Near-Complete Response to Osimertinib for Advanced Non-Small-Cell Lung Cancer in a Pretreated Patient Bearing Rare Compound Exon 20 Mutation (S768I + V774M): A Case Report.

Third-generation tyrosine kinase inhibitors are the first-line gold standard in treating advanced non-small-cell lung cancer bearing common EGFR mutations, but data documenting clinical efficacy in uncommon mutations are currently limited. In this paper, we describe the case of a patient bearing uncommon compound EGFR mutations in exon 20, who experienced a near-complete response to third-line Osimertinib, with metabolic complete response of pulmonary, nodal and ostheolytic lesions. This radiological assessment corresponded to an ECOG PS improvement (from three to one) and a substantial clinical benefit for the patients. Out of two mutations, S768I was associated with poor response to third-generation TKI and V774M had unknown clinical significance, highlighting the complexity of the correct management of these kinds of mutations. We reviewed the literature to document the up-to-date preclinical and clinical data concerning third-generation tyrosine kinase inhibitors for the treatment of patients bearing uncommon EGFR mutations.

Gefitinib, an effective treatment option for patients with pulmonary enteric adenocarcinoma harboring compound EGFR L858R and A871G mutation.

Pulmonary enteric adenocarcinoma (PEAC) is a rare lung adenocarcinoma with morphological and immunohistochemical similarities to colorectal adenocarcinoma and intestinal differentiation. PEAC belongs to the group of non-small-cell lung carcinoma (NSCLC) and is defined as having a more than 50% intestinal differentiation component. We report a postoperative (T4N2M0 stage IIIb) PEAC patient with EGFR L858R + A871G combined mutation. Following surgery, the patient underwent treatment with the first-generation EGFR-TKI, gefitinib, and achieved an impressive 5-year progression-free survival (PFS). This suggests that gefitinib may serve as an effective treatment option for PEAC patients with EGFR L858R + A871G compound mutations.

Overview on Therapeutic Options in Uncommon EGFR Mutant Non-Small Cell Lung Cancer (NSCLC): New Lights for an Unmet Medical Need.

The majority of epidermal growth factor receptor (EGFR) mutations (85-90%) are exon 19 deletions and L858R point mutations of exon 21, characterized by high sensitivity to EGFR-tyrosine kinase inhibitors (TKIs). Less is known about uncommon mutations (10-15% of EGFR mutations). The predominant mutation types in this category include exon 18 point mutations, exon 21 L861X, exon 20 insertions, and exon 20 S768I. This group shows a heterogeneous prevalence, partly due to different testing methods and to the presence of compound mutations, which in some cases can lead to shorter overall survival and different sensitivity to different TKIs compared to simple mutations. Additionally, EGFR-TKI sensitivity may also vary depending on the specific mutation and the tertiary structure of the protein. The best strategy remains uncertain, and the data of EGFR-TKIs efficacy are based on few prospective and some retrospective series. Newer investigational agents are still under study, and there are no other approved specific treatments targeting uncommon EGFR mutations. Defining the best treatment option for this patient population remains an unmet medical need. The objective of this review is to evaluate existing data on the outcomes, epidemiology, and clinical characteristics of lung cancer patients with rare EGFR mutations, with a focus on intracranial activity and response to immunotherapy.

Long-term response in a patient with adenocarcinoma harboring both common and uncommon EGFR mutations.

Recently, we read a paper "Dacomitinib overcomes afatinib-refractory carcinomatous meningitis in a lung cancer patient harbouring EGFR Ex.19 deletion and G724S mutation" published in Investigational New Drugs. Their patient had a very rare compound EGFR mutation. To share our experience, we present a case of 58-year-old man with a long-term response to afatinib in a patient with previously unreported compound EGFR mutation. In patients with rare compound EGFR mutations, afatinib might be one of the treatment option.

ARTP and NTG compound mutations improved Cry protein production and virulence of Bacillus thuringiensis X023.

