Hugo ML Sousa

Abstract: The tumor necrosis factor-alpha (TNF-α) is a strong proinflammatory cytokine produced by the activated macrophages in the immune response to viral infections. A common polymorphism on the promoter region of TNFA gene (-308G >A) has been associated with different susceptibilities to the development of several diseases including viral-associated neoplasias. Data suggest that the A allele has been associated with higher levels of TNF-α and, therefore, leads to increased risk of cancer development. We have performed a case-control study considering the role of the -308G >A polymorphism in 750 individuals from the northern region of Portugal, including 123 patients with nasopharyngeal carcinoma (NPC) and 627 healthy individuals. Our study revealed an increased frequency of the -308A TNFA allele in patients with NPC. The statistical analysis for recessive model revealed that -308AA genotype is associated with increased risk for the development of NPC (odds ratio = 2.46; 95% confidence interval, 0.98-6.17; p = 0.047); moreover, this effect was stronger in undifferentiated types, which are virtually 100% caused by the Epstein-Barr virus (odds ratio = 2.75; 95% confidence interval, 1.09-6.90; p = 0.025). These results reveal that in our population -308 TNFA AA genotype can represent a risk marker for NPC development and contributes for the definition of genetic susceptibility profiles for individuals at risk of development of a viral infection and associated neoplasia.

Abstract: The interaction between HPV E6 and p53 protein is known as the most important event in HPV-associated carcinogenesis. Some in vitro studies suggested that p53 genetic variants are targeted for ubiquitin-proteasome degradation induced by E6 with different abilities. A common p53 variant at position 72 (R72P) has leaded to the development of several studies regarding its role on cervical cancer development. However, only few reports have shown an association between the Arginine (R) variant at position 52 of p53 and increased susceptibility to HPV E6 mediated degradation and thus to increased cancer susceptibility. We revised the literature in order to obtain plausible data to discuss about these evidences for cervical cancer susceptibility. The more recent studies, including meta-analysis reviews, point out that there is no association of this p53 variant and cervical cancer development. This variant seems to be differently segregated in different ethnic/geographical locations; therefore, there might be a possible role of this genetic variant associated with a certain genetic background, which can explain why some studies reveal increased risk of cervical cancer development associated with Arginine p53 variant.

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Abstract: Recent studies refer that amplification/overexpression of the principal negative regulator of p53 (Mdm2) is frequently found in several malignancies. Several studies have associated a polymorphism (SNP309 T/G) in the promoter region of MDM2 with higher levels of this protein, which will favor p53-pathway abolishment, cell-cycle escape, and development of cancer. We aimed to study if MDM2 SNP309 T/G polymorphism contributes to the development of nasopharyngeal carcinoma (NPC). We have developed a case-control study with 124 patients with NPC and 509 healthy individuals from the north of Portugal to determine the genetic distribution of the MDM2 SNP309 polymorphism in DNA extracted from peripheral blood samples. Statistical analysis was performed to compare categorical variables adjusted for age and gender by multivariate logistic regression. Genotype-specific distributions according to age of onset were tested by Kaplan-Meier method and analyzed by Cox-regression proportional hazard model adjusted for gender. This study revealed that MDM2 SNP309 GG homozygous represent an increased risk adjusted for age and gender to develop NPC (OR = 2.15), with particular effect in undifferentiated types (OR = 2.46) and early clinical stages (OR = 3.32). We also found that median age of onset of NPC was significantly different (55.2 vs. 61.6) with increased effect in undifferentiated types (55.2 vs. 61.9) and early clinical stages (55.3 vs. 65.3). Our study suggests that MDM2 SNP309 can be considered a risk marker for the development of NPC mainly in early ages probably as an initiation marker for potential cancer development.

Abstract: Several reports have suggested the importance of p73 polymorphisms in tumor behavior. We investigated the role of a p73 gene polymorphism in the susceptibility to cervical lesions in a southwestern European population. Peripheral blood samples were obtained from Radiotherapy and Gynaecology Departments of Portuguese Institute of Oncology (Porto, Portugal), from 1998 to 2002. We analyzed the p73 cytosine thymine polymorphism in peripheral blood DNA of 176 healthy donors, 38 high-grade squamous intraepithelial lesions (HSIL), and 141 patients with primary untreated invasive cervical cancers (ICC), by polymerase chain reaction-restriction fragment length polymorphism. Our results demonstrate a twofold increased susceptibility to the development of HSIL in women carrying the p73 AT allele (OR=2.39; p=0.022). Further, this association seems to be more evident in women with high parity (OR=12.53; p=0.007). This is in agreement with the possible role of p73 in cervical carcinogenesis, namely, in human papillomavirus-infected transition zone subjected to the action of estrogens and in conjunction with disruption of differentiation program of this squamous epithelium that occurs in HSIL phase before the next step to invasiveness and squamous cervical cancer.

