Regulation of Tumor Suppressor Gene CDKN2A and Encoded p16-INK4a Protein by Covalent Modifications

Unravelling the molecular tapestry of pterygium: insights into genes for diagnostic and therapeutic innovations

Pterygium, an ocular surface disorder, manifests as a wing-shaped extension from the corneoscleral limbus onto the cornea, impacting vision and causing inflammation. With a global prevalence of 12%, varying by region, the condition is linked to UV exposure, age, gender, and socioeconomic factors. This review focuses on key genes associated with pterygium, shedding light on potential therapeutic targets. Matrix metalloproteinases (MMPs), especially MMP2 and MMP9, contribute to ECM remodelling and angiogenesis in pterygium. Vascular endothelial growth factor (VEGF) plays a crucial role in angiogenesis and is elevated in pterygium tissues. B-cell lymphoma-2, S100 proteins, DNA repair genes (hOGG1, XRCC1), CYP monooxygenases, p53, and p16 are implicated in pterygium development. A protein-protein interaction network analysis highlighted 28 edges between the aforementioned proteins, except for VEGF, indicating a high level of interaction. Gene ontology, microRNA and pathway analyses revealed the involvement of processes such as base excision repair, IL-17 and p53 signalling, ECM disassembly, oxidative stress, hypoxia, metallopeptidase activity and others that are essential for pterygium development. In addition, miR-29, miR-125, miR-126, miR-143, miR-200, miR-429, and miR-451a microRNAs were predicted, which were shown to have a role in pterygium development and disease severity. Identification of these molecular mechanisms provides insights for potential diagnostic and therapeutic strategies for pterygium.

Methylation signatures as biomarkers for non-invasive early detection of breast cancer: A systematic review of the literature

BACKGROUND

Early detection of breast cancer would help alleviate the burden of treatment for early-stage breast cancer and help patient prognosis. There is currently no established gene panel that utilizes the potential of DNA methylation as a molecular signature for the early detection of breast cancer. This systematic review aims to identify the optimal methylation biomarkers for a non-invasive liquid biopsy assay and the gaps in knowledge regarding biomarkers for early detection of breast cancer.

METHODS

Following the PRISMA-ScR method, Pubmed and Google Scholar was searched for publications related to methylation biomarkers in breast cancer over a five-year period. Eligible publications were mined for key data fields such as study aims, cohort demographics, types of breast cancer studied, technologies used, and outcomes. Data was analyzed to address the objectives of the review.

RESULTS

Literature search identified 112 studies of which based on eligibility criteria, 13 studies were included. 28 potential methylation gene targets were identified, of which 23 were methylated at the promoter region, 1 was methylated in the body of the gene and 4 were methylated at yet to be identified locations.

CONCLUSIONS

Our evaluation shows that at minimum APC, RASSFI, and FOXA1 genes would be a promising set of genes to start with for the early detection of breast cancer, based on the sensitivity and specificity outlined in the studies. Prospective studies are needed to optimize biomarkers for broader impact in early detection of breast cancer.

Validity of Xiphophorus fish as models for human disease

Platyfish and swordtails of the genus Xiphophorus provide a well-established model for melanoma research and have become well known for this feature. Recently, modelling approaches for other human diseases in Xiphophorus have been developed or are emerging. This Review provides a comprehensive summary of these models and discusses how findings from basic biological and molecular studies and their translation to medical research demonstrate that Xiphophorus models have face, construct and predictive validity for studying a broad array of human diseases. These models can thus improve our understanding of disease mechanisms to benefit patients.

Prevalence of P16 Immunohistochemistry Positive Staining and Its Correlation to Clinical and Radiological Staging of Squamous Cell Carcinoma of the Cervix

Background

Cervical cancer is the fourth most common genital tract cancer and fourth common cause of death among the causes of neoplasm-related mortality in women worldwide. Squamous cell carcinoma is the most common type and constitutes about 90% of all pathological types of cervical cancer. Cyclin-dependent kinase inhibitor 2A (CDKN2A; p16) is a gene that is located on chromosome 9 that encodes a protein (P16) that inhibits cyclin-dependent kinases 4 and 6 which are inhibitors of retinoblastoma protein; the net result is reactivation of retinoblastoma protein and arrest of cell cycle in G1 phase. So, expression of p16 protein within cancer cell may denote good prognosis. The presence of a soft marker that can detect hidden advanced stages in apparently clinically and radiologically early resectable stages of cervical cancer and can replace life-threatening preoperative lymphadenectomy is of great importance. Is P16 protein which when expressed is associated with good prognosis in other cancer can be this soft marker?

