Serine/threonine Kinase 11 Mutation Research Articles

Abstract 5584: Experimental ‘loss-of function’ annotation of STK11 mutations with prognostic and therapeutic implications (TNG260mutationfinder.com)

Abstract Loss of function mutations in Serine Threonine Kinase 11 (STK11) occur in 15% of lung adenocarcinoma and have been shown to drive resistance to immune checkpoint blockade clinically, as well as in preclinical models. Though STK11 is commonly inactivated in human cancer with strong implications for treatment outcomes, few STK11 mutations identified from tumor samples have been functionally characterized. TNG260 is an inhibitor of CoREST that is currently being investigated in combination with pembrolizumab for the treatment of STK11-mutant cancer (NCT05887492). Patients are eligible for enrollment in the TNG260 phase 1/2 trial if their tumor contains a deleterious STK11 mutation. To begin classifying non-annotated variants, over 2,000 distinct mutations in the STK11 gene were identified from STK11 literature or public repositories of tumor sequencing data such as AACR Project GENIE and ClinVar. Where possible, loss-of-function annotations were captured from literature or predictive tools such as PolyPhen-2. However, many STK11 variants, particularly missense mutations, have never been functionally characterized. We developed a functional screening approach to characterize STK11 alterations using the lung adenocarcinoma cell line A549. A549 cells contain homozygous loss of STK11 via a truncation mutation at Q37, and re-expression of wild-type STK11 in these cells strongly impairs their growth in vitro and in vivo. We created a library of STK11 variant cDNAs, each containing a unique barcode. This library was expressed in A549, and cells were maintained in vitro or in vivo to allow for positive selection of STK11 loss-of-function variants and depletion of variants that behave like wild-type STK11. At the end of the screen, variants were quantified by NGS using each mutant cDNA’s unique barcode and compared to well-annotated controls. These data were assembled to generate TNG260mutationfinder.com – the first website to curate STK11 variants with functional annotations. Citation Format: Leanne G. Ahronian, Preksha Shahagadkar, Lauren Flynn, Lauren Grove, Shangtao Liu, Samuel R. Meier, Binzheng Shen, Hannah Stowe, Hsin-Jung Wu, Yi Yu, Andre Mignault, Iga Sienczylo, Heather DiBenedetto, Silvia Fenoglio, Teng. Experimental ‘loss-of function’ annotation of STK11 mutations with prognostic and therapeutic implications (TNG260mutationfinder.com) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5584.

Abstract 6529: Multi-lineage de-differentiation (MLDD) towards the TTF1-low phenotype is a major determinant of immune response within STK11-deficient non-small cell lung cancer

Abstract Background: The loss of serine/threonine kinase 11 (STK11) in non-small cell lung cancer (NSCLC) is associated with poor prognosis and resistance to immune checkpoint blockade (ICB) in 20-25% of cases. Experimental evidence from murine models suggests that STK11 loss contributes to lineage plasticity, while clinical observations indicate its impact on differentiation phenotypes in patients. However, the intricate interplay between differentiation states, the tumor microenvironment (TME), and clinical outcomes remains poorly elucidated. This study aims to comprehensively characterize these interactions to enhance our understanding of the complex dynamics underlying STK11-deficient NSCLC pathogenesis and therapeutic responses. Methods: By leveraging large multi-omics datasets, we already demonstrated the low immune infiltration in TTF1-low and neuroendocrine MLDD subsets of LKB1-deficient tumors. In this study, we used GEMM-derived two KPL (Kras, TP53, and STK11 mutations) and one KPL-restored line to inject subcutaneously in F1 hybrid mice of B6 and Sv129 backgrounds. Tumor size was monitored at regular intervals, and upon reaching a sufficient size, tumors were harvested and partitioned for the characterization of immune cells (T-cells and NK cells) by flow cytometry and identification of the MLDD phenotypes through gene expression analysis using Nanostring technology. Results: Mice injected with the STK11 WT line (2695L) exhibited smaller tumor volumes compared to those injected with STK11 mutant lines (2695X and 2381T4). Our comprehensive analysis, combining flow cytometry and Nanostring techniques, revealed that STK11 mutant lines displayed notably low infiltration of CD8+ T-cells, an elevated proportion of exhausted T-cells, and a manifestation of the TTF1-low immune phenotype characterized by high myeloid-derived suppressor cells (MDSCs) and increased KLRC1/KLRC2 expression. The presence of MDSCs in the STK11 mutant line correlated with pro-inflammatory cytokines but exhibited an inverse correlation with MHC-2 expression. MHC-2 expression was inversely correlated with CD8+ T-cell percentage and positively correlated with naïve T-cell percentage. Conclusions: The data obtained from the study indicates that the MDSC phenotype seems to be important for immune evasion in STK11-loss tumors. Follow-up flow cytometry and gene expression experiments with combined T-cells and myeloid/PMN MDSC-related gene panels, along with further experiments involving cIAP1/PD1 inhibitors, are imperative to substantiate and expand upon our current findings. Citation Format: Rahul Shivahare, No Joon Song, Bahareh Nourmohammadi, Jemal Imam, Olivia Sanabria, Joseph M. Amann, Qin Ma, Zihai Li, David P. Carbone, Jacob Kaufman. Multi-lineage de-differentiation (MLDD) towards the TTF1-low phenotype is a major determinant of immune response within STK11-deficient non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6529.