Abstract: The interaction between the E6 protein of the high-risk human papillomaviruses (HPVs) with p53 seems to be crucial in cervical carcinogenesis. The presence of Arg/Arg genotype at codon 72 of TP53 gene was characterized as a risk factor in development of cervical cancer. However, the role of this polymorphism remains controversial and some authors suggested that the origin of DNA (blood or exfoliated cervical cells) might influence these results. This study analyzed the effect of the p53 codon 72 polymorphism (R72P) in exfoliated cervical cells of women from the northern region of Portugal using two methodologies: allele-specific polymerase chain reaction and real-time polymerase chain reaction. We studied 700 cervical exfoliated cells which showed: 334 cases from women without cervical cancer or cervical lesion (N), 114 low-grade squamous intraepithelial lesions (LSIL), 107 high-grade squamous intraepithelial lesions (HSIL), 20 invasive cervical cancers (ICC) and 125 atypical squamous cells of unknown significance (ASCUS). No statistically significant differences between cases and controls were found, regarding the influence of the R72P polymorphism with cytological classification, high risk-HPV infection and HPV16 presence (P = 0.336, P = 0.945, and P = 0.964, respectively). Also, the influence of this polymorphism in the median age of onset for LSIL, HSIL, and ICC was not statistically significant (P = 0.674, P = 0.810, and P = 0.928, respectively). Therefore, the hypothesis that women with Arg/Arg genotype have an increased risk of developing cervical cancer failed to be proven in this study. Moreover, our study reveals that results using exfoliated cervical cells are reliable as compared with studies on blood.

Abstract: Nasopharynx is a particular anatomic structure, located between the respiratory and digestive systems, and it is the geographic centre of all otorinolaringologic pathologies. Numerous filogenic, ontogenic and embryogenic factors contribute to the anatomic and physiologic structure of nasopharynx. These factors may directly contribute to the development of several pathologies, as the embryogenic pathology, or even in an indirect way, through the interaction with the environment, as the inflammatory and neoplastic pathologies, of which the nasopharyngeal carcinoma acquires great significance. The objective of this study was to endorse the importance of a multidisciplinary approach in the study of nasopharynx, contributing to a wider knowledge about the different kinds of diseases associated with this anatomic structure.

Abstract: To examine the possible role of the Epstein-Barr Virus (EBV) in the development of gastric adenocarcinoma (GC). It is unclear whether EBV is involved in GC development or is a consequence of gastric inflammation secondary to immunosuppressive treatments.

Abstract: We aimed to study the role of an insertion/deletion polymorphism in the Pepsinogen C (PGC) gene in the clinical outcome of 172 breast cancer patients. The six polymorphic alleles were amplified using PCR. Our results indicate that patients carrying the allele 6 present a higher 5-year survival mean (83.4% of 6 allele carriers were alive at 5 years vs. only 68.6% of noncarriers, p=0.001), suggesting a role for this polymorphism in the outcome of breast cancer patients. We hypothesize that PGC polymorphism can be a predictive biomarker in breast cancer, contributing to an individual profile of great interest in clinical oncology.

Abstract: Human papillomavirus (HPV) is the necessary cause for cervical cancer development, and the interaction of HPV-E6 with p53 is known as the most important event in HPV-associated carcinogenesis. In vitro studies have suggested that HPV-E6 interacts more efficiently with the arginine (Arg) p53 variant at position 72 as it appears to be more susceptible to degradation through the ubiquitin proteasome pathway. However, few reports have corroborated this data, and the role of the p53 codon 72 polymorphism in the development of cervical cancer requires further elucidation. We performed a meta-analysis review of all studies published within European populations to summarize the overall risk of this polymorphism considering the influence of the geographical/ethnic location as an important factor in defining a genetic profile and the susceptibility for cervical cancer development. Our analysis revealed that the p53 Arg/Arg genotype does not seem to represent a risk marker for the development of cervical lesions in the majority of the European countries analysed. However, in countries with low incidence rates of cervical cancer, this polymorphism might represent a significant genetic marker.

Abstract: Invasive squamous cell carcinomas of the cervix arise from earlier, reversible precursor lesions called low- and high-grade squamous intraepithelial lesions (LSIL and HSIL, respectively). The aim of our study was to analyse the influence of the CCR2-64I polymorphism in the development of SIL due to its preponderant role in the cervical carcinogenesis and in the progression of these lesions to invasive cervical carcinoma. We conducted a case-control study, analyzing 565 Caucasian women from the north of Portugal. The CCR2-64I polymorphism was analysed through polymerase chain reaction followed by restriction fragment length polymorphism. The frequency of GG, GA and AA genotypes was 76.5, 23.5 and 0.0% respectively, in HSIL patients, and 87.8, 11.1 and 1.1% respectively, in the control group. The G allele frequency was 88.2% in the HSIL group and 93.4% in the control group. Regarding the A allele frequency, it was 11.8% in the HSIL group and 6.6% in the control group. Overall, the frequency of A carrier genotypes was higher in HSIL patients than in the control group (p = 0.013; OR = 2.21; 95%CI: 1.17-4.15), suggesting that CCR2-64I polymorphism might contribute to the establishment of HSIL, through the disruption of the naturally fragile immune response directed towards human papillomavirus infection.