Aim of the study

The aim of this study is to estimate the prevalence of cyclin-dependent kinase inhibitor 2A (CDKN2A; p16) immunohistochemistry positive staining in squamous cell carcinoma of the cervix and to correlate its positivity  to clinical and radiological disease stage.

Patients and Methods

An analytical cross-sectional observational prospective and retrospective study was conducted on 60 invasive squamous cell cervical cancer patients from gyne-oncology unit at Al Shatby university hospital after taking a written consent and following approval by Alexandria medical school institutional ethics committee. Inclusion criteria included all patients with invasive squamous cell carcinoma of the cervix prospective and retrospective from January 2019 till June 2022 diagnosed by taking wedge, punch and cone biopsy followed by histopathological examination that confirmed the diagnosis and showed grading and types of squamous cell carcinoma. Clinical examination, vaginal ultrasonographic scanning, computerized axial tomography and magnetic resonance imaging were carried out to all cases, and data were recorded for clinical and radiological staging purposes. All data were collected, coded, tabulated and statistically analyzed to estimate the prevalence of p16 positivity in the study cases and to correlate its positivity with clinical and radiological disease stage.

Result

In relation to prevalence of p16 immunostaining, 34 cases (56.7%) were positive in comparison with 26 cases (43.3%) being negative. Considering correlation between early resectable stage and late nonresectable stage with P16 positive and negative staining, the result showed the following: 32 cases (53.3%) were resectable, 30 cases (88.2%) of them were P16 positive immunostaining compared to 2 cases (7.7%) being P16 negative immunostaining while nonresectable cases were 28 cases (46.7%), 4 cases (11.8%) only were P16 positive compared to 24 cases (92.3%) being P16 immunostaining negative, so most of early resectable stage cases were P16 positive immunostaining and most of late nonresectable stage cases were P16 negative immunostaining. There is a positive significant correlation between early resectable stage in relation to positive P16 immunostaining, and the same was present between late nonresectable stage and negative P16 immunostaining (p = 0.000).

Conclusion

The present study concluded that P16 positive immunostaining prevalence in cervical squamous cell carcinoma was 56.7% and its positive staining is highly correlated with early resectable clinically and radiologically disease stage.

The role of BMI1 in endometrial cancer and other cancers

Endometrial cancer (EC) is the third leading gynecological malignancy, and its treatment remains challenging. B cell-specific Moloney murine leukemia virus integration site-1 (BMI1) is one of the core members of the polycomb group (PcG) family, which plays a promoting role in the occurrence and development of various tumors. Notably, BMI1 has been found to be frequently upregulated in endometrial cancer (EC) and promote the occurrence of EC through promoting epithelial-mesenchymal transition (EMT) and AKT/PI3K pathways. This review summarizes the structure and upstream regulatory mechanisms of BMI1 and its role in EC. In addition, we focused on the role of BMI1 in chemoradiotherapy resistance and summarized the current drugs that target BMI1.

Radiological Differentiation Between Intracranial Meningioma and Solitary Fibrous Tumor/Hemangiopericytoma: A Systematic Literature Review

BACKGROUND

Intracranial solitary fibrous tumor (SFT) is characterized by aggressive local behavior and high post-resection recurrence rates. It is difficult to distinguish between SFT and meningiomas, which are typically benign. The goal of this study was to systematically review radiological features that differentiate meningioma and SFT.

METHODS

We performed a systematic review in accordance with PRISMA guidelines to identify studies that used imaging techniques to identify radiological differentiators of SFT and meningioma.

RESULTS

Eighteen studies with 1565 patients (SFT: 662; meningiomas: 903) were included. The most commonly used imaging modality was diffusion weighted imaging, which was reported in 11 studies. Eight studies used a combination of diffusion weighted imaging and T1- and T2-weighted sequences to distinguish between SFT and meningioma. Compared to all grades/subtypes of meningioma, SFT is associated with higher apparent diffusion coefficient, presence of narrow-based dural attachments, lack of dural tail, less peritumoral brain edema, extensive serpentine flow voids, and younger age at initial diagnosis. Tumor volume was a poor differentiator of SFT and meningioma, and overall, there were less consensus findings in studies exclusively comparing angiomatous meningiomas and SFT.

