Assessment of genomic instability in breast cancer and uveal melanoma by random amplified polymorphic DNA analysis

Molecular Evaluation of the Impact of Nd:YAG Laser and Static Magnetic Field on Genomic DNA of Some Bacterial Isolates using RAPD-PCR

Antimicrobial therapy is frequently associated with the emergence of resistant bacteria with a high rate of morbidity and mortality worldwide. The present study was aimed at investigating the impact of a neodymium-doped yttrium aluminum (Nd:YAG) laser, and a static magnetic field (SMF) on cellular growth and DNA alteration in some clinical bacterial isolates. Samples from cutaneous wounds were collected by sterile cotton swabs from three elderly women admitted to Tikrit Teaching Hospital, Tikrit City, Iraq. Isolation and identification of Streptococcus agalactiae, Staphylococcus aureus, and Pseudomonas aeruginosa were carried out using cultural characteristics, microscopy, and biochemical tests. Three broth cultures were prepared for each of the test isolates. The first broth culture served as untreated control, the second was exposed to an Nd:YAG laser and the third was exposed to SMF. Colony counting was done on all the samples. DNA was extracted from the test bacteria and used to perform the RAPD-PCR assay. In contrast to the untreated control, the results showed that Nd:YAG laser radiation was more effective than SMF at inhibiting the cellular growth of the test isolates. Also, the radiation caused DNA alteration, which was established by decreased microbial growth, as well as the development of new bands and the loss of original bands. According to the findings of this study, the Nd:YAG laser is a promising technique for influencing the healing of infected cutaneous wounds. RAPD-PCR is also a useful biomarker assay for assessing the biological impact of laser radiation and SMF on bacteria.

Identification of Some Breast Cancer Related Genes by RAPD Technique in Maysan Province, Iraq

Breast cancer is a heterogeneous disease regarding its morphology, invasive behavior, metastatic capacity, hormone receptor expression and clinical outcome. Many risk factors for breast cancer, including genetic factors, account for 25-30% of the incidence. About 15-30% of breast cancer is heritable due to known familiar highly penetrates genes and the others are sporadic; It is worthy to state that this study was the first in the world to include amplified genes as a PCR template to determine the relationship between their polymorphism and breast cancer incidence using, RAPD of amplified genes. The study was designed first to evaluate the association of ABCG2 gene polymorphism beside miRNA-152 and ER-a using the RAPD technique with breast cancer incidence in Maysan province women, and second to use those genes as indicators for breast cancer prediction and diagnosis. The study included 100 patients with breast cancer and 30 control healthy women, and then all samples were amplified by conventional PCR by specific F and R primer for (ABCG2, ER-α, miRNA-152) genes and then the best (20 PCR product) from which was chosen as the template for PCR RAPD PCR technique. The results revealed there are significant differences (P < 0.05) in the unique band of ABCG2 at marker OPAA 11, OPU 15, OPAA 17, significant differences (P < 0.05) in the total band of ER- α at marker OPAA11, significant differences in the polymorphic band of ER- α at marker OPU 15, significant differences in the unique band of ER- α at marker OPAA11, OPU 15, and significant differences (P < 0.05) in the bands that had been size (50-60) bp, (140 - 150) bp, (170-180 ) bp of miRNA-152 at marker OPAA 17, OPD 18 between breast cancer patients and control. Our study proved the relationship between genetic polymorphism of breast cancer-related genes (ABCG2, ER-α, miRNA-152) and a higher incidence of cancer; The current study recommends employing these results for future prediction and diagnosis of breast cancers.

Uveal melanoma pathobiology: Metastasis to the liver

Uveal melanoma (UM) is a type of intraocular tumor with a propensity to disseminate to the liver. Despite the identification of the early driver mutations during the development of the pathology, the process of UM metastasis is still not fully comprehended. A better understanding of the genetic, molecular, and environmental factors participating to its spread and metastatic outgrowth could provide additional approaches for UM treatment. In this review, we will discuss the advances made towards the understanding of the pathogenesis of metastatic UM, summarize the current and prospective treatments, and introduce some of the ongoing research in this field.

