Clinical Outcomes of TP53 Mutations in Cancers

TP53 mutation and immunohistochemical p53 expression characteristics in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) with TP53 mutations has specific clinicopathological features and is usually associated with a poor prognosis. TP53 gene mutations typically lead to aberrant expression patterns of the p53 protein. We studied 123 DLBCL patients at Henan Cancer Hospital, 35.8% (44/123) had TP53 mutations. Analysis of mutation sites in 44 cases of DLBCL patients revealed that the mutations primarily occur in the DNA-binding domain (DBD region) of the encoded p53 protein; among all mutation types, there were 8 truncation or frameshift mutations, and 36 missense mutations. Further, immunohistochemistry (IHC) detected expression levels of p53 protein in 123 DLBCL samples. The mutation results were used as a reference, and receiver operating characteristic (ROC) curve analysis was employed. Ultimately, the expression ratio of 65% and the moderate-strong expression intensity were regarded as the cut-off value, namely high p53 expression or p53 negative (<1%) indicated mutant-type p53 protein. the complete remission (CR) rate of the mutant-type p53 protein group after receiving R-CHOP regimen was 50% (14/28), and the objective response rate (ORR) was 75%, which differed significantly (P<0.01) compared with wild-type p53 protein group [CR rate of 75.86% (66/87) and ORR rate of 89.66%]. Common gene mutations in the mutant-type p53 protein group primarily involve alterations in pathways related to epigenetics, B cell antigen receptor signaling, cell cycle, among others. IHC analysis of the p53 protein is a simple and low-cost approach that can be employed to predict TP53 mutation status and therapy response.

Suppression of stress granule formation is a vulnerability imposed by mutant p53

Missense mutations in the TP53 (p53) gene have been linked to malignant progression. However, our in-silico analyses reveal that hepatocellular carcinoma (HCC) patients with mutant p53 (mutp53) have better overall survival compared to those with p53-null (p53null) HCC, unlike other cancer types. Given the historical use of sorafenib (SOR) monotherapy for advanced HCC, we hypothesize that mutp53 increases sensitivity to SOR, a multikinase inhibitor that induces endoplasmic reticulum (ER) stress. Here we show that mutp53 inhibits stress granule (SG) formation by binding to an ER stress sensor, PKR-like ER kinase (PERK), and a key SG component, GAP SH3 domain-binding protein 1 (G3BP1), contributing to increased sensitivity of SG-competent cells and xenografts to ER stress inducers including SOR. Our study identifies a unique vulnerability imposed by mutp53, suggesting mutp53 as a biomarker for ER stress-inducing agents and highlighting the importance of SG inhibition for cancer treatment.

Malignant phyllodes tumors with sarcomatous components: A histopathologic and molecular study

BACKGROUND

Malignant phyllodes tumors (MPTs) with sarcomatous components are often associated with substantial risks for local and distant recurrences. A more comprehensive characterization of their clinicopathological features and molecular profiles may offer significant potential innovative therapeutic strategies.

METHODS

A total of ten cases were collected with eight cases undergoing DNA next-generation sequencing (NGS). The clinicopathological characteristics, prognostic information, and genomic profiles were compared to those of MPTs without sarcomatous components.

RESULTS

Compared to MPT without sarcomatous components, no significant differences were found in age, tumor position, tumor size, menopausal status, or presence of fibroadenoma (p > 0.05). MPTs with osteosarcoma components had a poor prognosis either compared with other sarcomatous components (p = 0.027) or MPTs without sarcomatous components (p = 0.033). A notably high frequency of mutations was observed in several key genes within MPTs exhibiting sarcomatous components: TP53 (n = 6, 75.0 %), MUC16 (n = 4, 50.0 %), PTCH1 (n = 3, 37.5 %), and APC (n = 3, 37.5 %). In MPTs characterized by sarcomatous components, MCL1 (n = 6, 75.0 %) and MYC (n = 5, 62.5 %) demonstrated a notably high frequency of amplification. The NOTCH signaling pathway was significantly associated with MPTs characterized by sarcomatous components (13.6 % vs 75.0 %, p = 0.001).

CONCLUSIONS

The presence of an osteosarcoma component may serve as an indicator for unfavorable prognosis. Activating mutations in TP53 have been identified in these tumors. Furthermore, it typically facilitates tumor formation and progression via the NOTCH signaling pathway. These findings may offer valuable insights for clinical prognosis and identify potential therapeutic targets.

TP53 mutations in cancer: Molecular features and therapeutic opportunities (Review)

The tumour suppressor factor p53 plays an essential role in regulating numerous cellular processes, including the cell cycle, DNA repair, apoptosis, autophagy, cell metabolism and immune response. TP53 is the most commonly mutated gene in human cancers. These mutations are primarily non‑synonymous changes that produce mutant p53 proteins characterized by loss of function, a dominant negative effect on p53 tetramerisation and gain of function (GOF). GOF mutations not only disrupt the tumour‑suppressive activities of p53 but also endow the mutant proteins with new oncogenic properties. Recent studies analysing different pathogenic features of mutant p53 in cancer‑derived cell lines have demonstrated that restoring wild‑type p53, rather than removing GOF mutations, reduces cancer cell growth. These findings suggest that therapeutic strategies for reactivating wild‑type p53 function in cancer cells may bring a greater benefit than approaches halting mutant p53. This approach could involve the use of small molecules, gene therapy and other methods to re‑establish wild‑type p53 activity. This review describes the complexity of the biological activities of different p53 mutants and summarizes the current therapeutic approaches to restore p53 function.

Emerging strategies to investigate the biology of early cancer

Early detection and intervention of cancer or precancerous lesions hold great promise to improve patient survival. However, the processes of cancer initiation and the normal-precancer-cancer progression within a non-cancerous tissue context remain poorly understood. This is, in part, due to the scarcity of early-stage clinical samples or suitable models to study early cancer. In this Review, we introduce clinical samples and model systems, such as autochthonous mice and organoid-derived or stem cell-derived models that allow longitudinal analysis of early cancer development. We also present the emerging techniques and computational tools that enhance our understanding of cancer initiation and early progression, including direct imaging, lineage tracing, single-cell and spatial multi-omics, and artificial intelligence models. Together, these models and techniques facilitate a more comprehensive understanding of the poorly characterized early malignant transformation cascade, holding great potential to unveil key drivers and early biomarkers for cancer development. Finally, we discuss how these new insights can potentially be translated into mechanism-based strategies for early cancer detection and prevention.

Deep learning algorithm on H&E whole slide images to characterize TP53 alterations frequency and spatial distribution in breast cancer

The tumor suppressor TP53 is frequently mutated in hormone receptor-negative, HER2-positive breast cancer (BC), contributing to tumor aggressiveness. Traditional ancillary methods like immunohistochemistry (IHC) to assess TP53 functionality face pre- and post-analytical challenges. This proof-of-concept study employed a deep learning (DL) algorithm to predict TP53 mutational status from H&E-stained whole slide images (WSIs) of BC tissue. Using a pre-trained convolutional neural network, the model identified tumor areas and predicted TP53 mutations with a Dice coefficient score of 0.82. Predictions were validated through IHC and next-generation sequencing (NGS), confirming TP53 aberrant expression in 92 % of the tumor area, closely matching IHC findings (90 %). The DL model exhibited high accuracy in tissue quantification and TP53 status prediction, outperforming traditional methods in terms of precision and efficiency. DL-based approaches offer significant promise for enhancing biomarker testing and precision oncology by reducing intra- and inter-observer variability, but further validation is required to optimize their integration into real-world clinical workflows. This study underscores the potential of DL algorithms to predict key genetic alterations, such as TP53 mutations, in BC. DL-based histopathological analysis represents a valuable tool for improving patient management and tailoring treatment approaches based on molecular biomarker status.

Evaluation of the Prognostic Role of TP53 Gene Mutations in Prostate Cancer Outcome: A Systematic Review and Meta-Analysis

INTRODUCTION

Prostate cancer, 1 of the most common cancers in men, is influenced by age, genetics, race, and lifestyle. The TP53 gene, encoding the p53 protein crucial for cell cycle regulation and DNA repair, is frequently mutated in metastatic prostate cancers. These mutations impact prognosis and resistance to treatments, underscoring the role of genetic factors in disease progression and therapeutic challenges.

METHODS

Databases such as PubMed, Scopus, and ISI were searched using the keywords "prostate cancer," "P53," "TP53," "survival," and "prognosis," along with manual searches in other sources. Initial screening and selection of articles were conducted independently and blinded by 2 reviewers, focusing on titles abstracts, and full texts when necessary. The Newcastle-Ottawa Scale (NOS) was used for full-text evaluation. Data were analyzed using STATA 11, with heterogeneity assessed using the I² index.

RESULTS

Overall survival (OS) for prostate cancer patients with TP53 mutations was approximately 13% lower than for those without mutations at 1 year, 20% lower at 3 years, and 16% lower at 5 years. TP53 mutations were also associated with faster disease progression and a 15% reduction in progression-free survival (PFS) over 1 year. The hazard ratio (HR) for death in patients with TP53 mutations was 1.76, and for PFS, it was 1.62, indicating a 76% increased risk of death and a 62% increased risk of disease progression.

CONCLUSION

TP53 mutations are associated with shorter survival and faster disease progression in prostate cancer, underscoring the importance of precise evaluation and management of these mutations in treatment.

