Prognostic and predictive markers of response to treatment in patients with locally advanced unresectable and metastatic pancreatic adenocarcinoma treated with gemcitabine/nab-paclitaxel: Results of a retrospective analysis

BACKGROUND

Recent studies support the use of gemcitabine and nab-paclitaxel in adults with locally advanced unresectable or metastatic pancreatic adenocarcinoma although insufficient data are available on prognostic and predictive markers of response to treatment.

OBJECTIVE

The objective of this study is to identify treatment response markers in patients with locally advanced unresectable or metastatic pancreatic adenocarcinoma.

MATERIALS AND METHODS

This is an observational, retrospective, and multicenter study. Sociodemographic, clinical, and therapeutic data were collected. Cox regression models were applied to determine associations.

RESULTS

In total, 39 patients were included; 23.1% presented locally advanced pancreatic cancer and 76.9% metastatic disease. They received a mean of 6 ± 3 treatment cycles; 59% required dose reduction, 59% treatment delay, and 20.5% switched to a biweekly regimen. The overall response rate was 23% and the disease control rate was 81%. Median progression-free survival was 9 months and median overall survival (OS) was 15 months. A higher neutrophil/lymphocyte ratio (NLR) was significantly associated with lower OS. We reported Grades 1-4 nonhematological and hematological toxicities.

CONCLUSION

NLR is a useful prognostic factor for OS in patients with locally advanced unresectable or metastatic pancreatic adenocarcinoma treated with gemcitabine and nab-paclitaxel. Moreover, we suggest that a biweekly regimen is an option for certain groups of patients.

Retrospective analysis of prognostic and predictive markers in patients with locally advanced unresectable and metastatic pancreatic adenocarcinoma treated with gemcitabine/nabpaclitaxel: Influence of the presence of stent

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Background: Placement of a biliary stent is a standard measure for patients (pts) with pancreatic cancer. We evaluated prognostic/predictive factors that could predict the benefit of gemcitabine/nabpaclitaxel in pts with locally advanced unresectable and metastatic pancreatic adenocarcinoma and whether the presence of a biliary stent reduced the treatment efficacy Methods: We retrospectively analyzed 39 pts with locally advanced and metastatic pancreatic cancer treated with gemcitabine/nabpaclitaxel. Data included lactate dehydrogenase (LDH) level, alkaline phosphatase, neutrophil/lymphocyte ratio (NLR), performance status (PS), weight loss, presence of stent, analgesics use and CA 19.9 level. The correlation with response rate, progression-free survival (PFS) and overall survival (OS) was analyzed. Objective toxicities were assessed. Results: 30 pts (77%) had metastatic disease and 9 (23%) locally advanced pancreatic cancer. 46% had liver metastases and 41% lung metastases. Mean age of pts: 62 years (62% male). 20% had PS:0, 67% PS:1 and 13% PS:2. Stents were placed in 30% of pts, 69% had weight loss and 64% used analgesics at diagnosis. At the time of analysis 14 pts had died (25 alive). 56% had progressed, 3% were lost to follow-up and 41% had not progressed. A total of 54% disease stabilizations, 21% partial responses and 18% progressions were achieved (deaths: 7%). 43% required dose reduction. The main toxicity was hematologic (grade 1 anemia). Median PFS: 6 months (95%CI 4.4-7.6). Median OS: 15 months (95%CI 10.4-19.6). There was a statistically significant relationship between LDH level, NLR and PS and OS: LDH level higher than 363 increased the risk of death, NLR above 3.1 increased 1.8 times the risk of death and mean OS of pts with ECOG:0,1 was greater than that of pts with ECOG:2. No relationship between the presence of stent and PFS or OS was found, as well as with any of the other variables. Conclusions: The presence of stent did not reduce the efficacy of gemcitabine/nabpaclitaxel. Univariate analysis showed PS as a prognostic factor while multivariate showed LDH and NLR.

