Tumor suppressor genes

MKI67 with arterial hypertension predict a poor survival for prostate cancer patients, a real-life investigation

INTRODUCTION

Prostate cancer is a common urology malignant in males, ranking second globally. The disease is especially severe when diagnosed alongside hypertension. MKI67 is an established marker of neoplastic cell proliferation in humans, but the significance of its prognostic value in patients with prostate cancer and hypertension requires further research.

METHODS

In this retrospective analysis, we evaluated 296 hypertensive prostate cancer patients between March 2, 2012, and November 1, 2015. We used Cox regression models and prediction analysis to assess overall survival. Furthermore, we created a nomogram and verified its accuracy using a calibration curve.

RESULTS

Of all participants, 101 (34.12%) died. Our multi-factor analysis revealed that MKI67 expression was associated with an increased hazard ratio of death (> fivefold) (Hazard Ratio 5.829, 95% CI 3.349-10.138, p value < 0.01) and progression (twofold) (HR 2.059, 95% CI 1.368-3.102, p value < 0.01). Our Lasso analysis model displayed that several factors, including heart failure, smoking, ACS, serum albumin, Gealson score, prognostic nutritional index, MKI67 expression, surgery, and stage were high risks of prostate cancer. To ensure each covariate's contribution to cancer prognosis, we created a Cox model nomogram, which accurately predicted the risk of death (C-statistic of 0.8289) and had a proper calibration plot for risk assessment.

CONCLUSION

MKI67 expression predicts poor outcomes for overall mortality in prostate cancer and hypertension patients. Additionally, our cross-validated multivariate score, which includes MKI67, demonstrated accuracy efficacy of predicting prognosis.

Identification of Pheophytin a and Hydroxy Pheophytin a from Rang Chuet (Thunbergia laurifolia Linn.) as Potent NQO-1 Inducers in Liver Cells

Thunbergia laurifolia Linn. (Rang Chuet, RC), a Thai medicinal plant, possesses various bioactive compounds with potential health benefits. This study aimed to identify detoxifying compounds within RC crude extract. RC leaves were extracted using the Soxhlet method with chloroform. Total carotenoids, chlorophylls, extract yield, total phenolic contents (TPCs), and total flavonoid contents (TFCs) were measured. The extract's composition was analyzed. Cytotoxicity and effects on the detoxification enzyme NQO-1 were assessed in liver cell lines (AML12 and HepG2) using MTT and NQO-1 assays, respectively. Bioactive fractions were identified using fractionation techniques and mass spectrometry (LC-MS). RC extract displayed significant levels of carotenoids (0.375 mg/g), chlorophylls (2.682 mg/g), and favorable yield (15.3%). TPC and TFC were 363.776 mg/g and 112.22 mg/g of extract, respectively. Analysis revealed phenolic acids (gallic acid, caffeic acid), flavonoid (apigenin), chlorophylls (chlorophylls a, b, pheophytin a and b), and lutein. Among the fractions, Fraction 3 (F3) exhibited the highest NQO-1 enzyme activity. F3 contained pheophytin a and hydroxy pheophytin a, confirmed by LC-MS (m/z 871.59+ [M + H]+ and 887.59+ [M + H]+). F3 significantly induced NQO-1 activity in both HepG2 (3.908-fold) and AML12 (1.99-fold) cells. This study identified F3 from RC extract as a promising fraction containing pheophytin a and hydroxy pheophytin a, responsible for inducing the detoxification enzyme NQO-1 in liver cells. These findings suggest RC's potential for promoting detoxification.

Natural products for combating multidrug resistance in cancer

Cancer cells frequently develop resistance to chemotherapeutic therapies and targeted drugs, which has been a significant challenge in cancer management. With the growing advances in technologies in isolation and identification of natural products, the potential of natural products in combating cancer multidrug resistance has received substantial attention. Importantly, natural products can impact multiple targets, which can be valuable in overcoming drug resistance from different perspectives. In the current review, we will describe the well-established mechanisms underlying multidrug resistance, and introduce natural products that could target these multidrug resistant mechanisms. Specifically, we will discuss natural compounds such as curcumin, resveratrol, baicalein, chrysin and more, and their potential roles in combating multidrug resistance. This review article aims to provide a systematic summary of recent advances of natural products in combating cancer drug resistance, and will provide rationales for novel drug discovery.

Loss-of-function mutations are main drivers of adaptations during short-term evolution

We noticed that during short-term experimental evolution and carcinogenesis, mutations causing gene inactivation (i.e., nonsense mutations or frameshifts) are frequent. Our meta-analysis of 65 experiments using modified dN/dS statistics indicated that nonsense mutations are adaptive in different experimental conditions and we empirically confirmed this prediction. Using yeast S. cerevisiae as a model we show that fixed or highly frequent gene loss-of-function mutations are almost exclusively adaptive in the majority of experiments.

Rethinking cancer initiation: The role of large-scale mutational events

Cancer initiation is revisited in light of recent discoveries in cancer pathogenesis. Of note is the detection of mutated cancer genes in benign conditions. More significantly, somatic clones, which harbor mutations in cancer genes, arise in normal tissues from early development through adulthood, but seldom do they transform into cancer. Further, clustered mutational events-kataegis, chromothripsis and chromoplexy-are widespread in cancer, generating point mutations and chromosomal rearrangements in a single cellular catastrophe. These observations are contrary to the prevailing somatic mutation theory, which states that a cancer is caused by the gradual accumulation of mutations over time. A different perspective is proposed within the framework of Waddington's epigenetic landscape wherein tumorigenesis is viewed primarily as a disruption of cell development. Cell types are defined by their specific gene-expression profiles, determined by the gene regulatory network, and can be regarded as attractor states of the network dynamics: they represent specific, self-stabilizing patterns of gene activities across the genome. However, large-scale mutational events reshape the landscape topology, creating abnormal "unphysiological" attractors. This is the crux of the process of initiation. Initiation primes the cell for conversion into a tumor phenotype by oncogenes and tumor suppressor genes, which drive cell proliferation and clonal diversification. This view of tumorigenesis calls for a different approach to therapy.

Clinicopathological and genetic characteristics of gastric neuroendocrine tumour (NET) G3 and comparisons with neuroendocrine carcinoma and NET G2

AIMS

To characterise the clinicopathological and genetic characteristics of gastric neuroendocrine tumour G3 (gNET G3) and to compare them with those of gastric neuroendocrine carcinoma (gNEC) and gNET G2.