Abstract: Ovarian cancer (OC) is the most lethal gynaecologic cancer and its standard treatment consists of platinum-based chemotherapy after cytoreductive surgery. The p53 protein plays a critical role on different cellular processes in response to DNA damage and it is responsible for transcriptional induction of the P21 gene. We have analysed 114 blood samples in order to investigate the effect of the TP53 codon 72 and the P21 3'UTR polymorphisms in response to cisplatinum/paclitaxel chemotherapy for OC treatment. The genotypes of the TP53 codon 72 and P21 3'UTR polymorphism were identified using AS-PCR and PCR-RFLP, respectively. Our results indicate that the TP53 P allele is associated with a worse prognosis (P=0.011) while P21 polymorphism genotypes did not reveal any statistically significant result (P>0.05). Furthermore, simultaneous carriers of the TP53 AA genotype and the P21 CC genotype demonstrate a longer progression-free interval (P=0.020). This study suggests that the characterisation of a genetic profile can contribute to the definition of a better chemotherapy treatment.

Abstract: 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.

Abstract: To study the role of an insertion/deletion polymorphism in the pepsinogen C (PGC) gene, an effective marker for terminal differentiation of the stomach mucosa, in the susceptibility to the development of gastric lesions.

Abstract: To investigate the relationship between the -765G > C COX-2 polymorphism and the development of different gastric lesions: atrophy or intestinal metaplasia and gastric adenocarcinoma.

Abstract: Nasopharyngeal cancer (NPC) is multifactorial, and the genetic background may be a crucial etiologic factor. Cyclin D1 (CCND1) is a key regulator of the cell cycle, and its altered activity is associated with the development of cancer.

Abstract: TP53 and its downstream effector gene P21 are two important genes in cell cycle regulation. Genetic alterations on p53 and attenuation of p21 expression result in progression through cell cycle G1 checkpoint, which can lead to cancer development. We analysed the frequency of TP53 codon 72 and 3'UTR P21 polymorphisms in 681 blood samples from 371 cervical cancer patients, 122 ovarian cancer patients and 188 healthy controls using AS-PCR and PCR-RFLP. Approximately twofold increased risk of ovarian cancer (OC) was observed for TP53 Pro carriers (P = 0.038), with a significantly higher risk for advanced OC (P = 0.018). Furthermore, among the P21 CC genotypes, TP53 P allele was also associated with a twofold increased risk of OC (P = 0.014) and to a threefold increased risk for advanced OC (P = 0.003) with an attributable proportion of 44.2%. These results were confirmed in an age-adjusted logistic regression analysis. No association was found between these polymorphisms and cervical cancer. Our results suggest that the TP53 codon 72 genotypes may be considered as a molecular marker, contributing to a genetic profile for ovarian cancer in women.

Abstract: High-risk human papillomavirus are essential for the development of cervical cancer; however, TP53 is the most frequently altered tumor suppressor gene among tumors and is described as a cofactor for cervical carcinogenesis. TP53 has two common polymorphic forms encoding either proline or arginine, at position 72, and the presence of homozygous arginine has been reported as a risk factor for cervical cancer in many populations. We evaluated the effect of this TP53 polymorphism in a northern Portuguese population. We analyzed blood samples of 385 women; 20 with low-grade squamous intraepithelial lesion (SIL), 56 with high-grade SIL, 164 with invasive cervical cancer, and 145 healthy controls, using allele specific-polymerase chain reaction methodology. We observed an increased frequency of the Arg/Arg genotype in the cancer group, but no statistical significance was found between cases and controls (P>0.05). Our results indicate that there is no association between the presence of the Arg allele in codon 72 of TP53 polymorphism and risk of cervical cancer in our population.

Abstract: Cervical cancer is initiated by high-risk human papillomaviruses (HPV-16 and HPV-18), but an effective immune response may control the progression of this disease. Tumor necrosis factor-alpha (TNF-alpha) is a pro-inflammatory cytokine, that has been implicated in several cancers. In a case-control study, we evaluated the association between the G-308A TNF-alpha promoter polymorphism and the risk for invasive cervical cancer (ICC). TNF-alpha polymorphism was analyzed by PCR-RFLP and confirmed by sequencing. DNA was obtained from blood samples of 439 individuals, including 195 patients with ICC and 244 normal healthy controls. According to our results, women carrying the A allele present a twofold increased risk of developing ICC (p=0.006; OR=1.88; 95% CI [1.20-2.94]). In conclusion, our study suggests that the presence of the high producer allele -308A in the TNF-alpha gene appears to be associated with an increased risk for the development of ICC.