CONCLUSIONS

Clinicians can differentiate SFT from meningiomas on preoperative imaging by looking for higher apparent diffusion coefficient, lack of dural tail/narrow-based dural attachment, less peritumoral brain edema, and vascular flow voids on neuroimaging, in addition to younger age at diagnosis. Distinguishing between angiomatous meningioma and SFT is much more challenging, as both are highly vascular pathologies. Tumor volume has limited utility in differentiating between SFT and various grades/subtypes of meningioma.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosome Repairs Endometrial Epithelial Cells Injury Induced by Hypoxia via Regulating miR-663a/CDKN2A Axis

Aim

Thin endometrium remains a severe clinical challenge with no effective therapy to date. We aimed at exploring the role and molecular mechanism of human umbilical cord mesenchymal stem cell- (hucMSC-) derived exosomes (hucMSC-Ex) in repairing hypoxic injury of endometrial epithelial cells (EECs).

Methods

Exosomes were harvested from the conditioned medium of hucMSC and characterized using western blot, transmission electron microscopy (TEM), flow cytometry, and nanoparticle tracking analysis (NTA). EECs were subjected to hypoxic conditions before cocultured with hucMSC-Ex. Cell viability, apoptosis, and migration were determined with CCK-8, flow cytometry, and wound healing assay, respectively. Apoptosis/EMT-related proteins were detected by western blot. The miRNA profiling was determined by RNA sequencing. The expression of miR-663a and CDKN2A was measured by qRT-PCR. MiR-663a in EECs was overexpressed by transfecting with miR-663a mimics.

Results

Mesenchymal stem cells (MSCs) markers CD73, CD90, and CD106 were positively expressed in hucMSCs. Exosome isolated from hucMSC expressed CD63 and TSG101, and were 100-150 nm in diameter. HucMSC-Ex promoted cell proliferation inhibited by hypoxia. And hucMSC-Ex also inhibited hypoxia-induced apoptosis, migration, and EMT of EECs by upregulating the expression of Bcl-2 and E-cadherin and downregulating Bax and N-cadherin levels. Further, bioinformatics research found that hucMSC-Ex coculture can significantly upregulate the expression of miR-663a and decrease the expression of CDKN2A in hypoxia-induced EECs. Furthermore, miR-663a overexpression inhibited CDKN2A expression and increased the expression of Bcl-2 and E-cadherin in hypoxia-induced EECs.

Conclusions

HucMSC-Ex promoted cell proliferation, inhibited cell apoptosis, migration, and EMT in hypoxia-induced EECs, thereby alleviating hypoxia-induced EECs injury, which may be related to its regulation of miR-663a/CDKN2A expression. Our study indicated that hucMSC-Ex might benefit for repairing thin endometrium.

A Novel Cuproptosis-Related Signature Identified DLAT as a Prognostic Biomarker for Hepatocellular Carcinoma Patients

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of liver cancers, with more than a million cases per year by 2025. Cuproptosis is a novel form of programmed cell death, and is caused by mitochondrial lipoylation and destabilization of iron-sulfur proteins triggered by copper, which was considered as a key player in various biological processes. However, the roles of cuproptosis-related genes (CRGs) in HCC remain largely unknown.

METHODS

In the present study, we constructed and validated a four CRGs signature for predicting the overall survival (OS) of HCC patients in both The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases.

RESULTS

Patients with high CRGs risk score showed shorter OS than those with low CRGs risk score. Functional analysis suggested that the CRGs-based prognostic signature was associated with metabolism remodeling which facilitated liver cancer progression. In addition, reduced infiltration of CD8⁺ T cells and increased macrophages were found in HCCs from patients with high CRGs risk score. As one of the four CRGs, higher expression of dihydrolipoamide S-acetyltransferase (DLAT) was accompanied by higher expression of program death ligand 1 (PD-L1) in HCC. Further, we confirmed that DLAT was up-regulated and correlated with poor prognosis in a clinical HCC cohort.