Genetic variations among three major ethnic groups in Nigeria using RAPD

Genetically, every individual is unique; this may stem from inheritance, geographical locations, and/or environmental interactions. This study examined the possibility of developing a cheap and easy-to-use marker that can distinguish among the three ethnic groups in Nigeria using RAPD-PCR. Five RAPD primers, OPA1-3 and OPC1-2, were randomly selected and used to amplify DNA samples isolated from blood of eighteen human subjects representing the three major ethnic groups in Nigeria (six subjects each). Genomic DNAs were extracted using DNA isolation kit, RAPD-PCR amplification was performed and gel electrophoresis was done. Genetic similarity between the band polymorphism was evaluated as frequencies of occurrence and the phylogenetic tree constructed. Three of the five primers show various polymorphisms; the highest frequency band for primer OPA1 is 50% while that of primer OPA2 is 100% and for OPC2 is 83.33%. Although OPA2 has common bands in majority of the samples few of the bands are ethnic group specific. Bands 471 and 435 bp are specific for the Hausa ethnic group at 66.67% frequency. Similarly, in primer OPC2, band 320 can be used to distinguish the Hausas from the other two ethnic groups. Analysis of variance (ANOVA) and test for homogeneity showed that there is no significant difference in the polymorphism between and among the groups. In conclusion this research has given an insight into the possibility of developing RAPD primers that could be used to distinguish people of different ethnic groups.

Genetic prognostication in uveal melanoma

Uveal melanoma (UM) is a rare tumour with a high propensity to metastasize. Although no effective treatment for metastases yet exists, prognostication in UM is relevant for patient counselling, planning of follow-up and stratification in clinical trials. Besides conventional clinicopathologic characteristics, genetic tumour features with prognostic significance have been identified. Non-random chromosome aberrations such as monosomy 3 and gain of chromosome 8q are strongly correlated with metastatic risk, while gain of chromosome 6p indicates a low risk. Recently, mutations in genes such as BAP1, SF3B1 and EIF1AX have been shown to be related to patient outcome. Genetics of UM is a rapidly advancing field, which not only contributes to the understanding of the pathogenesis of this cancer, but also results in further refinement of prognostication. Concomitantly, advances have been made in the use of genetic tests. New methods for genetic typing of UM have been developed. Despite the considerable progress made recently, many questions remain, such as those relating to the reliability of prognostic genetic tests, and the use of biopsied or previously irradiated tumour tissue for prognostication by genetic testing. In this article, we review genetic prognostic indicators in UM, also comparing available genetic tests, addressing the clinical application of genetic prognostication and discussing future perspectives for improving genetic prognostication in UM.

Low-Dose Alkylphenol Exposure Promotes Mammary Epithelium Alterations and Transgenerational Developmental Defects, But Does Not Enhance Tumorigenic Behavior of Breast Cancer Cells

Fetal and neonatal exposure to long-chain alkylphenols has been suspected to promote breast developmental disorders and consequently to increase breast cancer risk. However, disease predisposition from developmental exposures remains unclear. In this work, human MCF-10A mammary epithelial cells were exposed in vitro to a low dose of a realistic (4-nonylphenol + 4-tert-octylphenol) mixture. Transcriptome and cell-phenotype analyses combined to functional and signaling network modeling indicated that long-chain alkylphenols triggered enhanced proliferation, migration ability, and apoptosis resistance and shed light on the underlying molecular mechanisms which involved the human estrogen receptor alpha 36 (ERα36) variant. A male mouse-inherited transgenerational model of exposure to three environmentally relevant doses of the alkylphenol mix was set up in order to determine whether and how it would impact on mammary gland architecture. Mammary glands from F3 progeny obtained after intrabuccal chronic exposure of C57BL/6J P0 pregnant mice followed by F1-F3 male inheritance displayed an altered histology which correlated with the phenotypes observed in vitro in human mammary epithelial cells. Since cellular phenotypes are similar in vivo and in vitro and involve the unique ERα36 human variant, such consequences of alkylphenol exposure could be extrapolated from mouse model to human. However, transient alkylphenol treatments combined to ERα36 overexpression in mammary epithelial cells were not sufficient to trigger tumorigenesis in xenografted Nude mice. Therefore, it remains to be determined if low-dose alkylphenol transgenerational exposure and subsequent abnormal mammary gland development could account for an increased breast cancer susceptibility.

