Clonal p53 mutation in primary cervical cancer: association with human-papillomavirus-negative tumours

HPV16 Genomes: In Silico Analysis of E6 and E7 Oncoproteins in 20 South American Variants

Background

Human papillomavirus (HPV) is the main risk factor for the development of squamous cell cervical cancer, and E6 oncoprotein and E7 oncoprotein are important components of the viral genome and its oncogenic potential. It is known that different viral variants of HPV16 have different pathology and impact on the development of neoplasia, although few studies have been performed on South American variants.

Objective

Therefore, the present study aimed to analyze in silico the genomic diversity of HPV16 in 20 complete genome variants of South America in the National Center for Biotechnology Information (NCBI) database.

Methods

We performed a descriptive study to characterize the polymorphic regions of the E6 and E7 genes in HPV16 variants, using software for genomic data and single nucleotide polymorphism (SNP) analysis and others for phylogenetic analysis.

Results

The variants analyzed included six SNPs linked to cancer (A131G, G145T, C335T, T350G, C712A, and T732C) and significant variation (798 nucleotide substitutions). Despite this, the variants showed low genetic diversity. Eighteen variants of unclear significance (VUS) were identified, 10 of which were in the coding E6 regions and 8 in the coding E7 regions. The prevalence of lineage D variants is of concern due to their pathology in cervical cancer and requires more research and epidemiological vigilance regarding their prevalence in the population.

Conclusion

The data obtained in this study may contribute to future research on South American variants of HPV16, their pathogenicity, and the development of treatments.

A Review: Genetic Mutations as a Key to Unlocking Drug Resistance in Cervical Cancer

Cervical cancer is the fourth most common cancer in women. Advanced stage and metastatic disease are often associated with poor clinical outcomes. This substantiates the absolute necessity for high-throughput diagnostic and treatment platforms that are patient and tumour specific. Cervical cancer treatment constitutes multimodal intervention. Systemic treatments such as chemotherapy and/or focal radiotherapy are typically applied as neoadjuvant and/or adjuvant strategies. Cisplatin constitutes an integral part of standard cervical cancer treatment approaches. However, despite initial patient response, de novo or delayed/acquired treatment resistance is often reported, and toxicity is of concern. Chemotherapy resistance is associated with major alterations in genomic, metabolomic, epigenetic and proteomic landscapes. This results in imbalanced homeostasis associated with pro-oncogenic and proliferative survival, anti-apoptotic benefits, and enhanced DNA damage repair processes. Although significant developments in cancer diagnoses and treatment have been made over the last two decades, drug resistance remains a major obstacle to overcome.

HPV-associated cancers: insights into the mechanistic scenario and latest updates

Cancer and related diseases are the second leading cause of death worldwide. The human papillomavirus (HPV) is an infectious agent that can be spread mainly through sexual contact and has been linked to several malignancies in both sexes. HPV is linked to almost all cases of cervical cancer. It is also linked to many head and neck cancer (HNC) cases, especially oropharyngeal cancer. Also, some HPV-related cancers, like vaginal, vulvar, penile, and anal cancers, are related to the anogenital area. Over the past few decades, testing for and preventing cervical cancer has improved, but anogenital cancers are still harder to confirm. HPV16 and HPV18 have been extensively researched due to their significant carcinogenic potential. The products of two early viral genes, E6 and E7, have been identified as playing crucial roles in cellular transformation, as emphasized by biological investigations. The complete characterization of numerous mechanisms employed by E6 and E7 in undermining the regulation of essential cellular processes has significantly contributed to our comprehension of HPV-induced cancer progression. This review focuses on the various types of cancers caused by HPV infection and also sheds light on the signaling cascades involved in the same.

Whole-Exome Sequencing Could Distinguish Primary Pulmonary Squamous Cell Carcinoma From Lung Metastases in Individuals With Cervical Squamous Cell Carcinoma

Aims: Metastatic cervical carcinoma is hard to cure using traditional treatment and new therapeutic approaches are needed. However, the process of clonal evolution and the molecular alterations that contribute to tumor progression from primary to metastatic carcinoma remain unclear. It is currently difficult to distinguish between the primary pulmonary squamous cell carcinoma (PPSCC) and metastatic cervical squamous cell carcinoma (CSCC). Methods: Paired primary CSCC and lung/lymph nodes metastatic lesions from eight patients were analyzed by whole-exome sequencing (WES). WES data of matched specimens and normal samples were aligned to the human reference genome and analyzed to identify somatic mutations in primary and metastatic lesions. Results: A total of 1,254 somatic variants were identified. All the primary lesions and metastatic lesions shared mutations, the percentage of shared mutations between primary lesions and corresponding metastatic lesions varied significantly, ranging from 6% to 70%. In other words, all the metastatic lesions are clonally related to primary lesions, confirming WES could prove they are metastatic from the cervix but not PPSCC. We tried to apply a gene panel to help distinguish PPSCC and metastatic CSCC but failed because the mutations were widely distributed in CSCC. Interestingly, lymph nodes metastasis (LNM) harbored fewer cancer driver mutations than primary CSCC specimens with a significant difference. Besides this, there was no significant difference in somatic mutations and copy number variation (CNV) between primary and metastatic CSCC. Conclusion: Our data demonstrate that WES is an additional helpful tool in distinguishing PPSCC and metastatic CSCC, especially for certain difficult cases.

A small-molecule inhibitor of MDMX suppresses cervical cancer cells via the inhibition of E6-E6AP-p53 axis

Dysfunction of p53 is observed in many malignant tumors, which is related to cancer susceptibility. In cervical cancer, p53 is primarily degradated through the complex of high-risk human papillomaviruses (HPV) oncoprotein E6 and E6-associated protein (E6AP) ubiquitin ligase. What is less clear is the mechanism and role of murine double minute X (MDMX) in cervical carcinogenesis due to the inactive status of murine double minute 2 (MDM2). In the current study, XI-011 (NSC146109), a small-molecule inhibitor of MDMX, showed robust anti-proliferation activity against several cervical cancer cell lines. XI-011 promoted apoptosis of cervical cancer cells via stabilizing p53 and activating its transcription activity. Moreover, XI-011 inhibited the growth of xenograft tumor in HeLa tumor-bearing mice, as well as enhanced the cytotoxic activity of cisplatin both in vitro and in vivo. Interestingly, MDMX co-locolized with E6AP and seems to be a novel binding partner of E6AP to promote p53 ubiquitination. In conclusion, this work revealed a novel mechanism of ubiquitin-dependent p53 degredation via MDMX-E6AP axis in cervical carcinogenesis, and offered the first evidence that MDMX could be a viable drug target for the treatment of cervical cancer.

Prognostic Markers and Driver Genes and Options for Targeted Therapy in Human-Papillomavirus-Positive Tonsillar and Base-of-Tongue Squamous Cell Carcinoma

The incidence of Human-papillomavirus-positive (HPV⁺) tonsillar and base-of-tongue squamous cell carcinoma (TSCC and BOTSCC, respectively) is increasing epidemically, but they have better prognosis than equivalent HPV-negative (HPV⁻) cancers, with roughly 80% vs. 50% 3-year disease-free survival, respectively. The majority of HPV⁺ TSCC and BOTSCC patients therefore most likely do not require the intensified chemoradiotherapy given today to head and neck cancer patients and would with de-escalated therapy avoid several severe side effects. Moreover, for those with poor prognosis, survival has not improved, so better-tailored alternatives are urgently needed. In line with refined personalized medicine, recent studies have focused on identifying predictive markers and driver cancer genes useful for better stratifying patient treatment as well as for targeted therapy. This review presents some of these endeavors and briefly describes some recent experimental progress and some clinical trials with targeted therapy.