Using biologic knowledge to discover molecular correlations between human renal cell carcinoma pathways

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Background: Renal cell carcinoma (RCC) is known to be resistant to chemotherapy. There is need for the identification of biomarkers capable to determine RCC prognosis factors and metastatic potential obtainable from non-invasive or minimally invasive techniques. Our aim was to derive predictive models which could predict more accurately than any one factor alone. Methods: To studythe cascade of events leading to the formation and progression of RCC, we assessed 29 markers by immunohistochemistry and qRT-PCR using tissue micro-array (TMA). Results: Multivariate logistic regression showed the best proteins combination for node status (NOTCH1 and GLUT5) and pelvis invasion (EGFR and DLL3). ROC curve analyses were made to analyse the accuracy of the best candidate proteins; it should be noted NOTCH1 and GLUT5 for node status prediction (AUC=0.833, 95% CI, 0.744-0.922; p<0.001) and EGFR and DLL3 for pelvis invasion (AUC=0.777, 95% CI, 0.631-0.922; p=0.007). Furthermore, we carried out the correlation between these candidate proteins and all mRNA measured in order to deepen in the cellular transcripts traffic associated with them. To highlight the correlation between high DLL3 protein levels and low Hif1-β expression, and the negative correlation between GLUT5 protein and low levels of Baxβ. Conclusions: In the age of individual therapy, the approach to percutaneous image-guided RCC biopsy procedures plays an expanded role. Applying a 2 mm punch needle for constructing a TMA we could describe for the first time how are combined and correlated 29 markers in regression equations to predict in the most optimal way a number of pathological variables associated with RCC. [Table: see text]

Searching for circulating microRNAs in genitourinary tumors

468

Background: Detection of circulating tumor cells (CTC) may provide diagnostic and prognostic information in genitourinary tumors (GT). The aim of this work was identify aberrantly expressed miRNAs potentially useful for CTC detection in blood samples from patients with GT to assess their potential clinical significance, and to gain a greater understanding of the mechanisms driving tumor progression. Methods: We examined blood levels of 92 microRNAs in 113 metastatic patients: prostate (mP), renal cell carcinoma (mRCC), bladder tumors (mB) and healthy volunteers (HV) (N=18) using SYBR-green-based microRNA RT-qPCR arrays (Exiqon). Array design was made by literature review and bioinformatics approach using free databases. Relative Expression Software Tool (REST) and SPPS 21.0 were used to data processing and analysis. Results: microRNAs differential expressed between tumors and HV (only up-regulated miRNAs are shown in Table). Conclusions: microRNAs in the circulation are relatively stable, very accessible, low invasive and easily testable biomarkers. These results suggest that our bioinformatic approach is an useful high-throughput method to identified tumors-associated miRNAs. The selected miRNAs should be further evaluated for their potential as markers for CTC detection, prognosis and therapeutic outcome. Further studies of precision and sensitivity on these markers in this GT population will clarify its role as novel stable blood-based markers. [Table: see text]

