Denise Peixoto Guimarães

Absence of association between HPV DNA, TP53 codon 72 polymorphism, and risk of oesophageal cancer in a high-risk area of China

We analyzed TP53 codon 72 polymorphism, HPV DNA in 32 subjects with oesophageal cancer and 57 healthy subjects with normal oesophageal cytology from an area of China with a high prevalence for this cancer (Linxian County, Henan Province). The frequency of the proline allele (0.63) was significantly higher in the Chinese population than in most European or American populations. No significant association was found between TP53 codon 72 genotype and cancer. We also found a low prevalence of HPV DNA (6.7%) in both cancer cases and healthy subjects. Our findings do not support the association between risk of oesophageal cancer, human papilloma virus infection, and TP53 codon 72 polymorphism in a Chinese population at high risk of oesophageal cancer.

Serrated pathway in colorectal carcinogenesis

Serrated adenocarcinoma is a recently described subset of colorectal cancer (CRC), which account for about 10% of all CRCs and follows an alternative pathway in which serrated polyps replace the traditional adenoma as the precursor lesion to CRC. Serrated polyps form a heterogeneous group of colorectal lesions that includes hyperplastic polyps (HPs), sessile serrated adenoma (SSA), traditional serrated adenoma (TSA) and mixed polyps. HPs are the most common serrated polyp followed by SSA and TSA. This distinct histogenesis is believed to have a major influence in prevention strategies, patient prognosis and therapeutic impact. Genetically, serrated polyps exhibited also a distinct pattern, with KRAS and BRAF having an important contribution to its development. Two other molecular changes that have been implicated in the serrated pathway include microsatellite instability and the CpG island methylator phenotype. In the present review we will address the current knowledge of serrated polyps, clinical pathological features and will update the most recent findings of its molecular pathways. The understanding of their biology and malignancy potential is imperative to implement a surveillance approach in order to prevent colorectal cancer development.

XAF1 mRNA expression improves progression-free and overall survival for patients with advanced bladder cancer treated with neoadjuvant chemotherapy

PURPOSE The aim of this study was to investigate whether mRNA expression of the apoptosis-associated genes, XAF1 and XIAP, in bladder cancer patients correlates with response to neoadjuvant treatment. METHODS Gene expression was analyzed by a real-time quantitative PCR method in paired samples from 14 bladder cancer patients treated with a combination of neoadjuvant gemcitabine and cisplatin. The prognostic significance of XAF1 and XIAP mRNA expression as well as the correlation with several clinical and pathological findings were evaluated. RESULTS The clinical response in the XAF1-high subset (n = 5) was remarkably higher compared with the XAF1-low subset (n = 9) (100% vs. 44.4%; P = 0.038). These results translated into a notably improvement of progression-free survival (PFS) in the XAF1-high subset (log-rank P = 0.012). In addition, patients in the XAF1-high subset had a 3.9-fold decreased chance of dying from the disease (hazard ratio for death (HR), 0.257; (CI 95%), 0.043-1.536, P = 0.036). When we evaluated the expression of XIAP, although an inverse correlation was found between expression and pathological response, there were no statistically significant associations with the clinical response, the length of PFS, and OS. CONCLUSIONS This is one of the few studies to address the role of XAF1 in a clinical setting. The data presented here identify XAF1 as a novel predictive and prognostic factor in bladder cancer patients. Furthermore, our observations are in line with previous studies, which point towards XAF1 as a tumor-suppressor gene. Nonetheless, additional studies, both mechanistic and translational, are warranted and may help not only in corroborating the role of XAF1 as a prognostic marker, but also as a potential target for anticancer therapy.

Interferon-inducible guanylate binding protein (GBP)-2: A novel p53-regulated tumor marker in esophageal squamous cell carcinomas

TP53 mutations are common in esophageal squamous cell carcinomas (SCC). To identify biological markers of possible relevance in esophageal SCC, we (i) searched for genes expressed in a p53‐dependent manner in TE‐1, an esophageal SCC cell line expressing the temperature‐sensitive TP53 mutant V272M, and (ii) investigated the expression of one of those genes, the interferon‐inducible Guanylate Binding Protein 2 (GBP‐2), in esophageal SCC tissues. Clontech Human Cancer 1.2 arrays containing 1,176 human cancer gene‐related sequences were used to identify differentially expressed genes in TE‐1 cells at permissive (32°C) and nonpermissive (37°C) temperatures. The expression of GBP‐2 and IRF‐1, its main transcriptional regulator, was analyzed by immunohistochemistry in a retrospective series of 41 esophageal SCC cases with a clear transition zone from noncancer, apparently normal epithelium to invasive cancer. The expression of the GBP‐2 gene is consistently increased in TE‐1 at 32°C in a p53‐dependent manner, as confirmed by inhibition of p53 expression by RNA interference. Increase in GBP‐2 is accompanied by an increase in protein levels of IRF‐1, the main transcriptional regulator of GBP‐2, and in the formation of complexes between p53 and IRF‐1. GBP‐2 expression is significantly higher in esophageal SCC than in adjacent normal epithelium (p < 0.01), in which GBP‐2 staining is limited to the basal layer. Our results suggest that p53 up‐regulates GBP‐2 by cooperating with IRF‐1. The association of GBP‐2 expression with proliferative squamous cells suggests that GBP‐2 may represent a marker of interest in esophageal SCC.

