Genomic ancestry and cancer among Latin Americans.

Latin American populations, characterized by intricate admixture patterns resulting from the intermingling of ancestries from European, Native American (NA) Asian, and African ancestries which result in a vast and complex genetic landscape, harboring unique combinations of novel variants. This genetic diversity not only poses challenges in traditional population genetics methods but also opens avenues for a deeper understanding of its implications in health. In cancer, the interplay between genetic ancestry, lifestyle factors, and healthcare disparities adds a layer of complexity to the varying incidence and mortality rates observed across different Latin American subpopulations. This complex interdependence has been unveiled through numerous studies, whether conducted on Latin American patients residing on the continent or abroad, revealing discernible differences in germline composition that influence divergent disease phenotypes such as higher incidence of Luminal B and Her2 breast tumors, EGFR and KRAS mutated lung adenocarcinomas in addition to an enrichment in BRCA1/2 pathogenic variants and a higher than expected prevalence of variants in colorectal cancer associated genes such as APC and MLH1. In prostate cancer novel risk variants have also been solely identified in Latin American populations. Due to the complexity of genetic divergence, inputs from each individual ancestry seem to carry independent contributions that interplay in the development of these complex disease phenotypes. By understanding these unique population characteristics, genomic ancestries hold a promising avenue for tailoring prognostic assessments and optimizing responses to oncological interventions.

Estandarización de requerimientos mínimos para la formación de centro de detección temprana de cáncer de pulmón en América Latina / Standardization of Minimum Requirements for the Formation of an Early Detection Center for Lung Cancer in Latin America

Introducción: El cáncer de pulmón (CP) es una enfermedad con gran impacto a nivel mundial en el número de muertes y en costos en salud. La alta incidencia y mortalidad de esta enfermedad asociada al diagnóstico tardío, y la mejoría del pronóstico ante una detección temprana, determinan que sea una patología pasible de beneficiarse mediante detección temprana. La tomografía de baja dosis de radiación (TCBD) demostró ser un método que se pue- de realizar periódicamente a un grupo de personas con alto riesgo de desarrollar CP y así reducir la mortalidad por esta enfermedad. Sin embargo, este beneficio es tal cuan- do se encuentra desarrollado bajo un programa organizado y con participación multi- disciplinaria especializada en cáncer de pulmón. Métodos: Se plantea determinar lineamientos básicos para el desarrollo de la detección temprana de cáncer de pulmón en América Latina para que pueda ser realizada en forma uniforme, con el menor riesgo y el máximo beneficio esperado. Se analizaron las principales publicaciones referidas a este tema, contemplando la diversidad de atención y acceso de América Latina. Resultado: Se desarrollan requerimientos mínimos para la implementación de un pro- grama. Discusión: El número de programas en la región es escaso y depende más de esfuerzos individuales que de políticas generales de salud. Consideramos que estos lineamien- tos pueden servir de apoyo para el desarrollo de más programas en la región y de for- ma más homogénea.

Introduction: Lung cancer (LC) is a disease with a great impact worldwide in the number of deaths and health costs. The high incidence and mortality of this disease associated with late diagnosis and the improved prognosis with early detection determine that it is a pathology that can benefit from early detection. Low radiation dose tomography (LDCT) demonstrated a method that can be performed periodically to a group of people at high risk of developing CP and thus reduce mortality from this disease. However, this benefit is such when it is developed under an organized program with multidisciplinary participation specialized in lung cancer. Methods: It is proposed to determine basic guidelines for the development of early de- tection of lung cancer in Latin America so that it can be carried out uniformly, with the lowest risk and the maximum expected benefit. The main publications referring to this topic were analyzed, considering the diversity of care and access in Latin America. Result: Minimum requirements are developed for the implementation of a program. Discussion: The number of programs in the region is small and depends more on individual efforts than on general health policies. We consider that these guidelines can serve as support for the development of more programs in the region and in a more ho- mogeneous way.

