Wild-type TP53 Research Articles

GATA6 amplification is associated with improved survival in TP53-mutated unresectable pancreatic cancer

Abstract Objectives: GATA6 expression has been recently recognized as a favorable prognostic marker of pancreatic cancer whereas TP53 is recognized as a poor prognostic marker. We evaluated treatment outcomes by genetic alterations in TP53 and GATA6 to determine the prognostic and predictive impact of co-alterations. Methods A single institution retrospective analysis was performed on patients diagnosed with PDAC between 2014 to 2023. TP53 genotype and GATA6 amplification status were included in an analysis of overall survival (OS) and progression free survival (PFS). Previously published patient-derived organoids were used to investigate correlation between genetic status and drug sensitivity. Results Patients with TP53 mutations had worse OS compared to the wild type TP53 population. In general, patients with GATA6 amplification had better OS and a trend towards better PFS than the non-amplified population. Among patients with a TP53 mutation, patients with GATA6 co-alteration had longer OS compared to those who were not GATA6 amplified. In contrast, among patients who were TP53 wild type, the presence or absence of a GATA6 amplification did not impact OS or PFS. GATA6 genotype was not associated chemotherapy drug response in an organoid pharmacotyping model. Conclusions We found that GATA6 amplification appeared to attenuate poor prognosis observed in TP53-mutant patients regardless of the type of standard chemotherapy received, suggesting the GATA6 amplification is a prognostic biomarker but not a predictive biomarker of standard-of-care chemotherapy.

TMOD-13. IDENTIFYING MOLECULAR SIGNATURES OF PPM1D-MUTANT DIPGS

Abstract Diffuse Intrinsic Pontine Glioma (DIPGs) are universally fatal pediatric tumors with a median survival of only 9-12 months. PPM1D-truncating mutations (PPM1Dtr), which promote its phosphatase activity and suppress TP53 function, are found in approximately 15% of DIPG tumors. PPM1Dtr are mutually exclusive to TP53 mutations, and present unique therapeutic opportunities to reactivate wild-type TP53. Another distinct feature of PPM1Dtr DIPGs is the co-occurrence of PI3K/AKT/mTOR pathway alterations, such as PIK3CA. There is an unmet need to elucidate the underlying molecular mechanisms of DIPG and identify novel therapeutic vulnerabilities that will improve outcomes of this devastating tumor. We hypothesize that PPM1D-mutant DIPGs can be therapeutically targeted by reactivating the p53 signaling pathway and other complementary pathways which cooperate with PPM1Dtr. To investigate this, we have generated Trp53- and Ppm1d-mutant isogenic DIPG murine models to determine how specific oncogenic alterations function in DIPG formation, growth and treatment sensitivity. Current studies aim to examine differences in sensitivity to standard of care treatment modalities and leverage next generation sequencing techniques to uncover additional vulnerabilities. We found notable differences upon addition of PIK3CA mutations in the context of PPM1Dtr DIPG tumor formation, growth, survival, and lineage identity. Ongoing studies using whole genome transcriptomics to compare tumor models will provide insight into the molecular signals and cell state changes driven by individual genetic alterations. Furthermore, by comparing isogenic TP53 and PPM1Dtr mutant DIPG models, we aim to further delineate the molecular mechanisms that drive differential sensitivity of TP53 wild-type tumors. The immune-competent nature of our murine models also provides us with a unique opportunity to delineate tumor immune microenvironment changes. Leveraging this information and our novel murine models, our long-term goal is to develop combinatorial therapeutic strategies to improve outcomes for this deadly disease.