METHODS AND RESULTS

A total of 115 gastric neuroendocrine neoplasms (NENs) were included, of which gNET G3 was different from gNET G1/G2 in terms of tumour location (P = 0.029), number (P = 0.003), size (P = 0.010), the Ki67 index (P < 0.001), lymph node metastasis (P < 0.001) and TNM stage (P = 0.011), and different from gNEC/gastric mixed neuroendocrine-non-neuroendocrine neoplasm (gMiNEN) in terms of tumour size (P = 0.010) and the Ki67 index (P = 0.001). High-resolution copy number (CN) profiling and validation experiments showed CN gains and high expression of DLL3 in gNET G3. Hierarchical clustering analysis based on CN characteristics showed that gNET G3 was separated from gNEC but mixed with gNET G2. In gene set enrichment analysis, eight pathways were significantly enriched in gNEC when comparing gNET G3 and gNEC (P < 0.05), while no pathways were enriched when comparing gNET G3 and gNET G2. Whole-exome sequencing and validation experiments showed nonsense mutation of TP53 in one gNET G3, with wild-type staining for p53. In gNEC, TP53 mutations were detected in four of eight cases, and abnormal expression of p53 was detected in all cases.

CONCLUSION

Gastric NET G3 is a distinct entity with unique genetic characteristics, which are different from those of gNEC than gNET G2. Our results provide insight into some molecular alterations that may contribute to the development and progression of gNET G3 and serve as potential therapeutic targets.

Clinical Significance of Extracellular Vesicles in Prostate and Renal Cancer

Extracellular vesicles (EVs)-including apoptotic bodies, microvesicles, and exosomes-are released by almost all cell types and contain molecular footprints from their cell of origin, including lipids, proteins, metabolites, RNA, and DNA. They have been successfully isolated from blood, urine, semen, and other body fluids. In this review, we discuss the current understanding of the predictive value of EVs in prostate and renal cancer. We also describe the findings supporting the use of EVs from liquid biopsies in stratifying high-risk prostate/kidney cancer and advanced disease, such as castration-resistant (CRPC) and neuroendocrine prostate cancer (NEPC) as well as metastatic renal cell carcinoma (RCC). Assays based on EVs isolated from urine and blood have the potential to serve as highly sensitive diagnostic studies as well as predictive measures of tumor recurrence in patients with prostate and renal cancers. Overall, we discuss the biogenesis, isolation, liquid-biopsy, and therapeutic applications of EVs in CRPC, NEPC, and RCC.

RBL2-E2F-GCN5 guide cell fate decisions during tissue specification by regulating cell-cycle-dependent fluctuations of non-cell-autonomous signaling

The retinoblastoma family proteins (RBs) and E2F transcription factors are cell-autonomous regulators of cell-cycle progression, but they also impact fate choice in addition to tumor suppression. The range of mechanisms involved remains to be uncovered. Here, we show that RBs, particularly RBL2/p130, repress WNT ligands such as WNT4 and WNT8A, thereby directing ectoderm specification between neural crest to neuroepithelium. RBL2 achieves this function through cell-cycle-dependent cooperation with E2Fs and GCN5 on the regulatory regions of WNT loci, which direct neuroepithelial versus neural crest specification by temporal fluctuations of WNT/β-catenin and DLL/NOTCH signaling activity. Thus, the RB-E2F bona fide cell-autonomous axis controls cell fate decisions, and RBL2 regulates field effects via WNT ligands. This reveals a non-cell-autonomous function of RBL2-E2F in stem cell and tissue progenitor differentiation that has broader implications for cell-cycle-dependent cell fate specification in organogenesis, adult stem cells, tissue homeostasis, and tumorigenesis.

Von-Hippel Lindau (VHL) syndrome with bilateral cerebellar hemangioblastomas and retinal angiomas: A rare presentation

INTRODUCTION AND IMPORTANCE

Hemangioblastomas are benign vascular neoplasms which originate almost exclusively from central nervous system (CNS). They account for 2 % of all intracranial neoplasms, 7 %-12 % of posterior fossa tumours. 60-75 % cases of hemangioblastomas occur sporadically and rest 25 % to 40 % occur in genetically inherited in the autosomal dominant neoplasia syndrome known as Von Hippel-Lindau (VHL) disease with mutation occurring on chromosome 3p.

CASE PRESENTATION

We, hereby, report a case of one such rare case of a 30-year old male who presented to us with the complaint of holocranial headache for past 2 months associated with vomiting along with bilateral cerebellar signs and symptoms. MRI Brain revealed multiple cysts with enhancing mural nodules present on both cerebellar hemispheres. Due to recurrence and multi-focality of lesions, VHL syndrome was suspected.

CLINICAL DISCUSSION

VHL is a rare autosomal dominant disease. MRI is the gold standard test. It demonstrates specific appearances depending on the tumour anatomy. Hemangioblastoma of the CNS in VHL usually develop from childhood at an age of <10 years or early teen until the age of 30 years. The most common locations for hemangioblastomas in VHL are cerebellum and spinal cord as seen in our patient.

CONCLUSION

VHL being a lifelong disease with no cure till date, the patients should be frequently screened for lesions at various potential sites in his/her lifetime so as to provide required intervention at the earliest. Hence, a genetic screening for VHL (VHL tumour suppressor gene), should be performed in cases of hemangioblastoma.

Secreted protease PRSS35 suppresses hepatocellular carcinoma by disabling CXCL2-mediated neutrophil extracellular traps

Hepatocytes function largely through the secretion of proteins that regulate cell proliferation, metabolism, and intercellular communications. During the progression of hepatocellular carcinoma (HCC), the hepatocyte secretome changes dynamically as both a consequence and a causative factor in tumorigenesis, although the full scope of secreted protein function in this process remains unclear. Here, we show that the secreted pseudo serine protease PRSS35 functions as a tumor suppressor in HCC. Mechanistically, we demonstrate that active PRSS35 is processed via cleavage by proprotein convertases. Active PRSS35 then suppresses protein levels of CXCL2 through targeted cleavage of tandem lysine (KK) recognition motif. Consequently, CXCL2 degradation attenuates neutrophil recruitment to tumors and formation of neutrophil extracellular traps, ultimately suppressing HCC progression. These findings expand our understanding of the hepatocyte secretome's role in cancer development while providing a basis for the clinical translation of PRRS35 as a therapeutic target or diagnostic biomarker.

Lineage tracing reveals the phylodynamics, plasticity, and paths of tumor evolution

Tumor evolution is driven by the progressive acquisition of genetic and epigenetic alterations that enable uncontrolled growth and expansion to neighboring and distal tissues. The study of phylogenetic relationships between cancer cells provides key insights into these processes. Here, we introduced an evolving lineage-tracing system with a single-cell RNA-seq readout into a mouse model of Kras;Trp53(KP)-driven lung adenocarcinoma and tracked tumor evolution from single-transformed cells to metastatic tumors at unprecedented resolution. We found that the loss of the initial, stable alveolar-type2-like state was accompanied by a transient increase in plasticity. This was followed by the adoption of distinct transcriptional programs that enable rapid expansion and, ultimately, clonal sweep of stable subclones capable of metastasizing. Finally, tumors develop through stereotypical evolutionary trajectories, and perturbing additional tumor suppressors accelerates progression by creating novel trajectories. Our study elucidates the hierarchical nature of tumor evolution and, more broadly, enables in-depth studies of tumor progression.