A high production mutated strain Bacillus thuringiensis X023PN (BtX023PN) was screened from the wild strain Bacillus thuringiensis X023 (BtX023) after atmospheric and room temperature plasma (ARTP) and nitrosoguanidine (NTG) mutation. BtX023PN grows faster than the wild strain, and its lysis of mother cell was 6 h ahead BtX023, but the ability of sporulation was significantly reduced. Bioassay indicated that compared with the wild type strain, the virulence of BtX023PN against Plutella xylostella (P. xylostella) and Mythimna seperata (M. seperata) increased to 2.33-fold and 2.13-fold respectively. qRT-PCR and SDS-PAGE demonstrated that the production of Cry1Ac increased by 61%. Resequence indicated that the mutated sites enriched on the key carbohydrate metabolism and amino acid metabolism. This study provides a new strain resource for the development of Bt insecticides and a feasible technical strategy for the breeding of Bt. KEY POINTS: • Atmospheric and room temperature plasma used in breeding of Bacillus thuringiensis. • Less stationary phase time with more ICP production. • Semi-lethal concentration against Plutella xylostella reduced by about 57.

The synergy of germline C634Y and V292M RET mutations in a northern Chinese family with multiple endocrine neoplasia type 2A.

Genetic analysis for germline mutations of RET proto-oncogene has provided a basis for individual management of medullary thyroid carcinoma (MTC) and pheochromocytoma. Most of compound mutations have more aggressive phenotypes than single point mutations, but the compound C634Y/V292M variant in MTC has never been reported. Thus, we retrospectively investigated synergistic effect of C634Y and V292M RET germline mutations in family members with multiple endocrine neoplasia type 2A. Nine of 14 family members in a northern Chinese family underwent RET mutation screening using next-generation sequencing and PCR followed by direct bidirectional DNA sequencing. Clinical features of nine individuals were retrospectively carefully reviewed. In vitro, the scratch-wound assay was used to investigate the difference between the cells carrying different mutations. We find no patients died of MTC. All 3 carriers of the V292M variant were asymptomatic and did not have biochemical or structural evidence of disease (age: 82, 62 and 58). Among 4 C634Y mutation carriers, 2 patients had elevated calcitonin with the highest (156 pg/mL) in an 87-year-old male. Two carriers of compound C634Y/V292M trans variant had bilateral MTC with pheochromocytoma or lymph node metastasis (age: 54 and 41 years, respectively). Further, the compound C634Y/V292M variant had a faster migration rate than either single point mutation in vitro (P < .05). In conclusion, the V292M RET variant could be classified as 'likely benign' according to ACMG (2015). The compound variant V292M/C634Y was associated with both more aggressive clinical phenotype and faster cell growth in vitro than was either single mutation.

Molecular dynamics reveal BCR-ABL1 polymutants as a unique mechanism of resistance to PAN-BCR-ABL1 kinase inhibitor therapy.

The acquisition of mutations within the BCR-ABL1 kinase domain is frequently associated with tyrosine kinase inhibitor (TKI) failure in chronic myeloid leukemia. Sensitive sequencing techniques have revealed a high prevalence of compound BCR-ABL1 mutations (polymutants) in patients failing TKI therapy. To investigate the molecular consequences of such complex mutant proteins with regards to TKI resistance, we determined by cloning techniques the presence of polymutants in a cohort of chronic-phase patients receiving imatinib followed by dasatinib therapy. The analysis revealed a high frequency of polymutant BCR-ABL1 alleles even after failure of frontline imatinib, and also the progressive exhaustion of the pool of unmutated BCR-ABL1 alleles over the course of sequential TKI therapy. Molecular dynamics analyses of the most frequent polymutants in complex with TKIs revealed the basis of TKI resistance. Modeling of BCR-ABL1 in complex with the potent pan-BCR-ABL1 TKI ponatinib highlighted potentially effective therapeutic strategies for patients carrying these recalcitrant and complex BCR-ABL1 mutant proteins while unveiling unique mechanisms of escape to ponatinib therapy.

Compound Mutations Cause Increased Cardiac Events in Children with Long QT Syndrome: Can the Sequence Homology-Based Tools be Applied for Prediction of Phenotypic Severity?

