Modern cancer epidemiological research: genetic polymorphisms and environment

Individual cancer susceptibility seems to be related to factors such as changes in oncogenes and tumor suppressor genes expression, and differences in the action of metabolic enzymes and DNA repair regulated by specific genes. Epidemiological studies on genetic polymorphisms of human xenobiotics metabolizing enzymes and cancer have revealed low relative risks. Research considering genetic polymorphisms prevalence jointly with environmental exposures could be relevant for a better understanding of cancer etiology and the mechanisms of carcinogenesis and also for new insights on cancer prognosis. This study reviews the approaches of molecular epidemiology in cancer research, stressing case-control and cohort designs involving genetic polymorphisms, and factors that could introduce bias and confounding in these studies. Similarly to classical epidemiological research, genetic polymorphisms requires considering aspects of precision and accuracy in the study design.

Deregulated expression of selected histone methylases and demethylases in prostate carcinoma

Prostate cancer (PCa), a leading cause of cancer-related morbidity and mortality, arises through the acquisition of genetic and epigenetic alterations. Deregulation of histone methyltransferases (HMTs) or demethylases (HDMs) has been associated with PCa development and progression. However, the precise influence of altered HMTs or HDMs expression and respective histone marks in PCa onset and progression remains largely unknown. To clarify the role of HMTs and HDMs in prostate carcinogenesis, expression levels of 37 HMTs and 20 HDMs were assessed in normal prostate and PCa tissue samples by RT-qPCR. SMYD3, SUV39H2, PRMT6, KDM5A, and KDM6A were upregulated, whereas KMT2A-E (MLL1-5) and KDM4B were downregulated in PCa, compared with normal prostate tissues. Remarkably, PRMT6 was the histone modifier that best discriminated normal from tumorous tissue samples. Interestingly, EZH2 and SMYD3 expression levels significantly correlated with less differentiated and more aggressive tumors. Remarkably, SMYD3 expression levels were of independent prognostic value for the prediction of disease-specific survival of PCa patients with clinically localized disease submitted to radical prostatectomy. We concluded that expression profiling of HMTs and HDMs, especially SMYD3, might be of clinical usefulness for the assessment of PCa patients and assist in pre-therapeutic decision-making.

Human biomonitoring: biomarkers, susceptibility, and nutrigenetics

The methods of molecular biology applied in epidemiological research lead us to the realm of molecular epidemiology, where there is immense potential for the establishment of associations between cancer and exposure to risk factors in lifestyle, profession, or pollution. Human biomonitoring consists, on the one hand, in research and identification of hazardous environmental conditions and, on the other hand, in the assessment of cancer risk following exposure to such conditions. Since carcinogenesis is a lengthy process, the biomarkers used to recognize biological abnormalities are selected and developed in the realm of molecular epidemiology. Such biomarkers are quantifiable and allow for the recognition of progression from normal to abnormal biological conditions at the molecular level. They can be categorized in biomarkers of exposure, effect, and genetic susceptibility. Genotoxicity biomarkers are a particular subset of effect biomarkers and are used to assess genomic instability caused by environmental or occupational exposure, being considered useful carcinogenesis predictors.

P53 and Cancer-Associated Sialylated Glycans Are Surrogate Markers of Cancerization of the Bladder Associated with Schistosoma haematobium Infection