Severe Hypocalcemia as an Atypical Manifestation of Seronegative Celiac Disease in a Patient with Systemic Lupus Erythematosus: Case Report

Aim: To describe the clinical picture and diagnosis of an episode of severe hypocalcemia in a patient with systemic lupus erythematosus (SLE) in remission, with chronic diarrhea that led to the diagnosis of celiac disease (CD). Case presentation: 22-year-old patient, diagnosed with SLE at age 10, in remission. He consulted for a two-month history of paresthesias, muscle spasms, myalgias, and episodes of tetany in the previous week, associated with malabsorptive postprandial diarrhea. His laboratory tests showed severe hypocalcemia, vitamin D deficiency, severe hypomagnesemia, and mild hypokalemia. In the study for CD, serology reported normal anti-tissue transglutaminase IgA, antigliadin IgA, and IgG and low total IgA levels. Enteroscopy revealed erosive bulbo-duodenitis, with villous atrophy and increased intraepithelial lymphocytes in the pathology, which, together with the immunohistochemical study, allowed the diagnosis of CD, Marsh 3a type. Management was initiated with a gluten-free diet, with a positive clinical response. Conclusion: CD should be suspected in patients with SLE who present with diarrhea, abdominal pain, nausea/vomiting, recurrent oral aphthosis, and anemia. In rare seronegative CD cases, other causes of villous atrophy, mainly infectious, toxic, and immunological, must be ruled out. There is an association between CD and SLE, so diagnosis must be early and timely with the best testing scheme available to achieve effective treatment before complications occur.

Objetivo: Describir la presentación clínica y diagnóstico de un episodio de hipocalcemia grave en un paciente con lupus eritematoso sistémico (LES) en remisión, con diarrea crónica que condujo al diagnóstico de enfermedad celíaca (EC). Presentación del caso: Paciente de 22 años, con diagnóstico de LES a los 10 años, en remisión. Consultó por 2 meses de evolución de parestesias, espasmos musculares, mialgias y episodios de tetania en la semana previa, asociado a diarrea posprandial malabsortiva. Sus laboratorios mostraron hipocalcemia grave, déficit de vitamina D, hipomagnesemia grave e hipopotasemia leve. En el estudio para EC la serología reportó antitransglutaminasa tisular IgA, antigliadina IgA e IgG normales y niveles de IgA total bajos. La enteroscopia evidenció bulboduodenitis erosiva, con atrofia de las vellosidades y aumento de linfocitos intraepiteliales en la patología, que junto al estudio inmunohistoquímico permitieron concluir el diagnóstico de EC, tipo Marsh 3a. Se inició el manejo con una dieta libre de gluten, con una respuesta clínica positiva. Conclusión: La EC debe sospecharse en pacientes con LES que inicien con diarrea, dolor abdominal, náuseas/vómitos, aftosis oral recurrente y anemia. En los casos de EC seronegativa, los cuales son poco comunes, se deben descartar otras causas de atrofia de las vellosidades principalmente infecciosas, tóxicas e inmunitarias. Existe una asociación entre EC y LES, por lo cual el diagnóstico debe ser precoz y oportuno con el mejor esquema de pruebas disponible para lograr realizar un tratamiento efectivo antes de que se presenten las complicaciones.

Periampullary Mass as an Unusual Manifestation of Coccidioidomycosis. Case Report and Literature Review

In Colombia, coccidioidomycosis is a rare entity, and the intestinal manifestation is infrequent, with around a dozen cases reported in the world literature. This article reports the case of a 29-year-old male Venezuelan immigrant with a 4-month history of abdominal pain, jaundice, nausea, and vomiting. The tomography and the endoscopic study revealed a circumferential exophytic mass in the second portion of the duodenum. The biopsy revealed multiple spherules filled with round fungal endospores with a final diagnosis of disseminated coccidioidomycosis. The patient was discharged before the final pathology report with fluconazole doses of 200 mg every other day and an order for outpatient magnetic resonance cholangiography for outpatient follow-up, which he has not attended.