The NOTCH1 and miR-34a signaling network is affected by TP53 alterations in CLL

In chronic lymphocytic leukemia (CLL), TP53 mutations or deletions on chromosome 17p lead to adverse prognosis and reduced levels of miR-34a, which targets NOTCH1. Also, hyperactivated NOTCH1 signaling is crucial for CLL progression. Here we explored the interaction between p53, miR-34a, and NOTCH1 in CLL. We investigated the effect of p53 and miR-34a on NOTCH1 signaling and expression in CLL cells with altered TP53. Our results indicate that miR-34a reduces NOTCH1 3' UTR activity but might not be a mediator between p53 signaling and NOTCH1. p53 activation increases miR-34a expression and NOTCH1 protein levels, correlating with decreased NOTCH1 and miR-34a levels in primary CLL cells with TP53 alterations. Some samples with high NOTCH1 levels presented increased BCL-2, suggesting an anti-apoptotic mechanism of a potentially direct p53-NOTCH1 relation in CLL. This study deepens the understanding of the p53-miR-34a-NOTCH1 signaling network, providing insights that could guide future therapeutic strategies for CLL.

The Ashkenazi-Centric G334R Variant of TP53 is Severely Impaired for Transactivation but Retains Tumor Suppressor Function in a Mouse Model

Mutations in the TP53 tumor suppressor gene are the most abundant genetic occurrences in cancer. Some of these mutations lead to loss of function of p53 protein, some are gain of function, and some variants are hypomorphic (partially functional). Currently, there is no clinical distinction between different p53 mutations and cancer therapy or prognosis. Mutations in the oligomerization domain of p53 appear to be quite distinct in function, compared to mutations in the DNA binding domain. Here we show that, like other p53 oligomerization domain mutants, the Ashkenazi-specific G334R mutant accumulates to very high levels in cells and is significantly impaired for the transactivation of canonical p53 target genes. Surprisingly, we find that this mutant retains the ability to bind to consensus p53 target sites. A mouse model reveals that mice containing the G334R variant show increased predisposition to cancer, but only a fraction of these mice develop late-onset cancer. We show that the G334R variant retains the ability to interact with the SP1 transcription factor and contributes to the transactivation of joint SP1-p53 target genes. The combined evidence indicates that G334R is a unique oligomerization domain mutant that retains some tumor suppressor function.

Toward a Unified Theory of Why Young People Develop Cancer

Epidemiologic and genetic studies have now defined specific patterns of incidence and distinct molecular features of cancers in young versus aging people. Here, I review a general framework for the causes of cancer in children and young adults by relating somatic genetic mosaicism and developmental tissue mutagenesis. This framework suggests how aging-associated cancers such as carcinomas, glioblastomas, and myelodysplastic leukemias are causally distinct from cancers that predominantly affect children and young adults, including lymphoblastic and myeloid leukemias, sarcomas, neuroblastomas, medulloblastomas, and other developmental cancers. I discuss the oncogenic activities of known developmental mutators RAG1/2, AID, and PGBD5, and describe strategies needed to define missing developmental causes of young-onset cancers. Thus, a precise understanding of the mechanisms of tissue-specific somatic mosaicism, developmental mutators, and their control by human genetic variation and environmental exposures is needed for improved strategies for cancer screening, prevention, and treatment.

A multimodal atlas of hepatocellular carcinoma reveals convergent evolutionary paths and 'bad apple' effect on clinical trajectory

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a highly fatal cancer characterized by high intra-tumor heterogeneity (ITH). A panoramic understanding of its tumor evolution, in relation to its clinical trajectory, may provide novel prognostic and treatment strategies.

METHODS

Through the Asia-Pacific Hepatocellular Carcinoma trials group (NCT03267641), we recruited one of the largest prospective cohorts of patients with HCC, with over 600 whole genome and transcriptome samples from 123 treatment-naïve patients.

RESULTS

Using a multi-region sampling approach, we revealed seven convergent genetic evolutionary paths governed by the early driver mutations, late copy number variations and viral integrations, which stratify patient clinical trajectories after surgical resection. Furthermore, such evolutionary paths shaped the molecular profiles, leading to distinct transcriptomic subtypes. Most significantly, although we found the coexistence of multiple transcriptomic subtypes within certain tumors, patient prognosis was best predicted by the most aggressive cell fraction of the tumor, rather than by overall degree of transcriptomic ITH level - a phenomenon we termed the 'bad apple' effect. Finally, we found that characteristics throughout early and late tumor evolution provide significant and complementary prognostic power in predicting patient survival.

CONCLUSIONS

Taken together, our study generated a comprehensive landscape of evolutionary history for HCC and provides a rich multi-omics resource for understanding tumor heterogeneity and clinical trajectories.

IMPACT AND IMPLICATIONS

This prospective study, utilizing comprehensive multi-sector, multi-omics sequencing and clinical data from surgically resected hepatocellular carcinoma (HCC), reveals critical insights into the role of tumor evolution and intra-tumor heterogeneity (ITH) in determining the prognosis of HCC. These findings are invaluable for oncology researchers and clinicians, as they underscore the influence of distinct evolutionary paths and the 'bad apple' effect, where the most aggressive tumor fraction dictates disease progression. These insights not only enhance prognostic accuracy post-surgical resection but also pave the way for personalized treatment strategies tailored to specific tumor evolutionary and transcriptomic profiles. The coexistence of multiple subtypes within the same tumor prompts a re-appraisal of the utilities of depending on single samples to represent the entire tumor and suggests the need for clinical molecular imaging. This research thus marks a significant step forward in the clinical understanding and management of HCC, underscoring the importance of integrating tumor evolutionary dynamics and multi-omics biomarkers into therapeutic decision-making.

CLINICAL TRIAL NUMBER

NCT03267641 (Observational cohort).

Clinical relevance of double heterozygosity revealed by next-generation sequencing of homologous recombination repair pathway genes in South African breast cancer patients

PURPOSE

Genetically predisposed breast cancer (BC) patients represent a minor but clinically meaningful subgroup of the disease, with 25% of all cases associated with actionable variants in BRCA1/2. Diagnostic implementation of next-generation sequencing (NGS) resulted in the rare identification of BC patients with double heterozygosity for deleterious variants in genes partaking in homologous recombination repair of DNA. As clinical heterogeneity poses challenges for genetic counseling, this study focused on the occurrence and clinical relevance of double heterozygous BC in South Africa.

METHODS

DNA samples were diagnostically screened using the NGS-based Oncomine™ BRCA Expanded Research Assay. Data was generated on the Ion GeneStudio S5 system and analyzed using the Torrent Suite™ and reporter software. The clinical significance of the variants detected was determined using international variant classification guidelines and treatment implications.

RESULTS

Six of 1600 BC patients (0.375%) tested were identified as being bi-allelic for two germline likely pathogenic or pathogenic variants. Most of the variants were present in BRCA1/2, including two founder-related small deletions in three cases, with family-specific variants detected in ATM, BARD1, FANCD2, NBN, and TP53. The scientific interpretation and clinical relevance were based on the clinical and tumor characteristics of each case.

CONCLUSION

This study increased current knowledge of the risk implications associated with the co-occurrence of more than one pathogenic variant in the BC susceptibility genes, confirmed to be a rare condition in South Africa. Further molecular pathology-based studies are warranted to determine whether clinical decision-making is affected by the detection of a second pathogenic variant in BRCA1/2 and TP53 carriers.

Comprehensive Bioinformatic Investigation of TP53 Dysregulation in Diverse Cancer Landscapes

P53 overexpression plays a critical role in cancer pathogenesis by disrupting the intricate regulation of cellular proliferation. Despite its firmly established function as a tumor suppressor, elevated p53 levels can paradoxically contribute to tumorigenesis, influenced by factors such as exposure to carcinogens, genetic mutations, and viral infections. This phenomenon is observed across a spectrum of cancer types, including bladder (BLCA), ovarian (OV), cervical (CESC), cholangiocarcinoma (CHOL), colon adenocarcinoma (COAD), diffuse large B-cell lymphoma (DLBC), esophageal carcinoma (ESCA), head and neck squamous cell carcinoma (HNSC), kidney chromophobe (KICH), kidney renal clear cell carcinoma (KIRC), liver hepatocellular carcinoma (LIHC), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and uterine corpus endometrial carcinoma (UCEC). This broad spectrum of cancers is often associated with increased aggressiveness and recurrence risk. Effective therapeutic strategies targeting tumors with p53 overexpression require a comprehensive approach, integrating targeted interventions aimed at the p53 gene with conventional modalities such as chemotherapy, radiation therapy, and targeted drugs. In this extensive study, we present a detailed analysis shedding light on the multifaceted role of TP53 across various cancers, with a specific emphasis on its impact on disease-free survival (DFS). Leveraging data from the TCGA database and the GTEx dataset, along with GEPIA, UALCAN, and STRING, we identify TP53 overexpression as a significant prognostic indicator, notably pronounced in prostate adenocarcinoma (PRAD). Supported by compelling statistical significance (p < 0.05), our analysis reveals the distinct influence of TP53 overexpression on DFS outcomes in PRAD. Additionally, graphical representations of overall survival (OS) underscore the notable disparity in OS duration between tumors exhibiting elevated TP53 expression (depicted by the red line) and those with lower TP53 levels (indicated by the blue line). The hazard ratio (HR) further emphasizes the profound impact of TP53 on overall survival. Moreover, our investigation delves into the intricate TP53 protein network, unveiling genes exhibiting robust positive correlations with TP53 expression across 13 out of 27 cancers. Remarkably, negative correlations emerge with pivotal tumor suppressor genes. This network analysis elucidates critical proteins, including SIRT1, CBP, p300, ATM, DAXX, HSP 90-alpha, Mdm2, RPA70, 14-3-3 protein sigma, p53, and ASPP2, pivotal in regulating cell cycle dynamics, DNA damage response, and transcriptional regulation. Our study underscores the paramount importance of deciphering TP53 dynamics in cancer, providing invaluable insights into tumor behavior, disease-free survival, and potential therapeutic avenues.

Relevance of mutations in protein deubiquitinases genes and TP53 in corticotroph pituitary tumors

Introduction

Corticotroph pituitary neuroendocrine tumors (PitNETs) develop from ACTH-producing cells. They commonly cause Cushing's disease (CD), however, some remain clinically silent. Recurrent USP8, USP48, BRAF and TP53 mutations occur in corticotroph PitNETs. The aim of our study was to determine frequency and relevance of these mutations in a possibly large series of corticotroph PitNETs.

