LKB1 Research Articles

A novel STK11 gene mutation (c.388dupG, p.Glu130Glyfs∗33) in a Peutz-Jeghers family and evidence of higher gastric cancer susceptibility associated with alterations in STK11 region aa 107-170

A novel STK11 gene mutation (c.388dupG, p.Glu130Glyfs∗33) in a Peutz-Jeghers family and evidence of higher gastric cancer susceptibility associated with alterations in STK11 region aa 107-170

Peutz-Jeghers Syndrome and the Role of Imaging: Pathophysiology, Diagnosis, and Associated Cancers.

Simple SummaryThe Peutz-Jeghers Syndrome is a rare autosomal dominant syndrome characterized by mucocutaneous pigmentations, multiple gastrointestinal hamartomatous polyps, and an elevated risk of malignancy. Awareness of various Peutz-Jeghers Syndrome imaging patterns, associated malignancies, and their complications is crucial for accurate imaging interpretation and patient management. In this manuscript, we provide an overview of this condition, associated malignancies, and imaging surveillance protocols.The Peutz-Jeghers Syndrome (PJS) is an autosomal dominant neoplastic syndrome defined by hamartomatous polyps through the gastrointestinal tract, development of characteristic mucocutaneous pigmentations, and an elevated lifetime cancer risk. The majority of cases are due to a mutation in the STK11 gene located at 19p13.3. The estimated incidence of PJS ranges from 1:50,000 to 1:200,000. PJS carries an elevated risk of malignancies including gastrointestinal, breast, lung, and genitourinary (GU) neoplasms. Patients with PJS are at a 15- to 18-fold increased malignancy risk relative to the general population. Radiologists have an integral role in the diagnosis of these patients. Various imaging modalities are used to screen for malignancies and complications associated with PJS. Awareness of various PJS imaging patterns, associated malignancies, and their complications is crucial for accurate imaging interpretation and patient management. In this manuscript, we provide a comprehensive overview of PJS, associated malignancies, and surveillance protocols.

Novel Models of Genetic Education and Testing for Pancreatic Cancer Interception: Preliminary Results from the GENERATE Study.

Up to 10% of patients with pancreatic ductal adenocarcinoma (PDAC) carry underlying germline pathogenic variants in cancer susceptibility genes. The GENetic Education Risk Assessment and TEsting (GENERATE) study aimed to evaluate novel methods of genetic education and testing in relatives of patients with PDAC. Eligible individuals had a family history of PDAC and a relative with a germline pathogenic variant in APC, ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2, PMS2, STK11, or TP53 genes. Participants were recruited at six academic cancer centers and through social media campaigns and patient advocacy efforts. Enrollment occurred via the study website (https://GENERATEstudy.org) and all participation, including collecting a saliva sample for genetic testing, could be done from home. Participants were randomized to one of two remote methods that delivered genetic education about the risks of inherited PDAC and strategies for surveillance. The primary outcome of the study was uptake of genetic testing. From 5/8/2019 to 5/6/2020, 49 participants were randomized to each of the intervention arms. Overall, 90 of 98 (92%) of randomized participants completed genetic testing. The most frequently detected pathogenic variants included those in BRCA2 (N = 15, 17%), ATM (N = 11, 12%), and CDKN2A (N = 4, 4%). Participation in the study remained steady throughout the onset of the Coronavirus disease (COVID-19) pandemic. Preliminary data from the GENERATE study indicate success of remote alternatives to traditional cascade testing, with genetic testing rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for PDAC interception approaches. PREVENTION RELEVANCE: Preliminary data from the GENERATE study indicate success of remote alternatives for pancreatic cancer genetic testing and education, with genetic testing uptake rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for pancreatic cancer interception.

Peutz-Jeghers syndrome: Skin manifestations and endocrine anomalies (Review).

