Augusto Nogueira

Circulating DNA: Diagnostic Tool and Predictive Marker for Overall Survival of NSCLC Patients

Purpose The purpose of our study was to determine whether the amounts of circulating DNA (cDNA) could discriminate between NSCLC patients and healthy individuals and assess its value as a prognostic marker of this disease. Methods We conducted a study of 309 individuals and the cDNA levels were assessed through real-time PCR methodology. Results We found increased cDNA levels in NSCLC patients compared to control individuals. We also found a decreased overall survival time in patients presenting high cDNA levels, when compared to lower cDNA concentrations. Conclusions Quantification of cDNA may be a good tool for NSCLC detection with potential for clinical applicability.

Renal cell carcinoma development and miRNAs: a possible link to the EGFR pathway

Renal cell carcinoma (RCC) is the most common solid cancer of the adult kidney and the majority of RCC cases are detected accidentally. This reality and the nonexistence of a standard screening test contribute to the fact that one third of patients are diagnosed with local invasive disease or metastatic disease. miRNAs are a family of small ncRNAs that regulate gene expression and have been identified as key regulators in many biological processes including cell development, differentiation, apoptosis and proliferation. The EGF receptor signaling pathway is usually deregulated in cancer and it is suggested to have an important role in RCC. Further studies are needed to characterize deregulation of this pathway during RCC development. In this review we highlight some potential miRNAs that could be involved in the modulation of the EGF receptor pathway and consequently in RCC development.

Prognostic Significance of Telomerase Polymorphism in Non-Small Cell Lung Cancer

Purpose: Lung cancer is the leading cause of death in oncologic patients of western countries, with very low survival rates. Telomerase main components are the catalytic subunit (hTERT) and the RNA template (hTR). A functional polymorphism in the hTERT gene was found in the promoter region (−1327T/C), and individuals homozygous for the −1327C/C genotype present shorter telomere length compared with T-carrier genotypes. Our purpose was to investigate the potential prognostic role of the hTERT functional genetic variant in non–small cell lung cancer (NSCLC) patients. Experimental Design: We prospectively conducted a study involving 226 patients with NSCLC treated with a first-line chemotherapeutic standard protocol. A follow-up study was undertaken (median follow-up time, 26 months) to evaluate treatment response and overall survival of NSCLC patients. The hTERT −1327T/C genetic variants were analyzed by allelic discrimination with real-time PCR. Results: Our results indicate an influence of the telomerase genetic variants in the overall survival of NSCLC patients. Cox regression analysis showed a significantly higher median estimated cumulative survival of 26.5 months in T-carrier patients, compared with that of 19.3 months in CC patients (hazard ratio, 0.52; 95% confidence interval, 0.35-0.77; P = 0.001). Conclusions: Telomerase functional polymorphism in the hTERT gene may contribute as a prognostic factor in NSCLC patients. Our findings indicate that hTERT genetic variants, by modulating telomere length, may confer an advantage in chemotherapy response. The assessment of telomerase genetic variants could supplement prognosis of survival in the course of NSCLC and may be a promising molecular marker of treatment response in these patients. Clin Cancer Res; 16(14); 3706–12. ©2010 AACR.

Improvement of a Predictive Model of Castration-Resistant Prostate Cancer: Functional Genetic Variants in TGFβ1 Signaling Pathway Modulation

Prostate cancer (PC) is the most frequently diagnosed cancer in men. The acquisition of castration-resistant (CR) phenotype is associated with the activation of signaling pathways mediated by growth factors. The TGFβ1 and its receptors have an important role in tumor progression, being the pro-apoptotic function modulated by the expression of TGFBR2. A single nucleotide polymorphism -875 G > A in TGFBR2 gene has been described, which may influence the expression levels of the receptor. Our purpose was to investigate the potential role of TGFBR2-875G>A in PC risk and in the response to androgen deprivation therapy (ADT). TGFBR2-875G>A polymorphism was studied by allelic discrimination using real-time polymerase chain reaction (PCR) in 891 patients with PC and 874 controls. A follow-up study was undertaken to evaluate response to ADT. The TGFBR2 and SMAD7 mRNA expression were analyzed by a quantitative real-time PCR. We found that TGFBR2-875GG homozygous patients present lower expression levels of TGFBR2 mRNA (AA/AG: 2-ΔΔCT =1.5, P=0.016). GG genotype was also associated with higher Gleason grade (OR=1.51, P=0.019) and increased risk of an early relapse after ADT (HR=1.47, P=0.024). The concordance (c) index analysis showed that the definition of profiles that contains information regarding tumor characteristics associated with genetic information present an increased capacity to predict the risk for CR development (c-index model 1: 0.683 vs model 2: 0.736 vs model 3: 0.746 vs model 4: 0.759). The TGFBR2-875G>A contribution to an early relapse in ADT patients, due to changes in mRNA expression, supports the involvement of TGFβ1 pathway in CRPC. Furthermore, according to our results, we hypothesize the potential benefits of the association of genetic information in predictive models of CR development.