BACKGROUND: Bladder cancer is a significant health problem in rural areas of Africa and the Middle East where Schistosoma haematobium is prevalent, supporting an association between malignant transformation and infection by this blood fluke. Nevertheless, the molecular mechanisms linking these events are poorly understood. Bladder cancers in infected populations are generally diagnosed at a late stage since there is a lack of non-invasive diagnostic tools, hence enforcing the need for early carcinogenesis markers. METHODOLOGY/PRINCIPAL FINDINGS: Forty-three formalin-fixed paraffin-embedded bladder biopsies of S. haematobium-infected patients, consisting of bladder tumours, tumour adjacent mucosa and pre-malignant/malignant urothelial lesions, were screened for bladder cancer biomarkers. These included the oncoprotein p53, the tumour proliferation rate (Ki-67>17%), cell-surface cancer-associated glycan sialyl-Tn (sTn) and sialyl-Lewisa/x (sLea/sLex), involved in immune escape and metastasis. Bladder tumours of non-S. haematobium etiology and normal urothelium were used as controls. S. haematobium-associated benign/pre-malignant lesions present alterations in p53 and sLex that were also found in bladder tumors. Similar results were observed in non-S. haematobium associated tumours, irrespectively of their histological nature, denoting some common molecular pathways. In addition, most benign/pre-malignant lesions also expressed sLea. However, proliferative phenotypes were more prevalent in lesions adjacent to bladder tumors while sLea was characteristic of sole benign/pre-malignant lesions, suggesting it may be a biomarker of early carcionogenesis associated with the parasite. A correlation was observed between the frequency of the biomarkers in the tumor and adjacent mucosa, with the exception of Ki-67. Most S. haematobium eggs embedded in the urothelium were also positive for sLea and sLex. Reinforcing the pathologic nature of the studied biomarkers, none was observed in the healthy urothelium. CONCLUSION/SIGNIFICANCE: This preliminary study suggests that p53 and sialylated glycans are surrogate biomarkers of bladder cancerization associated with S. haematobium, highlighting a missing link between infection and cancer development. Eggs of S. haematobium express sLea and sLex antigens in mimicry of human leukocytes glycosylation, which may play a role in the colonization and disease dissemination. These observations may help the early identification of infected patients at a higher risk of developing bladder cancer and guide the future development of non-invasive diagnostic tests.

SMYD3 contributes to a more aggressive phenotype of prostate cancer and targets Cyclin D2 through H4K20me3

Prostate cancer (PCa) is one of the most incident cancers worldwide but clinical and pathological parameters have limited ability to discriminate between clinically significant and indolent PCa. Altered expression of histone methyltransferases and histone methylation patterns are involved in prostate carcinogenesis. SMYD3 transcript levels have prognostic value and discriminate among PCa with different clinical aggressiveness, so we decided to investigate its putative oncogenic role on PCa.We silenced SMYD3 and assess its impact through in vitro (cell viability, cell cycle, apoptosis, migration, invasion assays) and in vivo (tumor formation, angiogenesis). We evaluated SET domain's impact in PCa cells' phenotype. Histone marks deposition on SMYD3 putative target genes was assessed by ChIP analysis.Knockdown of SMYD3 attenuated malignant phenotype of LNCaP and PC3 cell lines. Deletions affecting the SET domain showed phenotypic impact similar to SMYD3 silencing, suggesting that tumorigenic effect is mediated through its histone methyltransferase activity. Moreover, CCND2 was identified as a putative target gene for SMYD3 transcriptional regulation, through trimethylation of H4K20.Our results support a proto-oncogenic role for SMYD3 in prostate carcinogenesis, mainly due to its methyltransferase enzymatic activity. Thus, SMYD3 overexpression is a potential biomarker for clinically aggressive disease and an attractive therapeutic target in PCa.

MicroRNA-375 plays a dual role in prostate carcinogenesis

Background: Prostate cancer (PCa), a highly incident and heterogeneous malignancy, mostly affects men from developed countries. Increased knowledge of the biological mechanisms underlying PCa onset and progression are critical for improved clinical management. MicroRNAs (miRNAs) deregulation is common in human cancers, and understanding how it impacts in PCa is of major importance. MiRNAs are mostly downregulated in cancer, although some are overexpressed, playing a critical role in tumor initiation and progression. We aimed to identify miRNAs overexpressed in PCa and subsequently determine its impact in tumorigenesis. Results: MicroRNA expression profiling in primary PCa and morphological normal prostate (MNPT) tissues identified 17 miRNAs significantly overexpressed in PCa. Expression of three miRNAs, not previously associated with PCa, was subsequently assessed in large independent sets of primary tumors, in which miR-182 and miR-375 were validated, but not miR-32. Significantly higher expression levels of miR-375 were depicted in patients with higher Gleason score and more advanced pathological stage, as well as with regional lymph nodes metastases. Forced expression of miR-375 in PC-3 cells, which display the lowest miR-375 levels among PCa cell lines, increased apoptosis and reduced invasion ability and cell viability. Intriguingly, in 22Rv1 cells, which displayed the highest miR-375 expression, knockdown experiments also attenuated the malignant phenotype. Gene ontology analysis implicated miR-375 in several key pathways deregulated in PCa, including cell cycle and cell differentiation. Moreover, CCND2 was identified as putative miR-375 target in PCa, confirmed by luciferase assay. Conclusions: A dual role for miR-375 in prostate cancer progression is suggested, highlighting the importance of cellular context on microRNA targeting.