Clinical activity and safety of Pembrolizumab in Ipilimumab pre-treated patients with uveal melanoma

BACKGROUND

Untreated metastatic uveal melanoma (UM) carries a grave prognosis. Unlike cutaneous melanoma (CM), there are no established treatments known to significantly improve outcomes for a meaningful proportion of patients. Inhibition of the PD1-PDL1 axis has shown promise in the management of CM and we here report a two center experience of UM patients receiving pembrolizumab.

METHODS

To assess the efficacy and safety of pembrolizumab, we retrospectively analyzed outcome data of 25 consecutive UM patients participating in the MK3475 expanded access program (EAP) who received pembrolizumab at 2 mg/kg 3 weekly. Tumor assessment was evaluated using RECIST 1.1 and immune-related Response Criteria (irRC) by CT scanning. Toxicity was recorded utilizing Common Terminology Criteria for Adverse Events ("CTCAE") v4.03.

RESULTS

Twenty-five patients were identified receiving a median of six cycles of treatment. Two patients achieved a partial response and six patients stable disease. After a median follow-up of 225 d median progression free survival (PFS) was 91 d and overall survival (OS) was not reached. There was a significant trend for improved outcomes in patients with extrahepatic disease progression as opposed to liver only progression at the outset. Five patients experienced grade 3 or 4 adverse events (AEs); there were no treatment related deaths.

CONCLUSIONS

Pembrolizumab 2mg/kg q3w is a safe option in UM patients. Disease control rates, particularly in the subgroup of patients without progressive liver disease at the outset are promising; these results merit further investigation in clinical trials possibly incorporating liver targeted treatment modalities.

A review of advanced genetic testing for clinical prognostication in uveal melanoma

Uveal melanoma (UM) has a strong propensity to metastasize and the prognosis for metastatic disease is very poor. It has been suggested that occult micrometastases are already present, but undetectable, in many patients at the time when the primary ocular tumor is diagnosed and treated. To identify high-risk patients for close monitoring and early intervention with prophylactic adjuvant systemic therapy, an accurate predictive system is necessary for stratifying those patients at risk of developing metastatic disease. To date, many clinical and histopathological features, molecular pathway characteristics, and genetic fingerprints of UM have been suggested for disease prognostication. Among the newest of them, tumor genetics has received the most attention in demonstrating promise as a prognostic tool. Because of the plethora of recent developments, we summarize and compare in this review the important standard and more advanced cytogenetic prognostic markers. We further describe the variety of genetic tests available for prognostication of UM, and provide a critical assessment of the respective advantages and disadvantages of these tools.

The genetics of uveal melanoma: an emerging framework for targeted therapy

Uveal melanoma is the second most common form of melanoma and the most common primary intraocular malignancy. Until recently, very little was known about the genetics of this aggressive cancer. Mutations in oncogenes and tumor suppressors that are common in other cancers are conspicuously absent in uveal melanoma. In recent years, however, uveal melanoma has begun to yield its secrets, and a fascinating picture is emerging of how it develops and progresses. Mutations in the G(q) alpha subunits, encoded by GNAQ and GNA11, appear to be early or perhaps initiating events that require further mutations for malignant transformation. On the other hand, mutations in the BRCA1-associated protein-1 (BAP1) appear to occur later and demarcate a molecular brink beyond which metastasis becomes highly likely. BAP1 mutations can also occur in the germline, leading to a distinctive cancer predisposition syndrome. These mutations appear to be key events that provide the potential for targeted therapy. This article will review the genetic findings in uveal melanoma over the past two decades and suggest important areas for future work.

Genomic instability in human actinic keratosis and squamous cell carcinoma

OBJECTIVE

To compare the repetitive DNA patterns of human actinic keratoses and squamous cell carcinomas to determine the genetic alterations that are associated with malignant transformation.