Methods

Study included 147 patients (100 CD and 47 silent tumors) that were screened for hot-spot mutations in USP8, USP48 and BRAF with Sanger sequencing, while 128 of these patients were screened for TP53 mutations with next generation sequencing and immunohistochemistry.

Results

USP8 mutations were found in 41% CD and 8,5% silent tumors, while USP48 mutations were found in 6% CD patients only. Both were more prevalent in women. They were related to higher rate of biochemical remission, non-invasive tumor growth, its smaller size and densely granulated histology, suggesting that these mutation may be favorable clinical features. Multivariate survival analyses did not confirm possible prognostic value of mutation in protein deubiquitinases. No BRAF mutations were found. Four TP53 mutations were identified (2 in CD, 2 in silent tumors) in tumors with size >10mm including 3 invasive ones. They were found in Crooke's cell and sparsely granulated tumors. Tumors with missense TP53 mutations had higher TP53 immunoreactivity score than wild-type tumors. Tumor with frameshift TP53 variant had low protein expression. TP53 mutation was a poor prognostic factor in CD according to uni- and multivariate survival analyses in spite of low mutations frequency.

Conclusions

We confirmed high prevalence of USP8 mutations and low incidence of USP48 and TP53 mutations. Changes in protein deubiquitinases genes appear to be favorable prognostic factors in CD. TP53 mutations are rare, occur in both functioning and silent tumors and are related to poor clinical outcome in CD.

Therapeutic potential of combating cancer by restoring wild-type p53 through mRNA nanodelivery

Among the tumor suppressor genes, TP53 is the most frequently mutated in human cancers, and most mutations are missense mutations causing production of mutant p53 (mutp53) proteins. TP53 mutations not only results in loss of function (LOH) as a transcription factor and a tumor suppressor, but also gain wild-type p53 (WTp53)-independent oncogenic functions that enhance cancer metastasis and progression (Yamamoto and Iwakuma, 2018; Zhang et al., 2022). TP53 has extensively been studied as a therapeutic target as well as for drug development and therapies, however with limited success. Achieving targeted therapies for restoration of WTp53 function and depletion or repair of mutant p53 (mutp53) will have far reaching implication in cancer treatment and therapies. This review briefly discusses the role of p53 mutation in cancer and the therapeutic potential of restoring WTp53 through the advances in mRNA nanomedicine.

Deciphering treatment resistance in metastatic colorectal cancer: roles of drug transports, EGFR mutations, and HGF/c-MET signaling

In 2023, colorectal cancer (CRC) is the third most diagnosed malignancy and the third leading cause of cancer death worldwide. At the time of the initial visit, 20% of patients diagnosed with CRC have metastatic CRC (mCRC), and another 25% who present with localized disease will later develop metastases. Despite the improvement in response rates with various modulation strategies such as chemotherapy combined with targeted therapy, radiotherapy, and immunotherapy, the prognosis of mCRC is poor, with a 5-year survival rate of 14%, and the primary reason for treatment failure is believed to be the development of resistance to therapies. Herein, we provide an overview of the main mechanisms of resistance in mCRC and specifically highlight the role of drug transports, EGFR, and HGF/c-MET signaling pathway in mediating mCRC resistance, as well as discuss recent therapeutic approaches to reverse resistance caused by drug transports and resistance to anti-EGFR blockade caused by mutations in EGFR and alteration in HGF/c-MET signaling pathway.

Somatic mutations in a multigene panel and impact on prognosis based on TP53 status in Chinese HER2-positive patients undergoing neoadjuvant therapy: A single-institution retrospective cohort

BACKGROUND

Gene mutations play a crucial role in the occurrence and development of tumors, particularly in breast cancer (BC). Neoadjuvant therapy (NAT) has shown greater clinical benefit in HER2-positive breast cancer. However, further clinical investigation is needed to fully understand the correlation between genetic mutations and NAT efficacy and the long-term prognosis in HER2-positive BC.

METHODS

This was a retrospective cohort study of 222 patients receiving NAT between 2017 and 2021 in the Department of Breast Surgery of Fudan University Shanghai Cancer Center. Tumor samples from these patients were subjected to Next Generation Sequencing (NGS) to analyze mutations in 513 cancer-related genes. This study aimed to investigate the association between these genetic mutations and postoperative pathological complete response (pCR), as well as their impact on disease-free survival (DFS).

RESULTS

In total, 48.65% patients reached pCR, ER-negative status (p < 0.001), PR-negative status (p < 0.001), Ki67 ≥ 20 (p = 0.011), and dual-targeted therapy (p < 0.001) were all associated with enhanced pCR rates. The frequency of somatic alterations in TP53 (60%), PIK3CA (15%), and ERBB2 (11%) was highest. In the HER2+/HR- cohort, patients who achieved pCR had a significant benefit in prognosis (HR = 3.049, p = 0.0498). KMT2C (p = 0.036) and TP53 (p = 0.037) mutations were significantly increased in patients with DFS events. Moreover, TP53 mutations had prognostic significance in HER2-positive BC patients with HR-negative (HR = 3.712, p = 0.027) and pCR (HR = 6.253, p = 0.027) status and who received herceptin-only targeted therapy (HR = 4.145, p = 0.011).

CONCLUSIONS

The genetic mutation profiles of Chinese HER2+ patients who received NAT were discrepant with respect to HR status or DFS events. TP53 mutations have significant prognostic value in patients with NAT for HER2-positive BC and patients benefit differently depending on HR status, the neoadjuvant regimen and response, which highlights the significance of genetic factors in treatment customization based on individual genetic and clinical characteristics.

A novel multimodal prediction model based on DNA methylation biomarkers and low-dose computed tomography images for identifying early-stage lung cancer

Objective

DNA methylation alterations are early events in carcinogenesis and immune signalling in lung cancer. This study aimed to develop a model based on short stature homeobox 2 gene (SHOX2)/prostaglandin E receptor 4 gene (PTGER4) DNA methylation in plasma, appearance subtype of pulmonary nodules (PNs) and low-dose computed tomography (LDCT) images to distinguish early-stage lung cancers.

Methods

We developed a multimodal prediction model with a training set of 257 individuals. The performance of the multimodal prediction model was further validated in an independent validation set of 42 subjects. In addition, we explored the association between SHOX2/PTGER4 DNA methylation and driver gene mutations in lung cancer based on data from The Cancer Genome Atlas (TCGA) portal.

Results

There were significant differences between the early-stage lung cancers and benign groups in the methylation levels. The area under a receiver operator characteristic curve (AUC) of SHOX2 in patients with solid nodules, mixed ground-glass opacity nodules and pure ground-glass opacity nodules were 0.693, 0.497 and 0.864, respectively, while the AUCs of PTGER4 were 0.559, 0.739 and 0.619, respectively. With the highest AUC of 0.894, the novel multimodal prediction model outperformed the Mayo Clinic model (0.519) and LDCT-based deep learning model (0.842) in the independent validation set. Database analysis demonstrated that patients with SHOX2/PTGER4 DNA hypermethylation were enriched in TP53 mutations.

Conclusions

The present multimodal prediction model could more efficiently distinguish early-stage lung cancer from benign PNs. A prognostic index based on DNA methylation and lung cancer driver gene alterations may separate the patients into groups with good or poor prognosis.

Differences and Similarities between Colorectal Cancer Cells and Colorectal Cancer Stem Cells: Molecular Insights and Implications

Malignant tumors are formed by diverse groups of cancer cells. Cancer stem cells (CSCs) are a subpopulation of heterogeneous cells identified in tumors that have the ability to self-renew and differentiate. Colorectal cancer (CRC), the third most frequent malignant tumor, is progressively being supported by evidence suggesting that CSCs are crucial in cancer development. We aim to identify molecular differences between CRC cells and CRC CSCs, as well as the effects of those differences on cell behavior in terms of migration, EMT, pluripotency, morphology, cell cycle/control, and epigenetic characteristics. The HT-29 cell line (human colorectal adenocarcinoma) and HT-29 CSCs (HT-29 CD133+/CD44+ cells) were cultured for 72 h. The levels of E-cadherin, KLF4, p53, p21, p16, cyclin D2, HDAC9, and P300 protein expression were determined using immunohistochemistry staining. The migration of cells was assessed by employing the scratch assay technique. Additionally, the scanning electron microscopy method was used to examine the morphological features of the cells, and their peripheral/central elemental ratios were compared with the help of EDS. Furthermore, a Muse cell cycle kit was utilized to determine the cell cycle analysis. The HT-29 CSC group exhibited high levels of expression for E-cadherin, p53, p21, p16, cyclin D2, HDAC9, and P300, whereas KLF4 was found to be high in the HT-29. The two groups did not exhibit any statistically significant differences in the percentages of cell cycle phases. The identification of specific CSC characteristics will allow for earlier cancer detection and the development of more effective precision oncology options.

Protein-level mutant p53 reporters identify druggable rare precancerous clones in noncancerous tissues

Detecting and targeting precancerous cells in noncancerous tissues is a major challenge for cancer prevention. Massive stabilization of mutant p53 (mutp53) proteins is a cancer-specific event that could potentially mark precancerous cells, yet in vivo protein-level mutp53 reporters are lacking. Here we developed two transgenic protein-level mutp53 reporters, p53R172H-Akaluc and p53-mCherry, that faithfully mimic the dynamics and function of mutp53 proteins in vivo. Using these reporters, we identified and traced rare precancerous clones in deep noncancerous tissues in various cancer models. In classic mutp53-driven thymic lymphoma models, we found that precancerous clones exhibit broad chromosome number variations, upregulate precancerous stage-specific genes such as Ybx3 and enhance amino acid transport and metabolism. Inhibiting amino acid transporters downstream of Ybx3 at the early but not late stage effectively suppresses tumorigenesis and prolongs survival. Together, these protein-level mutp53 reporters reveal undercharacterized features and vulnerabilities of precancerous cells during early tumorigenesis, paving the way for precision cancer prevention.