Predictive genomic and transcriptomic analysis on endoscopic ultrasound-guided fine needle aspiration materials from primary pancreatic adenocarcinoma: a prospective multicentre study

We apply endoscopic ultrasound-guided fine needle aspiration biopsy to cytopathologically diagnose and sample nucleic acids from primary tumours regardless of the disease stage. 397 patients with proven pancreatic adenocarcinoma were included and followed up in a multicentre prospective study. DNA and mRNA were extracted from materials of primary tumours obtained by endoscopic ultrasound-guided fine needle aspiration biopsy and analysed using targeted deep sequencing and RNAseq respectively. The variant allele frequency of the KRAS mutation was used to evaluate the tumour cellularity, ranging from 15 to 20% in all cells, regardless of the tumour stage. The molecular profile of metastatic primary tumours significantly differed from other types of tumours, more frequently having TP53 mutations (p=0.0002), less frequently having RNF43 mutations, and possessing more basal-like mRNA component (p=0.001). Molecular markers associated with improved overall survival were: mutations in homologous recombination deficiency genes in patients who received first-line platinum-based chemotherapy (p=0.025) and wild-type TP53 gene in patients with locally advanced tumours who received radio-chemotherapy (p=0.01). The GemPred transcriptomic profile was associated with a significantly better overall survival in patients with locally advanced or metastatic pancreatic cancer who received a gemcitabine-based first-line treatment (p=0.019). The combination of genomic and transcriptomic analyses of primary pancreatic tumours enables us to distinguish metastatic tumours from other tumour types. Our molecular strategy may assist in predicting overall survival outcomes for platinum or gemcitabine-based chemotherapies, as well as radio-chemotherapy. Institut National Du Cancer (BCB INCa_7294), CHU of Toulouse, Inserm and Ligue Nationale Contre le Cancer (CIT program).

A Line in Shifting Sand: Can We Define and Target TP53 Mutated MDS?

Mutations in the tumor suppressor protein, TP53, lead to dismal outcomes in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Recent pathological re-classifications have integrated TP53 mutated MDS and AML under a unified category of TP53 mutated myeloid neoplasms, which allows for more flexibility in treatment approaches. Therapeutic strategies have predominantly mirrored those for AML, with allogeneic stem cell transplantation emerging as critical for long-term disease control. The question remains whether there are physiological distinctions within TP53 mutated myeloid neoplasms that will significantly impact prognosis and therapeutic considerations. This review explores the unique aspects of classically defined “TP53 mutated MDS”, focusing on its distinct biological characteristics and outcomes. Our current understanding is that TP53 mutated MDS and AML are globally quite similar, but as a group have unique features compared to TP53 wildtype (WT) disease. Optimizing immunotherapy and targeting vulnerabilities due to co-mutations and/or chromosome abnormalities should be the focus of future research.

DNA-PK inhibition shows differential radiosensitization in orthotopic GBM PDX models based on DDR pathway deficits.

Glioblastoma (GBM) remains one of the most therapy-resistant malignancies with frequent local failures despite aggressive surgery, chemotherapy, and ionizing radiation (IR). Small molecule inhibitors of DNA-dependent protein kinase (DNA-PKi's) are potent radiosensitizers currently in clinical trials. Determining which patients may benefit from radiosensitization with DNA-PKi's is critical to avoid unnecessary increased risk of normal tissue toxicity. In this study we used GBM patient derived xenografts (PDXs) in orthotopic murine models to study the relationship between molecular features, pharmacokinetics, and the radiosensitizing potential of the DNA-PKi peposertib. We show that peposertib radiosensitizes established and PDX GBM lines in vitro at 300nM and above, with significant increase in radiosensitization by maintaining post-IR exposure for >12 hours. Radiosensitization by peposertib is mediated by catalytic inhibition of DNA-PK, and knock-down of DNA-PK by short hairpin RNA (shRNA) largely abolished the radiosensitizing effect. Peposertib decreased auto-phosphorylation of DNA-PKcs after IR in a dose-dependent manner with delay in resolution of γH2AX foci at 24 hours. The addition of peposertib to IR significantly increased survival in GBM120 orthotopic xenografts, but not in GBM10. There was no difference in plasma or average tumor concentrations of peposertib in the two cohorts. While the mechanism underpinning this discordant effect in vitro vs. in vivo is not clear, there was an association for greater sensitization in TP53 mutant lines. Transfection of a dominant-negative TP53 mutant in baseline TP53 wildtype GBM lines significantly delayed growth and decreased NHEJ efficiency (but not Homologous Recombination), after peposertib exposure.

