (PCT or ATF4 expression, RET mutation, tumor differentiation, SMTC stage, lymphatic metastasis) for 5-year recurrence and survival of SMTC. The ATF4 and PCT expressions were significantly decreased and increased, respectively, with the increase of the SMTC stage. The most frequent mutation of RET gene in cancer tissue was M 22458A in exon 16. The ATF4 and PCT expressions, as well as RET mutation, were significantly associated with a 5-year recurrence, while the ATF4 expression was significantly related to better 5-year survival. ATF4 and PCT expressions combined with RET mutation are related to the clinical prognosis of SMTC and can predict SMTC staging.

Drug-adapted RET mutations

Drug-adapted RET mutations

Active Surveillance in RET Gene Carriers Belonging to Families with Multiple Endocrine Neoplasia.

Simple SummaryMEN2 has a very high penetrance for the development of medullary thyroid cancer. However, intra- and inter-familial variabilities have been described. Accordingly, in this precision medicine era, a personalized approach should be adopted in subjects harboring RET mutations. In these subjects, we showed that thyroid surgery could be safely timed according to basal and stimulated calcitonin, especially in children who can reach adulthood, avoiding the risks of thyroid surgery and decreasing the period of a long-life hypothyroidism treatment.Multiple Endocrine Neoplasia 2 (MEN2) is a hereditary cancer syndrome for developing medullary thyroid cancer (MTC) due to germline mutations of RET gene. Subjects harboring a germline RET mutation without any clinical signs of MTC are defined as gene carriers (GCs), for whom guidelines propose a prophylactic thyroid surgery. We evaluate if active surveillance of GCs, pursuing early thyroid surgery, can be safely proposed and if it allows safely delaying thyroid surgery in children until adolescence/adulthood. We prospectively followed 189 GCs with moderate or high risk germline RET mutation. Surgery was planned in case of: elevated basal calcitonin (bCT) and/or stimulated CT (sCT); surgery preference of subjects (or parents, if subject less than 18 years old); other reasons for thyroid surgery. Accordingly, at RET screening, we sub-grouped GCs in subjects who promptly were submitted to thyroid surgery (Group A, n = 67) and who were not (Group B, n = 122). Group B was further sub-grouped in subjects who were submitted to surgery during their active surveillance (Group B1, n = 22) and who are still in follow-up (Group B2, n = 100). Group A subjects presented significantly more advanced age, bCT and sCT compared to Group B. Mutation RETV804M was the most common variant in both groups but it was significantly less frequent in Group A than B. Analyzing age, bCT, sCT and genetic landscape, Group B1 subjects differed from Group B2 only for sCT at last evaluation. Group A subjects presented more frequently MTC foci than Group B1. Moreover, Group A MTCs presented more aggressive features (size, T and N) than Group B1. Accordingly, at the end of follow-up, all Group B1 subjects presented clinical remission, while 6 and 12 Group A MTC patients had structural and biochemical persistent disease, respectively. Thank to active surveillance, only 13/63 subjects younger than 18 years at RET screening have been operated on during childhood and/or adolescence. In Group B1, three patients, while actively surveilled, had the possibility to reach the age of 18 (or older) and two patients the age of 15, before being submitted to thyroid surgery. In Group B2, 12 patients become older than 18 years and 17 older than 15 years. In conclusion, we demonstrated that an active surveillance pursuing an early thyroid surgery could be safely recommended in GCs. This patient-centered approach permits postponing thyroid surgery in children until their adolescence/adulthood. At the same time, we confirmed that genetic screening allows finding hidden MTC cases that otherwise would be diagnosed much later.

Liquid biopsy: Novel perspectives on the importance and spectrum of PIK3CA, PTEN and RET mutations in solid tumors.

Many people die from lung and breast cancer. Consequently, both physicians and researchers strive to provide reliable monitoring for disease, diagnosis and prognosis as well as resistance prediction. In the present study, a comprehensive liquid biopsy panel was performed on 474 patients to examine the importance and spectrum of recurrent somatic cancer mutations. Most patients visited the clinic with a diagnosis of advanced resistant cancer. The patients underwent a comprehensive liquid biopsy panel. Patients were divided into four groups based on cancer type as follows: Lung (n=379, 79.9%), breast (n=72, 15.2%), gastrointestinal (n=11, 2.3%) and other (n=12, 2.5%). Tier I-II-III classified variants were included in the study. The mean age was 60 years, with a range of 20-86 years. There were notably more male (n=272, 57.4%) than female patients (n=202, 42.6%). The most commonly mutated genes were TP53, EGFR, PIK3CA, RET, PTEN, MET, ATM and KRAS. The most common mutations were ‘PIK3CA, c.3140A>G, p.His1047Arg’, ‘RET, c.2324delinsGAC, p.Glu775Glyfs*6’, ‘TP53, c.217G>C, p.Val73Leu’, ‘EGFR, c.2155G>A, p.Gly719Ser’, ‘PIK3CA, c.1624G>A, p.Glu542Lys’, ‘PTEN, c.397G>A, p.Val133Ile’ and ‘EGFR, c.2235_2249del, p.Glu746_Ala750del’. The PIK3CA, PTEN and RET variants showed a higher incidence in the breast and lung groups compared with other groups. To the best of our knowledge, the present study is the first to concentrate on PIK3CA, PTEN and RET mutations in the context of breast and lung adenocarcinoma and to evaluate both genetic variability and the effect of treatment. The present results showed that patients with solid tumors, particularly lung and breast cancer, may benefit from PIK3CA, PTEN and RET sequencing to assess clinical characteristics and prognosis. Discoveries regarding the gene structure and mechanisms of PIK3CA, PTEN and RET may inform more clinically meaningful therapeutic approaches for patients with cancer and serve an essential role in improving individual risk prediction, therapy and prognosis.