Targeted molecular profiling of solid tumours-Indian tertiary cancer centre experience

PURPOSE

Molecular Profiling of solid tumours is extensively used for prognostic, theranostic, and risk prediction. Next generation sequencing (NGS) has emerged as powerful method for molecular profiling. The present study was performed to identify molecular alterations present in solid tumours in Indian tertiary cancer centre.

METHODS

Study included 1140 formalin Fixed paraffin embedded samples. NGS was performed using two targeted gene panels viz. Ampliseq Focus panel and Sophia Solid Tumor Plus Solution. Data was analyzed using Illumina's Local Run Manager and SOPHiA DDM software. Variant interpretation and annotations were done as per AMP/ACMG guidelines.

RESULTS

Total 896 cases were subjected to NGS after excluding cases with suboptimal nucleic acid quality/quantity. DNA alterations were detected in 64.9% and RNA fusions in 6.9% cases. Among detected variants, 86.7% were clinically relevant aberrations. Mutation frequency among different solid tumours was 70.8%, 67.4%, 64.4% in non-small cell lung (NSCLC), lung squamous cell carcinomas and head neck tumours respectively. EGFR, KRAS, BRAF, ALK and ROS1were commonly altered in NSCLC. Gastrointestinal tumours showed mutations in 63.6% with predominant alterations in pancreatic (88.2%), GIST (87.5%), colorectal (78.7%), cholangiocarcinoma (52.9%), neuroendocrine (45.5%), gall bladder (36.7%) and gastric adenocarcinomas (16.7%). The key genes affected were KRAS, NRAS, BRAF and PIK3CA. NGS evaluation identified co-occurring alterations in 37.7% cases otherwise missed by conventional assays. Resistance mutations were detected in progressive lung tumours (39.5%) against EGFR TKIs and ALK/ROS inhibitors.

CONCLUSION

This is the largest Indian study on molecular profiling of solid tumours providing extensive information about mutational signatures using NGS.

The expression level of ARF and p53 in AML patients, and their relation to patients' outcome

Background

Acute myeloid leukemia (AML) is a cancer of hematopoietic progenitors characterized by gene mutations. The most popular deregulations are mutation and altered expression in the p53 gene, which is considered the guardian of the genome. Its activity is controlled by regulatory genes, e.g., alternate open reading frame (ARF), whose defects could affect p53 activity.

Aim

To study the effect of altered expression of p53 and ARF genes in de novo AML patients and correlate the results to the patients’ characteristics and outcomes.

Methods

Expression levels of p53 and ARF were assessed in 96 AML adult patients compared to 20 healthy controls using quantitative reverse-transcription PCR (RT-qPCR).

Results

There was significant up-regulation of p53 [77.6 (3.8–9528.3)] compared to controls [1.031 (0.210–9.051)], p < 0.001]. The expression level of ARF was significantly upregulated [6.2 (0.5–964.0)] compared to controls [0.854 (0.357–2.519), p < 0.001]. All of the low ARF expressers had low p53 overexpression, 61.1% of patients with high ARF expression had high p53 over-expression, and 38.9% with high ARF expression had low p53 over-expression (p < 0.001). ARF expression shows a trend of association with FLT3 mutation, as 89.3% with FLT3 mutation have high ARF expression (p = 0.080). Low p53 over-expression was seen in 77% of APL patients, while high p53 expression was associated with non-APL (p = 0.040). The median DFS of mutant NPM1 patients was higher than wild NPM1 (46.15 vs. 5.89 days, p = 0.045). Patients aged ≤ 50 years had better OS and DFS than those > 50 (p = 0.05, p = 0.035, respectively).There were no significant statistical associations between DFS and p53, ARF, and FLT3 mutations.

Conclusion

The p53 and ARF genes are overexpressed in de novo AML patients and they are interrelated. low p53 overexpression is associated with APL phenotype and t(15;17) and patients with t(15;17) had slightly better survival than patients with negative t(15;17) (p = 0.061). AML patients with mutated NPM1 had better DFS than wild NPM1 (p = 0.045). p53 pathway regulation can occur by many alternative ways rather than gene mutation.

Haploidentical haematopoietic stem cell transplantation for TP53-mutated acute myeloid leukaemia

Acute myeloid leukaemia (AML) patients with tumour protein p53 (TP53) mutations are often resistant to chemotherapy and have worse clinical outcomes than patients without TP53 mutations. In this study, we compared clinical outcomes of patients with AML with and without TP53 mutations who underwent haploidentical haematopoietic stem cell transplantation (haplo-HSCT). For the TP53-mutation group and TP53 wild-type group, the 2-year cumulative incidence of relapse (CIR) was (39.0% vs. 21.2% respectively, p = 0.088), the 2-year non-relapse mortality (NRM) rate was (3.2% vs. 8.4% respectively, p = 0.370), the 2-year leukaemia-free survival (LFS) was (57.7% vs. 71.3% respectively, p = 0.205), the 2-year overall survival (OS) rate was (69.9% vs. 81.3% respectively, p = 0.317), the 100-day cumulative incidence of Grade II-IV acute graft-versus-host disease (GvHD) was (6.5% vs. 20.7% respectively, p = 0.074), the 2-year cumulative incidence of chronic GvHD was (52.3% vs. 53.1% respectively, p = 0.493) and the 2-year GvHD-free/relapse-free survival (GRFS) was (57.7% vs. 69.6% respectively, p = 0.347). Our data showed that there were no significant differences in 2-year clinical outcomes between the two groups. Multivariable analysis showed TP53 mutations had no significant impact on CIR, NRM, OS, GvHD, LFS or GRFS. Our findings suggest that patients with AML with TP53 mutations may at least partially benefit from haplo-HSCT. Haplo-HSCT might be the recommended treatment for such patients.

Drugs Targeting p53 Mutations with FDA Approval and in Clinical Trials

Mutations in the tumor suppressor p53 (p53) promote cancer progression. This is mainly due to loss of function (LOS) as a tumor suppressor, dominant-negative (DN) activities of missense mutant p53 (mutp53) over wild-type p53 (wtp53), and wtp53-independent oncogenic activities of missense mutp53 by interacting with other tumor suppressors or oncogenes (gain of function: GOF). Since p53 mutations occur in ~50% of human cancers and rarely occur in normal tissues, p53 mutations are cancer-specific and ideal therapeutic targets. Approaches to target p53 mutations include (1) restoration or stabilization of wtp53 conformation from missense mutp53, (2) rescue of p53 nonsense mutations, (3) depletion or degradation of mutp53 proteins, and (4) induction of p53 synthetic lethality or targeting of vulnerabilities imposed by p53 mutations (enhanced YAP/TAZ activities) or deletions (hyperactivated retrotransposons). This review article focuses on clinically available FDA-approved drugs and drugs in clinical trials that target p53 mutations and summarizes their mechanisms of action and activities to suppress cancer progression.

Effect of TP53 deficiency and KRAS signaling on the bioenergetics of colon cancer cells in response to different substrates: A single cell study

Metabolic reprogramming is a hallmark of cancer. Somatic mutations in genes involved in oncogenic signaling pathways, including KRAS and TP53, rewire the metabolic machinery in cancer cells. We here set out to determine, at the single cell level, metabolic signatures in human colon cancer cells engineered to express combinations of activating KRAS gene mutations and TP53 gene deletions. Specifically, we explored how somatic mutations in these genes and substrate availability (lactate, glucose, substrate deprivation) from the extracellular microenvironment affect bioenergetic parameters, including cellular ATP, NADH and mitochondrial membrane potential dynamics. Employing cytosolic and mitochondrial FRET-based ATP probes, fluorescent NADH sensors, and the membrane-permeant cationic fluorescent probe TMRM in HCT-116 cells as a model system, we observed that TP53 deletion and KRAS mutations drive a shift in metabolic signatures enabling lactate to become an efficient metabolite to replenish both ATP and NADH following nutrient deprivation. Intriguingly, cytosolic, mitochondrial and overall cellular ATP measurements revealed that, in WT KRAS cells, TP53 deficiency leads to an enhanced ATP production in the presence of extracellular lactate and glucose, and to the greatest increase in ATP following a starvation period. On the other hand, oncogenic KRAS in TP53-deficient cells reversed the alterations in cellular ATP levels. Moreover, cell population measurements of mitochondrial and glycolytic metabolism using a Seahorse analyzer demonstrated that WT KRAS TP53-silenced cells display an increase of the basal respiration and tightly-coupled mitochondria, in the presence of glucose as substrate, compared to TP53 competent cells. Furthermore, cells possessing oncogenic KRAS, independently of TP53 status, showed less pronounced mitochondrial membrane potential changes in response to metabolic nutrients. Furthermore, analysis of cytosolic and mitochondrial NADH levels revealed that the simultaneous presence of TP53 deletion and oncogenic KRAS showed the most pronounced alteration in cytosolic and mitochondrial NADH during metabolic stress. In conclusion, our findings demonstrate how activating KRAS mutation and loss of TP53 remodel cancer metabolism and lead to alterations in bioenergetics under metabolic stress conditions by modulating cellular ATP production, NADH oxidation, mitochondrial respiration and function.

Somatic Mutations in Exon 7 of the TP53 Gene in Index Colorectal Lesions Are Associated with the Early Occurrence of Metachronous Adenoma

Simple Summary

Identifying patients with an increased risk of early recurrence of colorectal lesions is still a problem. In our study, we focused on improving this identification by determining the mutation profile of index lesions. We found a statistically significant association between the mutation in exon 7 of the TP53 gene in the index lesion and the risk of early metachronous adenoma.