A rationalized definition of general tumor suppressor microRNAs excludes miR-34a

While several microRNAs (miRNAs) have been proposed to act as tumor suppressors, a consensual definition of tumor suppressing miRNAs is still missing. Similarly to coding genes, we propose that tumor suppressor miRNAs must show evidence of genetic or epigenetic inactivation in cancers, and exhibit an anti-tumorigenic (e.g., anti-proliferative) activity under endogenous expression levels. Here we observe that this definition excludes the most extensively studied tumor suppressor candidate miRNA, miR-34a. In analyzable cancer types, miR-34a does not appear to be down-regulated in primary tumors relatively to normal adjacent tissues. Deletion of miR-34a is occasionally found in human cancers, but it does not seem to be driven by an anti-tumorigenic activity of the miRNA, since it is not observed upon smaller, miR-34a-specific alterations. Its anti-proliferative action was observed upon large, supra-physiological transfection of synthetic miR-34a in cultured cells, and our data indicates that endogenous miR-34a levels do not have such an effect. Our results therefore argue against a general tumor suppressive function for miR-34a, providing an explanation to the lack of efficiency of synthetic miR-34a administration against solid tumors.

Active RB causes visible changes in nuclear organization

RB restricts G1/S progression by inhibiting E2F. Here, we show that sustained expression of active RB, and prolonged G1 arrest, causes visible changes in chromosome architecture that are not directly associated with E2F inhibition. Using FISH probes against two euchromatin RB-associated regions, two heterochromatin domains that lack RB-bound loci, and two whole-chromosome probes, we found that constitutively active RB (ΔCDK-RB) promoted a more diffuse, dispersed, and scattered chromatin organization. These changes were RB dependent, were driven by specific isoforms of monophosphorylated RB, and required known RB-associated activities. ΔCDK-RB altered physical interactions between RB-bound genomic loci, but the RB-induced changes in chromosome architecture were unaffected by dominant-negative DP1. The RB-induced changes appeared to be widespread and influenced chromosome localization within nuclei. Gene expression profiles revealed that the dispersion phenotype was associated with an increased autophagy response. We infer that, after cell cycle arrest, RB acts through noncanonical mechanisms to significantly change nuclear organization, and this reorganization correlates with transitions in cellular state.

Nematode-Applied Technology for Human Tumor Microenvironment Research and Development

Nematodes, such as Caenorhabditis elegans, have been instrumental to the study of cancer. Recently, their significance as powerful cancer biodiagnostic tools has emerged, but also for mechanism analysis and drug discovery. It is expected that nematode-applied technology will facilitate research and development on the human tumor microenvironment. In the history of cancer research, which has been spurred by numerous discoveries since the last century, nematodes have been important model organisms for the discovery of cancer microenvironment. First, microRNAs (miRNAs), which are noncoding small RNAs that exert various functions to control cell differentiation, were first discovered in C. elegans and have been actively incorporated into cancer research, especially in the study of cancer genome defects. Second, the excellent sense of smell of nematodes has been applied to the diagnosis of diseases, especially refractory tumors, such as human pancreatic cancer, by sensing complex volatile compounds derived from heterogeneous cancer microenvironment, which are difficult to analyze using ordinary analytical methods. Third, a nematode model system can help evaluate invadosomes, the phenomenon of cell invasion by direct observation, which has provided a new direction for cancer research by contributing to the elucidation of complex cell–cell communications. In this cutting-edge review, we highlight milestones in cancer research history and, from a unique viewpoint, focus on recent information on the contributions of nematodes in cancer research towards precision medicine in humans.

Ginsenoside Rh4 Suppressed Metastasis of Lung Adenocarcinoma via Inhibiting JAK2/STAT3 Signaling

Lung adenocarcinoma (LAC) is a common lung cancer with a high malignancy that urgently needs to be treated with effective drugs. Ginsenoside Rh4 exhibits outstanding antitumor activities. However, few studies reported its effects on growth, metastasis and molecular mechanisms in LAC. Here, Rh4 is certified to show a strong anti-LAC efficiency in vitro and in vivo. Results of flow cytometry and Western blot are obtained to exhibited that Rh4 markedly restrained cellular proliferation and colony formation by arresting the cell cycle in the G1 phase. Results from a wound healing assay and transwell assays demonstrated that Rh4 is active in the antimigration and anti-invasion of LAC. The analysis of Western blot, immunofluorescence and RT-qPCR confirmed that Rh4 reverses the epithelial–mesenchymal transition (EMT) through upregulating the gene expression of E-cadherin and downregulating that of snail, N-cadherin and vimentin. In vivo results from immunohistochemistry show consistent trends with cellular studies. Furthermore, Rh4 suppresses the Janus kinases2/signal transducer and activator of the transcription3 (JAK2/STAT3) signaling pathway stimulated by TGF-β1. Silencing the STAT3 signal or co-treating with AG490 both enhanced the EMT attenuation caused by Rh4, which revealed that Rh4 suppressed EMT via inhibiting the JAK2/STAT3 signaling pathway. These findings explore the capacity and mechanism of Rh4 on the antimetastasis of LAC, providing evidence for Rh4 to LAC therapy.

Implications of mosaicism in variant interpretation: A case of a de novo homozygous NF1 variant

Neurofibromatosis type 1 is a common multisystem autosomal dominant syndrome caused by pathogenic heterozygous variants in the neurofibromin gene (NF1). It is associated with a substantially increased cancer risk. Mosaicism for NF1 has been clinically well-established for "second hit" variants in skin lesions and tumor tissues. Here, we report on a 3-month-old boy with multiple café au lait macules (CAMs) and juvenile myelomonocytic leukemia (JMML) who was found to carry a previously established pathogenic NF1 variant (c.586+5G>A), as revealed by whole-exome sequencing. Surprisingly, however, this variant was detected in the homozygous state in the patient and was absent in the parents and siblings. Deep sequencing of this variant using blood, buccal swabs and skin samples was performed. As expected for an NF1 gene mutation promoting JMML, the variant was detected in 90.6% of the blood DNA reads, in sharp contrast to the mere 5% and 0.74% of reads in the saliva- and skin fibroblast-derived DNA, respectively. Our analysis, therefore, confirmed postzygotic origin of the variant followed by a mitotic event resulting in its homozygosity, although we could not differentiate between the possibilities of a gene conversion and mitotic crossover. Apparently de novo homozygous variants should trigger a careful investigation into mosaicism to achieve accurate interpretation.