Searching for predictors markers in renal cell carcinoma: A regression model

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Background: Renal cell carcinoma (RCC) is known to be resistant to chemotherapy. The need for the identification of biomarkers capable of determining RCC prognosis factors and metastatic potential that are obtainable from non-invasive or minimally invasive techniques are desirable. The purpose from this analysis was to derive predictive models which could predict more accurately than any one factor alone. Methods: By tissue micro-array (TMA) technology we assessed 29 markers involved in the cascade of events leading to the formation and progression of this disease. The ability of multivariate logistic regression to improve the diagnostic accuracy for RCC by combining determinations of proteins markers and pathological variables was evaluated. Univariate analysis was used to select factors (p<0.05) for entry into a multivariate stepwise logistic regression model using the forward method. Odds ratios with 95% CI were calculated. A p-value of < 0.05 was significant. Results: The regression equations obtained were the next: for lymphatic vessels invasion, Y(x)=6.815- 0.442 (EGFR value); for node status Y(x)=2.07+ 0.494(NOTCH1 value) - 0.269(GLUT5 value); for veins invasion Y(x)=57.61+ 6.01 (NOTCH2 value)- 9.3 (GLUT1 value)+ 1.73 (C-KIT value); for breaking capsule Y(x)=2.713- 0.261(EGFR value)+ 0.407 (NOTCH1 value)- 0.305(NOTCH2 value)+ 0.463 (GLUT1 value); for pelvis invasion Y(x)=8.624-0.198 (EGFR value)- 0.514 (DLL3 value). Receiver-operator characteristic (ROC) curve analyses were made to analyse the accuracy of the best candidate proteins. Should be noted from this analysis NOTCH1 and GLUT5 for node status prediction (AUC=0.833, 95% CI, 0.744-0.922; p<0.001) and EGFR and DLL3 for pelvis invasion (AUC=0.777, 95% CI, 0.631-0.922; p=0.007). Conclusions: In the age of individual therapy, the approach to percutaneous image-guided RCC biopsy procedures plays an expanded role. Applying a 2 mm punch needle for constructing a TMA, thereby mimicking the percutaneous biopsy technique we could describe for the first time how are combined 29 protein markers in regression equations to predict in the most optimal way a number of pathological variables associated with RCC that may help in the diagnosis and prognosis of this disease.

Circulating miR-337-3p as a novel biomarker for prostate cancer

5087

Background: Recent studies have demonstrated that the aberrant expression of microRNAs (miRNAs)is related with the development of prostate cancer (PCa). Detection of circulating tumor cells (CTC) may provide diagnostic and prognostic information inPCa. The purpose is identifying circulating miRNAs potentially useful for CTC detection in patients with PCa. Methods: In the first study phase we examined blood levels of 92 miRNAs in 49 patients grouped in pools by risk classification: low-risk 42.8%, intermediate-risk 22.5% and high-risk 34.7% and healthy volunteers (N=10) using SYBR-green-based microARN RT-qPCR arrays (Exiqon). Prostate cancer diagnosis was obtained by transrectalultrasound guided biopsy of 10 cores, PSA and digital rectal examination was done previously. In the second study phase using quantitative real-time polymerase chain reaction (qPCR) by TaqMan Human MicroRNAAssays (Life Technologies), we compared the expression levels of miRNAs in blood samples from 34 patients of low-risk, 31 of intermediate-risk, 18 of high-risk localized disease and 22 healthy volunteers paired by age with cases. Receiver-operator characteristic (ROC) curve was used. Results: Blood samples from patients with low, intermediate, high-risk and healthy controls exhibit distinct circulating miRNA signatures. microRNAsdifferential expressed between risk groups (p<0.01) (low, intermediate and high) and control group: 0microARNs upregulated (MU), 12 MU and 68 MU respectively. Highlight the significantlyoverexpression in the intermediate risk group and maintained at the high-risk of microRNAs: 337-3p[247 PicTar predictions (PTP)], 330-3p (307 PTP) and 218 (551 PTP). Preliminary results of the second study phase showed that the median level of miRNA,337-3p was significantly higher in patients with high-risk than that in healthy controls (p=.001). ROC curve analyses indicated that this blood miRNA may beuseful for discriminating patients with high-risk from healthy controls (AUC=.724). Conclusions: miRNAs in the circulation are relatively stable, very accessible, low invasive and easily testable biomarkers. Our preliminary promisingresults suggest miR-337-3p as novel stable blood-based marker for PCa detection.

