Rui Medeiros

Importance of TP53 codon 72 and intron 3 duplication 16bp polymorphisms in prediction of susceptibility on breast cancer

BackgroundTP53 is one of major tumour suppressor genes being essential in preservation of genome integrity. Two very common polymorphisms have been demonstrated to contribute to cancer susceptibility and tumour behaviour. The purpose of this study was to evaluate the role of Arg72Pro and PIN3 Ins16bp polymorphisms in TP53 gene as genetic susceptibility and predictive markers to breast cancer.MethodsWe analysed DNA samples from 264 breast cancer patients and 440 controls, for TP53 Arg72Pro and PIN3 Ins16bp polymorphisms using PCR-RFLP.ResultsWe observed that women with A2A2 genotype have increased risk for developing breast cancer, either in women with or without familial history (FH) of the disease (OR = 4.40, 95% CI 1.60–12.0; p = 0.004; OR = 3.88, 95% CI 1.18–12.8; p = 0.026, respectively). In haplotype analysis, statistically significant differences were found between TP53 Arg-A2 haplotype frequencies and familial breast cancer cases and the respective control group (OR = 2.10, 95% CI 1.08–4.06; p = 0.028). Furthermore, both TP53 polymorphisms are associated with higher incidence of lymph node metastases.ConclusionOur findings suggest TP53 PIN3 Ins16bp polymorphism as a real risk modifier in breast cancer disease, either in sporadic and familial breast cancer. Furthermore, both TP53 polymorphisms are associated with higher incidence of lymph node metastases.

Platinum/paclitaxel-based chemotherapy in advanced ovarian carcinoma: glutathione S-transferase genetic polymorphisms as predictive biomarkers of disease outcome

AbstractBackground. The glutathione S-transferases (GSTs) are a group of multifunctional enzymes that catalyze the conjugation of glutathione with a variety of electrophilic compounds, including cytotoxic agents. A significant percentage of normal individuals exhibit genetic polymorphism with a homozygous deletion (null genotype) of the genes, leading to absence of the enzyme. Methods. In the present study we analyzed GSTM1 and GSTT1 polymorphisms in the genomic DNA isolated from peripheral blood of patients with ovarian cancer treated with chemotherapy (paclitaxel and cisplatinum) after cytoreductive surgery and assessed its correlation with the clinical outcome of these patients. The median follow-up for the patients was 30 months. Results. The estimated 3-year survival rate was 59.8% for all patients and 20.8% for carriers of GSTM1-wt/GSTT1-wt (wt indicates wild type) genotype combination (37.7% for GSTM1-wt alone) compared with 83.1% for non-GSTM1-wt/GSTT1-wt genotype carriers (100% for GSTM1-null). The mean survival time was significantly better in patients who are carriers of the GSTM1-null genotype (40.5 vs. 33.5; P = 0.006) or carriers of non-GSTM1-wt/GSTT1-wt genotypes (55.4 vs. 30.7; P = 0.009). The progression-free interval was more favorable for GSTM1-null carriers (41.9 vs. 27.4; P = 0.024). Conclusion. The study suggests that characterization of the drug-metabolizing genetic individual profile can be of great interest in clinical oncology. It can define the optimal chemotherapy for each patient, improve the efficiency, and reduce the incidence of drug toxicity and poor drug responses.

Linkage of angiotensin I-converting enzyme gene insertion/deletion polymorphism to the progression of human prostate cancer