Hallmarks of a genomically distinct subclass of head and neck cancer

Cancer is caused by an accumulation of somatic mutations and copy number alterations (CNAs). Besides mutations, these copy number changes are key characteristics of cancer development. Nonetheless, some tumors show hardly any CNAs, a remarkable phenomenon in oncogenesis. Head and neck squamous cell carcinomas (HNSCCs) arise by either exposure to carcinogens, or infection with the human papillomavirus (HPV). HPV-negative HNSCCs are generally characterized by many CNAs and frequent mutations in CDKN2A, TP53, FAT1, and NOTCH1. Here, we present the hallmarks of the distinct subgroup of HPV-negative HNSCC with no or few CNAs (CNA-quiet) by genetic profiling of 802 oral cavity squamous cell carcinomas (OCSCCs). In total, 73 OCSCC (9.1%) are classified as CNA-quiet and 729 as CNA-other. The CNA-quiet group is characterized by wild-type TP53, frequent CASP8 and HRAS mutations, and a less immunosuppressed tumor immune microenvironment with lower density of regulatory T cells. Patients with CNA-quiet OCSCC are older, more often women, less frequently current smokers, and have a better 5-year overall survival compared to CNA-other OCSCC. This study demonstrates that CNA-quiet OCSCC should be considered as a distinct, clinically relevant subclass. Given the clinical characteristics, the patient group with these tumors will rapidly increase in the aging population.

Lower-intensity CPX-351 plus venetoclax induction for adults with newly diagnosed AML unfit for intensive chemotherapy

Preclinical data suggest a rationale for combining CPX-351, a dual-drug liposomal encapsulation of daunorubicin and cytarabine, with venetoclax, a B-cell lymphoma-2 (BCL-2) inhibitor. This phase 1b study evaluated lower-intensity CPX-351 combined with venetoclax in adults with acute myeloid leukemia (AML) considered unfit/ineligible for intensive chemotherapy. In a dose-exploration phase using a 3+3 design, patients received stepwise dosing of CPX-351 intravenously on days 1 and 3 plus venetoclax 400 mg orally on days 2-21 per cycle to determine the recommended phase 2 dose (RP2D) for this combination. During the expansion phase, additional patients received CPX-351 plus venetoclax at the identified RP2D. The primary endpoints were the RP2D and safety of CPX-351 combined with venetoclax. Secondary endpoints included preliminary efficacy and pharmacokinetics. Overall, 35 patients were enrolled in the study. A RP2D of CPX-351 30 units/m2 (daunorubicin 13.2 mg/m2 and cytarabine 30 mg/m2) plus venetoclax 400 mg was established. The safety profile of the combination was consistent with the known safety profiles of CPX-351 and venetoclax. Complete remission (CR)/CR with incomplete hematologic recovery (CRi) was achieved by 17/35 (49%) patients, all after cycle 1; of these, 14 were negative for measurable residual disease. CR was achieved by 1/8 (13%) patients with a mutation in TP53, and CR/CRi was achieved by 15/26 (58%) patients with wild-type TP53. This study highlights that lower-intensity therapy of CPX-351 plus venetoclax as induction therapy provides a well-tolerated treatment option in adults with AML deemed unfit for intensive chemotherapy. This trial was registered at www.clinicaltrials.gov as #NCT04038437.

Activated single nucleotide mismatch determination through toehold-embedded hairpin-mediated strand displacement reaction alongside CRISPR-Cas12a for detection of TP53 point mutation

The CRISPR-Cas12a-based diagnostic platform is renowned for its high sensitivity and, when coupled with the toehold-mediated strand displacement (TMSD) reaction, enables the detection of single nucleotide mismatch (SNM). However, conventional TMSD with the CRISPR-Cas12a system suffers from signal leakage due to overlapping activator sequences and low displacement efficiency. Here, we propose a toehold-embedded hairpin-mediated strand displacement (THMSD) method and leverage the magnesium attenuation effect of CRISPR-Cas12a for selective single-point mutation detection in the TP53 gene. This approach effectively mitigates signal leakage as the hairpin DNA retains partial crRNA targeting sequences within its loop, preventing sequence overlap with the trigger and direct Cas12a activation. Additionally, the magnesium attenuation effect reduces background signal and enhances selectivity. We investigated toehold length and mismatch position to detect SNM with a high discrimination factor (DF). This high DF allows the THMSD/CRISPR-Cas12a system to differentiate between TP53 R273H mutant and TP53 wildtype genes for cancer screening at low abundances, down to 0.1 % with a concentration of 20 pM. When used for screening between H1975 and WI38 cells, the statistically significant difference was attainable with polymerase chain reaction (PCR) template loading as low as 4 ng. These results pave the way for developing CRISPR-Cas12a-based methods to effectively detect TP53 mutations as lung cancer biomarkers.