INTRODUCTION

Cancer cells are prone to genomic instability, which is often due to DNA polymerase slippage during the replication of repetitive DNA and to mutations in the DNA repair genes. The progression of benign actinic keratoses to malignant squamous cell carcinomas has been proposed by several authors.

MATERIAL AND METHODS

Eight actinic keratoses and 24 squamous cell carcinomas (SCC), which were pair-matched to adjacent skin tissues and/or leucocytes, were studied. The presence of microsatellite instability (MSI) and the loss of heterozygosity (LOH) in chromosomes 6 and 9 were investigated using nine PCR primer pairs. Random Amplified Polymorphic DNA patterns were also evaluated using eight primers.

RESULTS

MSI was detected in two (D6S251, D9S50) of the eight actinic keratosis patients. Among the 8 patients who had squamous cell carcinoma-I and provided informative results, a single patient exhibited two LOH (D6S251, D9S287) and two instances of MSI (D9S180, D9S280). Two LOH and one example of MSI (D6S251) were detected in three out of the 10 patients with squamous cell carcinoma-II. Among the four patients with squamous cell carcinoma-III, one patient displayed three MSIs (D6S251, D6S252, and D9S180) and another patient exhibited an MSI (D9S280). The altered random amplified polymorphic DNA ranged from 70% actinic keratoses, 76% squamous cell carcinoma-I, and 90% squamous cell carcinoma-II, to 100% squamous cell carcinoma-III.

DISCUSSION

The increased levels of alterations in the microsatellites, particularly in D6S251, and the random amplified polymorphic DNA fingerprints were statistically significant in squamous cell carcinomas, compared with actinic keratoses.

CONCLUSION

The overall alterations that were observed in the repetitive DNA of actinic keratoses and squamous cell carcinomas indicate the presence of a spectrum of malignant progression.

Different DNA methylation patterns detected by the Amplified Methylation Polymorphism Polymerase Chain Reaction (AMP PCR) technique among various cell types of bulls

Background

The purpose of this study was to apply an arbitrarily primed methylation sensitive polymerase chain reaction (PCR) assay called Amplified Methylation Polymorphism Polymerase Chain Reaction (AMP PCR) to investigate the methylation profiles of somatic and germ cells obtained from Holstein bulls.

Methods

Genomic DNA was extracted from sperm, leukocytes and fibroblasts obtained from three bulls and digested with a methylation sensitive endonuclease (HpaII). The native genomic and enzyme treated DNA samples were used as templates in an arbitrarily primed-PCR assay with 30 sets of single short oligonucleotide primer. The PCR products were separated on silver stained denaturing polyacrylamide gels. Three types of PCR markers; digestion resistant-, digestion sensitive-, and digestion dependent markers, were analyzed based on the presence/absence polymorphism of the markers between the two templates.

Results

Approximately 1,000 PCR markers per sample were produced from 27 sets of primer and most of them (>90%) were digestion resistant markers. The highest percentage of digestion resistant markers was found in leukocytic DNA (94.8%) and the lowest in fibroblastic DNA (92.3%, P ≤ 0.05). Spermatozoa contained a higher number of digestion sensitive markers when compared with the others (3.6% vs. 2.2% and 2.6% in leukocytes and fibroblasts respectively, P ≤ 0.05).

Conclusions

The powerfulness of the AMP PCR assay was the generation of methylation-associated markers without any prior knowledge of the genomic sequence. The data obtained from different primers provided an overview of genome wide DNA methylation content in different cell types. By using this technique, we found that DNA methylation profile is tissue-specific. Male germ cells were hypomethylated at the HpaII locations when compared with somatic cells, while the chromatin of the well-characterized somatic cells was heavily methylated when compared with that of the versatile somatic cells.

Frequent loss of heterozygosity and altered expression of the candidate tumor suppressor gene 'FAT' in human astrocytic tumors

BACKGROUND

We had earlier used the comparison of RAPD (Random Amplification of Polymorphic DNA) DNA fingerprinting profiles of tumor and corresponding normal DNA to identify genetic alterations in primary human glial tumors. This has the advantage that DNA fingerprinting identifies the genetic alterations in a manner not biased for locus.