Involvement of signaling molecules in the prediction of response to imatinib treatment in metastatic GIST patients.

Imatinib therapy has undoubtedly contributed to the treatment of metastatic gastrointestinal stromal (GIST) tumors that were previously untreatable. However, disease progression during treatment with tyrosine kinase inhibitors remains an issue in clinical practice not fully explained by KIT and PDGFRA mutation status. We investigated the role of three important signaling molecules (insulin-like growth factor 1 receptor [IGF1R], protein kinase C-θ [PKCθ], and Raf kinase inhibitor protein [RKIP]) that have been implicated in GIST pathogenesis as potential biomarkers for prediction of response to imatinib treatment. We retrospectively reviewed 76 patients with metastatic GIST submitted to imatinib treatment between 2002 and 2007, and analyzed 63 of them. Insulin-like growth factor 1, total PKCθ, phosphorylated PKCθ, and RKIP immunohistochemical expression were correlated with objective response to imatinib treatment and progression-free and overall survival. Median follow-up was 31.2 mo (95% confidence interval, 26.3-36.1 mo). There was a statistically significant association between IGF1R expression and type of response to imatinib treatment (P = 0.05)-that is, higher IGF1R expression was related to lower objective response. However, IGF1R higher expression did not affect progression-free and overall survival. Insulin-like growth factor 1, but not PKCθ and RKIP, emerges as a potential biomarker for prediction of response to imatinib treatment in metastatic GISTs. Validation studies are warranted.

The relation of HPV infection and expression of p53 and p16 proteins in esophageal squamous cells carcinoma

GOAL: To investigate the HPV prevalence and characterize the expression of potential molecular surrogate markers of HPV infection in esophageal squamous cell carcinoma. MATERIALS AND METHODS: The prevalence of HPV in individuals with and without esophageal cancer (EC) was determined by using multiplex PCR; p16 and p53 protein levels were assessed by immunohistochemistry (IHC). RESULTS: High-risk HPV (hr-HPV) was found in the same frequency (13.8%) in esophageal squamous cell carcinoma (ESCC) and in healthy individuals. The p53 expression was positive in 67.5% of tumor tissue, 20.0% of adjacent non-tumoral tissue and 1.8% of normal esophageal tissue. p16 was positive in 11.6% of esophageal cancer cases and 4.7% of adjacent non-tumoral tissue. p16 was undetectable among control group samples. p53 and p16 levels were not significantly associated with the HPV status. CONCLUSIONS: These results suggest that hr-HPV types are not associated with the development of ESCC and that p53 and p16 protein expression have no relationship with HPV infection in normal or cancerous esophagus.

Biomarkers and Novel Therapeutic Targets in Gastrointestinal Stromal Tumors (GISTs)

Gastrointestinal stromal tumors (GISTs) owe their development to the activating mutations in mast/stem cell growth factor receptor (KIT) or platelet-derived growth factor receptor A (PDGFRA) oncogenes. Both these KIT and PDGFRA oncogenes are members of the type III transmembrane receptor tyrosine kinase family that stimulates intracellular signaling pathways controlling cell proliferation, adhesion, apoptosis, survival, and differentiation. The presence and type of KIT/PDGFRA mutations help to predict the imatinib mesylate therapy, a selective tyrosine kinase inhibitor. Moreover, there is reported a small proportion of wild-type GISTs for both KIT and PDGFRA genes, and tumors more often acquire secondary mutations on KIT, that results into imatinib resistance. New patents to the GISTs imatinib resistant have recently been introduced. At present, sunitinib, is prescribed as second line therapy for patients with imatinibresistant or imatinib-intolerant GIST, and a number of other drugs, such as masitinib and valatinib, are in the pipeline. The present research focuses on GISTs diagnostic, prognostic and therapeutic biomarkers and addresses the development of novel patents for the treatment of these patients.