Abstract

(1) Background: this prospective study was focused on detailed analysis of the mutation heterogeneity in colorectal lesions removed during baseline (index) colonoscopy to identify patients at high risk of early occurrence of metachronous adenomas. (2) Methods: a total of 120 patients after endoscopic therapy of advanced colorectal neoplasia size ≥10 mm (index lesion) with subsequent surveillance colonoscopy after 10–18 months were included. In total, 143 index lesions and 84 synchronous lesions in paraffin blocks were divided into up to 30 samples. In each of them, the detection of somatic mutations in 11 hot spot gene loci was performed. Statistical analysis to correlate the mutation profiles and the degree of heterogeneity of the lesions with the risk of metachronous adenoma occurrence was undertaken. (3) Results: mutation in exon 7 of the TP53 gene found in the index lesion significantly correlated with the early occurrence of metachronous adenoma (log-rank test p = 0.003, hazard ratio 2.73, 95% confidence interval 1.14–6.56). We did not find an association between the risk of metachronous adenomas and other markers monitored. (4) Conclusions: the findings of this study could lead to an adjustment of existing recommendations for surveillance colonoscopies in a specific group of patients with mutations in exon 7 of the TP53 gene in an index lesion, where a shortening of surveillance interval may be warranted.

Outcome of aggressive B-cell lymphoma with TP53 alterations administered with CAR T-cell cocktail alone or in combination with ASCT

TP53 gene alteration confers inferior prognosis in refractory/relapse aggressive B-cell non-Hodgkin lymphoma (r/r B-NHL). From September 2016 to September 2020, 257 r/r B-NHL patients were assessed for eligibility for two trials in our center, assessing anti-CD19 and anti-CD22 chimeric antigen receptor (CAR19/22) T-cell cocktail treatment alone or in combination with autologous stem cell transplantation (ASCT). TP53 alterations were screened in 123 enrolled patients and confirmed in 60. CAR19/22 T-cell administration resulted in best objective (ORR) and complete (CRR) response rate of 87.1% and 45.2% in patients with TP53 alterations, respectively. Following a median follow-up of 16.7 months, median progression-free survival (PFS) was 14.8 months, and 24-month overall survival (OS) was estimated at 56.3%. Comparable ORR, PFS, and OS were determined in individuals with or without TP53 alterations, and in individuals at different risk levels based on functional stratification of TP53 alterations. CAR19/22 T-cell treatment in combination with ASCT resulted in higher ORR, CRR, PFS, and OS, but reduced occurrence of severe CRS in this patient population, even in individuals showing stable or progressive disease before transplantation. The best ORR and CRR in patients with TP53 alterations were 92.9% and 82.1%, respectively. Following a median follow-up of 21.2 months, 24-month PFS and OS rates in patients with TP53 alterations were estimated at 77.5% and 89.3%, respectively. In multivariable analysis, this combination strategy predicted improved OS. In conclusion, CAR19/22 T-cell therapy is efficacious in r/r aggressive B-NHL with TP53 alterations. Combining CAR-T cell administration with ASCT further improves long-term outcome of these patients.

p53 partial loss-of-function mutations sensitize to chemotherapy

The tumor suppressive transcription factor p53 is frequently inactivated in cancer cells by missense mutations that cluster in the DNA binding domain. 30% hit mutational hotspot residues, resulting in a complete loss of transcriptional activity and mutant p53-driven chemotherapy resistance. Of the remaining 70% of non-hotspot mutants, many are partial loss-of-function (partial-LOF) mutants with residual transcriptional activity. The therapeutic consequences of a partial-LOF have remained largely elusive. Using a p53 mutation engineered to reduce DNA binding, we demonstrate that partial-LOF is sufficient to enhance oncogene-driven tumorigenesis in mouse models of lung and pancreatic ductal adenocarcinoma and acute myeloid leukemia. Interestingly, mouse and human tumors with partial-LOF mutations showed mutant p53 protein accumulation similar as known for hotspot mutants. Different from the chemotherapy resistance caused by p53-loss, the partial-LOF mutant sensitized to an apoptotic chemotherapy response and led to a survival benefit. Mechanistically, the pro-apoptotic transcriptional activity of mouse and human partial-LOF mutants was rescued at high mutant protein levels, suggesting that accumulation of partial-LOF mutants enables the observed apoptotic chemotherapy response. p53 non-hotspot mutants with partial-LOF, therefore, represent tumorigenic p53 mutations that need to be distinguished from other mutations because of their beneficial impact on survival in a therapy context.

Clonal and subclonal TP53 molecular impairment is associated with prognosis and progression in multiple myeloma

Aberrations on TP53, either as deletions of chromosome 17p (del17p) or mutations, are associated with poor outcome in multiple myeloma (MM), but conventional detection methods currently in use underestimate their incidence, hindering an optimal risk assessment and prognostication of MM patients. We have investigated the altered status of TP53 gene by SNPs array and sequencing techniques in a homogenous cohort of 143 newly diagnosed MM patients, evaluated both at diagnosis and at first relapse: single-hit on TP53 gene, either deletion or mutation, detected both at clonal and sub-clonal level, had a minor effect on outcomes. Conversely, the coexistence of both TP53 deletion and mutation, which defined the so-called double-hit patients, was associated with the worst clinical outcome (PFS: HR 3.34 [95% CI: 1.37–8.12] p = 0.008; OS: HR 3.47 [95% CI: 1.18–10.24] p = 0.02). Moreover, the analysis of longitudinal samples pointed out that TP53 allelic status might increase during the disease course. Notably, the acquisition of TP53 alterations at relapse dramatically worsened the clinical course of patients. Overall, our analyses showed these techniques to be highly sensitive to identify TP53 aberrations at sub-clonal level, emphasizing the poor prognosis associated with double-hit MM patients.

Platinum-based systematic therapy in triple-negative breast cancer

Due to the lack of definitive hormone receptors, triple negative breast cancer (TNBC) patients receive little clinical benefit from endocrine or molecular targeted therapies, leading to a highly aggressive disease with a high recurrence rate and poor prognosis. In the past decades, chemotherapy has been the mainstay of treatment for TNBC, with taxane/anthracyclines as the representative regimen. However, increasing irreversible cardiotoxicity of anthracyclines and drug-resistance had to be noticed. Gradually, platinum-based chemotherapy has become a topic of interest for researchers. Based on the accumulating studies on platinum-containing regimens for TNBC patients, we will summarize the progress of relevant clinical trials focusing on platinum monotherapy (e.g., cisplatin, carboplatin and oxaliplatin) or in combination with other therapeutic modalities (e.g., other chemotherapeutic agents, molecular targeted therapies and immunotherapy). To further evaluate patient response to platinum and screen for the optimal population to benefit from platinum, we will also analyze current potential biomarkers, such as breast cancer susceptibility genes (BRCA1/2), homologous recombination repair deficiency (HRD), tumor infiltrating lymphocytes (TILs), TP53 family and other emerging indicators (e.g., intrinsic subtype, cyclin-dependent kinase 2 (CDK2) expression, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9)).

One-Two Punch Therapy for the Treatment of T-Cell Malignancies Involving p53-Dependent Cellular Senescence

T-cell malignancies are still difficult to treat due to a paucity of plans that target critical dependencies. Drug-induced cellular senescence provides a permanent cell cycle arrest during tumorigenesis and cancer development, particularly when combined with senolytics to promote apoptosis of senescent cells, which is an innovation for cancer therapy. Here, our research found that wogonin, a well-known natural flavonoid compound, not only had a potential to inhibit cell growth and proliferation but also induced cellular senescence in T-cell malignancies with nonlethal concentration. Transcription activity of senescence-suppression human telomerase reverse transcriptase (hTERT) and oncogenic C-MYC was suppressed in wogonin-induced senescent cells, resulting in the inhibition of telomerase activity. We also substantiated the occurrence of DNA damage during the wogonin-induced aging process. Results showed that wogonin increased the activity of senescence-associated β-galactosidase (SA-β-Gal) and activated the DNA damage response pathway mediated by p53. In addition, we found the upregulated expression of BCL-2 in senescent T-cell malignancies because of the antiapoptotic properties of senescent cells. Following up this result, we identified a BCL-2 inhibitor Navitoclax (ABT-263), which was highly effective in decreasing cell viability and inducing apoptotic cell death in wogonin-induced senescent cells. Thus, the “one-two punch” approach increased the sensibility of T-cell malignancies with low expression of BCL-2 to Navitoclax. In conclusion, our research revealed that wogonin possesses potential antitumor effects based on senescence induction, offering a better insight into the development of novel therapeutic methods for T-cell malignancies.

Clinical and molecular factors that impact the efficacy of first-line crizotinib in ROS1-rearranged non-small-cell lung cancer: a large multicenter retrospective study

BACKGROUND

ROS1-rearranged lung cancers benefit from first-line crizotinib therapy; however, clinical and molecular factors that could affect crizotinib efficacy in ROS1-rearranged lung cancers are not yet well-elucidated. Our retrospective study aimed to compare the efficacy of chemotherapy and crizotinib in the first-line treatment of ROS1-rearranged advanced lung cancer and evaluate various clinical and molecular factors that might impact crizotinib efficacy in real-world practice.

METHODS

Treatment responses, survival outcomes, and patterns of disease progression were analyzed for 235 patients with locally advanced to advanced disease who received first-line chemotherapy (n = 67) or crizotinib (n = 168).