Integrative Systems Biology Approaches to Identify Potential Biomarkers and Pathways of Cervical Cancer

Nowadays, cervical cancer (CC) is treated as the leading cancer among women throughout the world. Despite effective vaccination and improved surgery and treatment, CC retains its fatality rate of about half of the infected population globally. The major screening biomarkers and therapeutic target identification have now become a global concern. In the present study, we have employed systems biology approaches to retrieve the potential biomarkers and pathways from transcriptomic profiling. Initially, we have identified 76 of each up-regulated and down-regulated gene from a total of 4643 differentially expressed genes. The up-regulatory genes mainly concentrate on immune-inflammatory responses, and the down-regulatory genes are on receptor binding and gamma-glutamyltransferase. The involved pathways associated with these genes were also assessed through pathway enrichment, and we mainly focused on different cancer pathways, immunoresponse, and cell cycle pathways. After the subsequent enrichment of these genes, we have identified 12 hub genes, which play a crucial role in CC and are verified by expression profile analysis. From our study, we have found that genes LILRB2 and CYBB play crucial roles in CC, as reported here for the first time. Furthermore, the survivability of the hub genes was also assessed, and among them, finally, CXCR4 has been identified as one of the most potential differentially expressed genes that might play a vital role in the survival of CC patients. Thus, CXCR4 could be used as a prognostic and/or diagnostic biomarker and a drug target for CC.

Identification of significant genes signatures and prognostic biomarkers in cervical squamous carcinoma via bioinformatic data

Background

Cervical squamous cancer (CESC) is an intractable gynecological malignancy because of its high mortality rate and difficulty in early diagnosis. Several biomarkers have been found to predict the prognose of CESC using bioinformatics methods, but they still lack clinical effectiveness. Most of the existing bioinformatic studies only focus on the changes of oncogenes but neglect the differences on the protein level and molecular biology validation are rarely conducted.

Methods

Gene set data from the NCBI-GEO database were used in this study to compare the differences of gene and protein levels between normal and cancer tissues through significant pathway selection and core gene signature analysis to screen potential clinical biomarkers of CESC. Subsequently, the molecular and protein levels of clinical samples were verified by quantitative transcription PCR, western blot and immunohistochemistry.

Results

Three differentially expressed genes (RFC4, MCM2, TOP2A) were found to have a significant survival (P < 0.05) and highly expressed in CESC tissues. Molecular biological verification using quantitative reverse transcribed PCR, western blotting and immunohistochemistry assays exhibited significant differences in the expression of RFC4 between CESC and para-cancerous tissues (P < 0.05).

Conclusion

This study identified three potential biomarkers (RFC4, MCM2, TOP2A) of CESC which may be useful to clarify the underlying mechanisms of CESC and predict the prognosis of CESC patients.

Integrated Analysis of TP53 Gene and Pathway Alterations in The Cancer Genome Atlas

The TP53 tumor suppressor gene is frequently mutated in human cancers. An analysis of five data platforms in 10,225 patient samples from 32 cancers reported by The Cancer Genome Atlas (TCGA) enables comprehensive assessment of p53 pathway involvement in these cancers. More than 91% of TP53-mutant cancers exhibit second allele loss by mutation, chromosomal deletion, or copy-neutral loss of heterozygosity. TP53 mutations are associated with enhanced chromosomal instability, including increased amplification of oncogenes and deep deletion of tumor suppressor genes. Tumors with TP53 mutations differ from their non-mutated counterparts in RNA, miRNA, and protein expression patterns, with mutant TP53 tumors displaying enhanced expression of cell cycle progression genes and proteins. A mutant TP53 RNA expression signature shows significant correlation with reduced survival in 11 cancer types. Thus, TP53 mutation has profound effects on tumor cell genomic structure, expression, and clinical outlook.

Aberrant methylation-mediated downregulation of lncRNA CCND2 AS1 promotes cell proliferation in cervical cancer

Background

Long non-coding RNA (lncRNA) plays an important role in tumorigenesis. The lncRNA CCND2 AS1 has been shown to be involved in the growth of several tumors; however, its role in cervical cancer has not been elucidated. This study aimed to explore the expression, function, and underlying mechanism of action of CCND2 AS1 in cervical cancer. Expression of CCND2 AS1 was examined in cervical cancer and adjacent normal cervical tissues by quantitative real-time polymerase chain reaction (qRT-PCR) and by bioinformatic analysis of data from the Gene Expression Profiling Interactive Analysis (GEPIA) database. The function of CCND2 AS1 was investigated by overexpressing or silencing CCND2 AS1 in HeLa and SiHa cervical cancer cells followed by in vitro and in vivo analyses. Methylation-specific PCR (MSP) and bisulfite genomic sequencing (BGS) were used to detect CCND2 AS1 promoter methylation status in cervical cancer cells.

Results

CCND2 AS1 expression was lower in cervical cancer compared with normal cervical tissues, and the level was significantly correlated with the patient age and tumor size. CCND2 AS1 overexpression inhibited the proliferation and cell cycle progression of HeLa cells in vitro and/or in vivo, whereas CCND2 AS1 silencing had the opposite effects. CCND2 AS1 expression was elevated after treatment of cervical cancer cells with the DNA methyltransferase inhibitor 5′-azacytidine (5′-Aza), and this was mediated, at least in part, via reduced CpG methylation at the CCND2 AS1 promoter.

Conclusion

CCND2 AS1 expression is downregulated in cervical cancer, potentially through increased CCND2 AS1 promoter methylation, and the upregulation of CCND2 AS1 expression inhibited tumor growth. These data suggest that CCND2 AS1 could be a diagnostic marker and potential therapeutic target for cervical cancer.

p53-PHLDA3-Akt Network: The Key Regulators of Neuroendocrine Tumorigenesis

p53 is a well-known tumor suppressor gene and one of the most extensively studied genes in cancer research. p53 functions largely as a transcription factor and can trigger a variety of antiproliferative programs via induction of its target genes. We identified PHLDA3 as a p53 target gene and found that its protein product is a suppressor of pancreatic neuroendocrine tumors (PanNETs) and a repressor of Akt function. PHLDA3 is frequently inactivated by loss of heterozygosity (LOH) and methylation in human PanNETs, and LOH at the PHLDA3 gene locus correlates with PanNET progression and poor prognosis. In addition, in PHLDA3-deficient mice, pancreatic islet cells proliferate abnormally and acquire resistance to apoptosis. In this article, we briefly review the roles of p53 and Akt in human neuroendocrine tumors (NETs) and describe the relationship between the p53-PHLDA3 and Akt pathways. We also discuss the role of PHLDA3 as a tumor suppressor in various NETs and speculate on the possibility that loss of PHLDA3 function may be a useful prognostic marker for NET patients indicating particular drug therapies. These results suggest that targeting the downstream PHLDA3-Akt pathway might provide new therapies to treat NETs.

ALOX12B promotes carcinogenesis in cervical cancer by regulating the PI3K/ERK1 signaling pathway

Cervical cancer is a malignant disease and a threat to women's health worldwide. Surgical resection followed by radiotherapy or chemotherapy is the main treatment strategy for cervical cancer; however, patients with cervical cancer, especially those with late-stage disease, may not benefit from these traditional therapies, which results in poor clinical outcome. ALOX12B is a gene encoding lipoxygenase, and a mutation in ALOX12B was detected in lung and breast cancer. Furthermore, ALOX12B is essential to the proliferation of epidermoid carcinoma cells; however, the role of ALOX12B in cervical cancer has not been studied thus far, to the best of our knowledge. In the present study, the expression levels of ALOX12B were reduced in cervical cancer cells by lentiviral transfection, and it was found that both cell proliferation and clone formation ability were significantly reduced, and the cell cycle was blocked at G₁ phase. Tumor growth was also suppressed in vivo in a xenograft tumor model, but the migration of tumor cells was not affected by ALOX12B. Subsequently, using western blotting, it was demonstrated that knockdown of ALOX12B decreased the expression levels of PI3K, MEK1, ERK1, C-fos and cdc25. Meanwhile, overexpression of ALOX12B increased the expression levels of these five molecules. Conclusively, ALOX12B promoted cell proliferation in cervical cancer via regulation of the PI3K/ERK1 signaling pathway. The present study may improve our understanding of the molecular mechanisms underlying the function of ALOX12B in cervical cancer and inform new therapeutic strategies.