Peutz-Jeghers syndrome (PJS), a rare autosomal dominant serine/threonine kinase 11 (STK11)/ liver kinase B1 (LKB1) gene-related genodermatosis, is characterized by oral hyperpigmentation (OHP); multiple gastro-intestinal mucosal benign hamartomatous polyps causing local bleeding, occlusion, intussusception, post-resection small bowel syndrome, associated increased risk of small intestinal cancer (incidence during the third decade); and 76% cumulative higher risk than the global population of developing non-gastrointestinal tumors (female predominance) including ovarian/testicular neoplasia, pancreatic and gynecologic (breast, uterus, ovarian) cancers. Suggestive PJS-associated OHP requires STK11 genetic testing. Abdominal pain in an OHP patient may be related to PJS-associated polyps. Other features include focal depigmentation followed by hyperpigmentation, and xeroderma pigmentosum-like lesions. The severity of the dermatological findings is correlated with gastrointestinal polyps. The STK11 gene is linked to reserve of primordial follicles, polycystic ovary syndrome, female fertility, and spermatogenesis. PJS is associated with 2 types of ovarian sex-cord stroma tumors (SCSTs): annular tubules (SCTATs) and pure Sertoli cell tumors. SCSTs accounts for 8% of ovarian cancer and SCTATs represents 2% of SCST, which may be associated with the overproduction of progesterone. PJS-SCTAT vs. non-PJS-SCTAT reveals bilateral/multifocal, small tumors with a benign behavior vs. a unique ovarian, large tumor with increased malignant/metastasis risk. Male precocious puberty is due to large cell calcifying Sertoli cell tumors (LCCSCTs). Notably, 30-40% of LCCSCTs are caused by PJS or Carney complex. PJS-LCCSCT is not aggressive, but it may be bilateral/multifocal, with the ultrasound hallmark being micro-calcifications. Testicular, intra-tubular large cell hyalinizing Sertoli cell tumor is the second testicle neoplasia in PJS. The skin and mucosal lesions are useful markers of PJS, assisting with the early identification of hamartomatouspolyps and initiation of serial surveillance of ovarian, or testicular neoplasia.

Heterogeneity of Melanoma Cell Responses to Sleep Apnea-Derived Plasma Exosomes and to Intermittent Hypoxia.

Simple SummaryObstructive sleep apnea has been implicated in deleterious effects on cancer incidence and outcomes. Among the cancers identified as affected by sleep apnea, melanoma has consistently emerged as particularly susceptible. Furthermore, evidence suggests that exosomes, microparticles that originate from all cells and contain a variety of biologically active molecules such as microRNAs, can modify cancer cell properties. Here, we examined whether exosomes from sleep apnea patients can alter melanoma cell properties, and whether such effects were attributable to selected microRNA candidates, and affected melanoma cells harboring different mutations differently. In these experiments, the divergent responses of three melanoma cell lines to exosomes from sleep apnea patients before and after treatment indicated that STK11 gene mutations in melanoma cells make them particularly responsive to sleep apnea by altering cellular metabolism, and that specific microRNAs appear to underlie such effects.Obstructive sleep apnea (OSA) is associated with increased cutaneous melanoma incidence and adverse outcomes. Exosomes are secreted by most cells, and play a role in OSA-associated tumor progression and metastasis. We aimed to study the effects of plasma exosomes from OSA patients before and after adherent treatment with continuous positive airway pressure (CPAP) on melanoma cells lines, and also to identify exosomal miRNAs from melanoma cells exposed to intermittent hypoxia (IH) or normoxia. Plasma-derived exosomes were isolated from moderate-to-severe OSA patients before (V1) and after (V2) adherent CPAP treatment for one year. Exosomes were co-incubated with three3 different melanoma cell lines (CRL 1424; CRL 1619; CRL 1675) that are characterized by genotypes involving different mutations in BRAF, STK11, CDKN2A, and PTEN genes to assess the effect of exosomes on cell proliferation and migration, as well as on pAMK activity in the presence or absence of a chemical activator. Subsequently, CRL-1424 and CRL-1675 cells were exposed to intermittent hypoxia (IH) and normoxia, and exosomal miRNAs were identified followed by GO and KEG pathways and gene networks. The exosomes from these IH-exposed melanoma cells were also administered to THP1 macrophages to examine changes in M1 and M2 polarity markers. Plasma exosomes from V1 increased CRL-1424 melanoma cell proliferation and migration compared to V2, but not the other two cell lines. Exposure to CRL-1424 exosomes reduced pAMPK/tAMPK in V1 compared to V2, and treatment with AMPK activator reversed the effects. Unique exosomal miRNAs profiles were identified for CRL-1424 and CRL-1675 in IH compared to normoxia, with six miRNAs being regulated and several KEGG pathways were identified. Two M1 markers (CXCL10 and IL6) were significantly increased in monocytes when treated with exosomes from IH-exposed CRL-1424 and CRL-1625 cells. Our findings suggest that exosomes from untreated OSA patients increase CRL-1424 melanoma malignant properties, an effect that is not observed in two other melanoma cell lines. Exosomal cargo from CRL-1424 cells showed a unique miRNA signature compared to CRL-1675 cells after IH exposures, suggesting that melanoma cells are differentially susceptible to IH, even if they retain similar effects on immune cell polarity. It is postulated that mutations in STK-11 gene encoding for the serine/threonine kinase family that acts as a tumor suppressor may underlie susceptibility to IH-induced metabolic dysfunction, as illustrated by CRL-1424 cells.

STK11/LKB1 and KEAP1 mutations in non-small cell lung cancer: Prognostic rather than predictive?

