TP53 Mutations in Endometrial Cancers

In Vivo Intra-Uterine Delivery of TAT-Fused Cre Recombinase and CRISPR/Cas9 Editing System in Mice Unveil Histopathology of Pten/p53-Deficient Endometrial Cancers

Phosphatase and TENsin homolog (Pten) and p53 are two of the most frequently mutated tumor suppressor genes in endometrial cancer. However, the functional consequences and histopathological manifestation of concomitant p53 and Pten loss of function alterations in the development of endometrial cancer is still controversial. Here, it is demonstrated that simultaneous Pten and p53 deletion is sufficient to cause epithelial to mesenchymal transition phenotype in endometrial organoids. By a novel intravaginal delivery method using HIV1 trans-activator of transcription cell penetrating peptide fused with a Cre recombinase protein (TAT-Cre), local ablation of both p53 and Pten is achieved specifically in the uterus. These mice developed high-grade endometrial carcinomas and a high percentage of uterine carcinosarcomas resembling those found in humans. To further demonstrate that carcinosarcomas arise from epithelium, double Pten/p53 deficient epithelial cells are mixed with wild type stromal and myometrial cells and subcutaneously transplanted to Scid mice. All xenotransplants resulted in the development of uterine carcinosarcomas displaying high nuclear pleomorphism and metastatic potential. Accordingly, in vivo CRISPR/Cas9 disruption of Pten and p53 also triggered the development of metastatic carcinosarcomas. The results unfadingly demonstrate that simultaneous deletion of p53 and Pten in endometrial epithelial cells is enough to trigger epithelial to mesenchymal transition that is consistently translated to the formation of uterine carcinosarcomas in vivo.

Feasibility and clinical applicability of genomic profiling based on cervical smear samples in patients with endometrial cancer

Purpose

Cervical smear samples are easily obtainable and may effectively reflect the tumor microenvironment in gynecological cancers. Therefore, we investigated the feasibility of genomic profiling based on tumor DNA analysis from cervical smear samples from endometrial cancer patients.

Materials and methods

Preoperative cervical smear samples were obtained via vaginal sampling in 50 patients, including 39 with endometrial cancer and 11 with benign uterine disease. Matched blood samples were obtained simultaneously. Genomic DNA (gDNA) from cervical smear and/or cell-free DNA from whole blood were extracted and sequenced using the Pan100 panel covering 100 endometrial cancer-related genes.

Results

Cervical swab-based gDNA analysis detected cancer with 67% sensitivity and 100% specificity, showing a superior performance compared to that of the matched blood or Pap smear tests. Cervical swab-based gDNA effectively identified patients with loss of MSH2 or MSH6 and aberrant p53 expression based on immunohistochemistry. Genomic landscape analysis of cervical swab-based gDNA identified PTEN, PIK3CA, TP53, and ARID1A as the most frequently altered genes. Furthermore, 26 endometrial cancer patients could be classified according to the Proactive Molecular Risk Classifier for Endometrial Cancer.

Conclusion

Cervical swab-based gDNA test showed an improved detection potential and allowed the classification of patients, which has both predictive and prognostic implications.

Does obesity modify the expression of cyclin D1 and pten in endometrial polyps in postmenopausal women?

To assess cyclin D1 and PTEN immunoexpression in benign endometrial polyps (EPs) in asymptomatic postmenopausal women and its correlation with obesity. Methods: This was a cross-sectional study based on data from a sample of 52 patients diagnosed with EP between February 2018 and January 2019. The women included in this study were amenorrheal for at least 1 year and were asymptomatic (no postmenopausal bleeding). Obesity defined by body mass index (BMI) was investigated for correlation with Cyclin-D1 and PTEN gene expression (immunohistochemistry) in glandular and stromal compartments of polyps. Results: No significant differences among groups were identified in any clinical and epidemiological parameter (age, age of menopause, time since menopause, number of gestations, polyp size, leucocyte count, fasting blood glucose and basic pathologies), except for BMI. Body mass index did not alter PTEN or Cyclin D1 immunoexpression. Conclusion: Our study shows that obesity does not appear to be a relevant factor in the immunoexpression of PTEN and Cyclin D1 in benign EP, in either the stromal or glandular compartments.

Endometrial cancer: a genetic point of view

BACKGROUND

Endometrial cancer is the fourth most frequent gynecological cancer and the most frequent type of uterine cancer. There is an increase in the incidence and mortality of uterine cancers in the past few decades, and there are no well-established screening programs for endometrial cancer currently. Most endometrial cancers arise through the interplay of familial, genetic, and lifestyle factors. Although a number of genetic factors modify endometrial cancer susceptibility, they are not of standard use in the clinical assessment of prognosis. We conducted a comprehensive systematic literature review to provide an overview of the relationship between genetic factors and risk for endometrial cancer.