CONCLUSION

In conclusion, our study constructed a four CRGs signature prognostic model and identified DLAT as an independent prognostic factor for HCC, thus providing new clues for understanding the association between cuproptosis and HCC.

Association of IKZF1 and CDKN2A gene polymorphisms with childhood acute lymphoblastic leukemia: a high-resolution melting analysis

Background

Acute lymphoblastic leukemia is the most prevailing pediatric hematologic malignancy, and various factors such as environmental exposures and genetic variation affect ALL susceptibility and patients outcome. According to genome-wide association studies, several single nucleotide polymorphisms (SNPs) in IKZF1 (rs4132601) and CDKN2A (rs3731249 and rs3731217) genes are associated with ALL susceptibility. Hereupon, this study aimed to discover the association between these SNPs and the risk of childhood ALL among a sample of the Iranian population.

Methods

A total of fifty children with ALL were included in this case–control study, along with an additional fifty healthy children, matched for age and gender. High-resolution melting (HRM) analysis was employed to genotyping rs4132601, rs3731249, and rs3731217.

Results

In the patient group, the CT genotype and T allele frequency of rs3731249 were significantly greater than controls (p = 0.01 and p = 0.005, respectively). Moreover, the positive association of CT and dominant model (CT + TT) genotypes and T allele at rs3731249 with the risk of ALL was confirmed (OR = 9.56, OR = 10.76 and OR = 11.00, respectively). There was no significant relation between rs4132601 (IKZF1), rs3731217 (CDKN2A), and childhood ALL.

Conclusion

The present study indicates that CT genotype and T allele at rs3731249 (CDKN2A) can significantly increase the risk of ALL among children.

Protein post-translational modifications in the regulation of cancer hallmarks

Posttranslational modifications (PTMs) of proteins, the major mechanism of protein function regulation, play important roles in regulating a variety of cellular physiological and pathological processes. Although the classical PTMs, such as phosphorylation, acetylation, ubiquitination and methylation, have been well studied, the emergence of many new modifications, such as succinylation, hydroxybutyrylation, and lactylation, introduces a new layer to protein regulation, leaving much more to be explored and wide application prospects. In this review, we will provide a broad overview of the significant roles of PTMs in regulating human cancer hallmarks through selecting a diverse set of examples, and update the current advances in the therapeutic implications of these PTMs in human cancer.

Differential p16 expression levels in the liver, hepatocytes and hepatocellular cell lines

Background

One of the most frequently deleted genes in cancer is CDKN2A encoding p16. This protein is often overexpressed in senescent cells, while its suppression can bypass the oncogene-induced senescence to enable transformation and tumorigenesis. The roles of the protein p16 are recently being expanded from the cell cycle progression regulator to the cellular regulator interacting in several different pathways. Yet data on its liver and liver cells' expression are inconclusive.

Methods

The expression of the p16 gene in liver and liver cells was determined by RT-qPCR and compared to its protein amounts by western blotting.

Results

p16 is expressed at low levels in the liver and rat hepatocytes. Its expression varies from none to the considerable levels in the examined hepatocellular carcinoma cell lines (FaO and HepG2) and in immortalized mouse hepatocytes. Such significant expression differences of an important cellular regulator warrant the need to closely examine the differences in biochemical pathways correlated with the p16 expression when using hepatocytes and hepatoma liver models.

Integration of Epigenetic Mechanisms into Non-Genotoxic Carcinogenicity Hazard Assessment: Focus on DNA Methylation and Histone Modifications

Epigenetics involves a series of mechanisms that entail histone and DNA covalent modifications and non-coding RNAs, and that collectively contribute to programing cell functions and differentiation. Epigenetic anomalies and DNA mutations are co-drivers of cellular dysfunctions, including carcinogenesis. Alterations of the epigenetic system occur in cancers whether the initial carcinogenic events are from genotoxic (GTxC) or non-genotoxic (NGTxC) carcinogens. NGTxC are not inherently DNA reactive, they do not have a unifying mode of action and as yet there are no regulatory test guidelines addressing mechanisms of NGTxC. To fil this gap, the Test Guideline Programme of the Organisation for Economic Cooperation and Development is developing a framework for an integrated approach for the testing and assessment (IATA) of NGTxC and is considering assays that address key events of cancer hallmarks. Here, with the intent of better understanding the applicability of epigenetic assays in chemical carcinogenicity assessment, we focus on DNA methylation and histone modifications and review: (1) epigenetic mechanisms contributing to carcinogenesis, (2) epigenetic mechanisms altered following exposure to arsenic, nickel, or phenobarbital in order to identify common carcinogen-specific mechanisms, (3) characteristics of a series of epigenetic assay types, and (4) epigenetic assay validation needs in the context of chemical hazard assessment. As a key component of numerous NGTxC mechanisms of action, epigenetic assays included in IATA assay combinations can contribute to improved chemical carcinogen identification for the better protection of public health.