Long QT syndrome (LQTS) can cause syncope, ventricular fibrillation, and death. Recently, several disease-causing mutations in ion channel genes have been identified, and compound mutations have also been detected. It is unclear whether children who are carriers of compound mutations exhibit a more severe phenotype than those with single mutations. Although predicting phenotypic severity is clinically important, the availability of prediction tools for LQTS is unknown. To determine whether the severity of the LQTS phenotype can be predicted by the presence of compound mutations in children is needed. We detected 97 single mutations (Group S) and 13 compound mutations (Group C) between 1998 and 2012, age at diagnosis ranging 0-19 years old (median age is 9.0) and 18.0 years of follow-up period. The phenotypes and Kaplan-Meier event-free rates of the two groups were compared for cardiac events. This study investigated phenotypic severity in relation to the location of mutations in the protein sequence, which was analyzed using two sequence homology-based tools. In results, compound mutations in children were associated with a high incidence of syncope within the first decade (Group S: 32 % vs. Group C: 61 %), requiring an ICD in the second decade (Group S: 3 % vs. Group C: 56 %). Mortality in these patients was high within 5 years of birth (23 %). Phenotypic prediction tools correctly predicted the phenotypic severity in both Groups S and C, especially by using their coupling method. The coupling prediction method is useful in the initial evaluation of phenotypes both with single and compound mutations of LQTS patients. However, it should be noted that the compound mutation makes more severe phenotype.

Case report of a patient with stage IV lung adenocarcinoma and uncommon/compound EGFR mutations who responded to afatinib.

There is no established treatment for lung adenocarcinoma with uncommon/compound epidermal growth factor receptor (EGFR) mutations. We report a case of a 73-year-old man with stage IVB lung adenocarcinoma harboring E709G and L861Q EGFR mutations. After 2 months of afatinib treatment, significant tumor shrinkage was observed, and the patient's condition remained stable for 1 year. This case highlights the potential effectiveness of afatinib for treating rare stage IV lung adenocarcinoma with these specific EGFR mutations.

Successful therapy of a critically ill non-small cell lung cancer patient with compound mutations in EGFR G719X and S768I genes using furmonertinib: A case report.

Background: Somatic mutations in epidermal growth factor receptor (EGFR) genes, such as G719X and S768I, and tyrosine kinase inhibitors (TKIs) have been confirmed to be promising for developing new targeted therapies against advanced non-small-cell lung cancer (NSCLC). The G719X and S768I mutations are uncommon and often occur in the form of compound mutations. However, the efficacy of furmonertinib in patients with these uncommon compound mutations has not yet been elucidated. Case presentation: In this study, the G719X/S768I compound mutations were detected in a critically ill NSCLC patient. This patient received furmonertinib for 14 months and successfully responded to the treatment. The present case report highlights the ideal clinical response, with ongoing follow-up. Conclusion: We report the successful treatment of a critically ill NSCLC patient carrying rare compound EGFR G719X and S768I mutations using furmonertinib. To the best of our knowledge, this is the first reported case of a successful furmonertinib treatment of compound EGFR G719X and S768I mutations. Furmonertinib, a third-generation EGFR-TKI, may be effective in controlling the EGFR G719X and S768I compound mutations in NSCLC.

Impact of compound mutations I1171N + F1174I and I1171N + L1198H on the structure of ALK in NSCLC pathogenesis: atomistic insights.