44 (PB032): The MDM2 degraders KTX-049 and KT-253 are highly active in wild-type TP53 (WT p53) Merkel cell carcinoma (MCC)

44 (PB032): The MDM2 degraders KTX-049 and KT-253 are highly active in wild-type TP53 (WT p53) Merkel cell carcinoma (MCC)

Upfront Management of Blastoid Variant Mantle Cell Lymphoma: Making the Case for 2nd/3rd-Generation Bruton Tyrosine Kinase Inhibitor-Based Therapies.

Blastoid variant-mantle cell lymphoma (BV-MCL) represents an aggressive subset of patients with no established standard of care treatment approach. We performed a retrospective analysis of the clinical characteristics and outcomes of 17 de novo BV-MCL patients treated at our institution between May 2009 and September 2023. In addition, we reviewed the literature supporting 2nd/3rd generation Bruton's Tyrosine-kinase (BTKi)-based therapies for upfront management. The complete response rate to frontline and salvage therapy was 66.7% and 25%, respectively. Two-year overall survival (OS) was low at 62.5% (95% CI, 34.7%-81.1%). Variables associated with higher OS included receipt of consolidative HSCT (p = 0.017), TP53-wild type (p = 0.031), intermediate- versus high-risk Mantle Cell Lymphoma Prognostic Index score (p = 0.026), and achieving complete response with induction therapy (p = 0.027). Treatment outcomes with chemo-immunotherapy in BV-MCL patients are poor, especially among TP53-mutated patients. Recent findings describing positive outcomes with novel BTKi-based therapies are encouraging and should be considered in this high-risk population.

Association of Wild-Type TP53 with Downregulation of Lovastatin Sensitivity in Human Non-Small Cell Lung Cancer Cells.

Statins inhibit 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway, and reduce cholesterol synthesis. They also have been demonstrated to improve prognosis in patients with various cancers, suggesting a potential anti-cancer effect of statins. However, there is no consensus on the molecular targets of statins for their anti-cancer effects. Docetaxel (DOC) is a microtubule-stabilizing agent currently used as a chemotherapeutic drug in several cancers, including lung cancer. Interestingly, the anti-cancer effects of either drug that are related to abnormal or wild-type TP53 gene have been implied. Therefore, the drug sensitivity of DOC and lovastatin in human lung cancer cells was evaluated. We found that H1355 (mutant TP53-E285K), CL1 (mutant TP53-R248W), and H1299 (TP53-null) human non-small cell lung cancer cells were more sensitive to lovastatin than A549 and H460 cells expressing wild-type TP53. Conversely, A549 and H460 cells showed higher sensitivity to DOC than H1299 and CL1 cells, as demonstrated by the MTT assay. When endogenous TP53 activity was inhibited by pifithrin-α in A549 and H460 cells, lovastatin sensitivities significantly increased, and cancer cell viabilities markedly reduced. These results indicate that TP53 status is associated with the anti-cancer effect of statins in human lung cancer cells. Mutated or null TP53 status is correlated with higher statin sensitivity. Furthermore, DOC-resistant H1299 (H1299/D8) cells showed significant sensitivity to lovastatin treatment compared to DOC-resistant A549 (A549/D16) cells, indicating a potential application of statins/chemotherapy combination therapy to control wild-type and abnormal TP53-containing human lung tumors.