DNA repair and cytotoxic drugs: the potential role of RAD51 in clinical outcome of non-small-cell lung cancer patients

Many of the cytotoxic drugs used in the treatment of non-small-cell lung carcinoma patients can interfere with DNA activity and the definition of an individual DNA repair profile could be a key strategy to achieve better response to chemotherapeutic treatment. Although DNA repair mechanisms are important factors in the prevention of carcinogenesis, these molecular pathways are also involved in therapy response. RAD51 is a crucial element in DNA repair by homologous recombination and has been shown to interfere with the prognosis of patients treated with chemoradiotherapy. There is increasing evidence that genetic polymorphisms in repair enzymes can influence DNA repair capacity and, consequently, affect chemotherapy efficacy. We conducted this review to show the possible influence of the RAD51 genetic variants in damage repair capacity and treatment response in non-small-cell lung carcinoma patients.

Interleukin-1β genotype and circulating levels in cancer patients: Metastatic status and pain perception

OBJECTIVES Proinflammatory cytokines released during inflammation can cause hyperexcitability in pain transmission neurons, leading to hyperalgesia and allodynia. Polymorphisms in interleukin 1 (IL-1) family of genes (IL1A, IL1B) and in IL-1 receptor antagonist (IL-1Ra, coded by IL1RN) may therefore induce alterations in cytokine levels/effects and pain related response. Our purpose was to investigate the influence of polymorphisms in IL1A/B/RN on cytokine serum levels and its correlation with pain intensity, performance status, adverse effects, metastases and breakthrough pain in Caucasian cancer patients. DESIGN AND METHODS Serum IL-1α/β levels of 74 cancer patients were measured by competitive enzyme immunosorbent assay. All patients were also genotyped for the polymorphisms in IL1A (rs17561), IL1B (rs1143634) and IL1RN (rs419598) with Real-Time PCR. Results were then correlated to the appearance of bone or CNS metastases and several pain-related parameters. RESULTS IL-1β rs1143634 homozygous for T allele were associated with lower levels of IL1-β (p=0.032, Mann-Whitney test) and presented a trend for lower levels of pain (p=0.06, Fishers Exact Test). Also, IL1-β levels were related with cancer onset status, since a four-fold increase probability of metastatic disease was observed in high IL-1β individuals (OR=4.074, p=0.010, Pearson χ(2) test). Among the female patients presenting metastatic disease and carriers of the TT genotype we observed a trend to lower levels of IL1-β (p=0.053, Pearson χ(2) test). CONCLUSIONS Our results indicate that genetic variation at IL1-β gene may influence serum levels of IL1-β, with proportional consequences in cancer-related pain.

Restoring TGFβ1 pathway-related microRNAs: possible impact in metastatic prostate cancer development

In developed countries, prostate cancer (PC) is the neoplasia more frequently diagnosed in men. The signaling pathway induced by the transforming growth factor β1 (TGFβ1) has an important role in cell growth, differentiation, and development, the downregulation of this pathway being associated with cancer development. In PC, the activation of this signaling pathway is lost, resulting in favoring of tumor growth, proliferation, and evasion of apoptosis. Several studies have shown that microRNAs (miRNAs), small non-coding RNA, are closely associated with the development, invasion, and metastasis, suggesting that they have a critical role in cancer development. Recently, Smad proteins, the signal transducers of the TGFβ1 signaling pathway, were found to regulate miRNA expression, through both transcriptional and posttranscriptional mechanisms. In this review, we summarize the mechanisms underlying Smad-mediated regulation of miRNA biogenesis and the effects on cancer development, particularly in PC. We identify that TGFβ1-related miR-143, miR-145, miR-146a, and miR-199a may have a key role in the development of prostate cancer metastasis and the restoration of their expression may be a promising therapeutic strategy for PC treatment.

Role of the RAD51 G172T polymorphism in the clinical outcome of cervical cancer patients under concomitant chemoradiotherapy