Epithelial-mesenchymal transition markers in metastatic transitional cell carcinoma (mTCC) patients under vinflunine treatment

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Background: Vinflunine (VFL) demonstrated in vitro antiproliferative effects in human tumour cell lines, and in vitro antitumor activities against subcutaneous tumour xenografts. Recently, we demonstrated that VFL causes these effects through tubulin instability, which is one of the leading intracellular molecular process that drives epithelial-mesenchymal transition (EMT). In addition, VFL may induce up-regulation in expression levels of E-cadherin/N-cadherin cocient. Methods: The study included a retrospective analysis of 18 patients with mTCC treated with carboplatin-based chemotherapy. The patients who demonstrated objective response (38.8%) continued with vinflunine 320 mg/m2 one day every three weeks until progression. EMT protein expression (E-cadherin, beta-catenin, vimentin, CK18) was evaluated by Western blotting and also by immunohistochemistry (IHQ). Results: Overall mean age of patients was 71 years. The median overall survival was 3.5 years for the carboplatin-based chemotherapy (95% CI, 0.377-3.623). In patients treated with VFL, it was demonstrated a correlation of performance status and overall response with the histological type and age. We also found a relationship between different EMT markers in patients that received VFL. Conclusions: The above data provide evidence for an intrincate mechanism by which VFL could stop the transition from epithelial cells to the invasive mesenchymal phenotype. Molecular mechanism of Snail, Slug, Twist and Hakai will be reported.

Peripheral blood microRNAs expression profile: A fingerprint for metastatic prostate cancer

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Background: We previously have studied differentially microRNA expression levels related to hormone refractory and sensitive prostate cancer cell lines (VCap and LNCap respectively). Now, we investigated circulating miRNAs differentially expressed between metastatic prostate adenocarcinomas (mPA) and healthy controls (HC) that may serve as novel diagnostic and/or prognosis markers. Methods: Using SYBR-green-based custom microRNA RT-qPCR arrays technology (Exiqon), we compared the expression levels of miRNAs in blood samples from 18 HC and 48 mPA. Results: Among a panel of 92 candidates we found 41 underexpressed (UE) and 8 overexpressed (OE) miRNAs. The level of significance was p<0.05. Conclusions: Among the UE miRNAs are miR-203 and 129 which regulate a cohort of metastatic genes. Among the OE is miR-200a, a member of miR-200 family which directly targeted β-catenin mRNA and miR-135b which induce invasion and distant metastasis. The knowledge of miRNAs involved in mPA progression could provide us a profile that could identify patients for adjuvant therapy or even propose new target drugs to avoid disease progression or treat mPA. Our group is actively involved in the study of selected OE miRNAs for their potential as circulating markers for mPA. [Table: see text]

Molecular expression profiling and pathway analysis of formalin-fixed paraffin-embedded primary renal tumor specimens

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Background: Many studies have demonstrated genetic and environmental factors lead to renal cell carcinoma (RCC) occurring during a protracted period of tumorigenesis. It seemed suitable identify and characterize potential molecular markers which might provide rapid and effective possibilities for early detection of RCC. The purpose from this analysis was to derive predictive models which could predict more accurately than any one factor alone. Methods: We assessed using quantitative real-time PCR (qPCR) with SYBR Green the profile of 32 predictive markers involved in the cascade of events leading to the formation and progression of this disease to evaluate their involvement in oncogenesis. RNA of quality was obtained in 90% of samples (N=80, 52/80 clear RCC, 6/80 papillary RCC and 14/80 chromophobe RCC) to carry out the study of gene expression. GenEx software was used for qPCR data processing and analysis. The potential correlation between mRNA expression and the pathological features of the study subjects was assessed by Pearson Chi-squared. Linear rather than logistic regression models were used (SPSS statistics 21.0 software). Additionally, a knowledgebases of biological pathways, Reactome and Snow (Babelomics), were used to superimpose our quantitative expression data. Results: The best gene predictors related to different pathological variables (histological type, tumor size, Fuhrman grade, number of involved nodes, renal pelvis invasion, lymphatic vessels invasion, and rupture of the renal capsule): Hif1-α (p < 0.001), Hif1-β (p = 0.035), DLL1 (p = 0 .012), DLL3 (p< 0.001), c-Kit (p = 0.002), PDGFR-β (p =0.002), PDGFR-α (p = 0.026), Bax-β (p = 0.005), Survivin (p = 0.028), Notch1 (p = 0.006), Notch2 (p = 0.007), Notch3 (p = 0.016), Notch4 (p = 0.005), EGFR (p = 0.029), Glut3 (p = 0.026), Glut5 (p = 0.036), FH (p = 0.018), CA9 (p = 0.030), and VHL-1(p = 0.015). Conclusions: Our data suggested that altered expression of certain members involved in the main pathways which feed RCC and their downstream targets analyzed together could improve the diagnostic accuracy for renal cancer by combining determinations of mRNA markers.