Human Papillomavirus Infection, p16INK4a Expression and Genetic Alterations in Vietnamese Cervical Neuroendocrine Cancer

Neuroendocrine cervical cancer is a rare subtype of cervical cancer with a highly aggressive malignancy. This study was conducted to analyse the human papillomavirus (HPV) infection and molecular abnormalities in Vietnamese neuroendocrine carcinomas of the uterine cervix. HPV genotyping and p53 mutations were examined using polymerase chain reaction (PCR)-based direct sequencing. Mutations of epidermal growth factor receptor (EGFR), Kirsten rat sarcoma (KRAS), neuroblastoma RAS viral oncogene homolog (NRAS) and v-Raf murine sarcoma viral oncogene homolog B (BRAF) were identified using commercial kits. Four high-risk HPV genotypes were identified in 26 (86.7%) out of a total of 30 tumours. The prevalence of HPV 16, 18, 31 and 45 was 20.0%, 50.0%, 20.0% and 36.7%, respectively. Overexpression of p16^INK4a was observed in 93.3% of cases and was significantly correlated with high-risk HPV infections. Furthermore, p53 and NRAS mutations were detected in five (16.7%) and one (3.3%) cases, respectively, whereas no EGFR, KRAS or BRAF mutations were observed. These results demonstrate that high-risk HPV infection may be an important oncogenic factor for the development and progression of cervical neuroendocrine carcinoma.

Identification of driver genes regulating immune cell infiltration in cervical cancer by multiple omics integration

Cervical cancer (CC) is one of the most common cancers in women. However, copy number alteration (CNA)-driven dysregulated genes and their functions in CC are still rarely investigated. In the present study, we conducted integrative analysis of CNA and gene expression data from The Cancer Genome Atlas (TCGA) cervical cancer to identify dysregulated genes triggered by CNAs. The integration of copy number status and RNA expression revealed 763 amplified and 1,391 deleted genes significantly dysregulated by the CNAs (P-value < 1e-8). Among these CNA genes, five driver genes, including PI3KCA, PI3KCB, DVL3, WWTR1, and ERBB2, exhibited a strong association with immune cell infiltration, suggesting that the pathways that they participate in may be involved in regulating immune cell infiltration. Moreover, we also observed that the genes of immunotherapeutic targets were abundantly expressed in the wild-type samples, suggesting that immunotherapy based on these immunotherapeutic targets may be applied to wild-type samples. In addition, the two CNA driver genes, DVL3 and ERBB2, might be sensitive and resistant biomarkers for examining the tumor's response to chemoradiotherapy, respectively. Particularly, the expression of ERBB2 was also observed to be higher in responders of chemotherapy than non-responders. Furthermore, a subset of CNA genes was identified to predict the prognosis of cervical cancer. In summary, our systematic data analysis of these CNA genes not only improved our understanding of the veiled mechanism behind immune cell infiltration, but also provided the potential clinical application of these CNA genes in cervical cancer.

Identification of Significant Gene Signatures and Prognostic Biomarkers for Patients With Cervical Cancer by Integrated Bioinformatic Methods

Cervical cancer is the leading cause of death with gynecological malignancies. We aimed to explore the molecular mechanism of carcinogenesis and biomarkers for cervical cancer by integrated bioinformatic analysis. We employed RNA-sequencing details of 254 cervical squamous cell carcinomas and 3 normal samples from The Cancer Genome Atlas. To explore the distinct pathways, messenger RNA expression was submitted to a Gene Set Enrichment Analysis. Kyoto Encyclopedia of Genes and Genomes and protein–protein interaction network analysis of differentially expressed genes were performed. Then, we conducted pathway enrichment analysis for modules acquired in protein–protein interaction analysis and obtained a list of pathways in every module. After intersecting the results from the 3 approaches, we evaluated the survival rates of both mutual pathways and genes in the pathway, and 5 survival-related genes were obtained. Finally, Cox hazards ratio analysis of these 5 genes was performed. DNA replication pathway (P < .001; 12 genes included) was suggested to have the strongest association with the prognosis of cervical squamous cancer. In total, 5 of the 12 genes, namely, minichromosome maintenance 2, minichromosome maintenance 4, minichromosome maintenance 5, proliferating cell nuclear antigen, and ribonuclease H2 subunit A were significantly correlated with survival. Minichromosome maintenance 5 was shown as an independent prognostic biomarker for patients with cervical cancer. This study identified a distinct pathway (DNA replication). Five genes which may be prognostic biomarkers and minichromosome maintenance 5 were identified as independent prognostic biomarkers for patients with cervical cancer.

CRISPR/Cas9-mediated cervical cancer treatment targeting human papillomavirus E6

High-risk human papillomavirus (HPV) is a common cause of cervical cancer. HPV E6 oncoprotein promotes the degradation of host tumor suppressor gene p53, leading to the development of tumors. Therapeutic strategies that specifically target E6, which is constitutively expressed in tumors and is not present in normal tissues, may be highly effective and safe. CRISPR-CRISPR associated protein 9 (Cas9) is one of the genome editing technologies that has recently garnered attention, and is used to knockout target gene expression. By combining cervical cancer cell lines engineered to constitutively express Cas9 and an adeno-associated virus (AAV) vector carrying a single guide (sg) RNA targeting E6 (AAV-sgE6), the present study sought to investigate the effects of this novel therapeutic approach on cervical cancer. The Cas9 gene was transfected into three high-risk HPV-positive cervical cancer cell lines (HeLa, HCS-2, and SKG-I) to establish cell lines that constitutively expressed Cas9. Using these cell lines, genetic mutations and their frequencies, as well as the levels of protein expression, apoptosis and cell proliferation were examined in vitro. In addition, the effects of AAV-sgE6 were examined in a mouse model of cervical cancer in vivo by a single administration of AAV-sgE6 directly into subcutaneous tumors. The results demonstrated that multiple mutations occurred frequently in the targeted E6 genomic sequence in cervical cancer cells transduced with AAV-sgE6. In addition, these AAV-sgE6-transduced cells had reduced expression of E6, increased expression of p53, increased apoptosis and their growth was suppressed in a concentration-dependent manner. Furthermore, subcutaneous tumor growth was significantly suppressed in vivo following intratumoral administration of AAV-sgE6, and adverse events due to AAV-sgE6 administration were not observed. Collectively, the present results indicated that targeting E6 expression in high-risk HPV by CRISPR-Cas9 is a highly specific and effective strategy that may be effective in treating patients with cervical cancer.

Expression of Micro-RNA-492 (MiR-492) in Human Cervical Cancer Cell Lines is Upregulated by Transfection with Wild-Type P53, Irradiation, and 5-Fluorouracil Treatment In Vitro

Background

The status of p53 is critical to the chemoradiosensitivity of cervical cancer cells. Wild-type p53 is essential to orchestrate the cellular response to cytotoxic stimuli. Our previous data illustrated that cervical cancer patients whose specimens overexpressed microR-492 (miR-492) were highly sensitive to concurrent chemoradiation. Although p53 activation has been reported to upregulate miR-492 by a miRNA profiling assay in lung cancer cells, the transcriptional regulation of miR-492 in cervical cancer cells remains poorly understood. Therefore, we aimed to decipher the relationship between p53 and miR-492 in cervical cancer cells.

Material/Methods

The expression of p53 and miR-492 in cervical cancer cell lines was measured by western blot and real-time PCR. After cells were transfected with wild-type p53 plasmid or were treated by irradiation and 5-fluorouracil (5-FU), the expression changes of p53 as well as miR-492 were examined by western blot and real-time PCR. The putative p53 binding site of miR-492 was first analyzed by bioinformatics tools, then validated by chromatin immunoprecipitation and dual-luciferase reporter assays.