STK11 (LKB1) mutation suppresses ferroptosis in lung adenocarcinoma by facilitating monounsaturated fatty acid synthesis.

Serine/threonine kinase 11 (STK11), a tumor suppressor gene, exhibits frequent mutations in lung adenocarcinoma (LUAD). However, the specific molecular mechanisms by which STK11 mutations exert an influence on the biosynthesis of monounsaturated fatty acids (MUFAs) and subsequently affect ferroptosis in LUAD remain indistinct. In this study, bioinformatic analysis was employed to probe into the linkage between STK11 and key inhibitory genes of ferroptosis, namely SLC7A11 and SCD1, in LUAD tissues. Quantitative reverse transcription polymerase chain reaction was employed to assess the expression of STK11 in both wild-type and mutant STK11 LUAD cells, cell counting kit-8 to assess cell viability, and flow cytometry to detect apoptosis. A transmission electron microscope was utilized to observe mitochondrial morphology, and Western blot to ascertain the protein expression of STK11, ferroptosis-related proteins, and the enzyme SCD1 involved in MUFA synthesis. Oil red O staining was employed to test the distribution of lipid droplets in cancer cells, and a lipid quantification method to measure the content of MUFAs. Commercial kits were employed to assess the levels of lipid reactive oxygen species, malondialdehyde, glutathione, and Fe2+ in cells. The result revealed a negative correlation between STK11 and SLC7A11 as well as SCD1, with STK11 expression downregulated in mutant STK11 LUAD cells. Furthermore, STK11 mutations were found to suppress ferroptosis in LUAD cells by affecting MUFA synthesis. Subsequent rescue assays demonstrated that STK11 mutations hindered ferroptosis by impacting the synthesis of MUFAs in LUAD cells. This study provided evidence that STK11 mutations suppressed ferroptosis in LUAD cells by promoting MUFA synthesis, thus offering a novel research direction in the management of LUAD.

A Critical Review of the Prognostic and Predictive Implications of KRAS and STK11 Mutations and Co-Mutations in Metastatic Non-Small Lung Cancer.

The Kirsten rat sarcoma viral oncogene homolog (KRAS) and serine/threonine kinase 11 (STK11) co-mutations are associated with the diverse phenotypic and heterogeneous oncogenic subtypes in non-small cell lung cancer (NSCLC). Due to extensive mixed evidence, there needs to be a review of the recent KRAS and STK11 mutation literature to better understand the potential clinical applications of these genomic biomarkers in the current treatment landscape. This critical review highlights the clinical studies that have elucidated the potential prognostic and predictive implications of KRAS mutations, STK11 mutations, or KRAS/STK11 co-mutations when treating metastatic NSCLC across various types of treatments (e.g., immune checkpoint inhibitors [ICIs]). Overall, KRAS mutations are associated with poor prognoses and have been determined to be a valid but weak prognostic biomarker among patients diagnosed with NSCLC. KRAS mutations in NSCLC have shown mixed results as a predictive clinical biomarker for immune checkpoint inhibitor treatment. Overall, the studies in this review demonstrate that STK11 mutations are prognostic and show mixed results as predictive biomarkers for ICI therapy. However, KRAS/STK11 co-mutations may predict primary resistance to ICI. Prospective KRAS/STK11-biomarker-driven randomized trials are needed to assess the predictive effect of various treatments on the outcomes for patients with metastatic NSCLC, as the majority of the published KRAS analyses are retrospective and hypothesis-generating in nature.