Down-regulation of miR-219-5p increase the risk of cancer-related mortality in patients with prostate cancer

INTRODUCTION

Prostate cancer is a common malignancy in men that is difficult to treat and carries a high risk of death. miR-219-5p is expressed in reduced amounts in many malignancies. However, the prognostic value of miR-219-5p for patients with prostate cancer remains unclear.

METHODS

We retrospectively analysed data from 213 prostate cancer patients from 10 June 2012 to 9 May 2015. Overall survival was assessed by Kaplan-Meier analysis and Cox regression models. Besides, a prediction model was constructed, and calibration curves evaluated the model's accuracy.

RESULTS

Of the 213 patients, a total of 72 (33.8%) died and the median survival time was 60.0 months. We found by multifactorial analysis that miR-219-5p deficiency increased the risk of death by nearly fourfold (HR: 3.86, 95% CI): 2.01 to 7.44, p<0.001) and the risk of progression by twofold (HR: 2.79, 95% CI: 1.68 to 4.64, p<0.001). To quantify each covariate's weight on prognosis, we screened variables by cox model to construct a predictive model. The Nomogram showed excellent accuracy in estimating death's risk, with a corrected C-index of 0.778.

CONCLUSIONS

miR-219-5p can be used as a biomarker to predict death risk in prostate cancer patients. The mortality risk prediction model constructed based on miR-219-5p has good consistency and validity in assessing patient prognosis.

MethHC 2.0: information repository of DNA methylation and gene expression in human cancer

DNA methylation is an important epigenetic regulator in gene expression and has several roles in cancer and disease progression. MethHC version 2.0 (MethHC 2.0) is an integrated and web-based resource focusing on the aberrant methylomes of human diseases, specifically cancer. This paper presents an updated implementation of MethHC 2.0 by incorporating additional DNA methylomes and transcriptomes from several public repositories, including 33 human cancers, over 50 118 microarray and RNA sequencing data from TCGA and GEO, and accumulating up to 3586 manually curated data from >7000 collected published literature with experimental evidence. MethHC 2.0 has also been equipped with enhanced data annotation functionality and a user-friendly web interface for data presentation, search, and visualization. Provided features include clinical-pathological data, mutation and copy number variation, multiplicity of information (gene regions, enhancer regions, and CGI regions), and circulating tumor DNA methylation profiles, available for research such as biomarker panel design, cancer comparison, diagnosis, prognosis, therapy study and identifying potential epigenetic biomarkers. MethHC 2.0 is now available at http://awi.cuhk.edu.cn/∼MethHC.

Estrogen-related receptor alpha directly binds to p53 and cooperatively controls colon cancer growth through the regulation of mitochondrial biogenesis and function

BACKGROUND

Of the genes that control mitochondrial biogenesis and function, ERRα emerges as a druggable metabolic target to be exploited for cancer therapy. Of the genes mutated in cancer, TP53 remains the most elusive to target. A clear understanding of how mitochondrial druggable targets can be accessed to exploit the underlying mechanism(s) explaining how p53-deficient tumors promote cell survival remains elusive.

METHODS

We performed protein-protein interaction studies to demonstrate that ERRα binds to p53. Moreover, we used gene silencing and pharmacological approaches in tandem with quantitative proteomics analysis by SWATH-MS to investigate the role of the ERRα/p53 complex in mitochondrial biogenesis and function in colon cancer. Finally, we designed in vitro and in vivo studies to investigate the possibility of targeting colon cancers that exhibit defects in p53.

RESULTS

Here, we are the first to identify a direct protein-protein interaction between the ligand-binding domain (LBD) of ERRα and the C-terminal domain (CTD) of p53. ERRα binds to p53 regardless of p53 mutational status. Furthermore, we show that the ERRα and p53 complex cooperatively control mitochondrial biogenesis and function. Targeting ERRα creates mitochondrial metabolic stresses, such as production of reactive oxygen species (ROS) and mitochondrial membrane permeabilization (MMP), leading to a greater cytotoxic effect that is dependent on the presence of p53. Pharmacological inhibition of ERRα impairs the growth of p53-deficient cells and of p53 mutant patient-derived colon xenografts (PDX).

CONCLUSIONS

Therefore, our data suggest that by using the status of the p53 protein as a selection criterion, the ERRα/p53 transcriptional axis can be exploited as a metabolic vulnerability.

Context is key: Understanding the regulation, functional control, and activities of the p53 tumour suppressor

The p53 tumour suppressor is considered one of the most critical genes in cancer biology. By upregulating apoptosis, cell cycle arrest, and DNA damage repair in normal cells, p53 prevents the propagation of cells with tumorigenic potential; therefore, mutations in p53 are associated with carcinogenic transformation and can be accompanied by the accumulation of a novel gain-of-function oncogenic protein, mutant p53. Although p53 is most often understood to utilize context-dependent post-translational modifications to achieve regulation of its many target genes, recent research has also sought to define other mechanisms of regulating p53 gene expression prior to translation and to understand how this alternative regulation of p53 may influence target gene expression and cellular outcome. This review attempts to summarize what is known about p53 regulation at the transcriptional, post-transcriptional, and post-translational levels while paying special attention to the ways in which context may influence p53 regulation and subsequent regulation of its target genes.

RB1 Germline Variant Predisposing to a Rare Ovarian Germ Cell Tumor: A Case Report

Malignant ovarian germ cell tumors (MOGCTs) are neoplasms of the ovary, of which, due to their rarity and heterogeneity, few is reported about genetic background and development. Here, we report a 18-years old patient diagnosed with an ovarian mixed germ cell tumor, without any previous history of malignancies, who has been treated with surgery and chemotherapy and died 4 years later due to peritoneal metastasis complications. Patient's blood DNA was screened for a panel of 52 cancer-related genes in order to identify predisposing aberrations to this rare cancer. The analysis discovered the uncharacterized c.2393G>A variant in RB1, the retinoblastoma gene, leading both to a missense change and a splicing perturbation of the RB1 transcript. The variant was found to be hypomorphic, damaging the C-terminal domain with a partially impaired protein function. The variant is inherited from the unaffected mother. Due to an imprinting mechanism, the maternal allele is ~3-fold more expressed than the paternal one. The parent-of-origin effect combined with the hypomorphic impact of the variant determines a rescue of sufficient tumor-suppressor activity to prevent retinoblastoma development but can predispose to other cancers in the adult age. In order to understand the somatic events acting on the germline predisposition we used the NGS-liquid biopsy covering 77 cancer driver genes. Using this approach, we detected deleterious mutations in TP53, SMAD4, FGFR3, and MSH2, indicative of a dis-regulation of cell cycle and DNA repair mechanisms pathways. In conclusion, we have pinpointed for the first time that an RB1 leaky variant, not leading to retinoblastoma because of its maternal origin, can predispose in adults to a very rare form of ovarian cancer and that the somatic disruption of few genes contributes to the tumor progression and aggressiveness.