Results

We found that miR-492 was upregulated in cells with wild-type p53 compared to cells with mutant p53. Transfection of wild-type p53 plasmid or treatments with cytotoxic reagents including irradiation and 5-FU all induced miR-492 overexpression. Bioinformatics analysis and experimental validations further proved p53 interacted with miR-492 promoter directly.

Conclusions

In cervical cancer cells, p53 activated miR-492 expression transcriptionally.

Single cell whole genome sequencing reveals that NFKB1 mutation affects radiotherapy sensitivity in cervical cancer

Cervical cancer is the third most common cancer in women. Radiotherapy resistance remains a major obstacle for patients with cervical cancer. Somatic alterations in human genomes are responsible for radiotherapy resistance. Here, we performed single cell whole genome sequencing on 13 cells before radiotherapy and 12 cells after radiotherapy from a Chinese woman patient with cervical carcinoma. We identified one damaging mutation in NFKB1 (G430E), which showed significantly increased mutant allele frequency after radiotherapy than that before radiotherapy. Further functional assays showed that NFKB1 was a tumour suppressor in cervical cancer by inhibiting cell proliferation, colony formation and migration, while the mutation in NFKB1 could weaken the tumour suppressing functions of NFKB1. NFKB1 enhanced the sensitivity of cervical cancer cells to the effects of irradiation, and the mutation in NFKB1 weakened this effect. These results suggested that NFKB1 may be a potential molecular target in cervical cancer radiation therapy in the future.

Novel Somatic Copy Number Alteration Identified for Cervical Cancer in the Mexican American Population

Cervical cancer affects millions of Americans, but the rate for cervical cancer in the Mexican American is approximately twice that for non-Mexican Americans. The etiologies of cervical cancer are still not fully understood. A number of somatic mutations, including several copy number alterations (CNAs), have been identified in the pathogenesis of cervical carcinomas in non-Mexican Americans. Thus, the purpose of this study was to investigate CNAs in association with cervical cancer in the Mexican American population. We conducted a pilot study of genome-wide CNA analysis using 2.5 million markers in four diagnostic groups: reference (n = 125), low grade dysplasia (cervical intraepithelial neoplasia (CIN)-I, n = 4), high grade dysplasia (CIN-II and -III, n = 5) and invasive carcinoma (squamous cell carcinoma (SCC), n = 5) followed by data analyses using Partek. We observed a statistically-significant difference of CNA burden between case and reference groups of different sizes (>100 kb, 10-100 kb and 1-10 kb) of CNAs that included deletions and amplifications, e.g., a statistically-significant difference of >100 kb deletions was observed between the reference (6.6%) and pre-cancer and cancer (91.3%) groups. Recurrent aberrations of 98 CNA regions were also identified in cases only. However, none of the CNAs have an impact on cancer progression. A total of 32 CNA regions identified contained tumor suppressor genes and oncogenes. Moreover, the pathway analysis revealed endometrial cancer and estrogen signaling pathways associated with this cancer (p < 0.05) using Kyoto Encyclopedia of Genes and Genomes (KEGG). This is the first report of CNAs identified for cervical cancer in the U.S. Latino population using high density markers. We are aware of the small sample size in the study. Thus, additional studies with a larger sample are needed to confirm the current findings.

Attenuating the p53 Pathway in Human Cancers: Many Means to the Same End

The p53 pathway is perturbed in the majority of human cancers. Although this most frequently occurs through the direct mutation or deletion of p53 itself, there are a number of other alterations that can attenuate the pathway and contribute to tumorigenesis. For example, amplification of important negative regulators, MDM2 and MDM4, occurs in a number of cancers. In this work, we will review both the normal regulation of the p53 pathway and the different mechanisms of pathway inhibition in cancer, discuss these alterations in the context of the global genomic analyses that have been conducted across tumor types, and highlight the translational implications for cancer diagnosis and treatment.

TRIM65 negatively regulates p53 through ubiquitination

Tripartite-motif protein family member 65 (TRIM65) is an important protein involved in white matter lesion. However, the role of TRIM65 in human cancer remains less understood. Through the Cancer Genome Atlas (TCGA) gene alteration database, we found that TRIM65 is upregulated in a significant portion of non-small cell lung carcinoma (NSCLC) patients. Our cell growth assay revealed that TRIM65 overexpression promotes cell proliferation, while knockdown of TRIM65 displays opposite effect. Mechanistically, TRIM65 binds to p53, one of the most critical tumor suppressors, and serves as an E3 ligase toward p53. Consequently, TRIM65 inactivates p53 through facilitating p53 poly-ubiquitination and proteasome-mediated degradation. Notably, chemotherapeutic reagent cisplatin induction of p53 is markedly attenuated in response to ectopic expression of TRIM65. Cell growth inhibition by TRIM65 knockdown is more significant in p53 positive H460 than p53 negative H1299 cells, and knockdown of p53 in H460 cells also shows compromised cell growth inhibition by TRIM65 knockdown, indicating that p53 is required, at least in part, for TRIM65 function. Our findings demonstrate TRIM65 as a potential oncogenic protein, highly likely through p53 inactivation, and provide insight into development of novel approaches targeting TRIM65 for NSCLC treatment, and also overcoming chemotherapy resistance.

To analyze the concomitant expression of human papillomavirus-16 in the pathogenetic model of p53-dependant pathway in oral squamous cell carcinoma

Background:

Oral squamous cell carcinoma (OSCC) accounts for 90% of all primary oral malignancies. Association between human papillomavirus (HPV) as a risk factor of cervical cancer is well known; there is a need to widen the knowledge for its role in oral cancer development. The viral E6 protein of HPV binds to p53 making it nonfunctional.

Aims and Objective:

To study mutated/wild type p53 expression using immunohistochemistry and detect HPV-16 presence using polymerase chain reaction (PCR), in OSCC and correlating their expression.

Materials and Methods:

Immunohistochemical staining for p53 molecule in 24 sections of OSCC followed by DNA extraction of the cases using qiagen extraction kit and subsequent HPV-16 detection using PCR technique.

Statistical Analysis:

The data were analysed using SPSS software version 19.

Results:

Out of 24 cases of OSCC, twenty cases were positive for P 53 expression and four cases were negative for P 53 expression. Out of the four negative cases, one case was detected positive for HPV-16.

Conclusion:

HPV infection along with p53 expression helps in understanding its exact pathogenesis which further helps in expanding our spectrum of therapeutic modalities

Immunotherapy and targeted therapy for cervical cancer: an update

The prognosis of patients with metastatic cervical cancer is poor with a median survival of 8-13 months. Despite the potency of chemotherapeutic drugs, this treatment is rarely curative and should be considered palliative only. In the last few years, a better understanding of Human papillomavirus tumor-host immune system interactions and the development of new therapeutics targeting immune check points have renewed interest in the use of immunotherapy in cervical cancer patients. Moreover, next generation sequencing has emerged as an attractive option for the identification of actionable driver mutations and other markers. In this review, we provide background information on the molecular biology of cervical cancer and summarize immunotherapy studies, targeted therapies, including those with angiogenesis inhibitors and tyrosine kinase inhibitors recently completed or currently on-going in cervical cancer patients.