A case report of Potter’s syndrome in a newborn

Introduction. Potter’s sequence is a very rare and severe syndromic complex that includes congenital kidney defects leading to oligohydramnios, lung hypoplasia and structural skeletal disorders. Clinical case presentation: observation of a boy born from the 5th pregnancy to the mother at 37 weeks. Antenatally, the fetus was found to have bilateral renal and urinary bladder agenesis, malformations of the limbs, but the parents refused to terminate the pregnancy. After birth, the child was diagnosed with Potter’s syndrome with severe hypoplasia of the lungs, which required mechanical ventilation. In 2 hours after birth, the child developed a tension pneumothorax, which was arrested by performing drainage of the pleural cavity. During the day, the patient received complex treatment in the intensive care unit, despite which, by the 2nd day of life, the death of the child occurred. Currently, there are no guidelines for the treatment of Potter syndrome with proven positive long-term outcomes.Discussion. Children with Potter syndrome do not have the same set of symptoms, but they develop a chain of events leading to a common ultimate result - decreased amount of amniotic fluid. Abnormalities leading to oligohydramnios may include severe hypoplasia, dysplasia, polycystic, obstructive uropathy or renal agenesis. In most cases, the disease occurs sporadically, but there are also forms with transmission of the disorder through successive generations: autosomal dominant or recessive inheritance of polycystic disease, hereditary renal dysplasia caused by mutations in RET, UPK3A genes and other chromosomal abnormalities.Conclusion. Potter syndrome is a set of severe syndromes manifested by abnormalities in the development of kidneys, oligohydramnios, leading to lung hypoplasia, skeletal disorders and other congenital anomalies. The severity of congenital defects included in the set depends on the time periods when oligohydramnios occurred. Despite the availability of experimental therapies, the disease is now considered to be fatal.

Types and role of cytological molecular analysis in thyroid carcinomas

Estimates show that thyroid nodules are commonly reported among populations residing in iodine-sufficient countries, with estimated prevalence rates of 1%, and 4% of palpable nodules among men and women in these countries, respectively. Furthermore, early diagnosis can effectively direct clinicians to the right management modality, especially in cases with malignant lesions. In this literature review, we have discussed the types and roles of cytological molecular analysis in thyroid carcinomas. Our findings indicate the molecular analysis can significantly add to the diagnostic accuracy of cytological analysis and can greatly add to the efficacy of differentiating benign from malignant lesions. We have discussed the roles of different genetic mutations that were reported among the various studies in the literature, including BRAF, RAS, PAX8/PPARγ, and RET mutations. BRAF mutations are the most validated mutations among the current studies in the literature, which has been reported to greatly increase the positive predictive values in detecting thyroid carcinomas. Some genetic mutations can be used to diagnose difficult to differentiate malignancies by fine needle aspiration (FNA) analysis. For instance, RAS mutations were reported to accurately diagnose follicular variants of papillary thyroid carcinomas that are difficult to detect using routine FNA analysis.

Outcomes of BRAF, MET, RET, and ROS1 Mutated Non-Small Cell Lung Cancer With Brain Metastases (NSCLCBM)

Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) also accounts for the highest number of brain metastases. Recent advances have been made from standard platinum-based chemotherapy to gene-directed therapies. EGFR and ALK mutations are the most well-studied directed therapies. However, newer targets in NSCLC are being studied, including BRAF mutations, MET exon skipping, RET fusions, and ROS1 rearrangements. In this retrospective study, we evaluated overall survival (OS) and progression-free survival (PFS) in NSCLCBM patients with BRAF, MET, RET, and ROS1 gene mutations.NSCLCBM patients diagnosed between 2010 and 2019 at our tertiary care center were investigated. Molecular marker status, systemic therapies, and date of progression were collected for each patient. We defined OS as the date of diagnosis of brain metastases to the date of last follow-up or death. The Cox proportional model was used to estimate OS and PFS.2989 NSCLCBM patients were detected, 18 had a BRAF mutant, 12 had MET exon skipping, 4 had RET fusion, and 6 had ROS1 rearrangement. The median OS (mOS) in patients who were BRAF positive was 101.7 months, ALK positive was 97.7 months, RET positive was 49.3 months, and ROS1 positive was 50.8 months. The median PFS (mPFS) for BRAF, MET, RET, and ROS1 was 99.2 months, 97.7 months, 31.6 months, and 40.6 months, respectively.Molecular mutations continue to be a topic of great interest in the field of NSCLCBM. These molecular mutations function as both prognostic predictors and druggable targets. Our retrospective study showed improved mPFS in patients with BRAF and MET mutations when compared to RET and ROS mutated patients and improved mOS in patients with MET mutations when compared to patients with RET mutations. However, due to the small sample size and the fact that these mutations are not mutually exclusive, it is difficult to determine statistical significance. Further studies need to be completed with larger sample sizes to determine outcomes in isolated mutations.