Molecular aspects of hepatic carcinogenesis

Exogenous agents correlated with hepatocellular carcinoma (HCC) have been identified and well characterized. These agents, including the different viruses that cause chronic hepatitis and cirrhosis, can lead to regenerative nodules and dysplastic nodules/adenomatous hyperplasia. These conditions associated with several molecular alterations of hepatocyte ultimately culminate in hepatocellular carcinoma. Recently, there has been a great progress in the identification of somatic and germinative mutations that may be correlated with the development of HCC, justifying a review on the subject. Hence, the factors involved in the process of hepatic carcinogenesis, such as infection by the hepatitis B and C viruses, with a special focus in the molecular alterations described in recent years are discussed herein, pointing out areas potentially relevant for clinical development.

A retrospective study of histopathological findings in 894 cases of megacolon: what is the relationship between megacolon and colonic cancer?

Patients with megaesophagus (ME) have increased prevalence of cancer of the esophagus. In contrast, a higher incidence of colorectal cancer is not observed in patients with megacolon (MC). MC is very common in some regions of Brazil, where it is mainly associated with Chagas disease. We reviewed the pathology records of surgical specimens of all patients submitted for surgical resection of MC in the Hospital das Clínicas of the Faculty of Medicine of Ribeirão Preto (HC-FMRP), from the University of São Paulo. We found that 894 patients were operated from 1952 until 2001 for MC resection. Mucosal ulcers, hyperplasia and chronic inflammation were frequently found, while polyps were uncommon. No patients with MC presented any type of colonic neoplasm. This observation reinforces the hypothesis that MC has a negative association with cancer of the colon. This seems to contradict the traditional concept of carcinogenesis in the colon, since patients with MC presents important chronic constipation that is thought to cause an increase in risk for colon cancer. MC is also associated with other risk factors for cancer of colon, such as hyperplasia, mucosal ulcers and chronic inflammation. In ME these factors lead to a remarkable increase in cancer risk. The study of mucosal cell proliferation in MC may provide new insights and useful information about the role of constipation in colonic carcinogenesis.

A Communication Intervention for Training Southern European Oncologists to Recognize Psychosocial Morbidity in Cancer. I - Development of the Model and Preliminary Results on Physicians' Satisfaction

BACKGROUND: The detection of psychosocial distress is a significant communication problem in Southern Europe and other countries. Work in this area is hampered by a lack of data. Because not much is known about training aimed at improving the recognition of psychosocial disorders in cancer patients, we developed a basic course model for medical oncology professionals. METHODS: A specific educational and experiential model (12 hours divided into 2 modules) involving formal teaching (ie, journal articles, large-group presentations), practice in small groups (ie, small-group exercises and role playing), and discussion in large groups was developed with the aim of improving the ability of oncologists to detect emotional disturbances in cancer patients (ie, depression, anxiety, and adjustment disorders). RESULTS: A total of 30 oncologists from 3 Southern European countries (Italy, Portugal, and Spain) participated in the workshop. The training course was well accepted by most participants who expressed general satisfaction and a positive subjective perception of the utility of the course for clinical practice. Of the total participants, 28 physicians (93.3%) thought that had they been exposed to this material sooner, they would have incorporated the techniques received in the workshop into their practices; 2 participants stated they would likely have done so. Half of the doctors (n = 15) believed that their clinical communication techniques were improved by participating in the workshop, and the remaining half thought that their abilities to communicate with cancer patients had improved. CONCLUSIONS: This model is a feasible approach for oncologists and is easily applicable to various oncology settings. Further studies will demonstrate the effectiveness of this method for improving oncologists skills in recognizing emotional disorders in their patients with cancer.