Lack of microsatellite instability in gastrointestinal stromal tumors

The microsatellite instability (MSI) phenotype may constitute an important biomarker for patient response to immunotherapy, particularly to anti-programmed death-1 inhibitors. MSI is a type of genomic instability caused by a defect in DNA mismatch repair (MMR) proteins, which is present mainly in colorectal cancer and its hereditary form, hereditary nonpolyposis colorectal cancer. Gastrointestinal stromal tumor (GIST) development is associated with activating mutations of KIT proto-oncogene receptor tyrosine kinase (KIT) or platelet-derived growth factor receptor α (PDGFRA), which are oncogenes that predict the response to imatinib mesylate. In addition to KIT/PDGFRA mutations, other molecular alterations are important in GIST development. In GISTs, the characterization of the MSI phenotype is scarce and the results are not consensual. The present study aimed to assess MSI in a series of 79 GISTs. The evaluation of MSI was performed by pentaplex polymerase chain reaction comprising five markers, followed by capillary electrophoresis. The expression of MMR proteins was evaluated by immunohistochemistry. Regarding the KIT/PDGFRA/B-Raf proto-oncogene, serine/threonine kinase molecular profile of the 79 GISTs, 83.6% of the tumors possessed KIT mutations, 10.1% had PDGFRA mutations and 6.3% were triple wild-type. The mutated-PDGFRA cases were associated with gastric location and a lower mitotic index compared with KIT-mutated and wild-types, and these patients were more likely to be alive and without cancer. MSI analysis identified 4 cases with instability in one marker, however, additional evaluation of normal tissue and immunohistochemical staining of MMR proteins confirmed their microsatellite-stable nature. The results of the present study indicated that MSI is not involved in GIST tumorigenesis and, therefore, cannot serve as a biomarker to immunotherapy response in GIST.

Prevalence of high risk HPV DNA in esophagus is high in Brazil but not related to esophageal squamous cell carcinoma

BACKGROUNDS The first publication that associated Human Papillomavirus (HPV) infection and esophageal cancer was published in 1982. However, data are still contradictory and require further investigation. The aim of this study was to identify high risk HPV DNA in esophageal tissue of patients with and without esophageal squamous cell carcinoma (ESCC) and correlate HPV presence with classical risk factors. METHODS Invited patients signed the informed consent form, and interviews were conducted in order to obtain information about sociodemographic and lifestyle behavior. During endoscopy, esophageal biopsies were collected from case and controls. Multiplex polymerase chain reaction genotyping was conducted on endoscopic biopsies to identify HPV types and HPV-16 was further evaluated by specific PCR real time. RESULTS Among 87 cases, 12 (13.8%) had tumors harboring high risk HPV DNA and among 87 controls, 12 (13.8%) had high risk HPV DNA (OR:1.025 [CI:0.405:2.592]). Variables regarding consumption of alcohol and use of tobacco continued to characterize risk factors even after adjustments by presence or absence of high risk HPV. CONCLUSION HPV was demonstrated to be frequently and similarly associated to normal and malignant esophageal tissues, but not as an independent risk factor to esophageal cancer. IMPACT To contribute to the Brazilian population data on this subject, which is still contradictory.

Mutational profile of TP53 in esophageal squamous cell carcinoma associated with chagasic megaesophagus

Chagas disease is an important communicable neglected disease that is gaining wider attention due to its increasing incidence worldwide. Achalasia due to chagasic megaesophagus (CM), a complication of this disease, is a known-yet, poorly understood-etiological factor for esophageal squamous cell carcinoma (ESCC) development. In this study, we aimed to perform the analysis of TP53 mutations in a series of Brazilian patients with ESCC that developed in the context CM (ESCC/CM), and to compare with the TP53 mutation profile of patients with benign CM and patients with nonchagasic ESCC. Additionally, we intended to correlate the TP53 mutation results with patients clinical pathological features. By polymerase chain reaction (PCR) followed by direct sequencing of the hotspot regions of TP53 (exon 5 to 8), we found that TP53 mutations were present in 40.6% (13/32) of the ESCC/CM group, 45% (18/40) of the nonchagasic ESCC group, and in only 3% (1/33) of the benign CM group. Missense mutations were the most common in the three groups, yet, the type and mutated exon mutation varied significantly among the groups. Clinically, the groups exhibited distinct features, with both cancer groups (ESCC and ESCC/CM) been significantly associated higher consumption of alcohol and tobacco, older age, worse Karnofsky performance status, poor outcome than the patients with benign CM. No significant association was found between TP53 mutation profile and clinical-pathological features in any of the three groups. We describe first the time the analysis of TP53 mutations in ESCC that developed in the context of CM, and the observed high frequency of mutations, suggest that TP53 also plays an important role in the tumorigenic process of this unexplored etiological condition.