RESULTS

The overall response rate was 85.7% (144/168) for first-line crizotinib and 41.8% (28/67) for chemotherapy. Patients treated with first-line crizotinib (n = 168) had significantly longer median progression-free survival (PFS) than chemotherapy (n = 67) (18.0 months vs. 7.0 months, p < 0.001). Patients harboring single CD74-ROS1 (n = 90) had significantly shorter median PFS with crizotinib than those harboring non-CD74 ROS1 fusions (n = 69) (17.0 months vs. 21.0 months; p = 0.008). Patients with baseline brain metastasis (n = 45) had a significantly shorter PFS on first-line crizotinib than those without brain metastasis (n = 123) (16.0 months vs. 22.0 months; p = 0.03). At progression, intracranial-only progression (n = 40), with or without baseline CNS metastasis, was associated with longer median PFS than those with extracranial-only progression (n = 64) (19.0 months vs. 13.0 months, p < 0.001). TP53 mutations were the most common concomitant mutation, detected in 13.1% (7/54) of patients with CD74-ROS1 fusions, and 18.8% (6/32) with non-CD74 ROS1 fusions. Patients with concomitant TP53 mutations (n=13) had significantly shorter PFS than those who had wild-type TP53 (n = 81) (6.5 months vs. 21.0 months; p < 0.001). PFS was significantly shorter for the patients who harbored concomitant driver mutations (n = 9) (11.0 months vs 24.0 months; p = 0.0167) or concomitant tumor suppressor genes (i.e., TP53, RB1, or PTEN) (n = 25) (9.5 months vs 24.0 months; p < 0.001) as compared to patients without concomitant mutations (n = 58).

CONCLUSION

Our results demonstrate that baseline brain metastatic status and various molecular factors could contribute to distinct clinical outcomes from first-line crizotinib therapy of patients with ROS1-rearranged lung cancer.

CLINICAL TRIALS REGISTRATION

CORE, NCT03646994.

The Role of p53 Dysfunction in Colorectal Cancer and Its Implication for Therapy

Colorectal cancer (CRC) is one of the most common and fatal cancers worldwide. The carcinogenesis of CRC is based on a stepwise accumulation of mutations, leading either to an activation of oncogenes or a deactivation of suppressor genes. The loss of genetic stability triggers activation of proto-oncogenes (e.g., KRAS) and inactivation of tumor suppression genes, namely TP53 and APC, which together drive the transition from adenoma to adenocarcinoma. On the one hand, p53 mutations confer resistance to classical chemotherapy but, on the other hand, they open the door for immunotherapy, as p53-mutated tumors are rich in neoantigens. Aberrant function of the TP53 gene product, p53, also affects stromal and non-stromal cells in the tumor microenvironment. Cancer-associated fibroblasts together with other immunosuppressive cells become valuable assets for the tumor by p53-mediated tumor signaling. In this review, we address the manifold implications of p53 mutations in CRC regarding therapy, treatment response and personalized medicine.

CD80 expression is upregulated by TP53 activation in human cancer epithelial cells

CD80 is recognized as one of the most potent costimulatory molecules by which immune cells limit cancer progression; however, the current understanding of the regulation of its expression on human tumor cells is limited. The TP53 tumor suppressor plays a critical role in cancer and its significant role in the control of immune responses is emerging. Here, we evaluated the role of TP53 as a regulator of CD80 expression in human cancer cells. A set of well-known TP53-reactivating compounds were used on TP53-wild-type, TP53-deficient, TP53-mutated and TP53-knockdown cancer cell lines to determine if TP53 can regulate CD80. CD80 expression was analyzed in samples from patients with TP53-active vs TP53-inactive Colon Adenocarcinomas (COAD) from TCGA panCancer Atlas. We report that the pharmacological activation of TP53 can stimulate the expression of CD80 in human tumor cells of epithelial origin. We also provide evidence that CD80 expression exhibits a strong correlation with TP53 activation in a subgroup of colon tumors with better overall survival. These results confirm the link between TP53 and immune surveillance in human cancer and provide the possibility that conventional TP53-activation approaches for tumoricidal effects may be repurposed for immunotherapy strategies.

On the role of p53 in the cellular response to aneuploidy

Most solid tumors are aneuploid, and p53 has been implicated as the guardian of the euploid genome. Previous experiments using human cell lines showed that aneuploidy induction leads to p53 accumulation and p21-mediated G1 cell cycle arrest. We find that adherent 2-dimensional (2D) cultures of human immortalized or cancer cell lines activate p53 upon aneuploidy induction, whereas suspension cultures of a human lymphoid cell line undergo a p53-independent cell cycle arrest. Surprisingly, 3D human and mouse organotypic cultures from neural, intestinal, or mammary epithelial tissues do not activate p53 or arrest in G1 following aneuploidy induction. p53-deficient colon organoids have increased aneuploidy and frequent lagging chromosomes and multipolar spindles during mitosis. These data suggest that p53 may not act as a universal surveillance factor restricting the proliferation of aneuploid cells but instead helps directly or indirectly ensure faithful chromosome transmission likely by preventing polyploidization and influencing spindle mechanics.

FLT3 inhibition upregulates HDAC8 via FOXO to inactivate p53 and promote maintenance of FLT3-ITD+ acute myeloid leukemia

Internal tandem duplication (ITD) mutations within the FMS-like receptor tyrosine kinase-3 (FLT3) can be found in up to 25% to 30% of acute myeloid leukemia (AML) patients and confer a poor prognosis. Although FLT3 tyrosine kinase inhibitors (TKIs) have shown clinical responses, they cannot eliminate primitive FLT3-ITD+ AML cells, which are potential sources of relapse. Therefore, elucidating the mechanisms underlying FLT3-ITD+ AML maintenance and drug resistance is essential to develop novel effective treatment strategies. Here, we demonstrate that FLT3 inhibition induces histone deacetylase 8 (HDAC8) upregulation through FOXO1- and FOXO3-mediated transactivation in FLT3-ITD+ AML cells. Upregulated HDAC8 deacetylates and inactivates p53, leading to leukemia maintenance and drug resistance upon TKI treatment. Genetic or pharmacological inhibition of HDAC8 reactivates p53, abrogates leukemia maintenance, and significantly enhances TKI-mediated elimination of FLT3-ITD+ AML cells. Importantly, in FLT3-ITD+ AML patient-derived xenograft models, the combination of FLT3 TKI (AC220) and an HDAC8 inhibitor (22d) significantly inhibits leukemia progression and effectively reduces primitive FLT3-ITD+ AML cells. Moreover, we extend these findings to an AML subtype harboring another tyrosine kinase-activating mutation. In conclusion, our study demonstrates that HDAC8 upregulation is an important mechanism to resist TKIs and promote leukemia maintenance and suggests that combining HDAC8 inhibition with TKI treatment could be a promising strategy to treat FLT3-ITD+ AML and other tyrosine kinase mutation-harboring leukemias.

Mutant p53 drives the loss of heterozygosity by the upregulation of Nek2 in breast cancer cells

BACKGROUND

Mutations in one allele of the TP53 gene in early stages are frequently followed by the loss of the remaining wild-type p53 (wtp53) allele (p53LOH) during tumor progression. Despite the strong notion of p53LOH as a critical step in tumor progression, its oncogenic outcomes that facilitate the selective pressure for p53LOH occurrence were not elucidated.

METHODS

Using MMTV;ErbB2 mouse model of breast cancer carrying heterozygous R172H p53 mutation, we identified a novel gain-of-function (GOF) activity of mutant p53 (mutp53): the exacerbated loss of wtp53 allele in response to γ-irradiation.

RESULTS

As consequences of p53LOH in mutp53 heterozygous cells, we observed profound stabilization of mutp53 protein, the loss of p21 expression, the abrogation of G2/M checkpoint, chromosomal instability, centrosome amplification, and transcriptional upregulation of mitotic kinase Nek2 (a member of Never in Mitosis (NIMA) Kinases family) involved in the regulation of centrosome function. To avoid the mitotic catastrophe in the absence of G2/M checkpoint, cells with centrosome amplification adapt Nek2-mediated centrosomes clustering as pro-survival mutp53 GOF mechanism enabling unrestricted proliferation and clonal expansion of cells with p53LOH. Thus, the clonal dominance of mutp53 cells with p53LOH may represent the mechanism of irradiation-induced p53LOH. We show that pharmacological and genetic ablation of Nek2 decreases centrosome clustering and viability of specifically mutp53 cells with p53LOH.

CONCLUSION

In a heterogeneous tumor population, Nek2 inhibition may alter the selective pressure for p53LOH by contraction of the mutp53 population with p53LOH, thus, preventing the outgrowth of genetically unstable, more aggressive cells.

The Long-To-Short-Axis Ratio and Multifocality are Associated With TP53 Mutation Status in Surgically Resected Hepatocellular Carcinomas

RATIONALE AND OBJECTIVES

In hepatocellular carcinoma (HCC), the tumor protein 53 (TP53) gene is frequently mutated and the mutations have been associated with poor prognosis. We aim to retrospectively identify the relationship between TP53 mutation status, tumor size (long-axis diameter, short-axis diameter, and long-to-short-axis ratio [L/S ratio]), margin and multifocality in surgically resected HCC.

MATERIALS AND METHODS

The image features and TP53 mutation data from 78 patients generated with National Cancer Institute's multi-institutional The Cancer Genome Atlas (TCGA)/The Cancer Imaging Archive databases were assessed. Binary logistic regression analyses were performed to identify independent factors of harboring TP53 mutation status. The final model was selected by using the backward elimination method.