Huaier Inhibits Proliferation, Migration, and Invasion of Cutaneous Squamous Cell Carcinoma Cells by Inhibiting the Methylation Levels of CDKN2A and TP53

Cutaneous squamous cell carcinoma (CSCC) is a malignant tumor that originates from keratinocytes in the epidermis or appendage. Traditional Chinese medicine Huaier has anti-tumor activity in various malignancies. Little is known about the role of Huaier in CSCC. Here, we investigated the function of Huaier in CSCC. We treated CSCC cell line (SCL-1 and A431) with a series of concentration gradients of Huaier to examine the half maximal inhibitory concentration (IC50) of Huaier on SCL-1 and A431 cells. The IC50 of Huaier on growth of SCL-1 and A431 cells were 6.96 and 7.57 mg/mL, respectively. Moreover, Huaier reduced the methylation levels of CDKN2A and TP53, and enhanced the expression of CDKN2A and TP53 in SCL-1 and A431 cells in a dosage-dependent manner. The expression of DNA methyltransferase DNMT1 was severely repressed by Huaier treatment in SCL-1 and A431 cells. DNMT1 overexpression enhanced the methylation levels of CDKN2A and TP53, and suppressed the expression of CDKN2A and TP53 in Huaier-treated SCL-1 and A431 cells. Huaier treatment inhibited proliferation, migration, and invasion of SCL-1 and A431 cells. However, inhibition of CDKN2A or TP53 reversed the influence of Huaier treatment on proliferation, migration, and invasion of CSCC cells. In conclusion, our data demonstrate that Huaier inhibits proliferation, migration, and invasion of CSCC cells by regulating DNA methylation of CDKN2A and TP53, thereby attenuating the progression of CSCC. Thus, Huaier extract may act as a drug for treating CSCC.

The pan-cancer landscape of crosstalk between epithelial-mesenchymal transition and immune evasion relevant to prognosis and immunotherapy response

An emerging body of evidence has recently recognized the coexistence of epithelial-mesenchymal transition (EMT) and immune response. However, a systems-level view and survey of the interplay between EMT and immune escape program, and their impact on tumor behavior and clinical outcome across various types of cancer is lacking. Here, we performed comprehensive multi-omics analyses to characterize the landscape of crosstalk between EMT and immune evasion and their clinical relevance across 17 types of solid cancer. Our study showed the presence of complex and dynamic immunomodulatory crosstalk between EMT and immune evasion shared by pan-cancer, and the crosstalk was significantly associated with cancer prognosis and immunotherapy response. Integrative quantitative analyses of genomics and immunogenomics revealed that cellular composition of immune infiltrates, non-synonymous mutation burden, chromosomal instability and oncogenic gene alterations are associated with the balance between EMT and immune evasion. Finally, we proposed a scoring model termed EMT-CYT Index (ECI) to quantify the EMT-immunity axis, which was a superior predictor of prognosis and immunotherapy response across different malignancies. By providing a systematic overview of crosstalk between EMT and immune evasion, our study highlights the potential of pan-cancer EMT-immunity crosstalk as a paradigm for dissecting molecular mechanisms underlying cancer progression and guiding more effective and generalized immunotherapy strategies.

Pentraxin 3 is a diagnostic and prognostic marker for ovarian epithelial cancer patients based on comprehensive bioinformatics and experiments

BACKGROUND

Ovarian epithelial cancer is one of the leading malignant tumors in gynecology and lacks effective diagnostic and prognostic markers. Our study aims to screen and verify ovarian epithelial cancer biomarkers.