Anaplastic lymphoma kinase (ALK) fusion genes are found in 3%-5% of non-small cell lung cancers (NSCLCs). NSCLC is the most common type of lung cancer, accounting for 84% of all lung cancer diagnoses. Available treatment options for ALK-positive NSCLCs involve the use of ALK tyrosine kinase inhibitors (ALK-TKIs) which have shown to be effective with a high response rate. Nonetheless, the emergence of multiple compound mutations such as I1171N + F1174I or I1171N + L1198H has been reported to cause resistance to all approved ALK-TKIs. However, the underlying molecular mechanisms surrounding the impact of these compound mutants remain poorly understood. Hence, we performed molecular dynamics simulations to characterize the structural effects and functional implications of these compound mutations. Findings revealed a destabilizing effect on ALK by mutants as compared to the wild-type ALK structure. Also, further insights revealed a lower root-mean-squared fluctuation, radius of gyration, and solvent-accessible surface area values of I1171N + F1174I and I1171N + L1198H ALK compound mutations suggesting that the mutants have a more compact structure and a smaller surface area than the wild-type protein. The mutants also distorted the activation loop residues (Tyr1278, Tyr1282, and Tyr1283) in the ALK structure, which further identify them as possible disruptors of phosphorylation. In contrast to wild conformation, the mutant conformations exhibited a reduced node degree in their residue interaction networks. Collectively, our findings provide deeper insights into the deleterious effects of I1171N + F1174I and I1171N + L1198H ALK compound mutations, which may contribute to NSCLC pathogenesis.Communicated by Ramaswamy H. Sarma.

EGFR p.V774M/p.L833V compound mutations in lung adenocarcinoma responded well to almonertinib: a case report.

Background: There are about 10-15% of uncommon EGFR mutations found in NSCLC patients, and their sensitivity to EGFR TKIs still lack sufficient clinical evidence, especially for rare compound mutations. Almonertinib is the third generation of EGFR-TKI that has demonstrated excellent efficacy in classical mutations, however, effects in rare mutations have also been rarely reported. Case presentation: In this case report, we present a patient with advanced lung adenocarcinoma with a rare EGFR p.V774M/p.L833V compound mutations, who achieved long-lasting and stable disease control after first-line Almonertinib targeted therapy. This case report could provide more information for therapeutic strategy selecting of NSCLC patients harboring rare EGFR mutations. Conclusion: We report for the first time the long-lasting and stable disease control with Almonertinib for EGFR p.V774M/p.L833V compound mutations treatment, hoping to provide more clinical case references for the treatment of rare compound mutations.

Mutation analysis of the TGFBI gene in pedigrees of lattice corneal dystrophy in Eastern China.

BACKGROUND: To delineate the mutations of the TGFBI gene in Eastern China by whole-exome sequencing (WES) in eight Chinese families with lattice corneal dystrophy (LCD). MATERIALS AND METHODS: This retrospective study included eight families with LCD from Eastern China. Clinical features were examined using slit-lamp examination, anterior segment optical coherence tomography, and in vivo confocal microscopy. Peripheral blood samples of probands were collected for WES, and saliva samples from family members were collected for TGFBI screening using Sanger sequencing. The physicochemical effects of mutations were investigated using bioinformatics tools. RESULTS: Family 1 presented a classic LCD I with a p.R124C mutation of the TGFBI gene, while the other seven families were diagnosed with LCD IIIA. Six of the seven LCD IIIA families had heterozygous single-gene mutations (p.A546D, p.L565 H, p.T621P), and one had a compound heterozygous (cis) mutation (p.P501T and p.N622 H). The mutation of p.L565 H was the first time of integrated family report in contrast to the cases reported in 2019, and the p.T621P mutation was first reported in a Chinese population. Notably, the family with the compound mutation was associated with an obvious early-onset (in the 2nd decade of life) compared to the LCD IIIA patients with each single mutation (p.P501T or p.N622 H) showing late-onset (in the 7th decade of life). CONCLUSIONS: WES is efficient for the genomic testing of LCD and genetic relationship identification in different families with the same mutated gene. We identified a compound heterozygous mutation (p.P501T and p.N622 H) and two mutations (p.T621P and p.L565 H) uncommon in China.

Clinical outcomes of lung adenocarcinoma patients harboring uncommon epidermal growth factor receptor (EGFR) mutations treated with EGFR-tyrosine kinase inhibitors (TKIs).