Immune checkpoint inhibitors (ICIs), either alone or combined with chemotherapy, represent the cornerstone of the treatment of advanced non-small cell lung cancer (NSCLC) without targetable gene alterations. Programmed death ligand-1 expression currently represents the only available biomarker to predict response to ICI, although its reliability is debated. However, most patients still do not derive benefit from immunotherapy, making the identification of further predictive biomarkers extremely needed. Serine/threonine kinase 11 (STK11)/liver kinase B1 (LKB1) and Kelch-like ECH-associated protein 1 (KEAP1) mutations occur in 25–30% and 11–27% of advanced NSCLC, respectively. Several studies associated their presence with poor outcomes in patients treated with ICI. However, more recent evidence showed poor outcomes among NSCLC with STK11/LKB1 and/or KEAP1 mutations regardless of the treatment received. We reviewed the literature to provide a comprehensive, timely and structured overview of the role of STK11/LKB1 and KEAP1 mutations in NSCLC. Although conflicting outcomes have been reported by studies evaluating their impact in KRAS wild-type patients or regardless of KRAS mutation, the correlation between STK11/LKB1 and KEAP1 mutations and poor outcomes with ICI appears to be consistent in presence of concurrent KRAS mutations. The main limitations of most studies are represented by the inclusion of other gene mutations (e.g. TP53) together with STK11 and KEAP1 mutations as a group and by the lack of comparison arms including patients who received other treatments (e.g. chemotherapy). Studies evaluating the impact of STK11 and KEAP1 mutations on the outcomes with ICI and other therapies showed a similar effect regardless of the treatment received, suggesting a prognostic, rather than predictive, value.

Liver kinase B1 rs9282860 polymorphism and risk for multiple sclerosis in White and Black Americans

BackgroundWe previously reported that the single nucleotide polymorphism (SNP) rs9282860 in serine threonine kinase 11 (STK11) gene which codes for liver kinase B1 (LKB1) has higher prevalence in White relapsing-remitting multiple sclerosis (RRMS) patients than controls. However it is not known if this SNP is a risk factor for MS in other populations. MethodsWe assessed the prevalence of the STK11 SNP in samples collected from African American (AA) persons with MS (PwMS) and controls at multiple Veterans Affairs (VA) Medical Centers and from a network of academic MS centers. Genotyping was carried out using a specific Taqman assay. Comparisons of SNP frequencies were made using Fisher's exact test to determine significance and odds ratios. Group means were compared by appropriate t-tests based on normality and variance using SPSS V27. ResultsThere were no significant differences in average age at first symptom onset, age at diagnosis, disease duration, or disease severity between RRMS patients recruited from VAMCs versus non-VAMCs. The SNP was more prevalent in AA than White PwMS, however only in secondary progressive MS (SPMS) patients was that difference statistically significant. AA SPMS patients had higher STK11 SNP prevalence than controls; and in that cohort the SNP was associated with older age at symptom onset and at diagnosis. ConclusionsThe results suggest that the STK11 SNP represents a risk factor for SPMS in AA patients, and can influence both early (onset) and later (conversion to SPMSS) events.

New Approach for Detection of Normal Alternative Splicing Events and Aberrant Spliceogenic Transcripts with Long-Range PCR and Deep RNA Sequencing.

Simple SummaryRNA splicing defects, caused by genetic variants, are a common molecular mechanism of disease. To detect variants that cause splicing impairment, mRNA-based studies must be performed. Classical mRNA assays are time-consuming, which is why we have validated a new reliable straightforward approach to detect normal alternative splicing events and also splicing aberrations. Using our approach, we were able to reclassify three variants of uncertain significance in NBN and STK11 genes, which is of great importance for a proper clinical management of the patients.RNA sequencing is a promising technique for detecting normal and aberrant RNA isoforms. Here, we present a new single-gene, straightforward 1-day hands-on protocol for detection of splicing alterations with deep RNA sequencing from blood. We have validated our method’s accuracy by detecting previously published normal splicing isoforms of STK11 gene. Additionally, the same technique was used to provide the first comprehensive catalogue of naturally occurring alternative splicing events of the NBN gene in blood. Furthermore, we demonstrate that our approach can be used for detection of splicing impairment caused by genetic variants. Therefore, we were able to reclassify three variants of uncertain significance: NBN:c.584G>A, STK11:c.863-5_863-3delCTC and STK11:c.615G>A. Due to the simplicity of our approach, it can be incorporated into any molecular diagnostics laboratory for determination of variant’s impact on splicing.

Resistance to Durvalumab and Durvalumab plus Tremelimumab Is Associated with Functional STK11 Mutations in Patients with Non-Small Cell Lung Cancer and Is Reversed by STAT3 Knockdown.