METHODS

In this study we used RAPD-PCR to identify novel genomic alterations in the astrocytic tumors of WHO grade II (Low Grade Diffuse Astrocytoma) and WHO Grade IV (Glioblastoma Multiforme). Loss of heterozygosity (LOH) of the altered region was studied by microsatellite and Single Nucleotide Polymorphism (SNP) markers. Expression study of the gene identified at the altered locus was done by semi-quantitative reverse-transcriptase-PCR (RT-PCR).

RESULTS

Bands consistently altered in the RAPD profile of tumor DNA in a significant proportion of tumors were identified. One such 500 bp band, that was absent in the RAPD profile of 33% (4/12) of the grade II astrocytic tumors, was selected for further study. Its sequence corresponded with a region of FAT, a putative tumor suppressor gene initially identified in Drosophila. Fifty percent of a set of 40 tumors, both grade II and IV, were shown to have Loss of Heterozygosity (LOH) at this locus by microsatellite (intragenic) and by SNP markers. Semi-quantitative RT-PCR showed low FAT mRNA levels in a major subset of tumors.

CONCLUSION

These results point to a role of the FAT in astrocytic tumorigenesis and demonstrate the use of RAPD analysis in identifying specific alterations in astrocytic tumors.

Integrative genomic analysis of aneuploidy in uveal melanoma

PURPOSE

Aneuploidy is a hallmark of cancer and is closely linked to metastasis and poor clinical outcome. Yet, the mechanisms leading to aneuploidy and its role in tumor progression remain poorly understood. The extensive and complex karyotypic abnormalities seen in many solid tumors could hinder the identification of pathogenetically relevant chromosomal alterations. Uveal melanoma is an attractive solid tumor for studying aneuploidy because it is a relatively homogeneous cancer that is highly metastatic and has low nonspecific chromosomal instability.

EXPERIMENTAL DESIGN

Comparative genomic hybridization and gene expression profiling were used to analyze patterns of aneuploidy in 49 primary uveal melanomas. This analysis was supplemented by a review of cytogenetic findings in 336 published cases.

RESULTS

Three prognostically significant tumor subgroups were identified based on the status of chromosomes 3 and 6p. Discrete patterns of chromosomal alterations accumulated in these three subgroups in a nonrandom temporal sequence. Poor clinical outcome was associated with early chromosomal alterations rather than overall aneuploidy. A gene expression signature associated with aneuploidy was enriched for genes involved in cell cycle regulation, centrosome function, and DNA damage repair. One of these genes was PTEN, a tumor suppressor and genomic integrity guardian, which was down-regulated in association with increasing aneuploidy (P = 0.003).

CONCLUSIONS

The relationship between aneuploidy and poor prognosis may be determined by specific, pathogenetically relevant chromosomal alterations, rather than overall aneuploidy. Such alterations can be identified using integrative genomic methods and may provide insights for novel therapeutic approaches.

Use of RAPD to detect sodium arsenite-induced DNA damage in human lymphoblastoid cells

Inorganic arsenic is a known human carcinogen, yet its mechanism of action remains unclear. Our previous study showed that arsenite significantly induces oxidative DNA adducts and DNA-protein cross-links in several mammalian cell lines. In the present study, we used the random amplified polymorphic DNA (RAPD) assay to evaluate the possible target in the genomic DNA of human lymphoblastoid cells that were exposed to sodium arsenite. Treatment with both 10 and 80 microM arsenite for 4h induced significant changes in RAPD profiles compared with the control pattern. Two 10-mer RAPD primers (D11 and F1) produced the most distinguishable banding profiles between arsenite-treated and control genomic DNA. The sequencing of four arsenite-sensitive RAPD bands showed that the RB1CC1 and PACE4 genes might be the DNA targets of sodium arsenite treatment. We propose that arsenite may induce sequence- or gene-specific damage and then change the RAPD profile in human lymphoblastoid cells. The results of our study also show that RAPD combined with other techniques is a good tool for detecting alterations in genomic DNA and for the direct screening of new molecular markers related to arsenite-induced carcinogenesis.