Breaking the DNA damage response to improve cervical cancer treatment

Every year, cervical cancer affects ∼500,000 women worldwide, and ∼275,000 patients die of this disease. The addition of platin-based chemotherapy to primary radiotherapy has increased 5-year survival of advanced-stage cervical cancer patients, which is, however, still only 66%. One of the factors thought to contribute to treatment failure is the ability of tumor cells to repair chemoradiotherapy-induced DNA damage. Therefore, sensitization of tumor cells for chemoradiotherapy via inhibition of the DNA damage response (DDR) as a novel strategy to improve therapy effect, is currently studied pre-clinically as well as in the clinic. Almost invariably, cervical carcinogenesis involves infection with the human papillomavirus (HPV), which inactivates part of the DNA damage response. This HPV-mediated partial inactivation of the DDR presents therapeutic targeting of the residual DDR as an interesting approach to achieve chemoradio-sensitization for cervical cancer. How the DDR can be most efficiently targeted, however, remains unclear. The fact that cisplatin and radiotherapy activate multiple signaling axes within the DDR further complicates a rational choice of therapeutic targets within the DDR. In this review, we provide an overview of the current preclinical and clinical knowledge about targeting the DDR in cervical cancer.

Dysregulation of CDK inhibitors and p53 in HPV-negative endocervical adenocarcinoma

Human papillomavirus (HPV)-negative adenocarcinoma (AC) is a minor subset of endocervical cancer, but its pathogenesis has yet to be elucidated. This study investigated the clinicopathologic features of HPV-negative endocervical AC (n=14) in comparison with HPV-positive endocervical AC (n=30), and further studied aberrations of cell-cycle regulators. Expression patterns of cyclin-dependent kinase inhibitors (p16, p14, p27, and p21) and p53 were evaluated immunohistochemically, and nuclear high-risk HPV DNA signals were detected by in situ hybridization and polymerase chain reaction. Immunoexpression of p16, p14, p27, p21, and p53 were observed in 90%, 67%, 77%, 40%, and 20% of HPV-positive ACs, and in 0%, 0%, 29%, 14%, and 57% of HPV-negative ACs, respectively. A higher frequency of lymph node metastasis and worse prognosis were significantly associated with HPV-negative AC. Our findings suggest that alteration of cyclin-dependent kinase inhibitors and p53 status may contribute to carcinogenesis and the clinical behavior of HPV-negative AC of the uterine cervix.

Association of HPV with genetic and epigenetic alterations in colorectal adenocarcinoma from Indian population

Several studies from developing countries have shown human papillomavirus to be associated with colorectal cancers, but the molecular characteristics of such cancers are poorly known. We studied the various genetic variations like microsatellite instability (MSI), oncogenic mutations and epigenetic deregulations like CpG island methylation in HPV associated and nonassociated colorectal cancer patients from Indian population. HPV DNA was detected by PCR using My09/My11 and Gp5+/Gp6+ consensus primers and typed using HPV16 and HPV18 specific primers. MSI was detected using BAT 25 and BAT 26 markers, and mutation of KRAS, TP53 and BRAF V600E were detected by direct sequencing. Methyl specific polymerase chain reaction (MSP) was used to determine promoter methylation of the classical CIMP panel markers (P16, hMLH1, MINT1, MINT2 and MINT31) and other tumour-related genes (DAPK, RASSF1, BRCA1 and GSTP1). HPV DNA was detected in 34/93 (36.5 %) colorectal tumour tissues, HPV 18 being the predominant high-risk type. MSI was detected in 7.5 % cases; KRAS codon 12, 13, BRAF V600E and TP53 mutations were detected in 36.5, 3.2 and 37.6 % of the cases, respectively. CIMP-high was observed in 44.08 % cases. HPV presence was not associated with age, stage or grade of tumours, MSI or mutations in KRAS, TP53 or BRAF genes. Higher methylation frequencies of all genes/loci under study except RASSF1, as well as significantly higher CIMP-high characteristics were observed in HPV positive tumours as compared to negative cases. HPV in association with genetic and epigenetic features might be a potent risk factor for colorectal cancer in Indian population.

Absence of human papillomavirus infection and activation of PI3K-AKT pathway in cervical clear cell carcinoma

OBJECTIVE

Cervical cancer is the second most common cancer in females worldwide, and the majority of squamous cell carcinomas and adenocarcinomas are associated with high-risk human papillomavirus (HPV) infection. However, the relationship between clear cell carcinoma of the cervix (CCCC) and HPV is unclear. In this study, we sought to determine if HPV infection is associated with CCCC and to elucidate the signaling pathways involved.

METHODS

We collected samples from 13 CCCC patients and collated the relevant clinicopathologic data. We then evaluated the presence of HPV types 16, 18, 31, 33, 35, 52, and 58 by broad-spectrum amplification by polymerase chain reaction and HPV types 39, 45, 51, 56, 59, and 68 by nested polymerase chain reaction assay that combines degenerate E6/E7 consensus primers and type-specific primers from extracted genomic DNA. Immunohistochemistry was used to analyze the expression of EGFR (epidermal growth factor receptor), HER2, PTEN (phosphatase and tensin homolog), phospho-AKT, phospho-mTOR (mammalian target of rapamycin), p16, and p53. EGFR and HER2 gene amplification was determined by fluorescence in situ hybridization.

RESULTS

Patients with stage IB CCCC had a better 3-year overall survival rate compared with those with advanced-stage cancer (100% vs 44%; P = 0.014). High-risk HPVs were not detected in any of the cases examined. EGFR immunostaining was observed in 9 (75%) of 12 patients, HER2 in 3 (25%) of 12, PTEN in 6 (50%) of 12, and phospho-AKT in 7 (58%) of 12, and phospho-mTOR in 6 (50%) of 12. EGFR amplification could not be detected, but HER2 amplification was identified in 1 of (12.5%) 8 cases.

CONCLUSIONS

Patients with stage I CCCC demonstrated good overall survival and rare recurrence. Clear cell carcinoma of the cervix is unrelated to high-risk HPV infection; hence, current vaccines will not prevent the incidence of CCCC. However, increased EGFR or HER2 expression or activation of AKT or mTOR was observed in all cases, indicating that inhibitors of tyrosine kinases or the AKT-mTOR pathway may be suitable treatment regimens for CCCC.

Landscape of genomic alterations in cervical carcinomas

Cervical cancer is responsible for 10-15% of cancer-related deaths in women worldwide. The aetiological role of infection with high-risk human papilloma viruses (HPVs) in cervical carcinomas is well established. Previous studies have also implicated somatic mutations in PIK3CA, PTEN, TP53, STK11 and KRAS as well as several copy-number alterations in the pathogenesis of cervical carcinomas. Here we report whole-exome sequencing analysis of 115 cervical carcinoma-normal paired samples, transcriptome sequencing of 79 cases and whole-genome sequencing of 14 tumour-normal pairs. Previously unknown somatic mutations in 79 primary squamous cell carcinomas include recurrent E322K substitutions in the MAPK1 gene (8%), inactivating mutations in the HLA-B gene (9%), and mutations in EP300 (16%), FBXW7 (15%), NFE2L2 (4%), TP53 (5%) and ERBB2 (6%). We also observe somatic ELF3 (13%) and CBFB (8%) mutations in 24 adenocarcinomas. Squamous cell carcinomas have higher frequencies of somatic nucleotide substitutions occurring at cytosines preceded by thymines (Tp*C sites) than adenocarcinomas. Gene expression levels at HPV integration sites were statistically significantly higher in tumours with HPV integration compared with expression of the same genes in tumours without viral integration at the same site. These data demonstrate several recurrent genomic alterations in cervical carcinomas that suggest new strategies to combat this disease.

Individual karyotypes at the origins of cervical carcinomas

Background

In 1952 Papanicolaou et al. first diagnosed and graded cervical carcinomas based on individual “abnormal DNA contents” and cellular phenotypes. Surprisingly current papilloma virus and mutation theories of carcinomas do not mention these individualities. The viral theory holds that randomly integrated, defective genomes of papilloma viruses, which are often untranscribed, cause cervical carcinomas with unknown cofactors 20–50 years after infection. Virus-free carcinomas are attributed to mutations of a few tumor-suppressor genes, especially the p53 gene. But the paradox of how a few mutations or latent defective viral DNAs would generate carcinomas with endless individual DNA contents, degrees of malignancies and cellular phenotypes is unsolved. Since speciation predicts individuality, we test here the theory that cancers are autonomous species with individual clonal karyotypes and phenotypes. This theory postulates that carcinogens induce aneuploidy. By unbalancing mitosis genes aneuploidy catalyzes chain reactions of karyotypic evolutions. Most such evolutions end with non-viable karyotypes but a few become new cancer karyotypes. Despite congenitally unbalanced mitosis genes cancer karyotypes are stabilized by clonal selections for cancer-specific autonomy.