Mutations in the STK11 (LKB1) gene regulate resistance to PD-1/PD-L1 blockade. This study evaluated this association in patients with nonsquamous non-small cell lung cancer (NSCLC) enrolled in three phase I/II trials. STK11 mutations were associated with resistance to the anti-PD-L1 antibody durvalumab (alone/with the anti-CTLA4 antibody tremelimumab) independently of KRAS mutational status, highlighting STK11 as a potential driver of resistance to checkpoint blockade. Retrospective assessments of tumor tissue, whole blood, and serum revealed a unique immune phenotype in patients with STK11 mutations, with increased expression of markers associated with neutrophils (i.e., CXCL2, IL6), Th17 contexture (i.e., IL17A), and immune checkpoints. Associated changes were observed in the periphery. Reduction of STAT3 in the tumor microenvironment using an antisense oligonucleotide reversed immunotherapy resistance in preclinical STK11 knockout models. These results suggest that STK11 mutations may hinder response to checkpoint blockade through mechanisms including suppressive myeloid cell biology, which could be reversed by STAT3-targeted therapy. SIGNIFICANCE: Patients with nonsquamous STK11-mutant (STK11mut) NSCLC are less likely than STK11 wild-type (STK11wt) patients to respond to anti-PD-L1 ± anti-CTLA4 immunotherapies, and their tumors show increased expression of genes and cytokines that activate STAT3 signaling. Preclinically, STAT3 modulation reverses this resistance, suggesting STAT3-targeted agents as potential combination partners for immunotherapies in STK11mut NSCLC.This article is highlighted in the In This Issue feature, p. 2659.

Abstract 2682: STK11-loss-dependent YAP1-mediated transcriptional activation promotes immune evasion in KRAS-driven lung adenocarcinoma

Abstract Why Serine Threonine Kinase 11 (STK11) loss of function (LoF) correlates with anti-PD1 therapy resistance in the context of KRAS-driven lung adenocarcinomas remains unclear and represents a critical outstanding question in the field. To address this, we knocked out STK11 in KRAS-driven human lung adenocarcinoma cell lines and performed RNAseq to identify STK11-loss-dependent differentially expressed genes. Subsequent pathway enrichment analyses implied activation of the HIPPO/YAP1 signaling network occurs in the absence of STK11. Based on work linking YAP1 with transcriptional regulation of cytokine-mediated inflammation and immune-evasion in colorectal cancer and gastric cancer, we wondered whether YAP1 activation might impact anti-PD1 therapy response in KRAS-driven lung cancers lacking STK11. To evaluate this possibility, we applied a YAP1 transcriptional signature to the differentially expressed genes and performed gene set enrichment analysis (GSEA) revealing a strong positive correlation between STK11 LoF and upregulation of YAP1 target genes, most notably induction of IL-6, IL-8 and IL-32. To validate YAP1-mediated transcriptional activation is downstream of STK11 loss, we reasoned we could rescue STK11-loss-dependent YAP1-mediated cytokine induction by genetic disruption of YAP1, or pharmacologic inhibition of YAP1 with verteporfin. STK11/YAP1 double knock-out cell lines express significantly less IL-6, IL-8 and IL-32 compared with STK11 KO lines. Further, inhibition of YAP1 with verteporfin phenocopied YAP1 genetic disruption in these cell lines, changes mirrored at the level of secreted protein. Finally, we demonstrate YAP1 chromatin occupancy is STK11-dependent. Together these data link STK11 LoF with YAP1-mediated transcriptional activation, specifically the upregulation of immune-evasion promoting cytokines including IL-6, IL-8 and IL-32. We posit these STK11-loss-dependent YAP1-mediated tumor-intrinsic changes could result in anti-PD1 therapy resistance and immune-evasion by promoting recruitment of myeloid-derived suppressor cells, neutrophils and T-regulatory cells to the tumor microenvironment. Further, our results indicate that YAP1 antagonism may represent a valid therapeutic approach to circumvent STK11-loss-dependent transcriptional changes and potentially restore sensitivity to anti-PD1 therapy. Elucidating the mechanism(s) linking STK11 with YAP1 transcriptional activation and evaluating the potential for beneficial therapeutic intervention remains the focus of our continuing work. Citation Format: David Joseph Seward. STK11-loss-dependent YAP1-mediated transcriptional activation promotes immune evasion in KRAS-driven lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2682.