microRNAs targeting cellular cholesterol: implications for combating anticancer drug resistance

Over sixty percent of all mammalian protein-coding genes are estimated to be regulated by microRNAs (miRNAs), and unsurprisingly miRNA dysregulation has been linked with cancer. Aberrant miRNA expression in cancer cells has been linked with tumourigenesis and drug resistance. In the past decade, increasing number of studies have demonstrated that cholesterol accumulation fuels tumour growth and contributes to drug resistance, therefore, miRNAs controlling cholesterol metabolism and homeostasis are obvious hypothetical targets for investigating their role in cholesterol-mediated drug resistance in cancer. In this review, we have collated published evidences to consolidate this hypothesis and have scrutinized it by utilizing computational tools to explore the role of miRNAs in cholesterol-mediated drug resistance in breast cancer cells. We found that hsa-miR-128 and hsa-miR-223 regulate genes mediating lipid signalling and cholesterol metabolism, cancer drug resistance and breast cancer genes. The analysis demonstrates that targeting these miRNAs in cancer cells presents an opportunity for developing new strategies to combat anticancer drug resistance.

Histone Acetyltransferase (HAT) P300/CBP Inhibitors Induce Synthetic Lethality in PTEN-Deficient Colorectal Cancer Cells through Destabilizing AKT

PTEN, a tumor suppressor, is found loss of function in many cancers, including colorectal cancer. To identify the synthetic lethal compounds working with PTEN deficiency, we performed a synthetic lethality drug screening with PTEN-isogenic colorectal cancer cells. From the screening, we found that PTEN-/- colorectal cancer cells were sensitive to anacardic acid, a p300/CBP histone acetyltransferase (HAT) inhibitor. Anacardic acid significantly reduced the viability of PTEN-/- cells not in PTEN+/+ cells via inducing apoptosis. Inhibition of HAT activity of p300/CBP by anacardic acid reduced the acetylation of histones at the promoter region and inhibited the transcription of Hsp70 family of proteins. The down-regulation of Hsp70 family proteins led to the reduction of AKT-Hsp70 complex formation, AKT destabilization and decreased the level of phosphorylated AKT at Ser473, all of which are vital for the survival of PTEN-/- colorectal cells. The synthetic lethality effect of anacardic acid was further validated in tumor xenograft mice models, where PTEN-/- colorectal tumors showed greater sensitivity to anacardic acid treatment than PTEN+/+ tumors. These data suggest that anacardic acid induced synthetic lethality by inhibiting HAT activity of p300/CBP, thereby reducing Hsp70 transcription and destabilizing AKT in PTEN deficient colorectal cancer cells.

Involvement of Rev1 in alkylating agent-induced loss of heterozygosity in Oryzias latipes

Translesion synthesis (TLS) polymerases mediate DNA damage bypass during replication. The TLS polymerase Rev1 has two important functions in the TLS pathway, including dCMP transferase activity and acting as a scaffolding protein for other TLS polymerases at the C‐terminus. Because of the former activity, Rev1 bypasses apurinic/apyrimidinic sites by incorporating dCMP, whereas the latter activity mediates assembly of multipolymerase complexes at the DNA lesions. We generated rev1 mutants lacking each of these two activities in Oryzias latipes (medaka) fish and analyzed cytotoxicity and mutagenicity in response to the alkylating agent diethylnitrosamine (DENA). Mutant lacking the C‐terminus was highly sensitive to DENA cytotoxicity, whereas mutant with reduced dCMP transferase activity was slightly sensitive to DENA cytotoxicity, but exhibited a higher tumorigenic rate than wild‐type fish. There was no significant difference in the frequency of DENA‐induced mutations between mutant with reduced dCMP transferase activity and wild‐type cultured cell. However, loss of heterozygosity (LOH) occurred frequently in cells with reduced dCMP transferase activity. LOH is a common genetic event in many cancer types and plays an important role on carcinogenesis. To our knowledge, this is the first report to identify the involvement of the catalytic activity of Rev1 in suppression of LOH.

Ginsenoside Rk1 induces apoptosis and downregulates the expression of PD-L1 by targeting the NF-κB pathway in lung adenocarcinoma

Ginsenoside Rk1 can function as an antitumor modulator that induces apoptosis in lung adenocarcinoma cells by inhibiting NF-κB transcription and triggering cell cycle arrest.

Pharmaceutical Topical Delivery of Poorly Soluble Polyphenols: Potential Role in Prevention and Treatment of Melanoma

Melanoma is regarded as the fifth and sixth most common cancer in men and women, respectively, and it is estimated that one person dies from melanoma every hour in the USA. Unfortunately, the treatment of melanoma is difficult because of its aggressive metastasis and resistance to treatment. The treatment of melanoma continues to be a challenging issue due to the limitations of available treatments such as a low response rate, severe adverse reactions, and significant toxicity. Natural polyphenols have attracted considerable attention from the scientific community due to their chemopreventive and chemotherapeutic efficacy. It has been suggested that poorly soluble polyphenols such as curcumin, resveratrol, quercetin, coumarin, and epigallocatechin-3-gallate may have significant benefits in the treatment of melanoma due to their antioxidant, anti-inflammatory, antiproliferative, and chemoprotective efficacies. The major obstacles for the use of polyphenolic compounds are low stability and poor bioavailability. Numerous nanoformulations, including solid lipid nanoparticles, polymeric nanoparticles, micelles, and liposomes, have been formulated to enhance the bioavailability and stability, as well as the therapeutic efficacy of polyphenols. This review will provide an overview of poorly soluble polyphenols that have been reported to have antimetastatic efficacy in melanomas.

Protein Kinase C Quality Control by Phosphatase PHLPP1 Unveils Loss-of-Function Mechanism in Cancer

Protein kinase C (PKC) isozymes function as tumor suppressors in increasing contexts. In contrast to oncogenic kinases, whose function is acutely regulated by transient phosphorylation, PKC is constitutively phosphorylated following biosynthesis to yield a stable, autoinhibited enzyme that is reversibly activated by second messengers. Here, we report that the phosphatase PHLPP1 opposes PKC phosphorylation during maturation, leading to the degradation of aberrantly active species that do not become autoinhibited. Cancer-associated hotspot mutations in the pseudosubstrate of PKCβ that impair autoinhibition result in dephosphorylated and unstable enzymes. Protein-level analysis reveals that PKCα is fully phosphorylated at the PHLPP site in over 5,000 patient tumors, with higher PKC levels correlating (1) inversely with PHLPP1 levels and (2) positively with improved survival in pancreatic adenocarcinoma. Thus, PHLPP1 provides a proofreading step that maintains the fidelity of PKC autoinhibition and reveals a prominent loss-of-function mechanism in cancer by suppressing the steady-state levels of PKC.