Results

To test the prediction of the speciation theory that individual carcinomas have individual clonal karyotypes and phenotypes, we have analyzed here the phenotypes and karyotypes of nine cervical carcinomas. Seven of these contained papilloma virus sequences and two did not. We determined phenotypic individuality and clonality based on the morphology and sociology of carcinoma cells in vitro. Karyotypic individuality and clonality were determined by comparing all chromosomes of 20 karyotypes of carcinomas in three-dimensional arrays. Such arrays list chromosome numbers on the x-axis, chromosome copy numbers on the y-axis and the number of karyotypes arrayed on the z-axis. We found (1) individual clonal karyotypes and phenotypes in all nine carcinomas, but no virus-specific markers, (2) 1-to-1 variations between carcinoma-specific karyotypes and phenotypes, e.g. drug-resistance and cell morphology, (3) proportionality between the copy numbers of chromosomes and the copy numbers of hundreds of over- and under-expressed mRNAs, (4) evidence that tobacco-carcinogens induce cervical carcinomas via aneuploidy, consistent with the speciation theory.

Conclusions

Since the individual clonal karyotypes of nine carcinomas correlated and co-varied 1-to-1 with complex individual transcriptomes and phenotypes, we have classical genetic and functional transcriptomic evidence to conclude that these karyotypes encode carcinomas - much like the clonal karyotypes that encode conventional species. These individual karyotypes explain the individual “DNA contents”, the endless grades of malignancies and the complex individual transcriptomes and phenotypes of carcinomas.

WWOX induces apoptosis and inhibits proliferation in cervical cancer and cell lines

Cervical cancer is the second most common gynecological malignancy, but the molecular events involved in its development remain unclear. The tumor‑suppressor gene, WW domain-containing oxidoreductase (WWOX), has been found to be lost in various types of cancers. Few studies have been reported detailing the function of WWOX in human cervical cancer; therefore we aimed to investigate the role played by WWOX in human cervical cancer. Immunohistochemistry was used to study preinvasive and invasive primary cervical cancer. Full length cDNA was transfected into HeLa cells to overexpress WWOX, and short hairpin RNA (shRNA) was transfected into SiHa cells to deplete its expression, respectively. The cellular levels of WWOX RNA and protein were detected by real-time PCR and western immunoblotting. Proliferation rates were assessed by methyl thiazolyl tetrazolium (MTT), plate colony formation and soft agar colony assays. Cellular apoptosis was measured by flow cytometry and TdT-mediated dUTP nick-end labeling (TUNEL) assay. The activity of caspase-3 and its protein levels were determined by caspase-3 activity assay and western blot analysis. Xenografts were established by injecting cells into nude mice. The results showed that WWOX expression was decreased in human cervical cancer and cervical cancer cell lines. Reconstitution of WWOX in HeLa cells inhibited their proliferation and induced apoptosis, while knockdown of WWOX in SiHa cells promoted proliferation and inhibited apoptosis. Xenografts in groups of mice verified the effect in vivo. These data suggest that underexpression of WWOX is associated with cervical cancer development. Modulation of WWOX expression may be an effective and novel method for the treatment of cervical cancer.

Mutations of the TP53 gene in adenocarcinoma and squamous cell carcinoma of the cervix: a systematic review

OBJECTIVE

Mutations of the tumor suppressor gene TP53 are the most significant events in several human cancers. Few studies have analyzed the frequency of TP53 alterations in squamous cell carcinoma and adenocarcinoma of the cervix with controversial results. This study provides a detailed analysis of TP53 mutation spectra in cervical squamous cell carcinoma and adenocarcinoma from different geographical regions.

METHODS

The analysis of TP53 mutational profiles was performed in 1353 cervical cancers retrieved from the IARC p53 mutation database (R15, 2010) and the COSMIC data along with the literature review of related studies identified by PubMed searching.

RESULTS

This analysis showed a significant higher mutation frequency of TP53 gene in cervical adenocarcinoma (32 of 241; 13.3%) compared to squamous cell carcinoma (39 of 657; 5.9%; P=0.0003, χ(2) test). The proportion of adenocarcinoma with mutated TP53 varied from 4% in North America to 19% in Asia. Among the six hot-spot codons of TP53 gene, three codons (175, 248 and 273) were the most commonly mutated in both types of cervical cancer, one codon (249) mainly in squamous cell carcinoma and one codon (282) only in adenocarcinoma. The G to A and C to T transitions were the prevalent type of mutations in both squamous cell carcinoma and adenocarcinoma (48.7% and 53.5% of all mutations, respectively). The frequency of C to A transversion was relatively high only in adenocarcinoma (25%), while the mirror mutation G to T was comparatively frequent in squamous cell carcinoma (14.6%).

CONCLUSIONS

Different patterns of TP53 mutations occur in squamous cell carcinoma and adenocarcinoma of the cervix in different regions of the world. The highest frequency of mutated TP53 has been observed in cervical adenocarcinoma from Asia. Further studies are needed to better define the role of TP53 alterations in cervical cancer and possibly to understand the impact of mutations on cancer prognosis and outcomes.

Improved detection suggests all Merkel cell carcinomas harbor Merkel polyomavirus

A human polyomavirus was recently discovered in Merkel cell carcinoma (MCC) specimens. The Merkel cell polyomavirus (MCPyV) genome undergoes clonal integration into the host cell chromosomes of MCC tumors and expresses small T antigen and truncated large T antigen. Previous studies have consistently reported that MCPyV can be detected in approximately 80% of all MCC tumors. We sought to increase the sensitivity of detection of MCPyV in MCC by developing antibodies capable of detecting large T antigen by immunohistochemistry. In addition, we expanded the repertoire of quantitative PCR primers specific for MCPyV to improve the detection of viral DNA in MCC. Here we report that a novel monoclonal antibody detected MCPyV large T antigen expression in 56 of 58 (97%) unique MCC tumors. PCR analysis specifically detected viral DNA in all 60 unique MCC tumors tested. We also detected inactivating point substitution mutations of TP53 in the two MCC specimens that lacked large T antigen expression and in only 1 of 56 tumors positive for large T antigen. These results indicate that MCPyV is present in MCC tumors more frequently than previously reported and that mutations in TP53 tend to occur in MCC tumors that fail to express MCPyV large T antigen.

Nuclear accumulation of the papillomavirus E1 helicase blocks S-phase progression and triggers an ATM-dependent DNA damage response

Replication of the papillomavirus genome is initiated by the assembly of a complex between the viral E1 and E2 proteins at the origin. The E1 helicase is comprised of a C-terminal ATPase/helicase domain, a central domain that binds to the origin, and an N-terminal regulatory region that contains nuclear import and export signals mediating its nucleocytoplasmic shuttling. We previously reported that nuclear accumulation of E1 has a deleterious effect on cellular proliferation which can be prevented by its nuclear export. Here we have shown that nuclear accumulation of E1 from different papillomavirus types blocks cell cycle progression in early S phase and triggers the activation of a DNA damage response (DDR) and of the ATM pathway in a manner that requires both the origin-binding and ATPase activities of E1. Complex formation with E2 reduces the ability of E1 to induce a DDR but does not prevent cell cycle arrest. Transient viral DNA replication still occurs in S-phase-arrested cells but surprisingly is neither affected by nor dependent on induction of a DDR and of the ATM kinase. Finally, we provide evidence that a DDR is also induced in human papillomavirus type 31 (HPV31)-immortalized keratinocytes expressing a mutant E1 protein defective for nuclear export. We propose that nuclear export of E1 prevents cell cycle arrest and the induction of a DDR during the episomal maintenance phase of the viral life cycle and that complex formation with E2 further safeguards undifferentiated cells from undergoing a DDR when E1 is in the nucleus.