Alpha lipoic acid diminishes migration and invasion in hepatocellular carcinoma cells through an AMPK-p53 axis

Hepatocellular carcinoma (HCC) associated with viral or metabolic liver diseases is a growing cancer without effective therapy. AMPK is downregulated in HCC and its activation diminishes tumor growth. Alpha lipoic acid (ALA), an indirect AMPK activator that inhibits hepatic steatosis, shows antitumor effects in different cancers. We aimed to study its putative action in liver-cancer derived cell lines through AMPK signaling. We performed cytometric studies for apoptosis and cell cycle, and 2D and 3D migration analysis in HepG2/C3A and Hep3B cells. ALA led to significant inhibition of cell migration/invasion only in HepG2/C3A cells. We showed that these effects depended on AMPK, and ALA also increased the levels and nuclear compartmentalization of the AMPK target p53. The anti-invasive effect of ALA was abrogated in stable-silenced (shTP53) versus isogenic-TP53 HepG2/C3A cells. Furthermore, ALA inhibited epithelial-mesenchymal transition (EMT) in control HepG2/C3A but not in shTP53 nor in Hep3B cells. Besides, we spotted that in patients from the HCC-TCGA dataset some EMT genes showed different expression patterns or survival depending on TP53. ALA emerges as a potent activator of AMPK-p53 axis in HCC cells, and it decreases migration/invasion by reducing EMT which could mitigate the disease in wild-type TP53 patients.

Exploration of Key Genes Combining with Immune Infiltration Level andTumor Mutational Burden in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a lethal malignancy due to its heterogeneity and aggressive behavior. Recently, somatic mutations and tumor cell interactions with the surrounding tumor immune microenvironment (TIME) have been reported to participate in HCC carcinogenesis and predict HCC progression. In this study, we aimed to investigate the association between tumor mutational burden (TMB) and TIME in HCC. Additionally, we sought to identify differentially expressed genes (DEGs) associated with HCC prognosis and progression. The expression, clinical, and mutational data were downloaded from the cancer genome atlas (TCGA) database. The immune infiltration levels and TMB levels of the HCC samples were estimated and the samples were divided into immune cluster (ICR)-1 and 2 based on immune infiltration score and high and low TMB groups based on TMB score. Thereafter, differential gene expression analysis was conducted to identify the DEGs in the ICR1/2 and high/low TMB groups, and the intersecting DEGs were selected. Thereafter, Cox regression analysis was performed on 89 significant DEGs, among which 19 were associated with prognosis. These 19 DEGs were then used to construct a prognostic model based on their expression levels and regression coefficients. Thereafter, we analyzed the DEGs in mutant and wildtype TP53 HCC samples and identified high BCL10 and TRAF3 expression in the mutant TP53 samples. BCL10 and TRAF3 expression was detected by real-time quantitative reverse transcription PCR and immunohistochemistry, and their clinical correlation, biological function, and immune infiltration levels were analyzed by chi-square analyses, Gene Set Enrichment Analysis (GSEA), and "ssGSEA", respectively. The results of our study revealed that immune infiltration level was correlated with TMB and that they synergistically predicted poor prognosis of HCC patients. DEGs enriched in immune-related pathways could serve as indicators of immunotherapy response in HCC. Among these DEGs, BCL10 and TRAF3 were highly expressed in HCC tissues, especially in the mutant TP53 group, and they co-operatively exhibited immunological function, thereby affecting HCC progression and prognosis. In this study, we identified BCL10 and TRAF3 as potential prognostic indicators in HCC patients. Additionally, we found that BCL10 and TRAF3 influence TMB and TIME in HCC patients and can be used for the development of immune-based therapies for improving the long-term survival of HCC patients.

Impact of clonal TP53 mutations with loss of heterozygosity on adjuvant chemotherapy and immunotherapy in gastric cancer

BackgroundThis study aimed to reveal the effect of TP53 status on clinical outcomes and underlying mechanism in gastric cancer (GC) patients.MethodsTP53 status was divided into three groups according to genome sequencing, namely clonal mutations with LOH (C-LOH), clonal diploid or subclonal mutations (CD-SC), and wild type (WT). The p53 protein activity was divided into over-expression (OE), Null and WT according to immunohistochemical staining. Four cohorts, including the TCGA, SMC, ZSHS and FUSCC cohort, were analyzed for association between TP53 mutation status and clinical outcomes and the underlying mechanism.ResultsIn TCGA cohort, TP53 CD-SC were associated with superior overall survival compared to TP53 C-LOH cases. GC patients could benefit from ACT only in TP53 CD-SC/ p53 OE and TP53/ p53 WT subgroups, and TP53 C-LOH subgroup demonstrated the worst response to pembrolizumab among three subgroups. Genomic and immunophenotypic deconvolution revealed that TP53 C-LOH, CD-SC and WT differed for genomic and immune-related features.ConclusionsTP53 C-LOH GCs with genomic instability and immune evasion phenotype have poor clinical outcomes in patients treated with ACT or immunotherapy.