STK11 Causative Variants and Copy Number Variations Identified in Thai Patients With Peutz-Jeghers Syndrome.

Introduction Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant inherited disorder caused by germline mutations in the serine-threonine kinase 11 (STK11) tumor suppressor gene. This syndrome is characterized by hamartomatous gastrointestinal polyps, mucocutaneous melanin pigmentation, and a higher risk of developing various cancers. Methods We summarized the clinical and molecular characteristics of five unrelated Thai patients with PJS. Denaturing high-performance liquid chromatography (DHPLC) screening, coupled with direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA), were applied for the molecular analysis of STK11. Results A total of four STK11 pathogenic changeswere identified in the five PJS patients, including two frameshift variants (a novel c.199dup, p.Leu67ProfsTer96 and a known c.834_835del, p.Cys278TrpfsTer6) and two types of copy number variations (CNV), exon 1 deletion and exons 2-3 deletion. Among reported STK11 exonic deletions, exon 1 and exons 2-3 deletions were found to be the two most commonly deleted exons. Conclusion All identified STK11 mutations were null mutations that were associated with more severe PJS phenotypes and cancers. This study broadens the phenotypic and mutational spectrum of STK11 in PJS.

Esophageal squamous cell cancer with germline STK11 mutation - A possibility, a nightmare or the Peutz Jeghers Syndrome!

Background: Peutz Jeghers Syndrome (PJS) is characterized by multiple gastrointestinal hamartomatous polyps and muco-cutaneous pigmentation with increased risk of carcinomas of gastrointestinal tract, breast, lung and gynecological tumors. Only 2 % PJS have esophageal cancers, that too adenocarcinoma. So far esophageal Squamous Cell Carcinoma (SCC) has not been reported in association with PJS. We present a unique case in a young female with muco-cutaneous pigmentation who presented with esophageal SCC and was found to have germline Serine/Threonine Kinase 11 (STK11) mutation.

Serine/Threonine Kinase 11 Plays a Canonical Role in Malignant Progression of KRAS -Mutant and GNAS -Wild-Type Intraductal Papillary Mucinous Neoplasms of the Pancreas.

We aimed to elucidate the clinicopathobiological significance of Serine/Threonine Kinase 11 (STK11) in pancreatic intraductal papillary mucinous neoplasms (IPMNs). STK11 is a tumor suppressor involved in certain IPMNs; however, its significance is not well known. In 184 IPMNs without Peutz-Jeghers syndrome, we analyzed expression of STK11 and phosphorylated-AMPKa in all cases, and p16, p53, SMAD4, and β-catenin in 140 cases by immunohistochemistry; and we analyzed mutations in 37 genes, including whole coding exons of STK11, CDKN2A, TP53, and SMAD4, and hotspots of KRAS, BRAF, and GNAS in 64 cases by targeted sequencing. KRAS and GNAS were additionally analyzed in 86 STK11-normal IPMNs using digital-PCR. Consistent loss or reduction of STK11 expression was observed in 26 of 184 (14%) IPMNs. These STK11-aberrant IPMNs were 17 of 45 (38%) pancreatobiliary, 8 of 27 (30%) oncocytic, 1 of 54 (2%) gastric, and 0 of 58 (0%) intestinal subtypes ( P = 8.5E-11), and 20 of 66 (30%) invasive, 6 of 74 (8%) high-grade, and 0 of 44 (0%) low-grade ( P = 3.9E-06). Sixteen somatic STK11 mutations (5 frameshift, 6 nonsense, 1 splicing, and 4 missense) were detected in 15/26 STK11-aberrant IPMNs ( P = 4.1E-06). All STK11-aberrantIPMNs were GNAS -wild-type and 96% of them were KRAS or BRAF -mutant.Morphologically, STK11-aberrant IPMNs presented "fern-like" arborizing papillae with thin fibrovascular core. Phosphorylated-AMPKa was down-regulated in STK11-aberrant IPMNs (92%, P = 6.8E-11). Patients with STK11-aberrant IPMNs showed poorer survival than patients with STK11-normal IPMNs ( P = 3.6E-04 overall; P = 6.1E-04 disease-free). STK11 may play a canonical role in malignant progression and poor survival of patients with IPMNs. Aberrant STK11-driven phosphorylated AMPK downregulation may provide therapeutic opportunities with mTOR inhibitors/AMPK activators.