Abstract 2706: Utilizing RNAscope to assess STK11-LoF-dependent transcriptional phenotypes in human NSCLC biopsies and evaluate its potential to predict anti-PD1 therapy response

Abstract Our work demonstrates RNAscope allows simultaneous quantitative assessment of multiple transcripts in situ using formalin fixed paraffin embedded (FFPE) human non-small cell lung cancer (NSCLC) biopsies and suggests this methodology could be used as a rapid surrogate biomarker for genotype/transcriptome profiling stemming for Serine Threonine Kinase 11 (STK11) loss of function (LoF). Recent clinical studies have correlated anti-PD1 therapy resistance in NSCLC with somatic disruption of STK11. Historically, rapid assessment of STK11 status using immunohistochemistry (IHC) has been a challenge. Our work in human NSCLC cell lines suggests that STK11 loss correlates with changes in tumor intrinsic cytokine expression. Several recent studies have suggested such changes may drive immune evasion. We therefore wondered whether cytokine expression profiles from primary human NSCLC biopsies might be used as a reliable biomarker to predict anti-PD1 therapy response. Here we present our findings using multiplexed RNAscope probes on KRAS-driven primary human NSCLC biopsies with and without STK11 loss. This initial work focuses on cytokines identified using our cell culture models as a proof of principle approach. Using CRISPR-Cas9 we engineered paired STK11 KO cell lines derived from 3 independent KRAS-driven human lung adenocarcinomas (NCI-H441, NCI-H1792, NCI-H2009). RNAseq and differential gene expression analysis revealed STK11-loss-dependent increases in IL-6, IL-8 and IL-32 in all three lines. We then created FFPE cell blocks using these cell lines and validated the RNAseq expression changes with multiplexed RNAscope probes in situ. Next, we informatically searched the molecular pathology archives at the UVM medical center and identified primary KRAS-driven human NSCLC biopsies with and without predicted STK11 loss. We then performed multiplexed RNAscope analysis on these samples to quantify IL-6, IL-8 and IL-32 gene expression as a function of tumor genotype in vivo. Our data suggest RNAscope represents a valid methodology to exploit quantitative differential gene expression as a reliable and reproducible surrogate biomarker of somatic STK11 disruption in NSCLC. Our future studies aim to establish whether genotype-dependent cytokine profiles predict anti-PD1 therapy response in KRAS-driven lung adenocarcinomas. Citation Format: Hailey M. Sarausky, Sean M. Lenahan, David Joseph Seward. Utilizing RNAscope to assess STK11-LoF-dependent transcriptional phenotypes in human NSCLC biopsies and evaluate its potential to predict anti-PD1 therapy response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2706.

Abstract 2466: Stochastic loss of GLUL expression correlates with STK11-loss-dependent glutamine addiction and may impact anti-PD1 therapy resistance in NSCLC

Abstract Our work aims to delineate the molecular interactions linking somatic disruption of Serine-Threonine Kinase 11 (STK11) with anti-PD1 therapy resistance in KRAS-driven lung adenocarcinoma (LUAD). Data presented here suggests glutamine synthetase (GLUL) may modulate this phenotype. Immune checkpoint inhibitors (ICIs), including anti-PD1 monoclonal antibody therapy, represent a promising therapeutic option for non-small cell lung cancer (NSCLC) patients. Unfortunately, efficient use of these drugs is hampered by an inability to accurately predict which patients will respond. Clinical observations have correlated anti-PD1 therapy resistance in KRAS-driven LUAD with somatic STK11 disruption, but the mechanism(s) responsible remains unknown. To investigate this connection we knocked out STK11 in three different human KRAS-driven LUAD cell lines and performed RNA-seq analysis to identify STK11-loss-dependent differentially expressed genes. Intriguingly, GLUL expression was reproducibly lost in a subset of KRAS-driven/STK11 null clones across two different human lung adenocarcinoma cell lines. GLUL is an enzyme that converts glutamate to glutamine. Glutamine is a critical metabolite supplying carbon and nitrogen necessary for amino acid, nucleotide, and lipid synthesis. Additionally, glutamine plays an important role in redox homeostasis, chromatin organization, and intra-tumoral signaling. Glutamine dependency is a common phenotype across many solid tumor types, and has previously been linked with STK11-deficiency in the context of polycystic kidney disease. Our current work suggests loss of GLUL expression correlates with an altered tumor-intrinsic response to nutrient stress in KRAS-driven LUAD culminating in immune evasion and anti-PD1 therapy resistance. Ongoing experiments aimed to define the relationship between STK11 loss and GLUL expression suggest this phenomenon is stochastic in nature and may provide tumor cells with a selective advantage. In conclusion, understanding the biology underlying the molecular connection between STK11 and GLUL may reveal reliable biomarkers for anti-PD1 therapy response and suggest a method for restoring sensitivity to current therapies. Citation Format: Sean M. Lenahan, Hailey M. Sarausky, David Joseph Seward. Stochastic loss of GLUL expression correlates with STK11-loss-dependent glutamine addiction and may impact anti-PD1 therapy resistance in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2466.