Synthetic lethality of combined ULK1 defection and p53 restoration induce pyroptosis by directly upregulating GSDME transcription and cleavage activation through ROS/NLRP3 signaling

BackgroundHigh expression of ubiquitin ligase MDM2 is a primary cause of p53 inactivation in many tumors, making it a promising therapeutic target. However, MDM2 inhibitors have failed in clinical trials due to p53-induced feedback that enhances MDM2 expression. This underscores the urgent need to find an effective adaptive genotype or combination of targets.MethodsKinome-wide CRISPR/Cas9 knockout screen was performed to identify genes that modulate the response to MDM2 inhibitor using TP53 wild type cancer cells and found ULK1 as a candidate. The MTT cell viability assay, flow cytometry and LDH assay were conducted to evaluate the activation of pyroptosis and the synthetic lethality effects of combining ULK1 depletion with p53 activation. Dual-luciferase reporter assay and ChIP-qPCR were performed to confirm that p53 directly mediates the transcription of GSDME and to identify the binding region of p53 in the promoter of GSDME. ULK1 knockout / overexpression cells were constructed to investigate the functional role of ULK1 both in vitro and in vivo. The mechanism of ULK1 depletion to activate GSMDE was mainly investigated by qPCR, western blot and ELISA.ResultsBy using high-throughput screening, we identified ULK1 as a synthetic lethal gene for the MDM2 inhibitor APG115. It was determined that deletion of ULK1 significantly increased the sensitivity, with cells undergoing typical pyroptosis. Mechanistically, p53 promote pyroptosis initiation by directly mediating GSDME transcription that induce basal-level pyroptosis. Moreover, ULK1 depletion reduces mitophagy, resulting in the accumulation of damaged mitochondria and subsequent increasing of reactive oxygen species (ROS). This in turn cleaves and activates GSDME via the NLRP3-Caspase inflammatory signaling axis. The molecular cascade makes ULK1 act as a crucial regulator of pyroptosis initiation mediated by p53 activation cells. Besides, mitophagy is enhanced in platinum-resistant tumors, and ULK1 depletion/p53 activation has a synergistic lethal effect on these tumors, inducing pyroptosis through GSDME directly.ConclusionOur research demonstrates that ULK1 deficiency can synergize with MDM2 inhibitors to induce pyroptosis. p53 plays a direct role in activating GSDME transcription, while ULK1 deficiency triggers upregulation of the ROS-NLRP3 signaling pathway, leading to GSDME cleavage and activation. These findings underscore the pivotal role of p53 in determining pyroptosis and provide new avenues for the clinical application of p53 restoration therapies, as well as suggesting potential combination strategies.

Association between low incidence of TP53 mutations and reduced early relapse rates in Uygur DLBCL.

Diffuse large B-cell lymphoma (DLBCL) demonstrates significant heterogeneity, investigations into the distinctions in clinical and molecular characteristics between Chinese Uygur and Han DLBCL patients remain unexplored. We retrospectively reviewed 279 DLBCL patients (105 Uygur and 174 Han patients), of which 155 patients underwent genetic profiling by NGS. Compared with Han patient, Uygur patients have better clinical prognostic indicators, including a higher proportion of patients with 0-1 extranodal involvement and I/II Ann Arbor staging. Consistently, Uygur patients were significantly associated with lower risk of relapse (P = 0.06), with a one-year relapse rate of 5% vs 17% and two-year relapse rate of 19% vs 36% compared to Han patients. At the molecular level, TP53 (21.3%) was among the top frequently altered gene in the cohort. Notably, the Uygur patients exhibited a significantly lower frequency of TP53 alterations and higher frequency of ASXL3 alterations. Logistic regression analysis showed that the lowered frequency of TP53 and enrichment of ASXL3 in the Uygur patients were independent of other factors. However, only patients with TP53 mutations had higher relapse rate than those with wild type TP53 (one-year, 20% vs 10%; two-year, 51% vs 21%). Our findings highlight the notable contribution of a low TP53 mutation frequency in Uygur patients as a pivotal factor associated with the favorable prognosis of this population.