Molecular expression profiling and pathway analysis in human renal cell carcinoma

e15079

Background: Many studies have demonstrated genetic and environmental factors lead to renal cell carcinoma (RCC) occurring during a protracted period of tumorigenesis. It seemed suitable identify and characterize potential molecular markers appearing during of tumorigenesis which might provide rapid and effective possibilities for early detection of RCC. Methods: We assessed using quantitative real-time PCR (qPCR) the profile of 32 markers involved in the cascade of events leading to the formation and progression of RCC: invasiveness, angiogenesis and antiapoptotic mechanisms. RNA of quality was obtained in 90% of samples (N=80, 64/80 clear RCC, 8/80 papillary RCC and 8/80 chromophobe RCC) to carry out the study of gene expression. Nonparametric tests (Pearson's correlation coefficient test and Spearman's rho test, Kruskal — Wallis and Mann — Whitney) and Bonferroni post-hoc test were applied for statistical data analysis. Additionally, a knowledgebase of biological pathways, Reactome, was used to superimpose our quantitative expression data. Results: Statistical analysis comparing medians and means showed the following candidates as the best gene predictors related to different pathological variables (histological type, number of involved nodes, renal pelvis invasion, lymphatic vessels invasion and rupture of the renal capsule): Hif1-α (p<.001), Hif1-β (p=.035), DLL1 (p=0.012), DLL3 (p<.001), c-Kit (p=.002), PDGFR-β (p=.002), PDGFR-α (p=0.026), Bax-β (p=.005), Survivin (p=.028), Notch1 (p=.006), Notch2 (p=.007), Notch3 (p=.016), Notch4 (p=.005), EGFR (p=.029), Glut3 (p=.026), Glut5 (p=.036) and FH (p=.018). Analysis of these genes expression profiles in Reactome tool revealed those cellular pathways over-represented in our RCC cohort, among others, Extrinsic Pathway for Apoptosis and Double-Strand Break Repair (100 and 95% matching in our data, respectively). Conclusions: Our study highlights the reasons to deepen in the knowledge of pathways components and their associations with the underlying pathology characteristics in order to understand the molecular pathology of a tumor and how that influences its biologic behavior. More detailed studies of these pathways are in progress.

Circulating microRNAs as potential biomarkers in patients with renal tumors

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Background: MicroRNAs (miRNAs), a class of small RNAs, have been intensely investigated recently because of their important regulatory role in gene expression. Circulating miARNs are potential biomarkers for cancer not only abundant in blood, but also very stable, which are important prerequisites as clinical biomarkers. Detection of circulating tumor cells (CTC) may provide diagnostic and prognostic information in genitourinary renal tumors. The aim of this work is identify miRNAs potentially useful for CTC detection in blood samples from patients with renal tumors to assess their potential clinical significance.

Methods: We examined blood levels of three miRNAs, let-7c, miR-200c and miR-31 in 48 patients with renal tumors with locally advanced or metastatic disease and 18 healthy persons using quantitative real-time PCR. The clinicopathologic characteristics of the population under consideration include among other: sex, age, tumor location, histological type, Fuhrman grade, tumor size, number of involved nodes, tumor stage, time to progression and overall survival.

Results: We found that the median levels of miRNAs, let-7c, miR-200c and miR-31 were significantly higher in patients with renal tumors than those in healthy controls (p=.002, p=.000 and p=.004, respectively). Receiver-operator characteristic (ROC) curve analyses indicate that these blood miRNAs may be useful markers for discriminating patients with renal tumors from healthy controls (AUC=.750, AUC=.853 and AUC=.738, respectively).