INTRODUCTION Cervical cancer is one of the most common cancers diagnosed in women worldwide. Mammalian cells are constantly exposed to a wide variety of genotoxic agents from both endogenous and exogenous sources. The RAD51 protein is required for meiotic and mitotic recombination and plays a central role in homology-dependent recombinational repair of double-strand breaks (DSBs). Given the functional relevance of the DNA repair system on carcinogenesis, potential associations between genetic polymorphisms of DNA repair genes, cancer risk and response to therapy have been intensively evaluated. This is the first study evaluating the role of the RAD51 G172T genetic variants in cancer prognosis and clinical outcome of cervical cancer patients. MATERIAL AND METHODS We analyzed RAD51 G172T polymorphism genotypes in cervical cancer patients who underwent a platinum-based chemotherapy in combination with radiotherapy. Genotyping was performed by Taqman™ Allelic Discrimination methodology. RESULTS AND DISCUSSION Concerning the overall survival rates found using Kaplan-Meier method and Log Rank Test, we observed that the mean survival rates were statistically different according to the patients RAD51 genotypes. The group of patients carrying the T allele present a higher mean survival rate than the other patients (102.3months vs. 86.4months, P=0.020). Using the Cox regression analysis, we found an increased overall survival time for T-carrier patients, when compared with GG genotype, with tumor stage, age and presence of lymph nodes as covariates [hazard ratio (HR), 0.373; 95% CI, 0.181-0.770; P=0.008]. Among patients (n=193), RAD51 genotype frequency distributions were not under the influence of clinicopathologic characteristics, namely, treatment response (P=0.508), recurrence (P=0.150) and tumor stage (P=0.250). CONCLUSIONS This is the first study evaluating the role of the RAD51 G172T genetic variants in cancer prognosis and clinical outcome of cervical cancer patients. Our results indicate an influence of the RAD51 genetic variants in overall survival of cervical cancer. Thereby, RAD51 G172T genotypes may provide additional prognostic information in cervical cancer patients who underwent cisplatin-based chemotherapy in combination with radiotherapy.

Improvement of a predictive model in ovarian cancer patients submitted to platinum-based chemotherapy: implications of a GST activity profile

PurposeThe success of chemotherapy in ovarian cancer (OC) is directly associated with the broad variability in platinum response, with implications in patients survival. This heterogeneous response might result from inter-individual variations in the platinum-detoxification pathway due to the expression of glutathione-S-transferase (GST) enzymes. We hypothesized that GSTM1 and GSTT1 polymorphisms might have an impact as prognostic and predictive determinants for OC.MethodsWe conducted a hospital-based study in a cohort of OC patients submitted to platinum-based chemotherapy. GSTM1 and GSTT1 genotypes were determined by multiplex PCR.ResultsGSTM1-null genotype patients presented a significantly longer 5-year survival and an improved time to progression when compared with GSTM1-wt genotype patients (log-rank test, P = 0.001 and P = 0.013, respectively). Multivariate Cox regression analysis indicates that the inclusion of genetic information regarding GSTM1 polymorphism increased the predictive ability of risk of death after OC platinum-based chemotherapy (c-index from 0.712 to 0.833). Namely, residual disease (HR, 4.90; P = 0.016) and GSTM1-wt genotype emerged as more important predictors of risk of death (HR, 2.29; P = 0.039; P = 0.036 after bootstrap). No similar effect on survival was observed regarding GSTT1 polymorphism, and there were no statistically significant differences between GSTM1 and GSTT1 genotypes and the assessed patients’ clinical-pathological characteristics.ConclusionGSTM1 polymorphism seems to have an impact in OC prognosis as it predicts a better response to platinum-based chemotherapy and hence an improved survival. The characterization of the GSTM1 genetic profile might be a useful molecular tool and a putative genetic marker for OC clinical outcome.

Common genetic polymorphisms in the ABCB1 gene are associated with risk of major depressive disorder in male Portuguese individuals.

Major depressive disorder (MDD) is a highly prevalent disorder, which has been associated with an abnormal response of the hypothalamus-pituitary-adrenal (HPA) axis. Reports have argued that an abnormal HPA axis response can be due to an altered P-Glycoprotein (P-GP) function. This argument suggests that genetic polymorphisms in ABCB1 may have an effect on the HPA axis activity; however, it is still not clear if this influences the risk of MDD. Our study aims to evaluate the effect of ABCB1 C1236T, G2677TA and C3435T genetic polymorphisms on MDD risk in a subset of Portuguese patients. DNA samples from 80 MDD patients and 160 control subjects were genotyped using TaqMan SNP Genotyping assays. A significant protection for MDD males carrying the T allele was observed (C1236T: odds ratio (OR)=0.360, 95% confidence interval [CI]: [0.140-0.950], p=0.022; C3435T: OR=0.306, 95% CI: [0.096-0.980], p=0.042; and G2677TA: OR=0.300, 95% CI: [0.100-0.870], p=0.013). Male Portuguese individuals carrying the 1236T/2677T/3435T haplotype had nearly 70% less risk of developing MDD (OR=0.313, 95% CI: [0.118-0.832], p=0.016, FDR p=0.032). No significant differences were observed regarding the overall subjects. Our results suggest that genetic variability of the ABCB1 is associated with MDD development in male Portuguese patients. To the best of our knowledge, this is the first report in Caucasian samples to analyze the effect of these ABCB1 genetic polymorphisms on MDD risk.