METHODS

GSE18520 and GSE26712 were downloaded from the GEO database. The "limma" and "WGCNA" packages were used to explore hub genes. The Kaplan-Meier Plotter database was used for survival analysis of the hub genes. Immunohistochemical analysis was used to identify the expression level of Pentraxin 3 in ovarian epithelial cancer samples.

RESULTS

In this study, we integrated and analyzed two datasets, GSE18520 and GSE26712, and a total of 238 differentially expressed genes (DEGs) were screened out. Enrichment analysis showed that these DEGs were related to collagen-containing extracellular matrix and other pathways. Further application of WGCNA (weighted gene coexpression network analysis) identified 15 gene modules, with the purple module showing the highest correlation with ovarian epithelial cancer. Twenty-five genes were shared between the purple module and DEGs, 13 genes were related to the prognosis of ovarian epithelial cancer patients, and the PTX3 gene had the highest hazardous risk (HR) value. We performed immunohistochemical analyses on the 255 Pentraxin-3 (PTX3)-based clinical samples. PTX3 was found to be overexpressed in ovarian epithelial cancer and related to the degree of differentiation. The Cox proportional hazard model indicates that high PTX3 expression is an independent risk factor for the prognosis of ovarian epithelial cancer patients.

CONCLUSIONS

In conclusion, through WGCNA and a series of comprehensive bioinformatics analyses, PTX3 was first identified as a novel diagnostic and prognostic biomarker for ovarian epithelial cancer.

MicroRNA-29a inhibits cell proliferation and arrests cell cycle by modulating p16 methylation in cervical cancer

Cervical cancer is the second most common gynecological malignancy. Accumulating evidence has suggested that microRNAs (miRNAs) are involved in the occurrence and development of cervical cancer. The present study aimed to investigate the function and underlying molecular mechanism of microRNA (miRNA/miR)-29a in cervical cancer. Reverse transcription-quantitative PCR and methylation-specific PCR were used to examine the expression of miR-29a and methylated status of p16 promoter, respectively. Cell Counting Kit-8 analysis and flow cytometry were performed to evaluate cell viability and cycle, respectively. Dual-luciferase reporter assay was performed to verify the interaction between miR-29a and its targets. Western blot analysis was performed to detect the protein levels of DNA methyltransferases (DNMT)3A and DNMT3B. The results demonstrated that miR-29a expression was downregulated in cervical cancer tissues and cells, and negatively correlated with p16 promoter hypermethylation. Furthermore, cell experiments confirmed that miR-29a suppressed cell proliferation and induced cell cycle arrest in HeLa and C-33A cells. Mechanically, miR-29a restored normal methylation pattern of the p16 gene by sponging DNMT3A and DNMT3B. Taken together, the results of the present study demonstrated the epigenetic regulation of tumor suppressor p16 by miR-29a as a unique mechanism, thus providing a rationale for the development of miRNA-based strategies in the treatment of cervical cancer.

Genetic Alterations in the INK4a/ARF Locus: Effects on Melanoma Development and Progression

Genetic alterations in the INK4a/ARF (or CDKN2A) locus have been reported in many cancer types, including melanoma; head and neck squamous cell carcinomas; lung, breast, and pancreatic cancers. In melanoma, loss of function CDKN2A alterations have been identified in approximately 50% of primary melanomas, in over 75% of metastatic melanomas, and in the germline of 40% of families with a predisposition to cutaneous melanoma. The CDKN2A locus encodes two critical tumor suppressor proteins, the cyclin-dependent kinase inhibitor p16^INK4a and the p53 regulator p14^ARF. The majority of CDKN2A alterations in melanoma selectively target p16^INK4a or affect the coding sequence of both p16^INK4a and p14^ARF. There is also a subset of less common somatic and germline INK4a/ARF alterations that affect p14^ARF, while not altering the syntenic p16^INK4a coding regions. In this review, we describe the frequency and types of somatic alterations affecting the CDKN2A locus in melanoma and germline CDKN2A alterations in familial melanoma, and their functional consequences in melanoma development. We discuss the clinical implications of CDKN2A inactivating alterations and their influence on treatment response and resistance.