Alteration of STK11 Expression Associated With Cholangiocarcinoma Progression.

Serine/threonine kinase 11 (STK11), a tumor suppressor, controls 5' AMP-activated protein kinase (AMPK) signaling in a variety of cellular functions. Mutated STK11 has been identified as a novel driver gene that promotes cancer progression. The purpose of this study was to investigate the alteration of STK11 and its correlation with clinicopathological data in cholangiocarcinoma (CCA). Gene mutation and expression analyses were performed using cBioportal and Gene Expression Profiling Interactive Analysis version 2 (GEPIA2). qRT-PCR was performed to measure STK11 mRNA levels and immunohistochemistry was performed to investigate STK11 protein expression in CCA tissues. The results from publicly available cancer datasets showed that 2.7% of CCA cases had STK11 mutations. Most of STK11 gene mutations are of the truncating type and result in low STK11 mRNA and protein expression. We detected a correlation between STK11 mutation status and the tendency for shorter patient survival. The results of qRT-PCR revealed that STK11 mRNA levels were statistically significantly lower in CCA patients with mutated STK11 compared to those with wild-type STK11 (p-value=0.013). Immunohistochemical staining showed high STK11 expression in 43.8% and low expression in 56.2% of CCA tissues examined. Low STK11 protein expression resulted in poor prognosis compared with high STK11 expression, especially in CCA papillary carcinoma. Univariate and multivariate analysis revealed that high STK11 expression was associated with a decreased hazard ratio of patient survival rates (HR=0.696, p-value=0.06 and HR=0.666, p-value=0.04, respectively). Alteration of STK11 mutational or mRNA/protein status might be used as a potential predictive biomarker for the prognosis of the clinical outcomes in CCA patients.

Trial in progress: A phase 2 study of sotorasib as first-line treatment in patients with stage IV non–small cell lung cancer (NSCLC) whose tumors harbor a KRAS p.G12C mutation (CodeBreaK 201).

TPS9150 Background: Chemo-immunotherapy regimens represent a standard of care for the first-line treatment of metastatic NSCLC, yet clinical outcomes in patients bearing tumors that lack PD-L1 expression [PD-L1 Tumor Proportion Score (TPS) < 1%)] or harbor a serine/threonine kinase 11 ( STK11) mutation remain poor. Sotorasib is a selective, irreversible small molecule KRASG12C inhibitor that is approved for the treatment of patients with locally advanced or metastatic KRAS p.G12C-mutated NSCLC following failure of at least one prior line of systemic therapy and has previously demonstrated robust antitumor activity in subgroups of KRAS p.G12C mutant NSCLC with PD-L1 TPS <1% and/or STK11 co-mutations. We hypothesized that sotorasib may represent an effective first-line therapy for subgroups of NSCLC patients who may have suboptimal chemo-immunotherapy outcomes and a high unmet clinical need. Methods: This phase 2, open-label, global study is designed to evaluate the efficacy and safety of sotorasib (960 mg or 240 mg daily) as first-line treatment in approximately 170 patients with KRAS p.G12C-mutated, metastatic NSCLC with PD-L1 TPS <1% as determined by immunohistochemical assay and/or presence of STK11 mutation as determined by next-generation sequencing (NGS). Key eligibility criteria include patients with untreated metastatic NSCLC without active brain metastases. Patients will be stratified by known presence of STK11 mutation. The primary endpoint is objective response assessed by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Secondary endpoints include disease control, duration of response, time to response, progression-free survival per RECIST 1.1, overall survival, safety and tolerability, and pharmacokinetic profile. Enrollment began in January 2022 and is ongoing. Contact Amgen Medical Information for more information. Clinical trial information: NCT04933695.