La coccidioidomicosis en Colombia es una entidad infrecuente y la presentación intestinal es extremadamente rara, con alrededor de una docena de casos reportados en la literatura mundial. En el presente artículo se reporta el caso de un paciente inmigrante venezolano masculino de 29 años con historia de dolor abdominal, ictericia, náuseas y vómito de 4 meses de evolución. La tomografía y el estudio endoscópico evidenciaron una masa exofítica circunferencial en la segunda porción del duodeno. La biopsia reveló múltiples esférulas llenas de endosporas fúngicas redondas con diagnóstico final de coccidioidomicosis diseminada. El paciente fue dado de alta antes del reporte final anatomopatológico con dosis de fluconazol de 200 mg interdiario y orden de colangiorresonancia ambulatoria para control ambulatorio, mismo al cual no ha asistido.

Tackling Osimertinib Resistance in EGFR-Mutant Non-Small Cell Lung Cancer.

The current landscape of targeted therapies directed against oncogenic driver alterations in non-small cell lung cancer (NSCLC) is expanding. Patients with EGFR-mutant NSCLC can derive significant benefit from EGFR tyrosine kinase inhibitor (TKI) therapy, including the third-generation EGFR TKI osimertinib. However, invariably, all patients will experience disease progression with this therapy mainly due to the adaptation of cancer cells through primary or secondary molecular mechanisms of resistance. The comprehension and access to tissue and cell-free DNA next-generation sequencing have fueled the development of innovative therapeutic strategies to prevent and overcome resistance to osimertinib in the clinical setting. Herein, we review the biological and clinical implications of molecular mechanisms of osimertinib resistance and the ongoing development of therapeutic strategies to overcome or prevent resistance.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS syndrome) with prominent supraglottic larynx involvement: a case-based review.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS syndrome) is a recently described genetic disorder that gathers autoinflammatory symptoms and myeloid dysplasia. The first description was reported in 2020, and subsequently, a growing number of cases have been described worldwide. Herein, we describe a case of a 72-year-old male patient with VEXAS syndrome with p.Met41Val mutation of the UBA1 gene, prominent supraglottic larynx involvement, and costochondritis. To our knowledge, this is the first report of VEXAS syndrome in Colombia and South America. This disease could present features of relapsing polychondritis, polyarteritis nodosa, giant cell arteritis, and Sweet syndrome, associated with hematologic involvement, including cytopenias, myelodysplastic syndrome, or thromboembolic disease. Supraglottic larynx chondritis and costochondritis are atypical manifestations. These features were proposed previously to differentiate relapsing polychondritis from VEXAS syndrome but are not entirely reliable like in the case described. A diagnosis of VEXAS should be considered in male patients with incomplete or complete features of the previously described conditions, refractory to treatment, requiring high-dose glucocorticoids, and associated progressive hematologic abnormalities. Key Points • VEXAS syndrome is a recently described genetic (somatic mutations in UBA1 gene) disorder that gathers autoinflammatory and hematologic manifestations. • VEXAS syndrome should be considered in male patients with incomplete or complete features of relapsing polychondritis, polyarteritis nodosa, giant cell arteritis, and Sweet syndrome, refractory to treatment, associated with hematologic involvement, including cytopenias, myelodysplastic syndrome, or thromboembolic disease. • Glucocorticoids ameliorate symptoms effectively. However, other treatment options are limited due to a lack of evidence. Traditional immunosuppressants and biological therapy have been used empirically with limited efficacy and a transient effect. Bone marrow transplant offers a curative approach, but it has high morbidity and mortality.

Somatostatin analogues in treatment-refractory meningioma: a systematic review with meta-analysis of individual patient data.