Analysis of CDKN2A gene alterations in recurrent and non-recurrent meningioma

PURPOSE

Assessment of the risk of recurrence is essential to determine the therapeutic strategy of meningioma treatment. Many relapsing or aggressive meningiomas show elevated mitotic and/or Ki67 indices, reflecting cell cycle deregulation. As CDKN2A is a key tumor suppressor gene involved in cell cycle control, we investigated whether CDKN2A alterations may be involved in tumor recurrence.

METHODS

We carried out a comparative analysis of 17 recurrent and 13 non-recurrent meningiomas. CDKN2A single nucleotide variations (SNVs), deletions, methylation status of the promotor, and p16 expression were investigated. Results were correlated with the recurrent or non-recurrent status and clinicopathological data.

RESULTS

We identified a CDKN2A SNV (NM_000077, exon2, c.G442A, p.Ala148Thr) in five meningiomas that was significantly associated with recurrence (p = 0.03). This mutation, confirmed by Sanger sequencing and referenced in the COSMIC database in various cancers, has not been reported in meningioma. The presence of one of the three following CDKN2A alterations-p.(Ala148Thr) mutation, whole homozygous or heterozygous gene loss, or promotor methylation > 8%-was observed in 13 of the 17 relapsing meningiomas and was strongly associated with recurrence (p < 0.0001) and a Ki67 labeling index > 7% (p = 0.004).

CONCLUSION

We report an undescribed p.(Ala148Thr) CDKN2A mutation in meningioma that was only present in relapsing tumors. In our series, CDKN2A gene alterations were only found in recurrent meningiomas. However, our results need to be evaluated on a larger series to ensure that these CDKN2A alterations can be used as biomarkers of recurrence in meningioma.

Conjunctival Melanoma: Genetic and Epigenetic Insights of a Distinct Type of Melanoma

Conjunctival melanoma (CjM) is a rare, primary cancer of the ocular region. Genetic and epigenetic characteristics of conjunctival melanoma have not been completely elucidated yet. Conjunctival melanoma presents similarities with cutaneous melanoma, with substantial differences in the biological behavior. We reviewed the genetic and epigenetic insights of CjM involved in invasion and metastatic spread. CjM is commonly characterized by mutations of v-raf murine sarcoma viral oncogene homolog B1 (BRAF), neurofibromin 1 (NF1) and telomerase reverse transcriptase (TERT), high expression of mammalian target of rapamycin (mTOR) and heat shock protein 90 (HSP90), frequent phosphatase and tensin homolog (PTEN) loss and upregulation of specific miRNAs. These features should identify CjM as a distinct subset of melanoma with its own profile, which is more similar to cutaneous melanoma than mucosal melanoma and remarkably different from uveal melanoma.

Prenatal and ancestral exposure to di(2-ethylhexyl) phthalate alters gene expression and DNA methylation in mouse ovaries

Di(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer and known endocrine disrupting chemical, which causes transgenerational reproductive toxicity in female rodents. However, the mechanisms of action underlying the transgenerational toxicity of DEHP are not understood. Therefore, this study determined the effects of prenatal and ancestral DEHP exposure on various ovarian pathways in the F1, F2, and F3 generations of mice. Pregnant CD-1 dams were orally exposed to corn oil (vehicle control) or DEHP (20 μg/kg/day-750 mg/kg/day) from gestation day 10.5 until birth. At postnatal day 21 for all generations, ovaries were removed for gene expression analysis of various ovarian pathways and for 5-methyl cytosine (5-mC) quantification. In the F1 generation, prenatal DEHP exposure disrupted the expression of cell cycle regulators, the expression of peroxisome-proliferator activating receptors, and the percentage of 5-mC compared to control. In the F2 generation, exposure to DEHP decreased the expression of steroidogenic enzymes, apoptosis factors, and ten-eleven translocation compared to controls. It also dysregulated the expression of phosphoinositide 3-kinase (PI3K) factors. In the F3 generation, ancestral DEHP exposure decreased the expression of steroidogenic enzymes, PI3K factors, cell cycle regulators, apoptosis factors, Esr2, DNA methylation mediators, and the percentage of 5-mC compared to controls. Overall, the data show that prenatal and ancestral DEHP exposure greatly suppress gene expression of pathways required for folliculogenesis and steroidogenesis in the ovary in a transgenerational manner and that gene expression may be influenced by DNA methylation. These results provide insight into some of the mechanisms of DEHP-mediated toxicity in the ovary across generations.