Cell-free DNA from germline TP53 mutation carriers reflect cancer-like fragmentation patterns

Germline pathogenic TP53 variants predispose individuals to a high lifetime risk of developing multiple cancers and are the hallmark feature of Li-Fraumeni syndrome (LFS). Our group has previously shown that LFS patients harbor shorter plasma cell-free DNA fragmentation; independent of cancer status. To understand the functional underpinning of cfDNA fragmentation in LFS, we conducted a fragmentomic analysis of 199 cfDNA samples from 82 TP53 mutation carriers and 30 healthy TP53-wildtype controls. We find that LFS individuals exhibit an increased prevalence of A/T nucleotides at fragment ends, dysregulated nucleosome positioning at p53 binding sites, and loci-specific changes in chromatin accessibility at development-associated transcription factor binding sites and at cancer-associated open chromatin regions. Machine learning classification resulted in robust differentiation between TP53 mutant versus wildtype cfDNA samples (AUC-ROC = 0.710–1.000) and intra-patient longitudinal analysis of ctDNA fragmentation signal enabled early cancer detection. These results suggest that cfDNA fragmentation may be a useful diagnostic tool in LFS patients and provides an important baseline for cancer early detection.

Two-polarized roles of transcription factor FOSB in lung cancer progression and prognosis: dependent on p53 status

BackgroundActivator protein-1 (AP-1) represents a transcription factor family that has garnered growing attention for its extensive involvement in tumor biology. However, the roles of the AP-1 family in the evolution of lung cancer remain poorly characterized. FBJ Murine Osteosarcoma Viral Oncogene Homolog B (FOSB), a classic AP-1 family member, was previously reported to play bewilderingly two-polarized roles in non-small cell lung cancer (NSCLC) as an enigmatic double-edged sword, for which the reasons and significance warrant further elucidation.Methods and ResultsBased on the bioinformatics analysis of a large NSCLC cohort from the TCGA database, our current work found the well-known tumor suppressor gene TP53 served as a key code to decipher the two sides of FOSB – its expression indicated a positive prognosis in NSCLC patients harboring wild-type TP53 while a negative one in those harboring mutant TP53. By constructing a panel of syngeneically derived NSCLC cells expressing p53 in different statuses, the radically opposite prognostic effects of FOSB expression in NSCLC population were validated, with the TP53-R248Q mutation site emerging as particularly meaningful. Transcriptome sequencing showed that FOSB overexpression elicited diversifying transcriptomic landscapes across NSCLC cells with varying genetic backgrounds of TP53 and, combined with the validation by RT-qPCR, PREX1 (TP53-Null), IGFBP5 (TP53-WT), AKR1C3, and ALDH3A1 (TP53-R248Q) were respectively identified as p53-dependent transcriptional targets of FOSB. Subsequently, the heterogenous impacts of FOSB on the tumor biology in NSCLC cells via the above selective transcriptional targets were confirmed in vitro and in vivo. Mechanistic investigations revealed that wild-type or mutant p53 might guide FOSB to recognize and bind to distinct promoter sequences via protein-protein interactions to transcriptionally activate specific target genes, thereby creating disparate influences on the progression and prognosis in NSCLC.ConclusionsFOSB expression holds promise as a novel prognostic biomarker for NSCLC in combination with a given genetic background of TP53, and the unique interactions between FOSB and p53 may serve as underlying intervention targets for NSCLC.

A phase I/II study of nanoliposomal irinotecan and carboplatin in patients with advanced or metastatic, poorly differentiated gastroenteropancreatic neuroendocrine carcinoma characterized by tissue and liquid next-generation sequencing.