Mutating Identities: Clarice Lispector's um sopro de vida - pulsações and Virginia Woolf's between the acts

The questioning of fictional identities is central in both texts. Their structure illustrates the Bakhtinian notions of heteroglossia and dialogism and one of their main themes is the structuring and restructuring of social and personal history. Together with the use of irony and humour, the parody of social context, the use of intertextuality and metafiction, the exploration of fragment and of discontinuity, the development of self reflection and the interrogation of the author before the condition of his work, the focusing on the presence of a reader lost in the interpretation of the text, this problematisation of fictional identities places these two novels between the acts of modernism and postmodernism.

AN UPWARD TREND IN DNA P16INK4A METHYLATION PATTERN AND HIGH RISK HPV INFECTION ACCORDING TO THE SEVERITY OF THE CERVICAL LESION

SUMMARY High-risk human papillomavirus (hr-HPV) infection is necessary but not sufficient for cervical cancer development. Recently, P16INK4A gene silencing through hypermethylation has been proposed as an important cofactor in cervical carcinogenesis due to its tumor suppressor function. We aimed to investigate P16INK4A methylation status in normal and neoplastic epithelia and evaluate an association with HPV infection and genotype. This cross-sectional study was performed with 141 cervical samples from patients attending Hospital Moncorvo Filho, Rio de Janeiro. HPV detection and genotyping were performed through PCR and P16INK4A methylation by nested-methylation specific PCR (MSP). HPV frequency was 62.4% (88/141). The most common HPV were HPV16 (37%), HPV18 (16.3%) and HPV33/45(15.2%). An upward trend was observed concerning P16INK4A methylation and lesion degree: normal epithelia (10.7%), low grade lesions (22.9%), high grade (57.1%) and carcinoma (93.1%) (p < 0.0001). A multivariate analysis was performed to evaluate an association between methylation, age, tobacco exposure, HPV infection and genotyping. A correlation was found concerning methylation with HPV infection (p < 0.0001), hr-HPV (p = 0.01), HSIL (p < 0.0007) and malignant lesions (p < 0.0001). Since viral infection and epigenetic alterations are related to cervical carcinoma, we suggest that P16INK4A methylation profile maybe thoroughly investigated as a biomarker to identify patients at risk of cancer.

Enterobacteriaceae ISOLATES FROM THE ORAL CAVITY OF WORKERS IN A BRAZILIAN ONCOLOGY HOSPITAL

The evaluation of workers as potential reservoirs and disseminators of pathogenic bacteria has been described as a strategy for the prevention and control of healthcare-associated infections (HAIs). The aim of this study was to evaluate the presence of Enterobacteriaceae in the oral cavity of workers at an oncology hospital in the Midwest region of Brazil, as well as to characterize the phenotypic profile of the isolates. Saliva samples of 294 workers from the hospital’s healthcare and support teams were collected. Microbiological procedures were performed according to standard techniques. Among the participants, 55 (18.7%) were colonized by Enterobacteriaceae in the oral cavity. A total of 64 bacteria were isolated, including potentially pathogenic species. The most prevalent species was Enterobacter gergoviae (17.2%). The highest rates of resistance were observed for β-lactams, and 48.4% of the isolates were considered multiresistant. Regarding the enterobacteria isolated, the production of ESBL and KPC was negative. Nevertheless, among the 43 isolates of the CESP group, 51.2% were considered AmpC β-lactamase producers by induction, and 48.8% were hyper-producing mutants. The significant prevalence of carriers of Enterobacteriaceae and the phenotypic profile of the isolates represents a concern, especially due to the multiresistance and production of AmpC β-lactamases.