Conclusions: miRNAs in the circulation are relatively stable, very accessible, low invasive and easily testable biomarkers. Our results suggest let-7c, miR-200c and miR-31 as novel stable blood-based markers for renal cancer detection. This work was supported by Grants PI07/0477 from Fondo de Investigaciones Sanitarias (FIS), Instituto de Salud Carlos III.S. Díaz Prado is supported by an Isidro Parga Pondal research contract by Xunta de Galicia (A Coruña, Galicia, Spain). Cancer research in our laboratory is supported by the “Fundación do CHU A Coruña”.

Biomolecular characterization of formalin-fixed paraffin-embedded primary renal tumor specimens

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Background: Renal cell carcinoma (RCC) is the most common type of kidney cancer. It is required a better understanding of signalling pathways involved in renal cells.

Methods: We assessed using immunohistochemistry (IHC) and quantitative real-time PCR (qPCR) with SYBR Green the profile of predictive markers involved in the cascade of events leading to the formation and progression: invasiveness, angiogenesis and antiapoptotic mechanisms. 80 RCC tissues were detected by IHC. RNA of quality only was obtained in 72 (80% clear RCC, 10% papillary RCC and 10% chromophobe RCC) to carry out the study of gene expression through qPCR. A pool of normal kidney-derived RNA samples (N=5) was used as healthy control. GAPDH and YWHAZ were used as reference genes. GenEx software was used for qPCR data processing and analysis. Nonparametric tests (Pearson’s correlation coefficient test and Spearman’s rho test, Kruskal — Wallis and Mann — Whitney) were applied for statistical data analysis (SPSS 19).

Results: p53 showed higher expression in those cases with Furhman grade I (p=0.036). Moreover p53 showed a positive association with VEGF, GLUT1, GLUT4, VEGFR-2 and VHL (r=0.241, sig. level 0.05; r=0.291, sig. level 0.01; r=0.456, sig. level 0.01; r=0.187, sig. level 0.097 and Spearman’s rho=0.269, sig. level 0.05 respectively). Hif1- α, Hif1- β, Notch1 and Notch3 were upregulated in chromophobe RCC (p=0.045, p=0.03, p=0.03 and p=0.02 respectively). Hif1- α and Notch3 were upregulated in clear RCC (p=0.034 and p=0.041 respectively). Spearman’s correlation coefficient showed a strong positive correlation between Nocth1-4 members and their receptors and Hif1-α and β genes. Highlight the correlation found between: Notch1 and Hif1-α (Spearman’s rho = 0.740, significance level 0.01) and Hif1-β and Jagged1 (Spearman’s rho = 0.752, significance level 0.01).

Conclusions: The pathway involving the tumor suppressor gene p53 could regulate tumor angiogenesis. Co-expression of Notch receptors, their ligands and Hif-1 α and Hif1- β subunits may play a role in human RCC. Notch cascade may represent a novel and therapeutically accessible pathway in chromophobe and clear RCC. More detailed studies of these crossing pathways are in progress.

Diagnosis delay and follow-up strategies in colorectal cancer. Prognosis implications: a study protocol

Background

Controversy exists with regard to the impact that the different components of diagnosis delay may have on the degree of invasion and prognosis in patients with colorectal cancer. The follow-up strategies after treatment also vary considerably. The aims of this study are: a) to determine if the symptoms-to-diagnosis interval and the treatment delay modify the survival of patients with colorectal cancer, and b) to determine if different follow-up strategies are associated with a higher survival rate.

Methods/Design

Multi-centre study with prospective follow-up in five regions in Spain (Galicia, Balearic Islands, Catalonia, Aragón and Valencia) during the period 2010-2012. Incident cases are included with anatomopathological confirmation of colorectal cancer (International Classification of Diseases 9th revision codes 153-154) that formed a part of a previous study (n = 953).