Treatment-refractory meningiomas have a dismal prognosis and limited treatment options. Meningiomas express high-densities of somatostatin receptors (SSTR), thus potentially susceptible to antitumorigenic effects of somatostatin analogues (SSA). Evidence for SSA in meningiomas is scarce, and it is unclear if published literature would either (1) support wider use of SSA, if (2) more evidence is desirable, or if (3) available evidence is sufficient to discard SSA. We addressed the need for more evidence with a systematic review and meta-analysis. We performed an individual patient data (IPD) meta-analysis. Main outcomes were toxicity, best radiological response, progression-free survival, and overall survival. We applied multivariable logistic regression models to estimate the effect of SSA on the probability of obtaining radiological disease control. The predictive performance was evaluated using area under the curve and Brier scores. We included 16 studies and compiled IPD from 8/9 of all previous cohorts. Quality of evidence was overall ranked "very low." Stable disease was reported in 58% of patients as best radiological response. Per 100 mg increase in total SSA dosage, the odds ratios for obtaining radiological disease control was 1.42 (1.11 to 1.81, P = 0.005) and 1.44 (1.00 to 2.08, P = 0.05) for patients treated with SSA as monodrug therapy vs SSA in combination with everolimus, respectively. Low quality of evidence impeded exact quantification of treatment efficacy, and the association between response and treatment may represent reverse causality. Yet, the SSA treatment was well tolerated, and beneficial effect cannot be disqualified. A prospective trial without bias from inconsistent study designs is warranted to assess SSA therapy for well-defined meningioma subgroups.

Location of EGFR exon 20 insertions matters.

EGFR exon 20 insertions represent a subgroup of NSCLC patients posed with a therapy dilemma. In this issue of Cancer Cell, Elamin and colleagues demonstrate that only insertions localized in the near loop respond to poziotinib. Pharmacological inhibition of spindle assembly checkpoint components inhibits tumor growth in poziotinib-resistant exon 20 insertions.

Floating gallbladder in exomphalos minor an exceptional condition that should be considered, a case report.

BACKGROUND: The exomphalos minor or small omphalocele is a defect of the abdominal wall smaller than 5 cm, located in the umbilical cord. It presents a sac containing intra-abdominal organs, mainly the small intestine. The main surgical objective is to repair the defected wall, preserving the intra-abdominal structures inside the sac. A floating gallbladder is unusual in this pathology; however, it must be removed when that occurs due to the risk of torsion, inflammation, and volvulus. PRESENTATION OF CASE: We present the case of a 7-day-old patient who comes to the emergency room with an abdominal mass. The physical examination shows minor exomphalos with local signs of inflammation. Genetic, chromosomal, and imaging studies are solicited. The abdominal ultrasonography report shows the absence of the gallbladder in the liver. The patient requires surgical correction of abdominal wall defect. The gallbladder is found inside the sac of defect that does not have a hepatic fixation; a cholecystectomy is performed. The patient presents a satisfactory postoperative evolution and is discharged. CONCLUSIONS: The exomphalos minor is a malformation of the abdominal wall. It needs surgical treatment; this must be done carefully, preserving the intra-abdominal organs inside the sac as much as possible. The gallbladder without hepatic fixation, elongated meso, or suspended by its pedicle is unusual in pediatric age, and they present a higher risk of torsion, inflammation, and necrosis. For this reason, cholecystectomy is indicated. A minor exomphalos has a better prognosis when the defect is small. It is not associated with malformations or associated structural alterations.

Coregulation of pathways in lung cancer patients with EGFR mutation: therapeutic opportunities.

Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma are a frequent class of driver mutations. Single EGFR tyrosine kinase inhibitor (TKI) provides substantial clinical benefit, but almost nil radiographic complete responses. Patients invariably progress, although survival can reach several years with post-treatment therapies, including EGFR TKIs, chemotherapy or other procedures. Endeavours have been clinically oriented to manage the acquisition of EGFR TKI-resistant mutations; however, basic principles on cancer evolution have not been considered in clinical trials. For years, evidence has displayed rapidly adaptive mechanisms of resistance to selective monotherapy, posing several dilemmas for the practitioner. Strict adherence to non-small cell lung cancer (NSCLC) guidelines is not always practical for addressing the clinical progression that EGFR-mutant lung adenocarcinoma patients suffer. The purpose of this review is to highlight regulatory mechanisms and signalling pathways that cause therapy-induced resistance to EGFR TKIs. It suggests combinatorial therapies that target EGFR, as well as potential mechanisms underlying EGFR-mutant NSCLC, alerting the reader to clinical opportunities that may lead to a deeper and more durable response. Molecular reprogramming contributes to EGFR TKI resistance, and the compiled information is relevant in understanding the development of new combined targeted strategies in EGFR-mutant NSCLC.