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.

Relevance of STK11 Mutations Regarding Immune Cell Infiltration, Drug Sensitivity, and Cellular Processes in Lung Adenocarcinoma.

Serine/threonine kinase 11 (STK11) is one member of the serine/threonine kinase family, which is involved in regulating cell polarity, apoptosis, and DNA damage repair. In lung adenocarcinoma (LUAD), it can play as one tumor suppressor and always be mutated. In this study, we aimed to assess the relevance of STK11 mutations in LUAD, in which we also studied the correlation among immune cell infiltration, drug sensitivity, and cellular processes. By performing the bioinformatics analysis of the Cancer Genome Atlas (TCGA) about LUAD patients, we found that the mutation efficiency of STK11 mutations is about 19%. Additionally, the differentially expressed gene analysis showed that there were 746 differentially expressed genes (DEGs) between LUAD patients with and without STK11 mutations. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis showed that the DEGs were enriched in various tumorigenesis signaling pathways and metabolic processes. Among these DEGs, the top ranking 21 genes were found that they were more frequently mutated in the STK11 mutation group than in the wild-type group (p-value<0.01). Finally, the LUAD patients with STK11 mutations suffered the worse immune cell infiltration levels than the LUAD patients with wild-type. The STK11 gene copy number was correlated with immune cell infiltration. Aiming to develop the therapeutic drugs, we performed Genomics of Drug Sensitivity in Cancer (GDSC) data to identify the potential therapeutic candidate and the results showed that Nutlin-3a(-) may be a sensitive drug for LUAD cases harboring STK11 mutations. The specific genes and pathways shown to be associated with LUAD cases involving STK11 mutations may serve as targets for individualized LUAD treatment.

Abstract 793: Association of serine/threonine kinase 11 mutations and response to programmed cell death 1 inhibitors in metastatic gastric cancer

Abstract Background: Programmed cell death 1 (PD-1) inhibitors have shown therapeutic efficacy in metastatic gastric cancer (mGC). However, only a small portion the patients derive clinical benefits from PD-1 inhibitors, and no predictive biomarkers have been established in mGC. Inactivating mutations in serine/threonine kinase 11 (STK11), also known as liver kinase B1, are associated with immune suppression in the tumor microenvironment and poor response to PD-1 inhibitors in KRAS-mutant lung adenocarcinoma. Therefore, we hypothesized that STK11 inactivating mutations would be associated with inferior clinical response to PD-1 inhibitors in mGC. Methods: We analyzed 59 patients with mGC who had been treated with PD-1 inhibitors and whose tumors had been analyzed by targeted high-throughput sequencing. Clinicopathological characteristics, including Epstein-Barr virus positivity (EBV+), programmed death-ligand 1 (PD-L1) positivity, high microsatellite instability (MSI-H), response to PD-1 inhibitors, and survival were retrospectively evaluated. Result: STK11 mutations were identified in 30 (50.8%) patients, and were all missense mutations. Three patients (5.1%) had simultaneous STK11 gene amplification and mutation. STK11 mutations were not significantly associated with MSI-H, the number of tumor mutations, PD-L1+, EBV+, or the response to PD-1 inhibitors. Patients with STK11 mutations had prolonged overall survival (median: 19.0 vs 11.6 months, p=0.15), and progression-free survival (4.2 vs 1.9 months, p=0.06) when treated with PD-1 inhibitors, but these differences were not statistically significant. In addition, the distribution of STK11 mutations was not associated with the response to PD-1 inhibitor treatment. Patients with STK11 inactivating mutations without STK11 gene amplification had significantly prolonged progression-free survival compared to patients with intact wild type STK11 or STK11 gene amplification (4.8 vs 1.0 months, p=0.04). However, in multivariate Cox regression analysis with MSI-H, PD-L1+, EBV+, the number of mutations, and type of PD-1 inhibitor used (pembrolizumab vs nivolumab), only MSI-H and PD-L1+ were significantly associated with longer progression-free survival. Conclusions: In mGC, the presence of STK11 mutation was not predictive of the response to PD-1 inhibitors. Instead, patients with MSI-H or PD-L1+ tumors displayed superior clinical responses to PD-1 inhibitors. Citation Format: Minsuk Kwon, Kyung Kim, Suhye Choi, Jung Yong Hong, Seung Tae Kim, Se Hoon Park, Joon Oh Park, Young Suk Park, Ho Yeong Lim, Kyoung-Mee Kim, Jeeyun Lee. Association of serine/threonine kinase 11 mutations and response to programmed cell death 1 inhibitors in metastatic gastric cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 793.