52 Background: For locally advanced or metastatic gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs), standard chemotherapy typically incorporates etoposide or irinotecan plus platinum agents. Herein, we initiate a phase I/II trial to apply Nal-IRI in combination with carboplatin as the 1st line treatment in patients with GEP-NECs to define the dose-limiting toxicity (DLT) and recommended phase II dose (RP2D). Methods: In the phase I part, traditional 3+3 design was applied. Enrolled patients would receive escalating dose of 60 (level -1), 80 (starting dose, level 0) or 100 (level 1) mg/m2 salt-form nal-IRI plus carboplatin AUC=4 with maximum total dose of 600 mg on D1, every 21 days as a cycle. DLTs were evaluated during the first one cycle of treatment with tumor assessment every 6 weeks. Prophylaxis G-CSF was not allowed in the first cycle Paired testing of tissue (TBx) and liquid biopsy (LBx) was done by Illumina TSO500 platform before treatment. The second LBx would be repeated for confirmed partial responders when progression. Results: Totally 6 GEP-NEC patients with primary sites of colon in three, and each one in esophagus, ampulla of Vater and pancreas were enrolled to level 0. One patient had DLT of grade 4 neutropenia lasting for 3 days even under salvage G-CSF. Treatment-related adverse events showed grade 3/4 neutropenia (33.4%), grade 2 anemia (16.7%), grade 3 fatigue (16.7%), and grade 2 skin rash (16.7%). Four patients achieved confirmed partial response and 2 patients got stable disease, with the objective response rate of 66.7% (95% confidence interval: 22%-96%). After the data and safety monitoring board meeting, level 0 was decided as RP2D but not escalation to level 1 because of acceptable toxicity profiles and promising efficacies. Comprehensive genomic profiling showed that driver mutations were identified in three cases including two harboring BRAFV600E mutation and one with KRASG12D mutation. The other three cases lacking driver mutation showed frequent copy number alteration including 1 with MDM2 amplification (copy number 27) and a wild-type TP53. Homologous recombination deficiency (HRD), as determined by GIS score, was identified in a colon GEP-NEC who remained to be HRD-positive at progression but a higher TMB (from 4.7 to 10.2 Muts/Mb) and a higher BRAFV600E mutation allele frequency (from 24.1% to 43.6%) in tumor tissue, compared to the baseline profiling. Conclusions: Based on current data, the RP2D is 80 mg/m2 of nal-IRI (salt-form) and carboplatin of AUC=4, every 3 weeks. The extension phase II study in GEP-NEC is ongoing. Clinical trial information: NCT05385861 .

Association of TP53 Mutation Status and Sex with Clinical Outcome in NSCLC Treated with Immune Checkpoint Inhibitors: A Retrospective Cohort Study.

Some studies suggest that TP53 mutations are associated with the response to immune checkpoint inhibitors (ICI) in patients with non-small cell lung cancer (NSCLC) and also contribute to sex disparities in several cancers. Thus, we hypothesized that TP53 mutations might serve as sex-dependent genomic biomarkers of ICI treatment response in patients with NSCLC. Clinical data of 100 patients with metastatic NSCLC treated with ICI monotherapy at Seoul National University Bundang Hospital (SNUBH) were retrospectively reviewed. Genomic and clinical datasets of TCGA and an ICI-treated lung cancer cohort (cBioPortal) were also analyzed. In SNUBH cohort, no statistically significant difference was observed in disease control rate per the TP53 mutation status (p=0.503); however, female patients with TP53 mutated (MT) had a significantly prolonged median progression-free survival (PFS) compared to wild-type (WT) (6.1 months in TP53 MT vs. 2.6 months in TP53 WT; p=0.021). PD-L1 high (≥50%) expression was significantly enriched in female patients with TP53 MT (p=0.001). The analysis from publicly available dataset also revealed that females with NSCLC with TP53 MT showed significantly longer PFS than those with TP53 WT (p<0.001). In TCGA analysis, expression of immune-related genes, and TMB score in TP53 MT females were higher than in males without TP53 MT. Female patients with NSCLC with TP53 mutations had high PD-L1 expression and showed favorable clinical outcomes following ICI therapy, suggesting a need for further research to explore the role of TP53 mutations for sex disparities in response to ICI therapy.