A phase II study of everolimus in patients with advanced solid malignancies with TSC1, TSC2, NF1, NF2 or STK11 mutations.

BackgroundActivation of the mTOR pathway has been implicated in the development of several malignancies and alterations in TSC1, TSC2, STK11 and NF1, can lead to the dysregulation of this pathway. Furthermore, mutations in TSC1 and NF2 are known to confer sensitivity to everolimus—an mTOR inhibitor. Based on these data, a single-arm, open label, single-institution phase II basket study was designed to assess the activity of everolimus in patients with solid malignancies whose tumors harbored mutations in TSC1, TSC2, NF1, NF2, or STK11.MethodsA total of 12 patients with histologically confirmed diagnosis of advanced solid tumors (metastatic, recurrent, or unresectable) with mutations in TSC1, TSC2, NF1, NF2 or STK11 genes, who had failed at least one line of standard of care systemic therapy, were enrolled to this open label, single-arm study. Presence of mutations in TSC1, TSC2, NF1, NF2 or STK11 genes was assessed using targeted-next generation sequencing (NGS). All eligible patients were treated with everolimus at an initial dose of 10 mg orally once daily in cycles of 28 days. The primary endpoint of this study was overall response rate (ORR).ResultsOf 12 patients enrolled, 8 were evaluable for response at the end of 2 cycles. One complete response (CR) was observed (12.5%) and one patient (12.5%) had stable disease (SD), while six (75%) patients showed disease progression. Everolimus was overall well tolerated with anemia, decreased neutrophil and lymphocyte counts, peripheral edema and hyperglycemia representing the most common adverse events. One patient discontinued treatment due to a treatment related grade 4 pericardial effusion. Both patients with CR or SD had a diagnosis of lung adenocarcinoma with NF1 or STK11 mutations, respectively.ConclusionsAlthough this study failed to meet its prespecified ORR threshold for success of 30% or higher, exploratory analyses suggest potential activity for everolimus in a subset of patients with lung adenocarcinomas with STK11 or NF1 mutations. Further studies are necessary to systematically explore the clinical activity of everolimus, potentially as a combination therapy, in these patients.

Abstract CT164: Pharmacological ascorbate enhances platinum-based chemotherapy responses in metastatic non-small cell lung cancer (NSCLC): A phase II clinical trial

Abstract PURPOSE: First line treatment with platinum-based chemotherapy with or without immunotherapy improves survival in metastatic non-small cell lung cancer (NSCLC). Preclinical studies suggest that pharmacological ascorbate (P-AscH-) enhances tumor response to platinum therapy. Hence, we conducted a single-arm phase II study to evaluate the efficacy of P-AscH- in combination with platinum-doublet chemotherapy in patients with advanced stage NSCLC (NCT02420314). METHODS: Chemotherapy naïve advanced stage NSCLC patients with an ECOG PS of 0-2 were enrolled to receive 4-cycles of carboplatin (AUC 6) and paclitaxel (200 mg/m2) every 3 weeks (wks). Ascorbate (75 g) infusions were given twice a wk for 12-wks. The primary endpoint was to assess tumor objective response per RECIST v1.1. The trial was conducted as an optimal Simon two-stage design. After initial therapy, patients could receive maintenance or consolidation treatment. Secondary endpoints were to evaluate tolerability, progression-free survival (PFS) and overall survival (OS). Serum cytokines and chemokines were measured at baseline, C2d1, and C4d21± 7d. RESULTS: Forty subjects were enrolled. The study met its primary endpoint with 38 efficacy evaluable subjects. The objective response rate was 34.2%. All were confirmed partial responses (cPR). Disease control rate was 84.2% (stable disease + cPR). Median duration of follow up was 11.7 months (mo), mPFS was 5.7 mo (95% CI:4.2-6.7), and mOS was 12.5 mo (95% CI:7.5-21.4). Treatment-related adverse events (TRAE) included one grade 5 (neutropenic fever) and five grade 4 (cytopenia) events. These events were not attributed to P-AscH-. Common (≥5%) grade 3 TRAE included transient hypertension (27.5%), lymphopenia (22.5%), fatigue (7.5%), anemia (7.5%) and hypokalemia (5%). Cytokine and chemokines data suggest that protocol regimen elicited an immune response with multiple distinct cytokine signatures. Immunophenotyping of peripheral blood mononuclear cells (n=7) demonstrated a mean fold increase in effector CD8 T cells of 4.9 in patients with PFS ≥ 6 mo compare to 1.6 in patients with PFS < 6 mo. Assessments of serum iron profile and somatic alterations in KRAS, KEAP1, NFE2L2 and STK11 genes are underway. CONCLUSIONS: This phase II trial met the primary objective of improving the tumor response rate in advanced stage NSCLC by adding P-AscH- to platinum-based chemotherapy. P-AscH- appears to alter the host immune response. These promising findings warrant further investigation. Citation Format: Muhammad Furqan, Taher Abu-Hejleh, Kellie L. Bodeker, Laura M. Pietrok, Stacey M. Hartwig, Mikaela M. Tremblay, Micaela G. Fosdick, Jon Houtman, Steven Varga, Casey F. Pulliam, Michael Petronek, Melissa A. Fath, Sarah L. Mott, Aaron D. Bossler, Andrew M. Bellizzi, Jun Zhang, Hariharasudan Mani, Varun Monga, Brian J. Smith, Joseph Cullen, Brett A. Wagner, Garry R. Buettner, John M. Buatti, Douglas R. Spitz, Bryan G. Allen. Pharmacological ascorbate enhances platinum-based chemotherapy responses in metastatic non-small cell lung cancer (NSCLC): A phase II clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT164.