Association of serine/threonine kinase 11 mutations and response to programmed cell death 1 inhibitors in metastatic gastric cancer

Programmed cell death 1 (PD-1) inhibitors have shown therapeutic efficacy in metastatic gastric cancer (mGC). However, no predictive biomarkers have been established in mGC. Inactivating mutations in serine/threonine kinase 11 (STK11) are associated with poor response to PD-1 inhibitors in KRAS-mutant lung adenocarcinoma. Therefore, we hypothesized that STK11 inactivating mutations would be associated with inferior clinical response to PD-1 inhibitors in mGC. We analyzed 59 mGC patients who had been treated with PD-1 inhibitors and whose tumors had been analyzed by targeted high-throughput sequencing. STK11 mutations were identified in 30 (50.8%) patients, and were all missense mutations. Three patients (5.1%) had STK11 gene amplification and mutation, simultaneously. Patients with STK11 mutations had prolonged overall survival (median: 19.0 vs 11.6 months, p = 0.15), and progression-free survival (4.2 vs 1.9 months, p = 0.06) when treated with PD-1 inhibitors, but these differences were not statistically significant. Patients with STK11 inactivating mutations without STK11 gene amplification had significantly prolonged progression-free survival compared to patients with wild type STK11 or STK11 gene amplification (4.8 vs 1.0 months, p = 0.04). However, in multivariate Cox regression analysis with high microsatellite instability (MSI-H), the number of tumor mutations, PD Ligand-1 (PD-L1)+, Epstein-Barr virus positivity (EBV)+, and type of PD-1 inhibitor used (pembrolizumab vs nivolumab), only MSI-H and PD-L1+ were significantly associated with longer progression-free survival. In mGC, the presence of STK11 mutation was not predictive of the response to PD-1 inhibitors. Instead, patients with MSI-H or PD-L1+ tumors displayed superior clinical responses to PD-1 inhibitors.

STK11 gene analysis reveals a significant number of splice mutations in Chinese PJS patients

BackgroundThe combination of direct sequencing and multiple ligation-dependent probe amplification (MLPA) has resulted in an 80% detection rate of serine/threonine kinase 11 (STK11) gene mutations in Peutz-Jeghers syndrome (PJS); however, this rate varies in different ethnicities. AimsTo test the efficacy of the combination in Chinese patients with PJS. MethodsPJS probands visiting our center during one year were enrolled. Sanger sequencing and MLPA were used to detect STK11 mutations. Associations between the occurrence of severe complications and risk factors were analyzed statistically. ResultsWe identified 47 PJS probands. Among them, 34 received an STK11 mutation test, revealing 23 point mutations and 2 exonic deletions. Nine of the mutations were splicing errors, reflecting a significantly higher proportion (p < 0.05). Laparotomy history existed for 33 of the probands, and seven families had a history of cancer. Statistical analysis revealed no associations between the occurrence of severe complications or cancers and risk factors. ConclusionThe strategy achieved a high detection rate in Chinese people, validating its effectiveness. This cohort comprised a significantly higher proportion of splicing errors, reflecting the unique genetic characteristics Chinese people. No specific genotype-phenotype relationship was noted, while the wide usage of enteroscopy would benefit PJS surveillance.