METHODS

MEDLINE and EMBASE databases were searched for studies between January 2010 to March 2020 reporting the genes associated with endometrial cancer.

RESULTS

Through the selection process, we retrieved 186 studies comprising 329 genes identified using several molecular methodologies in all human chromosomes and in mitochondrial DNA. Endometrial cancer exhibits a molecular complexity and heterogeneity coherent with its clinical and histologic variability. Improved characterization of molecular alterations of each histological type provides relevant information about the prognosis and potential response to new therapies.

CONCLUSIONS

The current challenge is the integration of clinicopathologic and molecular factors to improve the diagnosis, prognosis, and treatment of endometrial cancer.

Concomitant p53 and PTEN immunoexpression to predict the risk of malignancy in endometrial polyps

The aim of this retrospective cross-sectional study was to assess the usefulness of phosphase and tensin homolog deleted on chromosome 10 (PTEN) and p53 protein immunoexpression in predicting the risk of malignancy in endometrial polyps. The study was conducted at tertiary public hospital, university teaching center, and private practice clinic.A total of 159 patients with endometrial polyps who underwent hysteroscopic polypectomy between January 2010 to December 2014 were included. p53 and PTEN immunoexpression were assessed in histologic endometrial polyp samples. Patients were allocated into 2 groups: group A, endometrial polyps without atypia (120), and group B, endometrial polyps with atypia (39), which were subdivided into A1 (80) and B1 (21) = p53-/PTEN+ immunostaining; A2 (20) and B2 (11) = p53+/PTEN+; A3 (14) and B3 (4) = p53+/PTEN-; A4 (6) and B4 (3) = p53-/PTEN-.There was no significant difference between groups regarding clinical and epidemiologic parameters, except for age. Neoplasia incidence within groups was higher when at least 1 marker was abnormally stained (in group A, P = .0089, odds ratio [OR] = 13.94 [1.62; 120.27]; in group B, P = .0255, OR 12.73 [1.38; 117.27]). Overall neoplasia incidence was higher in group B than in group A (20.5% vs 5.8%; P = .0113). Malignant neoplasia was found more frequently in patients with p53+ (P = .0006, OR = 7.67 [2.30; 25.54]) and PTEN- (P = .0043; OR = 5.43 [1.77; 16.61]).Immunohistochemical analysis using p53 and PTEN as markers, either alone or concomitantly, can be useful to predict malignant transformation in cases of endometrial polyps.

Tracing the path of cancer initiation: the AA protein-based model for cancer genesis

Background

Cancer is a defiant disease which cure is still far from being attained besides the colossal efforts and financial means deployed towards that end. The continuing setbacks encountered with today’s arsenal of anti-cancer drugs and cancer therapy modalities; show the need for a radical approach in order to get to the root of the problem. And getting to the root of cancer initiation and development leads us to challenge the present dogmas surrounding the pathogenesis of this disease.

Results

This comprehensive analysis brings to light the following points: (i) Cancer with its plethora of genetic and cellular symptoms could originate from one major event switching a cell from normalcy-to-malignancy; (ii) The switching event is postulated to involve a pathological breakup of a non-mutated protein, called here AA protein, resulting in the acquisition of new cellular functions present only in cancer cells; (iii) Following this event, DNA mutations begin to accumulate as secondary events to ensure perpetuity of cancer. Supporting arguments for this protein-based model come mainly from these observations: (i) The AA protein-based model reconciles together the clonal-and-stem cell theories into one inclusive model; (ii) The breakup of a normal protein could be behind the cancer-linked inflammation symptom; (iii) Cancer hallmarks are but adaptive traits, earned as a result of the switch from normalcy-to-malignancy.

Conclusions

Adaptation of cancer cells to their microenvironment and to different anti-cancer drugs is deemed here as the ultimate cancer hallmark, that needs to be understood and controlled. This adaptive power of cancer cells parallels that of bacteria also known with their resistance to a large range of substances in nature and in the laboratory. Consequently, cancer development could be viewed as a backward walk on the line of Evolution. Finally this unprecedented analysis demystifies cancer and puts the finger on the core problem of malignancy while offering ideas for its control with the ultimate goal of leading to its cure.