The random amplified polymorphic DNA (RAPD) assay and related techniques applied to genotoxicity and carcinogenesis studies: a critical review

More than 9000 papers using the random amplified polymorphic DNA (RAPD) or related techniques (e.g. the arbitrarily primed polymerase chain reaction (AP-PCR)) have been published from 1990 to 2005. The RAPD method has been initially used to detect polymorphism in genetic mapping, taxonomy and phylogenetic studies and later in genotoxicity and carcinogenesis studies. Despite their extensive use, these techniques have also attracted some criticisms, mainly for lack of reproducibility. In the light of their widespread applications, the objectives of this review are to (1) identify the potential factors affecting the optimisation of the RAPD and AP-PCR assays, (2) critically describe and analyse these techniques in genotoxicity and carcinogenesis studies, (3) compare the RAPD assay with other well used methodologies, (4) further elucidate the impact of DNA damage and mutations on the RAPD profiles, and finally (5) provide some recommendations/guidelines to further improve the applications of the assays and to help the identification of the factors responsible for the RAPD changes. It is suggested that after proper optimisation, the RAPD is a reliable, sensitive and reproducible assay, has the potential to detect a wide range of DNA damage (e.g. DNA adducts, DNA breakage) as well as mutations (point mutations and large rearrangements) and therefore can be applied to genotoxicity and carcinogenesis studies. Nevertheless, the interpretation of the changes in RAPD profiles is difficult since many factors can affect the generation of RAPD profiles. It is therefore important that these factors are identified and taken into account while using these assays. On the other hand, further analyses of the relevant bands generated in RAPD profile allow not only to identify some of the molecular events implicated in the genomic instability but also to discover genes playing key roles, particularly in the initiation and development of malignancy. Finally, to elucidate the potential genotoxic effects of environmental contaminants, a powerful strategy could be firstly to use the RAPD assay as a screening method and secondly to apply more specific methods measuring for instance DNA adducts, gene mutations or cytogenetic effects. It is also envisaged that these assays (i.e. RAPD and related techniques), which reflect effects at whole genome level, would continue to complement the use of emerging technologies (e.g. microarrays which aim to quantify expression of individual genes).

Genetic alterations of hepatocellular carcinoma by random amplified polymorphic DNA analysis and cloning sequencing of tumor differential DNA fragment

AIM: To study the genetic alterations and their association with clinicopathological characteristics of hepatocellular carcinoma (HCC), and to find the tumor related DNA fragments.

METHODS: DNA isolated from tumors and corresponding noncancerous liver tissues of 56 HCC patients was amplified by random amplified polymorphic DNA (RAPD) with 10 random 10-mer arbitrary primers. The RAPD bands showing obvious differences in tumor tissue DNA corresponding to that of normal tissue were separated, purified, cloned and sequenced. DNA sequences were analyzed and compared with GenBank data.

RESULTS: A total of 56 cases of HCC were demonstrated to have genetic alterations, which were detected by at least one primer. The detestability of genetic alterations ranged from 20% to 70% in each case, and 17.9% to 50% in each primer. Serum HBV infection, tumor size, histological grade, tumor capsule, as well as tumor intrahepatic metastasis, might be correlated with genetic alterations on certain primers. A band with a higher intensity of 480 bp or so amplified fragments in tumor DNA relative to normal DNA could be seen in 27 of 56 tumor samples using primer 4. Sequence analysis of these fragments showed 91% homology with Homo sapiens double homeobox protein DUX10 gene.

CONCLUSION: Genetic alterations are a frequent event in HCC, and tumor related DNA fragments have been found in this study, which may be associated with hepatocarcin-ogenesis. RAPD is an effective method for the identification and analysis of genetic alterations in HCC, and may provide new information for further evaluating the molecular mechanism of hepatocarcinogenesis.