Small Cell Lung Cancer: State of the Art of the Molecular and Genetic Landscape and Novel Perspective.

Small cell lung cancer (SCLC) is a highly proliferative lung cancer that is not amenable to surgery in most cases due to the high metastatic potential. Precision medicine has not yet improved patients' survival due to the lack of actionable mutations. Intra- and intertumoral heterogeneity allow the neoplasms to adapt to various microenvironments and treatments. Further studying this heterogeneous cancer might yield the discovery of actionable mutations. First-line SCLC treatment has added immunotherapy to its armamentarium. There has been renewed interest in SCLC, and numerous clinical trials are underway with novel therapeutic approaches. Understanding the molecular and genetic landscape of this heterogeneous and lethal disease will pave the way for novel drug development.

Resistance to KRASG12C Inhibitors in Non-Small Cell Lung Cancer.

KRAS mutations are one of the most prevalent oncogenic alterations in cancer. Until recently, drug development targeting KRAS did not convey clinical benefits to patients. Specific KRASG12C inhibitors, such as sotorasib and adagrasib, have been designed to bind to the protein's mutant structure and block KRASG12C in its GDP-bound inactive state. Phase 1/2 trials have shown promising anti-tumor activity, especially in pretreated non-small cell lung cancer patients. As expected, both primary and secondary resistance to KRASG12C inhibitors invariably occurs, and molecular mechanisms have been characterized in pre-clinical models and patients. Several mechanisms such as tyrosine kinase receptors (RTKs) mediated feedback reactivation of ERK-dependent signaling can result in intrinsic resistance to KRAS target therapy. Acquired resistance to KRASG12C inhibitors include novel KRAS mutations such as Y96D/C and other RAS-MAPK effector protein mutations. This review focuses on the intrinsic and acquired mechanisms of resistance to KRASG12C inhibitors in KRASG12C mutant non-small cell lung cancer and the potential clinical strategies to overcome or prevent it.

Multiplex RNA-based detection of clinically relevant MET alterations in advanced non-small cell lung cancer.

MET inhibitors have shown activity in non-small-cell lung cancer patients (NSCLC) with MET amplification and exon 14 skipping (METΔex14). However, patient stratification is imperfect, and thus, response rates have varied widely. Here, we studied MET alterations in 474 advanced NSCLC patients by nCounter, an RNA-based technique, together with next-generation sequencing (NGS), fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and reverse transcriptase polymerase chain reaction (RT-PCR), exploring correlation with clinical benefit. Of the 474 samples analyzed, 422 (89%) yielded valid results by nCounter, which identified 13 patients (3%) with METΔex14 and 15 patients (3.5%) with very-high MET mRNA expression. These two subgroups were mutually exclusive, displayed distinct phenotypes and did not generally coexist with other drivers. For METΔex14, 3/8 (37.5%) samples positive by nCounter tested negative by NGS. Regarding patients with very-high MET mRNA, 92% had MET amplification by FISH and/or NGS. However, FISH failed to identify three patients (30%) with very-high MET RNA expression, among which one received MET tyrosine kinase inhibitor treatment deriving clinical benefit. Our results indicate that quantitative mRNA-based techniques can improve the selection of patients for MET-targeted therapies.

Scientific publications in cancer: in Latin America, strong scientific networks increase productivity (the TENJIN study).