Angiotensin‐converting enzyme (ACE) degrades vasodilator kinins and generates angiotensin II (Ang II). It has been reported that ACE is synthesized by the prostate and that the AT‐1 receptor subtype is the predominant prostatic Ang II receptor. A polymorphism in the human ACE gene has been described and the highest levels of circulating and tissue ACE activity are found in carriers of the DD genotype. In the present study, ACE genotypes were determined in 170 patients with prostate cancer and their association with disease progression was analysed. It was found that the DD genotype was present in 31 of 78 (39.8%) patients with advanced disease and in 19 of 82 (23.2%) with localized disease: this difference was statistically significant (OR = 2.18, 95% CI = 1.11–4.03; p = 0.024). Step‐wise logistic regression analysis was used to identify predictive parameters of advanced disease and it was observed that the DD genotype (p = 0.002, OR = 5.4, 95% CI = 1.84–16.06), high‐grade tumour (p < 0.001, OR = 8.04, 95% CI = 3.03–21.33), and high serum PSA (p < 0.001, OR = 10.87, 95% CI = 4.06–29.13) were significantly associated with advanced disease. The results of this study support the hypothesis that genetic factors related to ACE may influence the behaviour of human prostate cancer. Copyright

The role of vitamin D receptor gene polymorphisms in the susceptibility to prostate cancer of a southern European population

AbstractEpidemiological data indicate a relationship between ultraviolet radiation, vitamin D, and prostate cancer risk. Antiproliferative effects of vitamin D require the expression of the nuclear vitamin D receptor (VDR). A three-fold increase in prostate cancer risk associated with the less active vitamin D receptor allele (the T allele from VDR TaqI polymorphism at codon 352) was reported. The role of VDR genotypes in the susceptibility to prostate cancer has not yet been studied in populations of southern Europe. In the present study, we determined VDR TaqI genotypes in Portuguese prostate cancer cases (n= 163) and controls (n= 211), a southern European population. When cases were compared with controls, we found an association of VDR T allele with prostate cancer risk (odds ratio [OR] = 1.87, 95% confidence interval [CI] 1.02–3.37; P= 0.035). This association was confirmed using logistic regression analysis (OR = 2.11, 95% CI 1.15–3.88; P= 0.015) and in particular associated to risk of prostate cancer onset in men over the age of 66 years (OR = 2.36, 95% CI 1.05–5.29; P= 0.036). Fifty percent of cases older than 66 years could be attributed to the influence of this risk factor. Our results indicate that the contribution of VDR genotypes to prostate cancer susceptibility might depend on the population studied and its geographic localization, and that VDR genotypes are important in the definition of the genetic risk profile of populations of southern Europe.

Endothelial nitric oxide synthase gene polymorphisms and genetic susceptibility to prostate cancer.

The endothelial cell-specific form of nitric oxide synthases (ecNOS) is localized at 7q35–q36 and is involved in vascular development and tumour growth in human prostate cancer. We have conducted a case–control study to investigate the prevalence of two polymorphisms at intron 4 (ecNOS4a/b) and exon 7 (Glu-Asp298) of ecNOS gene in 125 prostate cancer (PCa) patients and in 153 controls. We observed that the a-allele (aa or ab genotypes from ecNOS4a/b) was over-presented in the group of PCa with Gleason histological grade ≥7 (P =0.041). With regard to the Glu-Asp298 polymorphism, patients with the T-allele were younger than patients with no T-allele (P =0.037), and a statistically significant difference was noted in the Glu-Asp298 genotype distribution between cases with advanced disease and cases with localized disease (P =0.0013). When comparing cases and controls with logistic regression analysis we observed that the presence of the a-allele is associated with prostate cancer risk (odds ratio (OR) 1.83; 95% confidence interval (CI) 1.06–3.17;P =0.029), to high histological grade (Gleason ≥7) of PCa (OR 2.18; 95% CI 0.95–4.98;P =0.062) and with the risk of progression of the cancer disease (OR 2.85; 95% CI 1.19–6.82;P =0.018). Furthermore, we found that carriers with the combination of the a-allele (aa and ab ecNOS4a/b genotypes) and T-allele (GT and TT from Glu-Asp298) have a threefold increase in prostate cancer risk (OR 3.13; 95% CI 1.41–6.91, P =0.004). In summary, we have identified an NO-related genetic risk factor for prostate cancer that may help in understanding the molecular mechanism involved in the individual susceptibility to prostate cancer.