RESULTS

TP53 mutations were found in 19 (31.5%) of 78 patients. TP53 mutation rates were significantly higher (a) in L/S ratio ≤ 1.2 14 of 41 [34.1%]) lesions than in L/S ratio >1.2 lesions (five of 37 [13.5%]) (p = 0.034) and (b) in nonmultifocality (17 of 54[31.5%]) than in multifocality lesions (two of 24 [8.3%]) (p = 0.028). On univariate logistic regression analysis, L/S ratio (≤1.20 vs >1.20. odds ratio [OR]: 3.319; p = 0.040; 95% confidence interval [CI]: 1.059-10.401 Area Under Curve (AUC) = 0.634) and multifocality (no vs yes OR: 5.054; p = 0.041; 95% CI: 1.065-23.986 AUC = 0.640) were associated with TP53 mutations. On multivariate logistic regression analysis, L/S ratio (≤1.20 vs >1.20 OR: 3.430; p = 0.040; 95% CI: 1.058-11.118) and multifocality (no vs yes OR: 5.232; p = 0.041; 95% CI: 1.072-25.526) were associated with TP53 mutations. The area under the receiver operating characteristic curve for predicting TP53 mutation status was 0.714 (95% CI: 0.590-0.837).

CONCLUSION

Our study focusing on identifying imaging aspects related to TP53 positive HCC. L/S ratio of HCC in combination with multifocality might be used to prognosticate TP53 mutation status. And the discriminatory power for this prediction model was good.

Predictive and Prognostic Potential of TP53 in Patients With Advanced Non-Small-Cell Lung Cancer Treated With EGFR-TKI: Analysis of a Phase III Randomized Clinical Trial (CTONG 0901)

BACKGROUND

Mutations in TP53 are commonly found in patients with epidermal growth factor receptor (EGFR) mutant advanced non-small-cell lung cancer (NSCLC). In this study, we determined the predictive and prognostic potential of different subtypes of TP53 using data from a phase III randomized trial (CTONG 0901).

PATIENTS AND METHODS

The trial enrolled 195 patients who had undergone next-generation sequencing of 168 genes before treatment with EGFR tyrosine kinase inhibitors. Mutations in TP53 (exon 4 or 7, other mutations, and wild-type) were analyzed based on the therapeutic response and survival. A Cox proportional hazards model was used to determine the potential of the predictive and prognostic factors.

RESULTS

All 195 patients harbored activating EGFR mutations: the most common concomitant mutations were TP53 (134/195, 68.7%), CTNNB1 (20/195, 10.3%), and RB1 (16/195, 8.2%). The genetic profiles between patient subgroups administered first-line (132, 67.7%) or later-line (63, 32.3%) treatments did not significantly differ. The median progression-free survival in patients with mutations in exon 4 or 7 of TP53, other TP53 mutations, and wild-type TP53 were 9.4, 11.0, and 14.5 months (P = .009), respectively. Overall survival times were 15.8, 20.0, and 26.1 months (P = .004), respectively. Mutations in exon 4 or 7 of TP53 served as independent prognostic factors for progression-free (P = .001) and overall survival (P = .004) in patients.

CONCLUSION

Mutations in exon 4 and/or 7 in TP53 are promising predictive and prognostic indicators in EGFR-mutated NSCLC.

Liquid Biopsies in a Veteran Patient Population With Advanced Prostate and Lung Non-Small Cell Carcinomas: A New Paradigm and Unique Challenge in Personalized Medicine

Introduction

Liquid biopsy in solid tumors is a major milestone in the field of precision oncology by analyzing circulating tumor cells in peripheral blood and genomic alterations. DNA damage repair gene (DDR) mutations have been reported in 25 to 40% of prostatic cancers and > 50% of non-small cell lung cancers (NSCLC). Tp53 mutation has been found to be associated with a poor prognosis and increased germline mutations. We herein present a quality assurance study for the utility of liquid biopsies with frequency of DDR, Tp53, and androgen receptor (AR) mutations and the clinical impact in advanced lung and prostate cancers in the veteran patient population; these quality assurance observations are the study endpoints.

Methods

We reviewed documentation from advanced cancer biomarker tests on liquid biopsies performed at the Corporal Michael J. Crescenz Veteran Affairs Medical Center in Philadelphia, Pennsylvania, from May 2019 to April 15, 2020.

Results

Mutations were detected in 29 of 31 (93.5%) liquid biopsies, hence, 29 liquid biopsies had sufficient ctDNA for analysis. Notable mutations were found in 23 cases (79.3%), irrespective of the cancer type showed. Of 21 prostate cancers biopsies 4 (19.0%) biomarker test directed the targeted therapy to driver mutations of the AR gene. Gene mutations from the DDR gene family were detected in 8 of 23 (34.7%) advanced prostate and lung cancer liquid biopsies, and in 6 of 21 (28.5%) prostate cancer cases indicating poor outcome and possible resistance to the current therapy. Irrespective of the cancer type, 15 of 23 (65.2%) patients harbored Tp53 mutations, which is much more frequent than is documented in the literature. Of 31 patients, 15 (48.4%) were Vietnam era veterans with the potential of Agent Orange exposure and, 20 of 31 (64.5%) had a smoking history. Seven (46.6%) of the Vietnam era veterans with potential exposure to Agent Orange were positive for Tp53 mutations irrespective of the cancer type.

Conclusion

The minimally invasive liquid biopsy shows a great promise as a diagnostic and prognostic tool in the personalized clinical management of advanced prostate and NSCLC in veteran patient population with unique demographic characteristics. Difference in frequency of the genetic mutations (DDR, TP53, AR) in this cohort provides valuable information for disease progression, lack of response, mechanism of resistance to the implemented therapy and clinical decision making. Precision oncology can be further tailored for this cohort by focusing on DNA repair genes and Tp53 mutations in future for personalized targeted therapy.

Landscape of somatic single nucleotide variants and indels in colorectal cancer and impact on survival

Colorectal cancer (CRC) is a biologically heterogeneous disease. To characterize its mutational profile, we conduct targeted sequencing of 205 genes for 2,105 CRC cases with survival data. Our data shows several findings in addition to enhancing the existing knowledge of CRC. We identify PRKCI, SPZ1, MUTYH, MAP2K4, FETUB, and TGFBR2 as additional genes significantly mutated in CRC. We find that among hypermutated tumors, an increased mutation burden is associated with improved CRC-specific survival (HR = 0.42, 95% CI: 0.21–0.82). Mutations in TP53 are associated with poorer CRC-specific survival, which is most pronounced in cases carrying TP53 mutations with predicted 0% transcriptional activity (HR = 1.53, 95% CI: 1.21–1.94). Furthermore, we observe differences in mutational frequency of several genes and pathways by tumor location, stage, and sex. Overall, this large study provides deep insights into somatic mutations in CRC, and their potential relationships with survival and tumor features.

Large scale sequencing study is of paramount importance to unravel the heterogeneity of colorectal cancer. Here, the authors sequenced 205 cancer genes in more than 2000 tumours and identified additional mutated driver genes, determined that mutational burden and specific mutations in TP53 are associated with survival odds.

Age, sex, and specific gene mutations affect the effects of immune checkpoint inhibitors in colorectal cancer

The effect of age and sex on the predictive value of colorectal cancer (CRC) patients treated with immune checkpoint inhibitors (ICIs) has been controversial, and the effect of specific gene mutations on the predictive value of CRC patients treated with ICIs remains to be explored. Our study analyzed the influence of the above factors on the overall survival (OS) of CRC patients receiving ICIs and explored the influencing mechanism of various predictive biomakers. We performed survival prognostic correlation analysis and bioinformatics analysis on the clinical CRC cohort receiving ICIs in from the Memorial Sloan Kettering Cancer Center (MSKCC) and the clinical and genetic data from The Cancer Genome Atlas (TCGA)-CRC dataset, including immunogenicity analysis, tumor immune microenvironment analysis, and gene set enrichment analysis and so on. We found that mutation count >11 mutation/Mb (tumor mutation burden, TMB-high) (HR = 0.22, 95 %CI: 0.09-0.53; P < 0.001), male (HR = 0.51, 95 %CI: 0.28-0.93; P = 0.029), RNF43-mutant (MT) (HR = 0.12, 95 %CI: 0.03-0.49; P = 0.003), CREBBP-MT (HR = 0.23, 95 %CI: 0.07-0.76; P = 0.016), NOTCH3-MT (HR = 0.17, 95 %CI: 0.04-0.74; P = 0018), PTCH1-MT (HR = 0.27, 95 %CI: 0.08-0.9; P = 0.033), CIC-MT (HR = 0.23, 95 %CI: 0.05-0.93; P = 0.040), DNMT1-MT (HR = 0.12, 95 %CI: 0.02-0.93; P = 0.043) and SPEN-MT (HR = 0.31, 95 %CI: 0.09-0.99; P < 0.049) are all related to longer OS, but age≤65 years (HR = 3.01, 95 %CI: 1.18-7.65; P = 0.021), APC-MT (HR = 2.51, 95 %CI: 1.12-5.63; P = 0.026) and TP53-MT (HR = 1.94, 95 %CI: 1.03-3.65; P = 0.041) are associated with shorter OS. The reason why positive predictive markers provide survival benefits to CRC may be related to higher immunogenicity such as TMB, highly expression of mRNA related to immune response, highly infiltrating immune-active cells such as CD8 + T cells, active immune-active pathways, and DNA damage repair pathways with an increased number of mutations.

Integrated clinicomolecular characterization identifies RAS activation and CDKN2A deletion as independent adverse prognostic factors in cancer of unknown primary

Cancer of unknown primary (CUP) denotes a malignancy with histologically confirmed metastatic spread while the primary tumor remains elusive. Here, we address prognostic and therapeutic implications of mutations and copy number variations (CNVs) detected in tumor tissue in the context of a comprehensive clinical risk assessment. Targeted panel sequencing was performed in 252 CUP patients. 71.8% of patients had unfavorable CUP according to ESMO guidelines. 74.7% were adeno- and 13.7% squamous cell carcinomas. DNA was extracted from microdissected formalin-fixed, paraffin-embedded tissues. For library preparation, mostly multiplex PCR-based Ion Torrent AmpliSeq™ technology with Oncomine comprehensive assays was used. Most frequent genetic alterations were mutations/deletions of TP53 (49.6%), CDKN2A (19.0%) and NOTCH1 (14.1%) as well as oncogenic activation of KRAS (23.4%), FGFR4 (14.9%) and PIK3CA (10.7%). KRAS activation was predominantly found in adenocarcinomas (p = 0.01), PIK3CA activation in squamous cell carcinomas (p = 0.03). Male sex, high ECOG score, unfavorable CUP, higher number of involved organs and RAS activation predicted decreased event-free and overall survival in multivariate analysis. Deletions of CDKN2A were prognostically adverse regarding overall survival. TP53 mutations did not significantly influence prognosis in the overall cohort, but worsened prognosis in otherwise favorable CUP subtypes. Although not standard in CUP, for 17/198 (8.6%) patients molecularly targeted treatment was recommended and 10 patients (5.1%) were treated accordingly. In conclusion, besides the identification of drug targets, panel sequencing in CUP is prognostically relevant, with RAS activation and CDKN2A deletion emerging as novel independent risk factors in a comprehensive assessment with clinicopathological data.