OBJECTIVES: The objectives of this study are to evaluate the relationship between authorship networking, socioeconomic factors, and scientific productivity across Latin America. METHODS: In a bibliometric analysis of cancer-related Latin-American publications, the relationship between authorship network indicators, sociodemographic factors, and number of peer-reviewed indexed publications per country was explored. A systematic review of the literature for cancer publications between 2000 and 2018 using the Scopus database limited to Latin-American authors was used for the construction of coauthorship and publication networks and their respective metrics. Sociodemographic variables including percentage of invested gross domestic product in research, population, and cancer incidence were also estimated. Multiple linear regression models were constructed to determine the relationship between productivity and the aforementioned variables. RESULTS: A total of 8,528 articles across nine countries were included. Brazil was the most productive nation with 41.8% of identified references followed by Mexico (16.6%) and Argentina (12.9%). Latin America experienced a 9% growth in number of publications across the studied time frame. After analyzing networking and sociodemographic variables, number of authors in a collaboration network and percentage of invested gross domestic product were associated with high productivity yielding a multiple regression model with an R2 value of 0.983. CONCLUSIONS: This study indicates that extensive authorship networking and a high investment in research strongly predict cancer-related productivity.

Non-Small-Cell Lung Cancer Signaling Pathways, Metabolism, and PD-1/PD-L1 Antibodies.

Treatment of advanced (metastatic) non-small-cell lung cancer (NSCLC) is currently mainly based on immunotherapy with antibodies against PD-1 or PD-L1, alone, or in combination with chemotherapy. In locally advanced NSCLC and in early resected stages, immunotherapy is also employed. Tumor PD-L1 expression by immunohistochemistry is considered the standard practice. Response rate is low, with median progression free survival very short in the vast majority of studies reported. Herein, numerous biological facets of NSCLC are described involving driver genetic lesions, mutations ad fusions, PD-L1 glycosylation, ferroptosis and metabolic rewiring in NSCLC and lung adenocarcinoma (LUAD). Novel concepts, such as immune-transmitters and the effect of neurotransmitters in immune evasion and tumor growth, the nascent relevance of necroptosis and pyroptosis, possible new biomarkers, such as gasdermin D and gasdermin E, the conundrum of K-Ras mutations in LUADs, with the growing recognition of liver kinase B1 (LKB1) and metabolic pathways, including others, are also commented. The review serves to charter diverse treatment solutions, depending on the main altered signaling pathways, in order to have effectual immunotherapy. Tumor PDCD1 gene (encoding PD-1) has been recently described, in equilibrium with tumor PD-L1 (encoded by PDCD1LG1). Such description explains tumor hyper-progression, which has been reported in several studies, and poises the fundamental criterion that IHC PD-L1 expression as a biomarker should be revisited.

Characterising acquired resistance to erlotinib in non-small cell lung cancer patients.

Introduction: The therapy of patients with lung adenocarcinoma has significantly changed after the discovery of epidermal growth factor receptor (EGFR) mutations. EGFR mutations occur in 10-15% of Caucasian lung cancer patients and are associated with favorable outcome to orally administered EGFR tyrosine kinase inhibitors (TKIs), like erlotinib. However, as soon as the tumor cells are under the pressure of the specific inhibitor, compensatory signaling pathways are activated and resistance emerges. Areas covered: In this review we will focus on the mechanisms of resistance to the first-generation EGFR TKI, erlotinib, and will mainly summarize the findings throughout the last 10 years in the field of EGFR-mutant lung cancer. Expert opinion: Widespread research has been performed and several mechanisms of resistance to EGFR TKIs, especially first- and second-generation, have been identified. Still, no adequate combinatory therapies have received regulatory approval for the treatment of EGFR-mutant patients at the time of resistance. The third-generation EGFR TKI, osimertinib has been approved for patients whose tumor has become resistant through the secondary T790M resistant EGFR mutation. The identification of the mechanisms of resistance and the application of the adequate therapy to each patient is still an unmet need.

Germline Predisposition and Copy Number Alteration in Pre-stage Lung Adenocarcinomas Presenting as Ground-Glass Nodules.