Quantification of Free Circulating Tumor DNA as a Diagnostic Marker for Breast Cancer

AIM To determine whether the amounts of circulating DNA could discriminate between breast cancer patients and healthy individuals by using real-time PCR quantification methodology. METHODS Our standard protocol for quantification of cell-free plasma DNA involved 175 consecutive patients with breast cancer and 80 healthy controls. RESULTS We found increased levels of circulating DNA in breast cancer patients compared to control individuals (105.2 vs. 77.06 ng/mL, p < 0.001). We also found statistically significant differences in circulating DNA amounts in patients before and after breast surgery (105.2 vs. 59.0 ng/mL, p = 0.001). Increased plasma cell-free DNA concentration was a strong risk factor for breast cancer, conferring an increased risk for the presence of this disease (OR, 12.32; 95% CI, 2.09-52.28; p < 0.001). CONCLUSIONS Quantification of circulating DNA by real-time PCR may be a good and simple tool for detection of breast cancer with a potential to clinical applicability together with other current methods used for monitoring the disease.

IL-6/IL-6R as a potential key signaling pathway in prostate cancer development.

Interleukin-6 (IL-6) is a pleiotropic cytokine involved in prostate regulation and in prostate cancer (PC) development/progression. IL-6 acts as a paracrine and autocrine growth stimulator in benign and tumor prostate cells. The levels of IL-6 and respective receptors are increased during prostate carcinogenesis and tumor progression. Several studies reported that increased serum and plasma IL-6 and soluble interleukin-6 receptor levels are associated with aggressiveness of the disease and are associated with a poor prognosis in PC patients. In PC treatment, patients diagnosed with advanced stages are frequently submitted to hormonal castration, although most patients will eventually fail this therapy and die from recurrent castration-resistant prostate cancer (CRPC). Therefore, it is important to understand the mechanisms involved in CRPC. Several pathways have been proposed to be involved in CRPC development, and their understanding will improve the way to more effective therapies. In fact, the prostate is known to be dependent, not exclusively, on androgens, but also on growth factors and cytokines. The signaling pathway mediated by IL-6 may be an alternative pathway in the CRPC phenotype acquisition and cancer progression, under androgen deprivation conditions. The principal goal of this review is to evaluate the role of IL-6 pathway signaling in human PC development and progression and discuss the interaction of this pathway with the androgen recepto pathway. Furthermore, we intend to evaluate the inclusion of IL-6 and its receptor levels as a putative new class of tumor biomarkers.The IL-6/IL-6R signaling pathway may be included as a putative molecular marker for aggressiveness in PC and it may be able to maintain tumor growth through the AR pathway under androgen-deprivation conditions. The importance of the IL-6/IL-6R pathway in regulation of PC cells makes it a good candidate for targeted therapy.

Functional polymorphisms of Toll-like receptors 2 and 4 alter the risk for colorectal carcinoma in Europeans

BACKGROUND Colon carcinogenesis is associated with increased expression levels of Toll-like receptor 2 and Toll-like receptor 4. AIM To determine in a Caucasian population the role of Toll-like receptor 2 and Toll-like receptor 4 polymorphisms in colorectal cancer development. METHODS Hospital based multicentre case control study involving 193 colorectal cancer patients and 278 healthy individuals. DNA samples were extracted from blood cells and genotyping of TLR2+597T>C, TLR2-4760T>C, TLR4-3745A>G, TLR2Arg753Gln, TLR4Asp299Gly was performed. Functionality of risk polymorphisms was evaluated through production of TNF-α in cell culture and Toll-like receptors levels quantified by real-time RT-PCR. RESULTS TLR2+597CC homozygous had 5-fold decreased risk (odds ratio (OR)=0.21, 95% CI: 0.09-0.50, p<0.001) and TLR4 299Gly homozygous 3-fold increased risk of colorectal cancer (OR=3.30, 95% CI: 1.18-9.28, p=0.015). In stratified analysis, TLR2+597CC genotype protective effect was even higher in overweight individuals (OR=0.17, 95% CI: 0.06-0.53, p<0.001) and in never smokers (OR=0.11, 95% CI: 0.02-0.51, p=0.001). Also, the increased risk effect for TLR4 299Gly homozygous genotype was higher in overweight individuals (OR=8.67, 95% CI: 1.11-87.85, p=0.011). TLR2+597T>C polymorphism conferred 41% less (p=0.03) and TLR4Asp299Gly 65% more TNF-α production (p=0.02) with no differences in Toll-like receptors levels. CONCLUSION Functional Toll-like receptor 2 and Toll-like receptor 4 polymorphisms significantly alter the risk to have colorectal cancer. Obesity and smoking may influence the risk for colorectal cancer in individuals presenting these genetic profiles.