The altered activity of P53 signaling pathway by STK11 gene mutations and its cancer phenotype in Peutz-Jeghers syndrome

BackgroundPeutz-Jeghers syndrome (PJS) is caused by mutations in serine/threonine kinase 11 (STK11) gene. The increased cancer risk has been connected to P53 pathway.MethodsPJS probands with STK11 mutation were included in the function analysis. P53 activity elevated by STK11 mutants was investigated using dual-luciferase reporter assay in vitro after constructing expression vectors of STK11 wild type and mutants generated by site-directed substitution. The association between the P53 activity and clinicopathological factors was analysis, especially the cancer history.ResultsThirteen probands with STK11 mutations were involved, and within the mutations, c.G924A was novel. P53 activity elevation caused by 6 truncating mutations were significantly lower than that of STK11 wild type (P < 0.05). Family history of cancer was observed in 5 families. Within them, P53 activity was reduced and cancer occurred before 40 in 2 families, while it was not significantly changed and cancers happened after 45 in the other 3 families.ConclusionsThe affected P53 activity caused by STK11 mutations in PJS patients is significantly associated with protein truncation, while cancer risk in PJS can be elevated through pathways rather than P53 pathway. P53 activity test is probably a useful supporting method to predict cancer risk in PJS, which could be helpful in clinical practice.

Prenatal diagnosis in a hereditary Peutz-Jeghers syndrome family with high cancer risk

BackgroundPeutz-Jeghers Syndrome (PJS) is a hereditary cancer predisposing syndrome caused by autosomal dominant mutations in the serine/threonine kinase 11 (STK11) gene and is associated with decreased life expectancy. Many families experience a poorer quality of life due to the psychological burden associated with the carrier status of their child. Therefore early genetic testing and confirmation of the diagnosis is important for patients’ psychological status, as well as for clinical management, genetic counseling and possible prenatal family planning.MethodsIn this study, peripheral blood genomic DNA samples from a Chinese PJS family with a high cancer risk were examined for STK11 mutations using Sanger sequencing and MLPA analysis. Furthermore, prenatal PJS testing from transabdominal chorionic villi sample was performed in one female member of the family. This family was followed up for three years.ResultsIn this family, the STK11 exon 1 deletion (c.-1114-?_290 +?del) was predicted to affect the kinase domain of the protein and co-segregated with the disease phenotype. The same mutation was detected in the fetus and genetic sequencing and MLPA of the infant’s DNA and the pigmentation on his lips confirmed the result of prenatal testing. To the best of our knowledge, this is the first report on PJS prenatal diagnosis of a PJS family in China.ConclusionsAn accurate and convenient PJS prenatal testing provides an opportunity for affected families to focus on polyp-related symptoms and cancer prevention and may be helpful for couples in family planning decision-making.

Close and regular surveillance is key to prevent severe complications for Peutz-Jeghers syndrome patients without gastrointestinal polyps: case report of a novel STK11 mutation (c.471_472delCT) in a Chinese girl

BackgroundPeutz-Jeghers syndrome (PJS) is a Mendelian disease characterized by gastrointestinal hamartomas, mucocutaneous pigmentation (MP), and increased cancer risk. Serine/threonine kinase 11 (STK11) is the only validated causative gene in PJS. Clinical observation reveals MP and intussusception in childhood are more frequent and severe than in adults.Case presentationWe report here a girl without a positive family history, who grew oral and fingertip MP at her age of 2 and got abdomen dull pain from 7 years old. Endoscopy revealed no obvious polyps in the stomach or the colon until 10 years old, when she received enteroscopy. Tens of polyps were resected during enteroscopy, and pathological examination confirmed them hamartomas. A heterozygous deletion in STK11, c.471_472delCT, was detected in the proband but not in her parents, which is not recorded in databases.ConclusionThe mutation we reported here is a novel one and a de-novo one, so our results enlarge the spectrum of STK11. We speculate close and regular endoscopy especially enteroscopy is necessary for complication prevention when the former endoscopy discovers no polyps temporarily in a child of suspect PJS.