Objective: Synchronous multiple ground-glass nodules (SM-GGNs) are a distinct entity of lung cancer which has been emerging increasingly in recent years in China. The oncogenesis molecular mechanisms of SM-GGNs remain elusive. Methods: We investigated single nucleotide variations (SNV), insertions and deletions (INDEL), somatic copy number variations (CNV), and germline mutations of 69 SM-GGN samples collected from 31 patients, using target sequencing (TRS) and whole exome sequencing (WES). Results: In the entire cohort, many known driver mutations were found, including EGFR (21.7%), BRAF (14.5%), and KRAS (6%). However, only one out of the 31 patients had the same somatic missense or truncated events within SM-GGNs, indicating the independent origins for almost all of these SM-GGNs. Many germline mutations with a low frequency in the Chinese population, and genes harboring both germline and somatic variations, were discovered in these pre-stage GGNs. These GGNs also bore large segments of copy number gains and/or losses. The CNV segment number tended to be positively correlated with the germline mutations (r = 0.57). The CNV sizes were correlated with the somatic mutations (r = 0.55). A moderate correlation (r = 0.54) was also shown between the somatic and germline mutations. Conclusion: Our data suggests that the precancerous unstable CNVs with potentially predisposing genetic backgrounds may foster the onset of driver mutations and the development of independent SM-GGNs during the local stimulation of mutagens.

AURKB as a target in non-small cell lung cancer with acquired resistance to anti-EGFR therapy.

Non-small cell lung cancer (NSCLC) tumors harboring mutations in EGFR ultimately relapse to therapy with EGFR tyrosine kinase inhibitors (EGFR TKIs). Here, we show that resistant cells without the p.T790M or other acquired mutations are sensitive to the Aurora B (AURKB) inhibitors barasertib and S49076. Phospho-histone H3 (pH3), a major product of AURKB, is increased in most resistant cells and treatment with AURKB inhibitors reduces the levels of pH3, triggering G1/S arrest and polyploidy. Senescence is subsequently induced in cells with acquired mutations while, in their absence, polyploidy is followed by cell death. Finally, in NSCLC patients, pH3 levels are increased after progression on EGFR TKIs and high pH3 baseline correlates with shorter survival. Our results reveal that AURKB activation is associated with acquired resistance to EGFR TKIs, and that AURKB constitutes a potential target in NSCLC progressing to anti-EGFR therapy and not carrying resistance mutations.

Cancer Stem Cell Biomarkers in EGFR-Mutation-Positive Non-Small-Cell Lung Cancer.

INTRODUCTION: Epidermal growth factor receptor (EGFR) pathway deregulation promotes the acquisition of stemlike properties in non-small-cell lung cancer. EGFR inhibition through NOTCH enriches lung cancer stem cells (CSCs). Src through Yes-associated protein 1 (YAP1) activates NOTCH. Signal transduction and activator of transcription 3 (STAT3) activation occurs upon EGFR blockade and regulates the generation of CSCs. PATIENTS AND METHODS: Using the Aldefluor assay kit, we investigated the enrichment of aldehyde dehydrogenase (ALDH)-positive cells in EGFR-mutation-positive cells treated with gefitinib, afatinib, and osimertinib. Western blot analysis was performed to evaluate changes in CSC marker expression upon EGFR blockade. We performed gene expression analysis in a cohort of EGFR-mutation-positive non-small-cell lung cancer patients. We evaluated the association of gene expression with treatment outcomes. RESULTS: The cell subpopulation surviving EGFR inhibition had high ALDH activity and elevated CSC marker expression. Concurrent inhibition of EGFR, STAT3, and Src diminished the CSC subpopulation in an EGFR-mutation-positive cellular model. In a cohort of 64 EGFR-mutation-positive patients, 2 ALDH1 isoforms and the NOTCH target hairy and enhancer of split 1 (HES1), when highly expressed, were predictive of worse outcome to EGFR blockade. The gene expression of B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) that maintains the self-renewal of stem cells was also related to treatment outcome. CONCLUSION: Single EGFR inhibitors increase the population of CSCs. Combinatory therapy targeting STAT3 and Src may be of potential benefit. ALDH1, HES1, and Bmi-1 are essential biomarkers in the initial assessment of EGFR-mutation-positive patients.