Preventive Efficacy of Vanillic Acid on Regulation of Redox Homeostasis, Matrix Metalloproteinases and Cyclin D1 in Rats Bearing Endometrial Carcinoma

Endometrial carcinoma is a malignant tumor of the female genital tract. This study has been performed to evaluate the chemopreventive efficacy of vanillic acid (a bio flavonoid) on endometrial carcinoma (EC) by assessing the levels of thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH), cytochrome P450, antioxidants-superoxide dismutase (SOD), catalase (CAT), glutathione peroxides (GPx), reduced glutathione (GSH), vitamins C and E, matrix metalloproteinases (MMP-2 and 9) and cell cycle check point protein (cyclin D1) in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induced carcinogenic rats. EC provoked by intravaginal detention of MNNG (150 mg/kg b.w. for 90 days), lead to enhancement of the levels of TBARS, LOOH, cytochrome P450, and decrement in the levels of antioxidants (SOD, CAT, GPx, GSH, vitamins C and E) and upregulated expression of MMP-2 and 9 and cyclin D1 (by western blot analysis). The treatment of vanillic acid (100 mg/kg b.w.) to MNNG treated rats (1) normalized the histopathological alterations, (2) reduced the levels of TBARS, LOOH and cytochrome P450 (3) increased the levels of antioxidants (SOD, CAT, GPx, GSH, vitamins C and E) in plasma and uterus and (4) down regulated the expression of MMP-2, 9 and cyclin D1. The effect of vanillic acid is more predominant in pre-treatment group than co-treated rats. Our results designate that vanillic acid inhibits the EC by elevating antioxidants and by regulating the levels of metalloproteinase and cell cycle check point protein.

Oncogenes and tumor suppressor genes: comparative genomics and network perspectives

BACKGROUND

Defective tumor suppressor genes (TSGs) and hyperactive oncogenes (OCGs) heavily contribute to cell proliferation and apoptosis during cancer development through genetic variations such as somatic mutations and deletions. Moreover, they usually do not perform their cellular functions individually but rather execute jointly. Therefore, a comprehensive comparison of their mutation patterns and network properties may provide a deeper understanding of their roles in the cancer development and provide some clues for identification of novel targets.

RESULTS

In this study, we performed a comprehensive survey of TSGs and OCGs from the perspectives of somatic mutations and network properties. For comparative purposes, we choose five gene sets: TSGs, OCGs, cancer drug target genes, essential genes, and other genes. Based on the data from Pan-Cancer project, we found that TSGs had the highest mutation frequency in most tumor types and the OCGs second. The essential genes had the lowest mutation frequency in all tumor types. For the network properties in the human protein-protein interaction (PPI) network, we found that, relative to target proteins, essential proteins, and other proteins, the TSG proteins and OCG proteins both tended to have higher degrees, higher betweenness, lower clustering coefficients, and shorter shortest-path distances. Moreover, the TSG proteins and OCG proteins tended to have direct interactions with cancer drug target proteins. To further explore their relationship, we generated a TSG-OCG network and found that TSGs and OCGs connected strongly with each other. The integration of the mutation frequency with the TSG-OCG network offered a network view of TSGs, OCGs, and their interactions, which may provide new insights into how the TSGs and OCGs jointly contribute to the cancer development.

CONCLUSIONS

Our study first discovered that the OCGs and TSGs had different mutation patterns, but had similar and stronger protein-protein characteristics relative to the essential proteins or control proteins in the whole human interactome. We also found that the TSGs and OCGs had the most direct interactions with cancer drug targets. The results will be helpful for cancer drug target identification, and ultimately, understanding the etiology of cancer and treatment at the network level.

Regulatory network of microRNAs, target genes, transcription factors and host genes in endometrial cancer

Genes and microRNAs (miRNAs) have important roles in human oncology. However, most of the biological factors are reported in disperse form which makes it hard to discover the pathology. In this study, genes and miRNAs involved in human endometrial cancer(EC) were collected and formed into regulatory networks following their interactive relations, including miRNAs targeting genes, transcription factors (TFs) regulating miRNAs and miRNAs included in their host genes. Networks are constructed hierarchically at three levels: differentially expressed, related and global. Among the three, the differentially expressed network is the most important and fundamental network that contains the key genes and miRNAs in EC. The target genes, TFs and miRNAs are differentially expressed in EC so that any mutation in them may impact on EC development. Some key pathways in networks were highlighted to analyze how they interactively influence other factors and carcinogenesis. Upstream and downstream pathways of the differentially expressed genes and miRNAs were compared and analyzed. The purpose of this study was to partially reveal the deep regulatory mechanisms in EC using a new method that combines comprehensive genes and miRNAs together with their relationships. It may contribute to cancer prevention and gene therapy of EC.

MGMT promoter hypermethylation and K-RAS, PTEN and TP53 mutations in tamoxifen-exposed and non-exposed endometrial cancer cases

BACKGROUND

Tamoxifen has anti-oestrogenic and anti-tumour activity in the breast, but is oestrogenic and carcinogenic in the endometrium. It can induce experimental tumours by both hormonal and DNA-damaging mechanisms, but its carcinogenic mode of action in human endometrium remains unclear.