Breaking Bad: How Viruses Subvert the Cell Cycle

Interactions between the host and viruses during the course of their co-evolution have not only shaped cellular function and the immune system, but also the counter measures employed by viruses. Relatively small genomes and high replication rates allow viruses to accumulate mutations and continuously present the host with new challenges. It is therefore, no surprise that they either escape detection or modulate host physiology, often by redirecting normal cellular pathways to their own advantage. Viruses utilize a diverse array of strategies and molecular targets to subvert host cellular processes, while evading detection. These include cell-cycle regulation, major histocompatibility complex-restricted antigen presentation, intracellular protein transport, apoptosis, cytokine-mediated signaling, and humoral immune responses. Moreover, viruses routinely manipulate the host cell cycle to create a favorable environment for replication, largely by deregulating cell cycle checkpoints. This review focuses on our current understanding of the molecular aspects of cell cycle regulation that are often targeted by viruses. Further study of their interactions should provide fundamental insights into cell cycle regulation and improve our ability to exploit these viruses.

Hyper-phosphorylation of Rb S249 together with CDK5R2/p39 overexpression are associated with impaired cell adhesion and epithelial-to-mesenchymal transition: Implications as a potential lung cancer grading and staging biomarker

Prediction of lung cancer metastasis relies on post-resection assessment of tumor histology, which is a severe limitation since only a minority of lung cancer patients are diagnosed with resectable disease. Therefore, characterization of metastasis-predicting biomarkers in pre-resection small biopsy specimens is urgently needed. Here we report a biomarker consisting of the phosphorylation of the retinoblastoma protein (Rb) on serine 249 combined with elevated p39 expression. This biomarker correlates with epithelial-to-mesenchymal transition traits in non-small cell lung carcinoma (NSCLC) cells. Immunohistochemistry staining of NSCLC tumor microarrays showed that strong phospho-Rb S249 staining positively correlated with tumor grade specifically in the squamous cell carcinoma (SCC) subtype. Strong immunoreactivity for p39 positively correlated with tumor stage, lymph node invasion, and distant metastases, also in SCC. Linear regression analyses showed that the combined scoring for phospho-Rb S249, p39 and E-cadherin in SCC is even more accurate at predicting tumor staging, relative to each score individually. We propose that combined immunohistochemistry staining of NSCLC samples for Rb phosphorylation on S249, p39, and E-cadherin protein expression could aid in the assessment of tumor staging and metastatic potential when tested in small primary tumor biopsies. The intense staining for phospho-Rb S249 that we observed in high grade SCC could also aid in the precise sub-classification of poorly differentiated SCCs.

Gene Therapy: A New Approach for Treatment of Cancer

The identification of critical genes that encode for regulatory proteins has helped elucidate the molecular mechanisms that govern cell proliferation and malignant transformation. Several approaches to gene therapy for cancer have been described. These include the use of fibroblasts expressing suicide genes, restoration of expression of tumor suppressor genes, cytokine gene therapy, genetic modification of T lymphocytes, and protection of normal hemopoiesis in cancer patients. Clinical trials are underway in all these areas.

Downregulation of Rap1Gap: A Switch from DCIS to Invasive Breast Carcinoma via ERK/MAPK Activation

Diagnosis of breast ductal carcinoma in situ (DCIS) presents a challenge since we cannot yet distinguish those cases that would remain indolent and not require aggressive treatment from cases that may progress to invasive ductal cancer (IDC). The purpose of this study is to determine the role of Rap1Gap, a GTPase activating protein, in the progression from DCIS to IDC. Immunohistochemistry (IHC) analysis of samples from breast cancer patients shows an increase in Rap1Gap expression in DCIS compared to normal breast tissue and IDCs. In order to study the mechanisms of malignant progression, we employed an in vitro three-dimensional (3D) model that more accurately recapitulates both structural and functional cues of breast tissue. Immunoblotting results show that Rap1Gap levels in MCF10.Ca1D cells (a model of invasive carcinoma) are reduced compared to those in MCF10.DCIS (a model of DCIS). Retroviral silencing of Rap1Gap in MCF10.DCIS cells activated extracellular regulated kinase (ERK) mitogen-activated protein kinase (MAPK), induced extensive cytoskeletal reorganization and acquisition of mesenchymal phenotype, and enhanced invasion. Enforced reexpression of Rap1Gap in MCF10.DCIS-Rap1GapshRNA cells reduced Rap1 activity and reversed the mesenchymal phenotype. Similarly, introduction of dominant negative Rap1A mutant (Rap1A-N17) in DCIS-Rap1Gap shRNA cells caused a reversion to nonmalignant phenotype. Conversely, expression of constitutively active Rap1A mutant (Rap1A-V12) in noninvasive MCF10.DCIS cells led to phenotypic changes that were reminiscent of Rap1Gap knockdown. Thus, reduction of Rap1Gap in DCIS is a potential switch for progression to an invasive phenotype. The Graphical Abstract summarizes these findings.

An integrated framework for identification of effective and synergistic anti-cancer drug combinations

Combination drug therapy is considered a better treatment option for various diseases, such as cancer, HIV, hypertension, and infections as compared to targeted drug therapies. Combination or synergism helps to overcome drug resistance, reduction in drug toxicity and dosage. Considering the complexity and heterogeneity among cancer types, drug combination provides promising treatment strategy. Increase in drug combination data raises a challenge for developing a computational approach that can effectively predict drugs synergism. There is a need to model the combination drug screening data to predict new synergistic drug combinations for successful cancer treatment. In such a scenario, machine learning approaches can be used to alleviate the process of drugs synergy prediction. Experimental data from a single-agent or multi-agent drug screens provides feature data for model training. On the contrary, identification of effective drug combination using clinical trials is a time consuming and resource intensive task. This paper attempts to address the aforementioned challenges by developing a computational approach to effectively predict drug synergy. Single-drug efficacy is used for predicting drug synergism. Our approach obviates the need to understand the underlying drug mechanism to predict drug combination synergy. For this purpose, nine machine learning algorithms are trained. It is observed that the Random forest models, in comparison to other models, have shown significant performance. The <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>K</mml:mi></mml:math> -fold cross-validation is performed to evaluate the robustness of the best predictive model. The proposed approach is applied to mutant-BRAF melanoma and further validated using melanoma cell-lines from AstraZeneca-Sanger Drug Combination Prediction DREAM Challenge dataset.