Luirink R, P. Geerke D, Op de Beeck K, Hermans C, Tiseo M, Van Schil P, Lardon F, Germonpré P, Rolfo C, Giovannetti E, J. Peters G, Pauwels P. The Role of c-Met as a Biomarker and Player in Innate and Acquired Resistance in Non-Small-Cell Lung Cancer: Two New Mutations Warrant Further Studies

The c-Met receptor is a therapeutically actionable target in non-small-cell lung cancer (NSCLC), with one approved drug and several agents in development. Most suitable biomarkers for patient selection include c-Met amplification and exon-14 skipping. Our retrospective study focused on the frequency of different c-Met aberrations (overexpression, amplification and mutations) in 153 primary, therapy-naïve resection samples and their paired metastases, from Biobank@UZA. Furthermore, we determined the correlation of c-Met expression with clinicopathological factors, Epidermal Growth Factor Receptor (EGFR)-status and TP53 mutations. Our results showed that c-Met expression levels in primary tumors were comparable to their respective metastases. Five different mutations were detected by deep sequencing: three (E168D, S203T, N375S) previously described and two never reported (I333T, G783E). I333T, a new mutation in the Sema(phorin) domain of c-Met, might influence the binding of antibodies targeting the HGF-binding domain, potentially causing innate resistance. E168D and S203T mutations showed a trend towards a correlation with high c-Met expression (p = 0.058). We found a significant correlation between c-MET expression, EGFR expression (p = 0.010) and EGFR mutations (p = 0.013), as well as a trend (p = 0.057) with regards to TP53 mutant activity. In conclusion this study demonstrated a strong correlation between EGFR mutations, TP53 and c-Met expression in therapy-naïve primary resection samples. Moreover, we found two new c-Met mutations that warrant further studies.

Exosomal miRNA: Small Molecules, Big Impact in Colorectal Cancer

Colorectal cancer (CRC) is one of the major causes of cancer-related deaths worldwide. Tumor microenvironment (TME) contains many cell types including stromal cells, immune cells, and endothelial cells. The TME modulation explains the heterogeneity of response to therapy observed in patients. In this context, exosomes are emerging as major contributors in cancer biology. Indeed, exosomes are implicated in tumor proliferation, angiogenesis, invasion, and premetastatic niche formation. They contain bioactive molecules such as proteins, lipids, and RNAs. More recently, many studies on exosomes have focused on miRNAs, small noncoding RNA molecules able to influence protein expression. In this review, we describe miRNAs transported by exosomes in the context of CRC and discuss their influence on TME and their potential as circulating biomarkers. This overview underlines emerging roles for exosomal miRNAs in cancer research for the near future.

Residual apoptotic activity of a tumorigenic p53 mutant improves cancer therapy responses

Engineered p53 mutant mice are valuable tools for delineating p53 functions in tumor suppression and cancer therapy. Here, we have introduced the R178E mutation into the Trp53 gene of mice to specifically ablate the cooperative nature of p53 DNA binding. Trp53^R178E mice show no detectable target gene regulation and, at first sight, are largely indistinguishable from Trp53^−/− mice. Surprisingly, stabilization of p53^R178E in Mdm2^−/− mice nevertheless triggers extensive apoptosis, indicative of residual wild‐type activities. Although this apoptotic activity suffices to trigger lethality of Trp53^R178E;Mdm2^−/− embryos, it proves insufficient for suppression of spontaneous and oncogene‐driven tumorigenesis. Trp53^R178E mice develop tumors indistinguishably from Trp53^−/− mice and tumors retain and even stabilize the p53^R178E protein, further attesting to the lack of significant tumor suppressor activity. However, Trp53^R178E tumors exhibit remarkably better chemotherapy responses than Trp53^−/− ones, resulting in enhanced eradication of p53‐mutated tumor cells. Together, this provides genetic proof‐of‐principle evidence that a p53 mutant can be highly tumorigenic and yet retain apoptotic activity which provides a survival benefit in the context of cancer therapy.

Mutational Patterns in Pancreatic Juice of Intraductal Papillary Mucinous Neoplasms and Concomitant Pancreatic Cancer

OBJECTIVES

The aims of this study were to identify genetic characteristics of intraductal papillary mucinous neoplasm (IPMN)-associated pancreatic ductal carcinoma (PDC) and to detect these markers using pancreatic juice.

METHODS

From 76 cases, 102 tissues were obtained: 29 cases were noninvasive IPMN, 18 were PDC derived from IPMN (D-PDC; noninvasive part, n = 16; invasive part, n = 18), and 29 were PDC concomitant with IPMN (C-PDC; IPMN part, n = 10; PDC part, n = 29). Moreover, pancreatic juice samples from 28 cases were obtained (noninvasive IPMN, n = 13; D-PDC, n = 7; C-PDC, n = 8). Fifty-one cancer-related genes were analyzed by next-generation sequencing.

RESULTS

TP53 mutation rates in D-PDC, C-PDC, and noninvasive IPMN were 67%, 66%, and 10%, respectively. Moreover, KRAS mutational patterns between 2 simultaneous tumors differed in 1 (6.3%) of the 16 D-PDC cases and in 8 (80%) of the 10 C-PDC cases (P = 0.0006). TP53 or multiple KRAS mutations were detected using pancreatic juice more frequently in C-PDC cases than in noninvasive IPMN cases (75% and 23%, respectively, P = 0.03).

CONCLUSIONS

Multiple KRAS mutations along with TP53 mutation are genetic markers for C-PDC, which could be detected using pancreatic juice preoperatively.

Flavopereirine Suppresses the Growth of Colorectal Cancer Cells through P53 Signaling Dependence

Colorectal cancer (CRC) is a significant cause of morbidity and mortality worldwide. The outcome of CRC patients remains poor. Thus, a new strategy for CRC treatment is urgently needed. Flavopereirine is a β-carboline alkaloid extracted from Geissospermum vellosii, which can reduce the viability of various cancer cells through an unknown mode of action. The aim of the present study was to investigate the functional mechanism and therapeutic potential of flavopereirine on CRC cells in vitro and in vivo. Our data showed that flavopereirine significantly lowered cellular viability, caused intrinsic and extrinsic apoptosis, and induced G2/M-phase cell cycle arrest in CRC cells. Flavopereirine downregulated Janus kinases-signal transducers and activators of transcription (JAKs-STATs) and cellular myelocytomatosis (c-Myc) signaling in CRC cells. In contrast, the enforced expressions of constitutive active STAT3 and c-Myc could not restore flavopereirine-induced viability reduction. Moreover, flavopereirine enhanced P53 expression and phosphorylation in CRC cells. CRC cells with P53 knockout or loss-of-function mutation significantly diminished flavopereirine-mediated viability reduction, indicating that P53 activity plays a major role in flavopereirine-mediated CRC cell growth suppression. Flavopereirine also significantly repressed CRC cell xenograft growth in vivo by upregulating P53 and P21 and inducing apoptosis. In conclusion, flavopereirine-mediated growth suppression in CRC cells depended on the P53-P21, but not the JAKs-STATs-c-Myc signaling pathway. The present study suggests that flavopereirine may be efficacious in the clinical treatment of CRC harboring functional P53 signaling.

Frequency of MAP2K1, TP53, and U2AF1 Mutations in BRAF-mutated Langerhans Cell Histiocytosis: Further Characterizing the Genomic Landscape of LCH

Langerhans cell histiocytosis is a proliferative disorder of neoplastic Langerhans cells with activating mutations in the Erk signaling pathway. TP53 and U2AF1 mutations have been implicated in other myelomonocytic malignancies and we hypothesized that mutations in these genes may cosegregate in LCH patients according to BRAF mutation status. Towards this end, we collected cases with a pathologic diagnosis of Langerhans cell histiocytosis from Stanford University Hospital. We analyzed the status of known pathogenic alleles in BRAF, ARAF, TP53, U2AF1, and MAP2K1 on formalin-fixed, paraffin-embedded tissue by direct sequencing. A total of 41 cases (71%) had a BRAFV600E allele detected by sequencing. MAP2K1 mutations were also detected in 5 cases: 3 of 17 (18%) cases with wild-type BRAF and 2 of 41 (5%) cases with BRAFV600E mutations (P=0.14). No cases contained the previously reported ARAF mutation, Q347_A348del. All 10 cases with TP53 mutations contained mutant BRAFV600E allele (P=0.021). Of the 11 cases with U2AF1 mutated, 9 of 41 cases co-occurred with BRAFV600E mutations (P=0.31) and 2 of 17 with wild-type BRAF. Interestingly, we do not find that somatic activating MAP2K1 mutations are mutually exclusive with BRAFV600E mutations as has been reported previously. Instead, our data suggests that MAP2K1 mutations may be present along with BRAF either at diagnosis or may be acquired during disease progression. Furthermore, we demonstrated that likely deleterious TP53 mutations correlate with BRAF mutational status and may play a role in the underlying pathogenesis.