METHODS

We investigated whether an epigenetic mechanism, involving promoter hypermethylation of the gene for the DNA repair enzyme MGMT (O6-methylguanine DNA methyltransferase), was associated with K-RAS, TP53 and PTEN mutations in endometrial tumours from women treated with tamoxifen (TAM, n=30) or unexposed to the drug (EC, n=38).

RESULTS

There were significant (P<0.05) differences in tumour grade between the TAM and EC groups, with more favourable morphology in the latter. K-RAS mutations, predominantly G>A, occurred in small numbers in both groups. TP53 mutations were of mainly A>G, C>T and indel modifications in both groups, but more frequent in TAM cases. PTEN mutations dominated in EC tumours and were of the type that has large impact on protein function, such as indel or nonsense mutations. These observations alongside the mutational spectrum in PTEN suggest that the malignancies arise from different backgrounds, hence pointing to an effect of tamoxifen. Both groups displayed MGMT promoter hypermethylation. This coincided with mutations more frequently in the TAM (78%) than in the EC (50%) group, even though there were significantly (P<0.05) fewer mutations and methylations in TAM cases.

CONCLUSIONS

Although the difference in coincidence did not reach significance with the current sample size, the findings suggest that epigenetic processes may play a role in the way tamoxifen induces endometrial cancer.

Frequent mutations in the RPL22 gene and its clinical and functional implications

OBJECTIVE

To determine the frequency and spectrum of mutations in RPL22 a gene identified by The Cancer Genome Atlas (TCGA) as mutated in endometrioid endometrial cancer, and determine the relationship between RPL22 defects and clinicopathologic features.

METHODS

Direct sequencing of the entire coding region of the RPL22 cDNA and exons 2/4 was performed in tumors with/without microsatellite instability (MSI). RPL22 expression was assessed by immunofluorescence microscopy in the KLE, RL952 and AN3CA cell lines, wildtype, heterozygous and homozygous mutants, respectively. Relationships between RPL22 mutation and clinicopathological features were assessed using Chi-squared analysis and Student's t test. Progression-free survival (PFS) was calculated from the date of diagnosis to the date of recurrence.

RESULTS

A single nucleotide deletion in an A8 coding repeat was identified in exon 2 of the RPL22 gene in 116/226 (52%) of MSI-high tumors. No mutations were identified in MSI-stable tumors. Only 2% of the tumors expressed a homozygous A deletion. RPL22 mutation was not associated with stage, grade, race and lymphovascular space invasion. Women whose tumors harbored RPL22 mutations were significantly older (67 vs. 63years, p=0.005). There was no difference in PFS between patients with the wildtype and mutant genotypes.

CONCLUSIONS

RPL22 is frequently mutated in MSI-high endometrioid endometrial cancers. The A8 mutation identified was not reported in the whole exome sequences analyzed by the TCGA. The demonstration of frequent mutation in RPL22 may point to a limitation of the exome capture and next generation sequencing analysis methods for some mononucleotide string mutations. Functional assessment of the RPL22 knockdown may be warranted.

New insights in endometrial carcinogenesis

Endometrial carcinoma is the most common cancer of the female genital tract in Europe and in the United States. Despite advances in defining the biology of endometrial carcinomas, there has been poor progress in determining markers that distinguish preinvasive endometrial proliferations. The aim of this review is to highlight the most recent studies regarding the molecular markers involved in endometrial adenocarcinoma pathogenesis and carcinogenesis. We focus on studies that describe markers with potential to progress from endometrial hyperplasia to invasive disease.

Allelic loss of 10q23.3, the PTEN gene locus in cervical carcinoma from Northern Indian population

Cervical cancer is one of the most common malignant diseases affecting women worldwide. Studies on loss of heterozygosity have been made for PTEN gene specific microsatellite markers in malignancies like breast, ovary and lungs and the results have shown a significant association. However the role of this gene is not clearly understood in cervical cancer from Indian population. A total of 135 cervical carcinoma tissues samples were analyzed for loss of heterozygosity. DNA was isolated from the samples and their matched control specimens. Polymerase chain reaction was performed using primer specific for two intragenic markers (D10S198 & D10S192) and one marker (D10S541) in flanking region and further electrophoresed on 8% denaturing polyacrylamide gel. Overall, 31 out of 133(23%) informative cases showed loss of heterozygosity in at least one locus in the region examined. The percentage of loss of heterozygosity for these markers ranged from 8% (D10S192) to 13% (D10S198). Loss of heterozygosity was more frequently detected in intragenic region (D10S198 & D10S192) than in flanking region, D10S541 (21% versus 9%). These data argue that PTEN is a tumor suppressor gene whose inactivation may play an important role in the carcinoma of uterine cervix.