Flow Cytometric and Immunohistochemical Correlations in High Incidence Human Solid Tumors

475 patients with carcinoma at different sites (141 colon-rectum; 102 breast; 50 stomach; 48 kidney; 46 head and neck; 41 bladder; 47 other sites) submitted to surgery have been analyzed after histopathological staging and grading, by flow cytometry (monoparametric DNA content analysis) and immunohistochemistry (p53, c-erbB-2, and PCNA expression). In breast cancer patients the presence of receptors for estrogen (ER) and progesterone (PGR) has also been determined. Flow cytometry-derived parameters were DNA ploidy, fraction of cells in S-phase (SPF), and DNA content heterogeneity (multiclonal stem cell lines with different DNA index and/or more than one subpopulations with different ploidy levels in different samples from the same tumor). Correlations of the results obtained by the different techniques have been attempted by the non-parametric Spearman's rank correlation approach. Significant associations (P «0.05) were found between the histopathological, immunohistochemical and flow cytometric parameters considered in some anatomical regions, such as stomach (p53 vs DNA content aneuploidy and vs heterogeneity), colon-rectum (TNM vs p53 and vs heterogeneity), bladder (grading vs DNA content aneuploidy and vs heterogeneity). Tumor heterogeneity proved to be dependent on the number of tumor samples taken. The results of this preliminary assessment will subsequently be compared with the data obtained from a currently ongoing follow-up survey.

Abnormalities in Cell Cycle Control in Cancer and Their Clinical Implications

Recent studies indicate that the functions of several genes that control the cell cycle are altered during the carcinogenic process and that these changes perturb both cell proliferation and genomic stability, thus promoting cell transformation and enhancing the process of tumor progression. The purpose of this paper is to review current information on the role of cyclins and related genes in the control of the mammalian cell cycle, the types of abnormalities in these genes found in human tumors and the possible clinical implications of these findings.

Advances in sarcoma gene mutations and therapeutic targets

Sarcomas are rare and complex malignancies that have been associated with a poor prognostic outcome. Over the last few decades, traditional treatment with surgery and/or chemotherapy has not significantly improved outcomes for most types of sarcomas. In recent years, there have been significant advances in the understanding of specific gene mutations that are important in driving the pathogenesis and progression of sarcomas. Identification of these new gene mutations, using next-generation sequencing and advanced molecular techniques, has revealed a range of potential therapeutic targets. This, in turn, may lead to the development of novel agents targeted to different sarcoma subtypes. In this review, we highlight the advances made in identifying sarcoma gene mutations, including those of p53, RB, PI3K and IDH genes, as well as novel therapeutic strategies aimed at utilizing these mutant genes. In addition, we discuss a number of preclinical studies and ongoing early clinical trials in sarcoma targeting therapies, as well as gene editing technology, which may provide a better choice for sarcoma patient management.

Cell cycle transcription control: DREAM/MuvB and RB-E2F complexes

The precise timing of cell cycle gene expression is critical for the control of cell proliferation; de-regulation of this timing promotes the formation of cancer and leads to defects during differentiation and development. Entry into and progression through S phase requires expression of genes coding for proteins that function in DNA replication. Expression of a distinct set of genes is essential to pass through mitosis and cytokinesis. Expression of these groups of cell cycle-dependent genes is regulated by the RB pocket protein family, the E2F transcription factor family, and MuvB complexes together with B-MYB and FOXM1. Distinct combinations of these transcription factors promote the transcription of the two major groups of cell cycle genes that are maximally expressed either in S phase (G1/S) or in mitosis (G2/M). In this review, we discuss recent work that has started to uncover the molecular mechanisms controlling the precisely timed expression of these genes at specific cell cycle phases, as well as the repression of the genes when a cell exits the cell cycle.

Mutational analysis of driver genes with tumor suppressive and oncogenic roles in gastric cancer

Gastric cancer (GC) is a complex disease with heterogeneous genetic mechanisms. Genomic mutational profiling of gastric cancer not only expands our knowledge about cancer progression at a fundamental genetic level, but also could provide guidance on new treatment decisions, currently based on tumor histology. The fact that precise medicine-based treatment is successful in a subset of tumors indicates the need for better identification of clinically related molecular tumor phenotypes, especially with regard to those driver mutations on tumor suppressor genes (TSGs) and oncogenes (ONGs). We surveyed 313 TSGs and 160 ONGs associated with 48 protein coding and 19 miRNA genes with both TSG and ONG roles. Using public cancer mutational profiles, we confirmed the dual roles of CDKN1A and CDKN1B. In addition to the widely recognized alterations, we identified another 82 frequently mutated genes in public gastric cancer cohort. In summary, these driver mutation profiles of individual GC will form the basis of personalized treatment of gastric cancer, leading to substantial therapeutic improvements.

Tumors arise from the excessive repair of damaged stem cells

Although many hypotheses for tumorigenesis have been proposed, none can explain the occurrence and development of tumors comprehensively until now. We put forward a new hypothesis: tumors arise from the excessive repair of damaged stem cells. There are stem cells in all tissues and organs, and the stem cells have perfect damage repair mechanisms, including damage repair systems and repair-inhibiting systems. Tumors arise from the excessive repair of damaged stem cells, i.e., carcinogens induce stem cell damage, leading to overexpression of damage repair systems, and simultaneous inactivation of repair-inhibiting systems through genetic or non-genetic mechanisms, finally forming tumors. The outcome (forming clinically significant tumors or death) and development (tumor recurrence, metastasis or spontaneous healing) of the tumor cells depends on whether the injury and the excessive repair persists, whether immune surveillance function is normal and the tumor microenvironment is appropriate. This hypothesis not only addresses the issues of where tumor cells arise from, how tumors form and where they go, but also provides a reasonable explanation for many unresolved issues in tumor occurrence, development, metastasis or healing. In addition, this hypothesis could guide the early diagnosis, reasonable treatment and effective prevention of tumors.

Tumor suppressor gene methylation on the short arm of chromosome 1 in chronic myelogenous leukemia

OBJECTIVES

We previously reported loss of heterozygosity on 1p in chronic myelogenous leukemia (CML). We analyzed promoter methylation and mutation of tumor suppressor genes on 1p36 in CML.

METHODS

We performed methylation-specific PCR (MS-PCR) analysis of the PRDM2, RUNX3, and TP73 genes in 61 patients with CML (43 chronic phase, CP; two accelerated phase; and 16 blast crisis, BC). Oxidative MS-PCR, PCR-single-strand conformation polymorphism, and real-time reverse transcriptase PCR were also analyzed. K-562 cells were grown in the presence of 5-Aza-dC and trichostatin A.