Upregulation of the mitochondrial transport protein, Tim50, by mutant p53 contributes to cell growth and chemoresistance

The p53 gene is one of the most frequently mutated genes in human cancer. Some p53 mutations impart additional functions that promote oncogenesis. To investigate how these p53 mutants function, a proteomic analysis was performed. The protein, translocator of the inner mitochondrial membrane 50 (Tim50), was upregulated in a non-small cell lung carcinoma cell line (H1299) that expressed the p53 mutants R175H and R273H compared to cells lacking p53. Tim50 was also elevated in the breast cancer cell lines MDA-MB-468 and SK-BR-3, that endogenously express the p53 mutants R175H and R273H, respectively, compared to MCF-10A. The p53 mutants R175H and R273H, but not WT p53, upregulated the expression of a Tim50 promoter construct and chromatin immunoprecipitation (ChIP) analysis indicated increased histone acetylation and increased interaction of the transcription factors Ets-1, CREB and CREB-binding protein (CBP) with the Tim50 promoter in the presence of mutant p53. Finally, reduction of Tim50 expression reduced the growth rate and chemoresistance of cells harboring mutant p53 but had no effect upon cells lacking p53. Taken together, these findings identify the Tim50 gene as a transcriptional target of mutant p53 and suggest a novel mechanism by which p53 mutants enhance cell growth and chemoresistance.

Human papillomavirus 16 E6 increases the radiosensitivity of p53-mutated cervical cancer cells, associated with up-regulation of aurora A

PURPOSE

To examine the effect of the human papillomavirus (HPV) type 16-E6 (HPV 'early' gene) oncoprotein on in vitro radiosensitivity of HPV-negative/p53 mutant C33a cervical cancer cells.

METHODS AND MATERIALS

The human cervical cancer cell line C33a was stably transfected with either the HPV16 E6 cDNA cloned into the vector pcDNA3.0 (C33aE6) or the empty-vector control (C33aV). Radiosensitivity, DNA damage, and cell cycle measurements were made using standard clonogenic assays, immunofluorescent assessment of nuclear histone H2AX phosphorylated on serine-139 (gamma-H2AX) foci, and flow cytometry. Western immunoblotting and fluorescence confocal microscopy were used to analyse the changes in cellular proteins. Real-time polymerase chain reaction (PCR) was used to compare levels of aurora A mRNA.

RESULTS

Compared to C33aV cells, C33aE6 cells showed enhanced radiation cell killing. This was associated with a large amount of polyploidy which was followed by late cell death in C33aE6 cells. Aurora A was highly expressed in C33aE6 cells at pre- and post-irradiation times compared to C33aV cells. Silencing aurora A resulted in a reduced amount of residual gamma-H2AX foci in C33aE6 cells, and diminished the difference in radiosensitivity between the C33aE6 and C33aV cells.

CONCLUSION

Our in vitro results indicate that genetic instability could be augmented in the HPV-infected cancer cells by up-regulation of aurora A, especially against a background of dysfunctional p53. Further studies are needed to examine whether aurora A could be a viable therapeutic target in HPV-related tumours.

Multi-site study of HPV type-specific prevalence in women with cervical cancer, intraepithelial neoplasia and normal cytology, in England

BACKGROUND

Knowledge of the prevalence of type-specific human papillomavirus (HPV) infections is necessary to predict the expected, and to monitor the actual, impact of HPV immunisation and to design effective screening strategies for vaccinated populations.

METHODS

Residual specimens of cervical cytology (N=4719), CIN3/CGIN and cervical cancer biopsies (N=1515) were obtained from sites throughout England, anonymised and tested for HPV DNA using the Linear Array typing system (Roche).

RESULTS

The prevalence of HPV 16 and/or 18 (with or without another high-risk (HR) type) was 76% in squamous cell carcinomas, 82% in adeno/adenosquamous carcinomas and 63% and 91% in CIN3 and CGIN, respectively. Of all HR HPV-infected women undergoing cytology, non-vaccine HPV types only were found in over 60% of those with mild dyskaryosis or below, and in <20% of those with cancer. In women of all ages undergoing screening, HR HPV prevalence was 16% and HPV 16 and/or 18 prevalence was 5%.

CONCLUSION

Pre-immunisation, high-grade cervical disease in England was predominantly associated with HPV 16 and/or 18, which promises a high impact from HPV immunisation in due course. Second-generation vaccines and screening strategies need to consider the best ways to detect and prevent disease due to the remaining HR HPV types.

MDM-2 protein expression in nasopharyngeal carcinomas. Comparative study with p53 protein expression

Aims-To investigate the immunohistochemical expression of MDM-2 protein in comparison with that of p53 protein in nasopharyngeal carcinomas.Methods-Formalin fixed, paraffin wax embedded tissue from 59 cases of nasopharyngeal carcinoma was stained by immunohistochemistry for MDM-2 and p53 proteins.Results-The tumours were divided histologically into seven cases of keratinising nasopharyngeal carcinoma (KNPC), 14 cases of non-keratinising nasopharyngeal carcinoma (NKNPC), and 38 cases of undifferentiated nasopharyngeal carcinoma (UNPC). MDM-2 nuclear expression was observed in 0/7 KNPC, 1/14 NKNPC, and 11/38 UNPC. p53 nuclear expression was observed in 1/7 KNPC, 2/14 NKNPC, and 15/38 UNPC. Parallel MDM-2 and p53 expression was found in 12 cases (11 UNPC and one NKNPC). Discordant MDM-2-/p53 + expression was found in six cases (four UNPC, one NKNPC, and one KNPC), and absence of expression of both proteins in the remaining 41 cases.Conclusions-Expression of MDM-2 and p53 proteins may be associated with the level of tumour cell differentiation in nasopharyngeal carcinoma. Simultaneous expression of MDM-2/p53 in a proportion of UNPC suggests that MDM-2 protein may be responsible for stabilisation of p53 protein in these cases, in view of the previous demonstration of the p53 gene in germ line configuration. This could be important in the pathogenesis of these cases, since MDM-2 may deregulate the p53 dependent growth suppressive pathway. Discordant MDM-2-/p53 + expression in a few cases of nasopharyngeal carcinoma may reflect stabilisation of p53 protein by other proteins, or p53 mutations unable to activate MDM-2.

Current advancement in radiation therapy for uterine cervical cancer

Radiation therapy is one of the effective curative treatments for uterine cervical cancer. However poor clinical results for the advanced stages require further improvement of the treatment. Intensive studies on basic and clinical research have been made to improve local control, primarily important for long term survival in radiation therapy. Regarding current advancement in radiation therapy for uterine cervical cancer, the following three major subjects are pointed out; technological development to improve dose distribution by image guided radiation therapy technology, the concomitant anticancer chemotherapy with combination of radiation therapy, and radiation biological assessment of the radiation resistance of tumors. The biological factors overviewed in this article include hypoxia relating factors of HIF-1alpha, SOD, cell cycle parameters of pMI, proliferation factors of Ki67, EGFR, cerbB2, COX-2, cycle regulation proteins p53, p21, apoptosis regulation proteins Bcl2 and Bax and so on. Especially, the variety of these radiation biological factors is important for the selection of an effective treatment method for each patient to maximize the treatment benefit.

Functions of p53 in metabolism and invasion

The p53 protein is an important tumour suppressor that is inactivated in many human cancers. Understanding how p53 is regulated and the downstream consequences of p53 function is helping us to devise novel therapies based on the reactivation of p53. Such approaches may be useful in the treatment of cancer, but a growing understanding of a role for p53 in other conditions suggests that modulation of p53 may have broader applications.