BACKGROUND: This study aimed to explore the efficacy of different epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in lung adenocarcinoma (AC) patients harboring uncommon EGFR mutations. METHODS: Between January 1st, 2013 and October 1st, 2019, 2,680 EGFR mutation-positive patients with confirmed stage IIIB/IV lung AC were enrolled from Zhejiang Cancer Hospital. Uncommon EGFR mutations were detected in 132 patients using next-generation-sequencing. Clinicopathological features between patients with uncommon EGFR mutations and common EGFR mutations were evaluated by the chi-square test. The clinical outcomes of patients with uncommon EGFR mutations were analyzed by the Kaplan-Meier method. RESULTS: Of 132 AC patients with uncommon EGFR mutations, 115 received EGFR-TKIs. Second-generation EGFR-TKIs were associated with longer progression-free survival (PFS) (P=0.116) and overall survival (OS) (P=0.005) than first or third-generation EGFR-TKIs. We also found that patients with compound mutations and double uncommon EGFR mutations had longer PFS (P=0.725) and OS (P=0.741) than those with single uncommon EGFR mutation, although the difference was not significant. In addition, third-generation EGFR-TKIs were more effective than the other two agents in patients with primary T790M mutation regarding PFS (P=0.150) and OS (P=0.033), although the difference in PFS was not significant. CONCLUSIONS: Patients with uncommon EGFR mutations treated with second-generation EGFR-TKIs showed better PFS and OS. EGFR-TKIs were more effective in patients with compound mutations or double uncommon mutations.

Sensitivity analysis of EGFR L861Q mutation to six tyrosine kinase inhibitors.

PURPOSE: Lung cancer is one of the most common carcinomas with the highest mortality in the world. Non-small cell lung carcinoma has a large proportion of epidermal growth factor receptor (EGFR) mutations, of which rare EGFR mutations account for about 10%-20%. Currently, tyrosine kinase inhibitors (TKIs) therapy is a standard treatment for patients with non-small cell lung carcinoma with EGFR mutations. To date, the toxicological effects of the EGFR L861Q variant (less than 2%) have been rarely reported, so further investigation of its sensitivity to six first-in-class TKIs is of great clinical interest. METHODS: In this study, two EGFR L861Q variants cell lines (EGFR L861Q variant and EGFR L861Q + exon 19 deletion variant) were established by CRISPR-Cas9 gene-editing technology. The steady-state plasma concentrations of six TKIs (gefitinib/erlotinib/icotinib, the first generation; dacomitinib/afatinib, the second generation; and osimertinib, the third generation) were tested, respectively. The change of cell viability, proliferation, cloning ability, mitochondrial membrane potential and apoptosis were detected by MTT assay, EdU staining assay, colony formation assay, mitochondrial membrane potential and apoptosis test. TUNEL and Annexin V / PI staining were used to detect cell apoptosis, and flow cytometry was employed to explore the sensitivity of two variants to six TKIs. RESULTS: Our study indicated that the six TKIs inhibited the viability of the two cell lines in a time-dependent manner, and the inhibitory time of six TKIs on proliferation was different between the two cell lines. The proliferation and cloning ability of two cell lines were inhibited by six TKIs. The cytoskeleton morphology, microfilament structure and distribution of the two cell lines were changed by six TKIs. Compared with the control, the mitochondrial membrane potential decreased while the apoptosis increased of the two of variants after treatment with the six TKIs, and the associated mechanisms were elucidated. CONCLUSIONS: Based on the above results, EGFR L861Q + 19del variant and EGFR L861Q variant showed significant sensitivity to six first-in-class TKIs. Among the six TKIs, the first generation TKIs (gefitinib/erlotinib/icotinib), showed stronger inhibition ability to the EGFR L861Q + 19del variant and EGFR L861Q variant, among which gefitinib showed the strongest inhibition.

Association Between Late-Onset Leukoencephalopathy With Vanishing White Matter and Compound Heterozygous EIF2B5 Gene Mutations: A Case Report and Review of the Literature.