Pseudomonas spp. ISOLATED FROM THE ORAL CAVITY OF HEALTHCARE WORKERS FROM AN ONCOLOGY HOSPITAL IN MIDWESTERN BRAZIL

This cross-sectional study, performed in an oncology hospital in Goiania, aimed to characterize the prevalence of oral colonization and antimicrobial susceptibility of Pseudomonas spp. isolated from the saliva of healthcare workers. Microorganisms were subjected to biochemical tests, susceptibility profile, and phenotypic detection. Of 76 participants colonized with Gram negative bacilli, 12 (15.8%) harbored Pseudomonas spp. Of all isolates, P. aeruginosa (75.0%), P. stutzeri (16.7%), and P. fluorescens (8.3%), were resistant to cefoxitin, and therefore likely to be AmpC producers. The results are clinically relevant and emphasize the importance of surveillance to minimize bacterial dissemination and multiresistance.

Long-Term Recurrence of Nonmelanoma Skin Cancer after Topical Methylaminolevulinate Photodynamic Therapy in a Dermato-Oncology Department

BACKGROUND: Most available studies on the efficacy of topical photodynamic therapy focus on short-to medium-term results. Long-term data are scarce. OBJECTIVE: To evaluate the long-term efficacy of photodynamic therapy with topical methylaminolevulinate to treat Bowen's disease and basal cell carcinoma in the clinical practice setting of a dermato-oncology department. METHODS: The study included patients diagnosed with Bowen's disease or basal cell carcinoma, and who received photodynamic therapy from 2004 to 2008. Treatment protocol and clinical follow-up were standardized. The primary endpoint was clinically observed recurrence in a previous photodynamic therapy-treated area. Descriptive and survival analyses were performed. RESULTS: A total of 31 Bowen's disease lesions and 44 superficial basal cell carcinoma were treated, with a median follow-up of 43.5 months. Recurrence was observed in 14 Bowen's disease lesions (53.8%) and in 11 superficial basal cell carcinoma (33.3%). Significantly higher estimates for recurrence rates were found in patients with Bowen's disease (p=0.0036) or those aged under 58 years (p=0.039). The risk of recurrence was higher in patients with Bowen's disease than in those with superficial basal cell carcinoma and younger patients. CONCLUSIONS: Recurrence should be considered when choosing to treat non-melanoma skin cancer with photodynamic therapy. Younger age and Bowen's disease were independent predictors for long-term recurrence, suggesting the need to establish an extended period of follow-up for this subset of patients.

Determinants of mortality in oncology patients colonized or infected with Staphylococcus aureus

Oxacillin-resistant Staphylococcus aureus (ORSA) infection is an important cause of hospital morbidity and mortality. The objective of this study was to identify the main factors associated with death in patients colonized or infected with Staphylococcus aureus in a cancer center. A matched-pair case-control study enrolled all patients infected or colonized with ORSA (cases) admitted to the Hospital do Câncer in Rio de Janeiro from 01/01/1992 to 12/31/1994. A control was defined as a patient hospitalized during the same period as the case-patients and colonized or infected with oxacillin-susceptible Staphylococcus aureus (OSSA). The study enrolled 95 cases and 95 controls. Patient distribution was similar for the two groups (p > or = 0.05) with respect to gender, underlying diseases, hospital transfer, prior infection, age, temperature, heart and respiratory rates, neutrophil count, and duration of hospitalization. Univariate analysis of putative risk factors associated with mortality showed the following significant variables: admission to the intensive care unit (ICU), presence of bacteremia, use of central venous catheter (CVC), ORSA colonization or infection, pneumonia, use of urinary catheter, primary lung infection, prior use of antibiotics, mucositis, and absence of cutaneous abscesses. Multivariate analysis showed a strong association between mortality and the following independent variables: admission to ICU (OR [odds ratio]=7.2), presence of Staphylococcus bacteremia (OR=6.8), presence of CVC (OR=5.3), and isolation of ORSA (OR=2.7). The study suggests a higher virulence of ORSA in comparison to OSSA in cancer patients.