RESULTS

Methylation of the PRDM2, RUNX3, and TP73 genes was detected in 24/60 (40%), 21/61 (34%), and 28/60 (47%) patients, respectively. Methylation of all three genes was detected in 19/59 (32%) patients. Methylation was more frequent in BC than in CP. Oxidative MS-PCR analysis detected 5-mC in the PRDM2, RUNX3, and TP73 genes in 10/22 (45%), 15/21 (71%), and 16/26 (62%) samples with methylation detected by MS-PCR, respectively. Decreased expression was observed in several samples with methylation, while no mutations were found in the genes. Treatment of K-562 cells induced growth suppression, demethylation, and reexpression of the PRDM2 and RUNX3 genes.

CONCLUSION

Multiple tumor suppressor genes on 1p were inactivated in CML by methylation.

The one-carbon metabolism pathway highlights therapeutic targets for gastrointestinal cancer (Review)

After the initial use of anti-folates for treatment of malignancies, folate metabolism has emerged as a rational diagnostic and therapeutic target in gastrointestinal cancer. The one-carbon metabolic pathway, which comprises three critical reactions (i.e., folate and methionine cycles), underlies this effect in conjunction with the trans-sulfuration pathway. Understanding of the one-carbon metabolism pathway has served to unravel the link between the causes and effects of cancer phenotypes leading to several seminal discoveries such as that of diadenosine tri-phosphate hydrolase, microRNAs, 5-FU and, more recently, trifluridine. In the folate cycle, glycine and serine fuel the mitochondrial enzymes SHMT2, MTHFD2 and ALDH1L2, which play critical roles in the cancer survival and proliferation presumably through purine production. In the methionine cycle, S-adenocyl methionine serves hydrocarbons and polyamines that are critical for the epigenetic controls. The trans-sulfuration pathway is a critical component in the synthesis of glutathione, which is involved in the production of reactive oxygen species in cancer stem cells. Therefore, characterization of one-carbon metabolism is indispensable to the development of precision medicine in the context of cancer diagnostics and therapeutics. In the present study, we review the historical issues associated with one-carbon metabolism and highlight the recent advances in cancer research.

Semiparametric profile likelihood estimation for continuous outcomes with excess zeros in a random-threshold damage-resistance model

Continuous outcome data with a proportion of observations equal to zero (often referred to as semicontinuous data) arise frequently in biomedical studies. Typical approaches involve two-part models, with one part a logistic model for the probability of observing a zero and some parametric continuous distribution for modeling the positive part of the data. We propose a semiparametric model based on a biological system with competing damage manifestation and resistance processes. This allows us to derive a closed-form profile likelihood based on the retro-hazard function, leading to a flexible procedure for modeling continuous data with a point mass at zero. A simulation study is presented to examine the properties of the method in finite samples. We apply the method to a data set consisting of pulmonary capillary hemorrhage area in lab rats subjected to diagnostic ultrasound. Copyright © 2017 John Wiley & Sons, Ltd.

Clinical Outcomes of TP53 Mutations in Cancers

High-throughput sequencing of cancer genomes is increasingly becoming an essential tool of clinical oncology that facilitates target identification and targeted therapy within the context of precision medicine. The cumulative profiles of somatic mutations in cancer yielded by comprehensive molecular studies also constitute a fingerprint of historical exposures to exogenous and endogenous mutagens, providing insight into cancer evolution and etiology. Mutational signatures that were first established by inspection of the TP53 gene somatic landscape have now been confirmed and expanded by comprehensive sequencing studies. Further, the degree of granularity achieved by deep sequencing allows detection of low-abundance mutations with clinical relevance. In tumors, they represent the emergence of small aggressive clones; in normal tissues, they signal a mutagenic exposure related to cancer risk; and, in blood, they may soon become effective surveillance tools for diagnostic purposes and for monitoring of cancer prognosis and recurrence.

The Significance of c-erbB-2 Overexpression and p53 Expression in Patients With Axillary Lymph Node—Negative Breast Cancer: A Tissue Microarray Study

We conducted this study to examine whether the expression of c-erbB-2 and p53 is the prognostic indicator for patients with early-stage breast cancer in which axillary lymph node metastasis is absent. We examined 326 patients with early-stage breast cancer in which axillary lymph node metastasis is absent. Tissue microarrays were constructed. Following this, immunohistochemical staining was done for estrogen receptor (ER), progesterone receptor (PR), c-erbB2, and p53. The results were as follows: (1) expression of c-erbB-2 was correlated with other clinicopathologic factors (eg, patient's age, presence of menopause, tumor size, histologic and nuclear grade, and presence of hormone receptors such as ER and PR); and (2) expression of p53 was correlated with survival rate, patient's age, presence of menopause, and tumor size. However, these results were not statistically significant. In conclusion, our results indicate that expression of c-erbB-2 and p53 did not have any prognostic value in patients with early-stage breast cancer in which axillary lymph node metastasis is absent.

p53 Mutations and Tumor Progression in Well-differentiated Liposarcoma and Dermatofibrosarcoma Protuberans

Mutations of the tumor suppressor gene p53 have been identified in a wide variety of human tumors, including soft tissue sarcomas. Most missense mutations of p53 increase the half-life of the protein resulting in its accumulation in the nucleus. Immunohistochemical staining with a monoclonal antibody PABI801 (Oncogene Science, Uniondale, NY) detects the intranuclear accumulation of p53 protein in formalin-fixed tissue, and, thus, indicates the presence of missense mutations within the p53 gene. We compared p53 immunoreactivity in paraffin sections of low-grade sarcomas that progressed to high-grade lesions with low-grade sarcomas that had not progressed to high-grade lesions to determine if (1) histologic progression is associated with increasing incidence of p53 missense mutations, and (2) p53 missense mutations within low-grade areas are predictive of which lesions undergo histologic progression. To examine these questions we studied well-differentiated liposarcoma with and without dedifferentiation and dermatofibrosarcoma protuberans with and without areas of fibrosarcoma. Nuclear p53 immunoreactivity was detected in 48% (12/25) of well-differentiated liposarcoma with dedifferentiation compared to only 6% (1/17) of well-differentiated liposarcoma alone. p53 nuclear immunoreactivity was also detected in 25% (4/16) of dermatofibrosarcoma protuberans with fibrosarcoma, and in 0% (0/24) of dermatofibrosarcoma protuberans lacking fibrosarcoma. In cases of well-differentiated liposarcoma with dedifferentiation and dermatofibrosarcoma protuberans with fibrosarcoma displaying immunoreactivity, the staining occurred almost exclusively in the high-grade areas and very infrequently in the low-grade regions as well. We conclude that histologic progression of well-differentiated liposarcoma and dermatofibrosarcoma protuberans is associated with increased nuclear p53 immunoreactivity. Since p53 immunoreactivity occurs infrequently in the low-grade areas of those sarcomas that had transformed to higher grade lesions, it does not appear to be a useful predictor of tumor progression in low-grade lesions. Int J Surg Pathol 3(1):35-42, 1995