Repetitive DNA alterations in human skin cancers

Repetitive sequences constitute landmarks for genome regulation, evolution, and chromatin architecture. Patterns of specific and non-specific repetitive sequences change in many types and stages of tumor cells, characterized by band loss, gain, and (de) increased staining of pre-existing bands. In this work, repetitive DNA was studied in search of genome instability of skin cancers: basal and squamous cell carcinomas (BCC and SCC), malignant melanoma (MM), melanocytic nevus (MN), and actinic keratosis (AK) lesions. DNAs were extracted from blood and tumor samples from 21 BCC, 7 SCC, 11 MM and 7 lesions. Banding patterns were obtained by random amplification of polymorphic DNA (RAPD), and specific D9S50 and D9S52 microsatellites (9p21). D9S50 patterns revealed microsatellite instability (MSI) and/or loss of heterozygosity (LOH) in 36% BCC, 25% SCC, and 57% MM tumors. D9S52 microsatellite showed 28.5%; 42.8%; and 71.4% altered tumors, respectively. No microsatellite alterations were found in MN and AK. On the other hand, genomic rearrangements detected by RAPD were present in 100% tumors. In BCC, the mean number of tumor DNA alterations showed predominant gain of bands. On the contrary, MM samples presented loss, or decreased intensity signal of RAPD bands. Genome alterations in skin cancers would result from chromosomal rearrangements, aneuploidy and/or polysomies. The low-cost and quick RAPD technique may reveal unknown genes or DNA sequences associated with tumor development and progression, and may be easily implemented in clinical diagnosis.

Genomic instability in hepatocellular carcinoma revealed by using the random amplified polymorphic DNA method

PURPOSE

To investigate the genomic instability and their association with clinicopathological characteristics in hepatocellular carcinoma (HCC).

METHODS

DNA isolated from tumors and corresponding non-cancerous liver tissues of 56 patients with HCC was amplified with ten random 10-mer arbitrary primers by the random amplified polymorphic DNA (RAPD) method.

RESULTS

All the cases of HCC were demonstrated to have genomic instability by at least one primer. The incidence of genomic instability ranged from 20 to 70% in each case, and 17.9-50% in each primer. Serum AFP concentration, HBV infection, tumor size, histological grade, tumor capsule invasion, as well as intrahepatic metastasis were associated with the genomic instability on certain primers.

CONCLUSIONS

Genomic instability is a frequent event in HCC. The RAPD is an effective method for the identification and analysis of genomic instability in HCC, and it may provide new information for further evaluating the molecular mechanism of hepatocarcinogenesis.

Genetic alteration and gene expression modulation during cancer progression

Cancer progresses through a series of histopathological stages. Progression is thought to be driven by the accumulation of genetic alterations and consequently gene expression pattern changes. The identification of genes and pathways involved will not only enhance our understanding of the biology of this process, it will also provide new targets for early diagnosis and facilitate treatment design. Genomic approaches have proven to be effective in detecting chromosomal alterations and identifying genes disrupted in cancer. Gene expression profiling has led to the subclassification of tumors. In this article, we will describe the current technologies used in cancer gene discovery, the model systems used to validate the significance of the genes and pathways, and some of the genes and pathways implicated in the progression of preneoplastic and early stage cancer.

Exploiting the hallmarks of cancer: the future conquest of breast cancer

What separates a malignant from a normal cell? This question has occupied scientists for decades. Although a simple answer remains elusive, several hallmarks of malignancy have been identified. These critical features include uncontrolled proliferation, insensitivity to negative growth regulation, evasion of apoptosis, lack of senescence, invasion and metastasis, angiogenesis and genomic elasticity. Existing therapies predominantly target proliferation either with cytotoxic agents, ionising radiation or more targeted attacks on growth factor signalling pathways. Our most successful therapies to date inhibit proliferation via the oestrogen receptor (ER) and HER2 pathways. Further improvements in therapy must attack the other hallmarks of malignancy and will undoubtedly be accompanied by a better means of individual patient selection for such therapies. Indeed, each of these hallmarks presents a therapeutic opportunity. To believe otherwise would be to assume that a feature is both biologically crucial, yet therapeutically unimportant, an unlikely paradox. Here, we suggest the hallmarks of malignancy as a conceptual framework for understanding novel breast cancer therapies.