Interplay between human papilloma virus infection and p53 gene alterations in head and neck squamous cell carcinoma of an Indian patient population

AIM

To investigate the complex interplay between human papilloma virus (HPV) infection and p53 gene alteration in 92 head and neck squamous cell carcinoma (HNSCC) and 28 leukoplakia samples from eastern India.

METHODS

DNA isolated from the patient samples was subjected to HPV detection, loss of heterozygosity (LOH) analysis of the chromosome 17p region harbouring p53, genotyping at the p53 codon 72 locus and sequencing of the entire p53 gene to identify somatic mutations. Codon 72 heterozygotes carrying the p53 mutation were further cloned and resequenced to identify the allele harbouring the mutation.

RESULTS

HPV positivity in the HNSCC samples was 69%; 21% of the HNSCC were found to harbour p53 mutations in the coding region of the gene. The absence of the p53 mutation in HPV positive tumours was statistically significant compared to the HPV negative tumours (p = 0.01), but the same did not hold true for p53 LOH (p = 1.0). Among the germline p53 codon 72 heterozygotes, the Pro allele was preferentially lost (p = 0.02) while the Arg allele was mutated in the majority of cases. The risk of HPV mediated tumourigenesis increased with the increase in number of Arg alleles at the codon 72 locus.

CONCLUSION

It is proposed that genetic and epigenetic alteration of p53 follow distinct pathways during the development of HNSCC from normal epithelium via dysplasia. The p53 mutation and HPV mediated p53 inactivation possibly constitute two independent pathways of tumourigenesis.

Phenotypic features with p53 alterations related to human papillomavirus and prognostic evaluation in cervical cancer

Cervical cancer is one of the most common tumor affecting women worldwide. Human papillomavirus (HPV) was found to have a causal relationship with cervical cancer and its precursors. The interaction between HPV E6 protein and p53 was identified in in vitro studies. The aim of the study was to evaluate the prevalence of p53 alterations related to HPV infection and the prognostic significance of p53 alterations in cervical cancer. Studies were identified by a MEDLINE search, and all relevant articles were retrieved from 1991 to March 2004. The prevalence of p53 mutations is a rare event in cervical cancer. The correlation between p53 mutations and HPV or prognosis is controversial. Loss of heterozygosity (LOH) of p53 is more commonly found in cervical cancer and is related with the prognosis of this disease. There is no significant correlation between p53 polymorphism and development of cervical cancer. The p53 mutations were not commonly found in cervical cancer. LOH of p53 may contribute to the progression of this malignancy. p53 polymorphism failed to be an independent prognostic factor in predicting the outcome of patients with cervical cancer. Further, epidemiologic surveys should be undertaken in larger populations and in different geographical regions.

HPV prevalence, E6 sequence variation and physical state of HPV16 isolates from patients with cervical cancer in Sichuan, China

OBJECTIVES

Infection with high-risk human papillomavirus (hr-HPV) is an important factor associated with cervical cancer. The genetic mutation of HPV16 E6 and integration of HPV16 DNA in the cervical carcinoma tissues are considered important genetic changes in cervical lesion progression. But the studies of hr-HPV epidemiology are relatively less in the area of Sichuan, China. Therefore, we investigated the prevalence of 9 high-risk subtypes and analyzed the genetic mutation characteristic of HPV16 E6 and physical state of HPV16 DNA.

METHODS

The fragments of L1 and E6 genes were amplified by PCR or nested PCR and then directly sequenced. Further, the multiplex PCR for HPV16 E2 and E6 genes was performed for detection of integration.

RESULTS

HPV16, 58 and 18 were prominent, accounting for 78.6%, 20.0% and 9.7%, respectively in 145 isolates. E6 variants revealed that the European (EP) prototype and East Asia (EA) strain were 26 (23.0%) and 34 (30.1%), respectively. Furthermore, there were 14 base substitutions in E6 regions of the study group, of which 12 resulted in amino acid changes and the rest was silent mutation. Significantly, the 240G substitution exactly located the P53 degradation site. Overall, 8 of 114 (7.0%) isolates only contained integrated HPV16 DNA, 43 (37.7%) only contained episomal DNA and 63 (55.3%) contained both integrated and episomal DNA. The proportion of disruption of an intact E2 gene in the patients with cervical cancer is much lower than that in the previous studies.

CONCLUSIONS

HPV16, 58 and 18 were mainly prevailing subtypes in patients with cervical cancer from Sichuan areas, China and EP/EA strains were predominant in these areas. Some mutations of E6 gene, which lead to the amino acid changes, may be more potentially carcinogenic and the proportion of disruption of an intact E2 gene is much lower.

Relationship between p21 and p53 Expression, Human Papilloma Virus Infection and Malignant Transformation in Sinonasal-inverted Papilloma

AIMS

To identify the relationship between p21 and p53 expression, human papilloma virus (HPV) infection and malignant transformation in sinonasal-inverted papilloma.

MATERIAL AND METHODS

Nasal tissues, exophytic papilloma, inverted papilloma (IP) with dysplasia, IP with carcinoma and invasive squamous cell carcinoma (SCC) were stained with the monoclonal antibodies p21 and p53. In-situ hybridisation for HPV DNA was also carried out for types 6/11, 16/18 and 31/33.

RESULTS

Significant increased staining of p21 and p53 was observed in IP with severe dysplasia, IP with carcinoma and invasive carcinoma compared with control nasal mucosa. A significant increase of dysplasia was observed in IP in the HPV 6/11 and 16/18-positive group, compared with the HPV 6/11 and 16/18-negative group. Significant decrease in expression of p21 and p53 was observed in HPV 16/18-positive IP compared with HPV 16/18-negative IP.

CONCLUSIONS

Our data raise the possibility that testing for p21, p53 and HPV may help to screen out papilloma lesions with a potential for dysplasia or carcinoma.

The bone morphogenetic protein antagonist gremlin 1 is overexpressed in human cancers and interacts with YWHAH protein

BACKGROUND

Basic studies of oncogenesis have demonstrated that either the elevated production of particular oncogene proteins or the occurrence of qualitative abnormalities in oncogenes can contribute to neoplastic cellular transformation. The purpose of our study was to identify an unique gene that shows cancer-associated expression, and characterizes its function related to human carcinogenesis.

METHODS

We used the differential display (DD) RT-PCR method using normal cervical, cervical cancer, metastatic cervical tissues, and cervical cancer cell lines to identify genes overexpressed in cervical cancers and identified gremlin 1 which was overexpressed in cervical cancers. We determined expression levels of gremlin 1 using Northern blot analysis and immunohistochemical study in various types of human normal and cancer tissues. To understand the tumorigenesis pathway of identified gremlin 1 protein, we performed a yeast two-hybrid screen, GST pull down assay, and immunoprecipitation to identify gremlin 1 interacting proteins.

RESULTS

DDRT-PCR analysis revealed that gremlin 1 was overexpressed in uterine cervical cancer. We also identified a human gremlin 1 that was overexpressed in various human tumors including carcinomas of the lung, ovary, kidney, breast, colon, pancreas, and sarcoma. PIG-2-transfected HEK 293 cells exhibited growth stimulation and increased telomerase activity. Gremlin 1 interacted with homo sapiens tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, eta polypeptide (14-3-3 eta; YWHAH). YWHAH protein binding site for gremlin 1 was located between residues 61-80 and gremlin 1 binding site for YWHAH was found to be located between residues 1 to 67.

CONCLUSION

Gremlin 1 may play an oncogenic role especially in carcinomas of the uterine cervix, lung, ovary, kidney, breast, colon, pancreas, and sarcoma. Over-expressed gremlin 1 functions by interaction with YWHAH. Therefore, Gremlin 1 and its binding protein YWHAH could be good targets for developing diagnostic and therapeutic strategies against human cancers.