Peutz-Jeghers syndrome: what has been known for 125 years of research? (review)

Peutz-Jeghers syndrome (PJS) is an extremely rare autosomal dominant hereditary disease characterized by the growth of hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmented macules and an increased risk of malignant neoplasms of various localizations. In most cases the development of PJS is associated with the presence of a mutation in the STK11 gene, but not all patients have this mutation. This review presents the historical aspects of the first data on PJS, considers the clinical manifestations of the disease, current diagnostic methods, as well as recent knowledge about the genetic causes, about the risk of malignant neoplasms in patients with PJS, existing guidelines for screening and treatment of patients with PJS. However, the presence of a number of unresolved issues in genetics, monitoring and treatment indicates the need for further research.

Delayed diagnosis of Peutz\u2013Jeghers syndrome due to pathological information loss or mistake in family/personal history

ObjectiveTo report Peutz–Jeghers syndrome (PJS) cases with non-definitive clues in the family or personal history and finally diagnosed through pathological examination and STK11 gene mutation test.Clinical presentation and interventionPJS was suspected in 3 families with tortuous medical courses. Two of them had relatives departed due to polyposis or colon cancer without pathological results, and the other one had been diagnosed as hyperplastic polyposis before. Diagnosis of PJS was confirmed by endoscopy and repeated pathological examinations, and the STK11 mutation test finally confirmed the diagnosis at genetic level, during which 3 novel mutation were detected (536C > A, 373_374insA, 454_455insGGAGAAGCGTTTCCCAGTGTGCC).ConclusionEarly diagnosis of PJS is important and may be based on a family history with selective features among family members, and the pathological information is the key. The novel mutations also expand the STK11 variant spectrum.

A novel pathogenic splice site variation in STK11 gene results in Peutz-Jeghers syndrome.

BackgroundPeutz–Jeghers syndrome (PJS) is a rare autosomal dominantly inherited disease resulting in multiple gastrointestinal hamartomatous polyps, mucocutaneous pigmentation, and an increased risk of various types of cancer, and is caused by variations in the serine/threonine protein kinase STK11 (LKB1).MethodsSTK11 gene variations were identified by analyzing STK11 cDNA and genomic DNA. Minigenes carrying the wild‐type and mutant sequences were subjected to in vitro splicing assay to dissect the features of these mutations. The different distribution of wild‐type and mutant protein in cells were tested by Immunofluorescence assays and the functional analysis of the variation were performed using Western blot.ResultsA novel heterozygous splice‐acceptor site variation (c.921‐2 A>C) in intron 7 of the STK11 gene which is co‐segregates with the PJS phenotypes in the proband and all the affected family members and three previously reported variations (c.180C>G, c.580G>A, c.787_790del) were identified in the four families. The c.921‐2 A>C substitution resulted in the inactivation of a splice site and the utilization of a cryptic splice acceptor site surrounding exon 8, generating three different aberrant RNA transcripts, leading to frameshift translation and protein truncation. The results of minigenes indicated that the spliceosome can use a variety of 3’ acceptor site sequences to pair with a given 5’ donor site. The immunofluorescent visualization showed that the distribution of mutant STK11 was different from that of wild‐type STK11, suggesting the mutation may be the causative effect on the dysfunction of the mutant protein. The rescue experiments indicated that the failure of suppressing mTOR phosphorylation by shRNA STK11 could be eliminated by supply of wild‐type STK11 rather than mutant STK11.ConclusionWe identified a novel heterozygous mutation (c.921‐2 A>C) in the STK11 in a Chinese PJS family. Haploinsufficiency of STK11 might contribute to the pathogenesis of the disease.