Steroid hormone genotypes ARStuI and ER325 are linked to the progression of human prostate cancer

Steroid hormones and their receptors are involved as initiators or promoters in prostate carcinogenesis. The intrauterine-perinatal period and maternal estrogen and testosterone levels have been proposed to be of etiologic importance in prostate tumorigenesis and cancer progression. The objective of this study was to analyze genetic polymorphisms in the androgen receptor ARStuI by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and in the estrogen receptor ER325 by PCR-single-strand conformational polymorphism (PCR-SSCP). In our study of 170 prostate cancer patients, ARStuI and ER325 genotypes and their association with disease progression and metastasis were analyzed. Age-adjusted logistic regression analysis indicates the association of ARStuI S1 allele with high-grade tumor (P = 0.033; OR = 3.0, 95% CI = 1.1-8.3) and the association of ER325 with high-grade tumor (P = 0.003; OR = 3.0, 95% CI = 1.4-6.4), advanced disease (P = 0.020; OR = 2.4, 95% CI = 1.1-5.1), risk of progression (P = 0.027; OR = 2.5, 95% CI = 1.1-5.7) and the presence of metastatic disease (P = 0.006; OR = 3.1, 95% CI = 1.4-6.8). In summary, this study has demonstrated androgen receptor (ARStuI) and estrogen receptor (ER325) genetic polymorphisms in prostate cancer patients and its association with disease progression and metastasis. Our results support the hypothesis that genetic factors related to steroid hormone receptors may influence the behavior of human prostate cancer.

Linkage of TP53 codon 72 pro/pro genotype as predictive factor for nasopharyngeal carcinoma development.

Genetic predisposition has been suggested as a cofactor for cancer aetiology and a polymorphism in TP53 codon 72 has been associated as a susceptibility factor for several cancers. Nasopharyngeal carcinoma is a rare neoplasia in western civilizations and genetic predisposition might play an important role in its development. We evaluated the linkage of the polymorphic variants (Arg/Pro) on TP53 codon 72 with nasopharyngeal cancer development in a case–control study with 392 individuals from a northern Portuguese population, including 107 patients with nasopharyngeal carcinoma and 285 healthy controls. This study revealed a three-fold risk for carriers of Pro/Pro genotype either against carriers of Arg/Arg (OR=2.62; 95% CI=1.10–6.30; P=0.016) or total Arg carriers (OR=2.67; 95% CI=1.21–5.90; P=0.012). Moreover, step-wise logistic regression analysis identified Pro/Pro genotype (OR=3.1; 95% CI=1.3–7.3; P=0.009), age >49 at diagnosis (OR=2.5; 95% CI=1.6–4.0; P<0.001) and male gender (OR=2.7; 95% CI=1.6–4.4; P<0.001) as predictive factors for the development of nasopharyngeal carcinoma. These results confirm the data from Asiatic populations suggesting that Pro/Pro genotype represents a stable risk factor for nasopharyngeal carcinoma development in Portugal and that TP53 codon 72 polymorphism can contribute as a genetic susceptibility marker, providing additional information to improve the knowledge about nasopharyngeal carcinoma aetiology.