At the time of diagnosis, each patient was given a structured interview. Their clinical records will be reviewed during the follow-up period in order to obtain information on the explorations and tests carried out after treatment, and the progress of these patients.

Symptoms-to-diagnosis interval is defined as the time calculated from the diagnosis of cancer and the first symptoms attributed to cancer. Treatment delay is defined as the time elapsed between diagnosis and treatment. In non-metastatic patients treated with curative intention, information will be obtained during the follow-up period on consultations performed in the digestive, surgery and oncology departments, as well as the endoscopies, tumour markers and imaging procedures carried out.

Local recurrence, development of metastases in the follow-up, appearance of a new tumour and mortality will be included as outcome variables.

Actuarial survival analysis with Kaplan-Meier curves, Cox regression and competitive risk survival analysis will be performed.

Discussion

This study will make it possible to verify if the different components of delay have an impact on survival rate in colon cancer and rectal cancer. In consequence, this multi-centre study will be able to detect the variability present in the follow-up of patients with colorectal cancer, and if this variability modifies the prognosis. Ideally, this study could determine which follow-up strategies are associated with a better prognosis in colorectal cancer.

Evaluation of COX-2, EGFR, and p53 as biomarkers of non-dysplastic oral leukoplakias

OBJECTIVE

Identify candidate SEBs (surrogate endpoint biomarkers) for premalignant trends in head and neck mucosa.

STUDY DESIGN

Study, by qPCR (quantitative real-time polymerase chain reaction), the expression of COX-2, EGFR and p53 in 24 biopsies of non-dysplastic oral leukoplakia and contra-lateral normal-appearing mucosa.

RESULTS

COX-2 was up-regulated in leukoplakia (79.2%); whereas EGFR and p53 were up-regulated (p>0.05) in oral contra-lateral normal-appearing mucosa (60% and 46% respectively). Also, p53 expression was correlated with tobacco smoke habits and Spearman's rank correlation coefficient showed a positive linear correlation between p53 and EGFR mRNA expression levels.

CONCLUSIONS

COX-2 would serve as SEB of oral leukoplakia. The results suggest that p53 appears to be one of the molecular targets of tobacco-related carcinogens in leukoplakia and that the co-expression of p53 and EGFR may play a role in this kind of oral pre-cancerous lesion. More detailed studies of EGFR and p53 should be continued in the future.

Origin of renal cell carcinomas

Cancer is a heritable disorder of somatic cells: environment and heredity are both important in the carcinogenic process. The primal force is the "two hits" of Knudson's hypothesis, which has proved true for many tumours, including renal cell carcinoma. Knudson et al. [1, 2] recognised that familial forms of cancer might hold the key to the identification of important regulatory elements known as tumour-suppressor genes. Their observations (i.e., that retinoblastoma tend to be multifocal in familial cases and unifocal in sporadic presentation) led them to propose a two-hit theory of carcinogenesis. Furthermore, Knudson postulated that patients with the familial form of the cancer would be born with one mutant allele and that all cells in that organ or tissue would be at risk, accounting for early onset and the multifocal nature of the disease. In contrast, sporadic tumours would develop only if a mutation occurred in both alleles within the same cell, and, as each event would be expected to occur with low frequency, most tumours would develop late in life and in a unifocal manner [3, 4]. The kidney is affected in a variety of inherited cancer syndromes. For most of them, both the oncogene/tumour-suppressor gene involved and the respective germline mutations have been identified. Each of the inherited syndromes predisposes to distinct types of renal carcinoma. Families with hereditary predisposition to cancer continue to provide a unique opportunity for the identification and characterisation of genes involved in carcinogenesis. A surprising number of genetic syndromes predispose to the development of renal cell carcinoma, and genes associated with five of these syndromes have been already identified: VHL, MET, FH, BHD and HRPT2. Few cancers have as many different types of genetic predisposition as renal cancer, although to date only a small proportion of renal cell cancers can be explained by genetic predisposition.