Two novel STK11 missense mutations induce phosphorylation of S6K and promote cell proliferation in Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome (PJS) is a rare hereditary disease caused by mutations in serine threonine kinase 11 (STK11) and characterized by an increased risk of developing cancer. Inactivation of STK11 has been associated with the mammalian target of rapamycin (mTOR) pathway. Hyperactivation and phosphorylation of the key downstream target genes ribosomal protein S6 kinase 1 (S6K1) and S6 promote protein synthesis and cell proliferation. To better understand the effects of STK11 dysfunction in the pathogenesis of PJS, genomic DNA samples from 21 patients with PJS from 11 unrelated families were investigated for STK11 mutations in the present study. The results revealed 6 point mutations and 2 large deletions in 8 (72.7%, 8/11) of the unrelated families. Notably, 3 novel mutations were identified, which included 2 missense mutations [c.88G>A (p.Asp30Asn) and c.869T>C (p.Leu290Pro)]. Subsequent immunohistochemical analysis revealed staining for phosphorylated-S6 protein in colonic hamartoma and breast benign tumor tissues from patients with PJS carrying the two respective missense mutations. Additionally, the novel missense STK11 mutants induced phosphorylation of S6K1 and S6, determined using western blot analysis, and promoted the proliferation of HeLa and SW1116 cells, determined using Cell Counting Kit-8 and colony formation assays. Collectively, these findings extend the STK11 mutation spectrum and confirm the pathogenicity of two novel missense mutations. This study represents a valuable insight into the molecular mechanisms implicated in the pathogenesis of PJS.

Correlation between genotype and phenotype in three families with Peutz-Jeghers Syndrome.

Peutz-Jeghers syndrome (PJS) is a hereditary disorder characterized by mucocutaneous pigmentations, gastrointestinal (GI) polyposis and an increased risk of certain malignancies. Little is known about the causative genes of PJS, or their association with the clinical phenotypes of PJS. The present study reports the results of clinical and genetic analysis of three Chinese families with PJS. In addition, the medical histories and clinical manifestations of these families were compared. DNA was collected from the blood samples of patients with PJS and controls. Serine/threonine kinase 11 (STK11), olfactory receptor family 4 subfamily C member 45 (OR4C45) and zonadhesin (ZAN) were amplified by polymerase chain reaction, and analyzed by sequencing and cloning. Two PJS-affected members of one family had a de novo single base deletion (NM_000455.4:c.842delC) in the STK11 gene, and their clinical presentations reflected the quantity of mutant STK11 copies in a dose-dependent manner. No pathogenic variants of OR4C45 or ZAN were found in the patients with PJS, although a new single nucleotide polymorphism (NM_003386.2:c.5768delG) of ZAN was identified. The results of the current study identified that a STK11 mutation dose-dependent genotype-phenotype relationship exists in patients with PJS. In addition, an early onset and high severity of oral pigmentations in PJS was indicative of serious GI phenotypes. These findings may aid the diagnosis and treatment of PJS.

STK11Domain XI Mutations: Candidate Genetic Drivers Leading to the Development of Dysplastic Polyps in Peutz-Jeghers Syndrome

Peutz-Jeghers syndrome (PJS) is a rare hereditary disorder resulting from mutations in serine/threonine kinase 11 (STK11) and characterized by gastrointestinal (GI) hamartomatous polyps, mucocutaneous pigmentation, and an increased risk for specific cancers. Little is known about the genetic implications of specific STK11 mutations with regard to their role in dysplastic and malignant transformation of GI polyps. Peripheral blood genomic DNA samples from 116 Chinese PJS patients from 52 unrelated families were investigated for STK11 mutations. Genotype-phenotype correlations were investigated. The mutation detection rate was 67.3% (51.9% point mutations, 15.4% large deletions). Fourteen out of the 25 point mutations identified were novel. Nearly one-third of all mutations, 8/27 (29.6%), were in exon 7, the shortest out of the nine exons. Strikingly, mutations affecting protein kinase domain XI, encoded in part by exon 7, correlated with a 90% (9/10) incidence of GI polyp dysplasia. In contrast, only two out of 17 (11.8%) nondomain XI mutations were linked to polyp dysplasia (P=0.0001). The extent of the association between dysplasia and the development of GI-related cancers is currently unknown but our results highlight a novel STK11 genotype-phenotype association as the basis for future genetic counseling and basic research studies.