Prevalence of hyperprogressive disease (HPD) mutations and correlations to immune-related biomarkers in a large pan-cancer Chinese cohort.

2649 Background: Immune checkpoint blockade (ICI) therapies have demonstrated inspiring clinical efficacy in multiple types of cancer. However, a subset of patients suffered rapid tumor growth after ICI treatment, which is known as hyperprogressive disease (HPD). Although the mechanism of HPD has not been fully elucidated, some genomic alterations, such as CDKN2A/CDKN2B loss and MDM2/MDM4 amplification were reported to occur in tumors with ICI-related HPD. We analyzed the prevalence of these four “HPD mutations” and their association with PD-L1 expression, TMB, and occurrence of driver gene mutations in a large pan-cancer Chinese cohort. Methods: Patients whose tumor tissues were subjected to molecular profiling using targeted next-generation sequencing from January 2017 – November 2020 were included. Single nucleotide variants (SNV), copy number variants (CNV), insertion/deletions (indels) and fusions were called. PD-L1 expression was stratified by CPS 5. Fisher’s exact test were conducted to compare the frequencies of biomarkers and Mann-Whitney U test was used to compare the TMB level between the “HPD mutations” group and their wild-type counterpart. Results: 45,785 patients of 22 types of cancer were queried. Across all 22 cancers, CDKN2A loss and CDKN2B loss were most commonly seen in ESCA (23.3%, 19.8%), while with the lowest frequency in PRAD (0.18%, 0.18%). MDM2 gain and MDM4 gain occurred most frequently in SARC (14.6%) and BRCA (3.3%), respectively, with the lowest frequency in COAD (0.05%, 0.07%). PD-L1 positive (CPS≥5) rates were similar in CDKN2A/B loss, MDM2/4 amp and wild-type groups in the whole cohort (26.1%, 25%, 27.7%). Enrichment of PD-L1 positivity was not observed in HPD-mutant groups in a specific cancer type. Compared with wild-type group, CDKN2A/B loss significantly correlated with higher TMB levels in NSCLC and SARC (p < 0.05) while MDM2/4 amp correlated with lower TMB levels in NSCLC, BTC, and STAD (p < 0.05). In NSCLC, SNV in EGFR, TP53, KEAP1, NFE2L2, STK11, PIK3CA, and SMARCA4 genes were significantly enriched in the CDKN2A/B loss group, while SNV in EGFR, RBM10, AR, KDR genes, and fusion in RET were significantly enriched in MDM2/4 amp group. Conclusions: HPD mutations were significantly associated with TMB level and occurrence of some driver genes, but were not correlated with PD-L1 expression. Our results revealed the immune-related molecular characteristics in tumors with HPD mutations, providing more insights into the exploration for mechanism of HPD.

Peutz–Jeghers' syndrome in pediatric dermatological practice

Peutz–Jeghers' syndrome is a rare hereditary disease inherited by an autosomal dominant type, manifested by a characteristic clinical picture of skin lesions and hamartomas of the gastrointestinal tract. Complications of the disease include bleeding from polyps, anemia, intussusception and intestinal necrosis, as well as a high likelihood of developing malignant tumors. For the first time the syndrome was described at the beginning of the last century, and it is of interest to dermatologists, gastroenterologists, oncologists and surgeons due to the clinical heterogeneity of intestinal and skin manifestations. The article describes a clinical case of a 5-year-old girl with the Peutz–Jaegers syndrome. The patient complained of periodic dull abdominal pain that worsened after eating solid food. During the examination of the skin and mucous membranes the doctors discovered rashes on the face: perioral area, on the red border of the lips and on the mucous membrane of the lips, inside the cheeks, hard palate. Esophagogastroduodenoscopy (EGDS) revealed a polyp on a pedicle in the prepyloric part – it was removed during repeated EGDS under endotracheal anesthesia. Fibrocolonoscopy revealed hyperpigmentation of the dome of the cecum. To confirm the diagnosis, the doctors carried out DNA testing which found a mutation of the STK11 gene. Pigmentation of the perioral area is an early symptom of Peutz–Jeghers' syndrome suggesting optimal examination. Early recognition of the syndrome in children is important in the context of reducing the risk of developing intestinal obstruction, bleeding, and cancer complications in the future.

122P STK11 and/or KEAP1 mutations and outcomes in non-small cell lung cancer patients treated with immune checkpoint inhibitors: A systematic literature review

Background: Immune checkpoint inhibitors (ICIs) have recently become a major strategy in treatment of non-small cell lung cancer (NSCLC), but somatic mutations involving the STK11 and KEAP1 genes may elicit resistance to anti-PD(L)1 agents. We conducted a systematic review aiming to determine if these mutations are significantly related to poorer outcomes in NSCLC patients (pts) treated with ICIs.