Leukoencephalopathy with vanishing white matter (LVWM) is an autosomal recessive disease. Ovarioleukodystrophy is defined as LVWM in females showing signs or symptoms of gradual ovarian failure. We present a 38-year-old female with ovarioleukodystrophy who showed status epilepticus, gait instability, slurred speech, abdominal tendon hyperreflexia, and ovarian failure. Abnormal EEG, characteristic magnetic resonance, and unreported EIF2B5 compound heterozygous mutations [c.1016G>A (p.R339Q) and c.1157G>A (p.G386D)] were found. Furthermore, the present report summarizes 20 female patients with adult-onset ovarioleukodystrophy and EIF2B5 gene mutations. In conclusion, a new genetic locus for LVWM was discovered. Compared with previous cases, mutations at different EIF2B5 sites might have different clinical manifestations and obvious clinical heterogeneity.

SCN5A compound heterozygosity mutation in Brugada syndrome: Functional consequences and the implication for pharmacological treatment.

AIMS: SCN5A gene encodes the α-subunit of Nav1.5, mainly found in the human heart. SCN5A variants are the most common genetic alterations associated with Brugada syndrome (BrS). In rare cases, compound heterozygosity is observed; however, its functional consequences are poorly understood. We aimed to analyze the functional impact of de novo Nav1.5 mutations in compound heterozygosity in distinct alleles (G400R and T1461S positions) previously found in a patient with BrS. Moreover, we evaluated the potential benefits of quinidine to improve the phenotype of mutant Na+ channels in vitro. MATERIALS AND METHODS: The functional properties of human wild-type and Nav1.5 variants were evaluated using whole-cell patch-clamp and immunofluorescence techniques in transiently expressed human embryonic kidney (HEK293) cells. KEY FINDINGS: Both variants occur in the highly conservative positions of SCN5A. Although all variants were expressed in the cell membrane, a significant reduction in the Na+ current density (except for G400R alone, which was undetected) was observed along with abnormal biophysical properties, once the variants were expressed in homozygosis and heterozygosis. Interestingly, the incubation of transfected cells with quinidine partially rescued the biophysical properties of the mutant Na+ channel. SIGNIFICANCE: De novo compound heterozygosis mutations in SNC5A disrupt the Na+ macroscopic current. Quinidine could partially reverse the in vitro loss-of-function phenotype of Na+ current. Thus, our data provide, for the first time, a detailed biophysical characterization of dysfunctional Na+ channels linked to compound heterozygosity in BrS as well as the benefits of the pharmacological treatment using quinidine on the biophysical properties of Nav1.5.

Efficacy of Osimertinib in NSCLC Harboring Uncommon EGFR L861Q and Concurrent Mutations: Case Report and Literature Review.

The efficacy of first-and second-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in NSCLC patients with the EGFR L861Q mutation has been studied previously. However, there is little evidence on the efficacy of osimertinib in NSCLC patients with uncommon mutations. Here, we report the case of a 68-year-old man with advanced NSCLC with concurrent EGFR L861Q mutation as well as TP53 and RB1 mutations. The patient was treated with osimertinib as first-line therapy and achieved a remarkable progression-free survival of 15 months. His symptoms were significantly alleviated and the dose was well tolerated. The findings of the present study indicate that osimertinib might be a good treatment option for NSCLC patients with the L861Q mutation.

Durable Response to Osimertinib in a Chinese Patient with Metastatic Lung Adenocarcinoma Harboring a Rare EGFR L858R/D761Y Compound Mutation.

Uncommon mutations account for 10-15% of epidermal growth factor receptor (EGFR) mutations in patients with non-small-cell lung cancer (NSCLC). However, in spite of the wealth of knowledge of the clinical significance and tyrosine kinase inhibitor (TKI) sensitivity of these mutations, acquisition of deeper insights is limited by the paucity of case reports and cohort studies of the exceptionally rare mutations, including compound mutations. In the present case, we describe the clinical efficacy of icotinib and osimertinib in a metastatic lung adenocarcinoma patient carrying a highly uncommon EGFR L858R/D761Y compound mutation. The progression-free survival (PFS) with osimertinib treatment was much longer than that with icotinib (19 mo vs 8.2 mo), and the overall survival (OS) has currently exceeded three years. To the best of our knowledge, this is the first report of durable osimertinib response in an NSCLC patient with a rare EGFR L858R/D761Y mutation.