Novel and recurrent BRCA1/BRCA2 germline mutations in patients with breast/ovarian cancer: a series from the south of Tunisia.

BACKGROUND: The incidence of breast cancer (BC) and/or ovarian cancer (OC) is increasing in Tunisia especially in young women and mostly those with family history. However, the spectrum of BRCA mutations remains little explored in Tunisian patients in particular in the southern region. METHODS: We sequenced the entire coding regions of BRCA1and BRCA2 genes using next generation sequencing (NGS) in 134 selected patients with BC and/or OC. RESULTS: Among the 134 patients, 19 (14.17%) carried pathogenic mutations (10 are BRCA1 mutation carriers and 9 are BRCA2 mutation carriers) that are mainly frameshift index (76.9%). Interestingly, 5 out of the 13 variants (38.46%) were found at least twice in unrelated patients, as the c.1310-1313 delAAGA in BRCA2 and the c.5030_5033 delCTAA that has been identified in 4/98 BC patients and in 3/15 OC patients from unrelated families with strong history of cancer. Besides recurrent mutations, 6 variant (4 in BRCA1 and 2 in BRCA2) were not reported previously. Furthermore, 3 unrelated patients carried the VUS c.9976A > T, (K3326*) in BRCA2 exon 27. BRCA carriers correlated significantly with tumor site (p = 0.029) and TNBC cases (p = 0.008). In the groups of patients aged between 31 and 40, and 41-50 years, BRCA1 mutations occurred more frequently in patients with OC than those with BC, and conversely BRCA2 carriers are mostly affected with BC (p = 0.001, and p = 0.044 respectively). CONCLUSIONS: The overall frequency of the BRCA germline mutations was 14.17% in patients with high risk of breast/ovarian cancer. We identified recurrent mutations as the c.1310_1313 delAAGA in BRCA2 gene and the c.5030_5033 delCTAA in BRCA1 gene that were found in 4% and 20% of familial BC and OC respectively. Our data will contribute in the implementation of genetic counseling and testing for families with high-risk of BC and/or OC.

Tuberculosis and non-pulmonary malignancies : study of ten cases.

INTRODUCTION: Tuberculosis (TBC) is a major public health problem with high mortality especially in developing countries. It is associated with a higher risk of developing pulmonary and non-pulmonary malignancies including solid and hematologic cancers. Association between TBC and nonpulmonary malignancies is rarely described in the literature. AIM: To describe the epidemiological, clinical, therapeutic modalities and the evolutive aspects of patients treated for cancer and TBC. METHODS: This is a retrospective study conducted over a period of 19 years (between 1993 and 2012), including 10 patients followed up for cancer and tuberculosis at the department of oncology and the department of infectious disease, CHU Habib Bourguiba Hospital and CHU HediChaker, Sfax, Tunisia. RESULTS: The average age of patients was 55 years old. The sex ratio was 1. The different locations of cancer were represented by the breast (4 cases), the nasopharynx (1 case), the colon (1 case), the kidney (1 case) the gum (1 case), the endometrium (1 case) and the blood (1 case).TBC and cancer were synchronous in 5 cases. Concerning the metachronous presentation that interested 5 patients, the average time betweenthe onset of TBC after cancer diagnosis was 3.5 years. Three of these patients were treated by chemotherapy with radiation therapy. TBClocalization was nodal in 6 cases, spinal one case, nasopharyngeal in one case, peritoneal in one case and urogenital in one case. The diagnosisof TBC was made incidentally in two cases during axillary lymph node dissection. The therapeutic management of cancer was based on surgery,chemotherapy and / or radiotherapy. All patients received anti TBC treatment for at least six months. Surgery was indicated in one case(laminectomy). A complete remission of cancer was observed in 9 patients. Concerning TBC, recovery was observed in 8 patients, 1 patient hada spinal recurrence and 1 patient is being treated. CONCLUSION: Chronic inflammation during TBC can lead to cancer development. The etiopathogenesis of this association is still imperfectly known. Association between TBC and non-pulmonary cancer, although rare, should be always kept in mind in order to handle in time these two diseases in order provide the best chances of recovery for patients.

Cardiac metastases: 4 cases report.

Cardiac metastases are rare. They are found in one to 10% of autopsies of patients withmalignant neoplasm. Adenocarcinoma represents the most common histologicaltype. The most common neoplasms that metastasize to the heart are lung andbreast cancers, melanoma, mesothelioma and lymphoma. However, Cardiacinvolvement is unusual in Hepatic, cutaneous and gastric cancer. We reportedthese three primary localizations in our cases.

CpG methylation of ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) and P53 mutation pattern in sporadic colorectal cancer.

The ubiquitin-proteasome system plays an essential regulatory role in various cellular processes. Besides its involvement in normal cellular functions, the alteration of proteasomal activity contributes to the pathological states of several clinical disorders, including cancer. Aberrant methylation of the CpG islands has been reported as an alternative way to inactivate gene expression involved in the ubiquitination process and thus protein degradation in tumor tissues. In this study, we aimed to determine the CpG methylation pattern of the UCHL1 promoter, as well as the mutation spectrum and the expression pattern of P53 in sporadic colorectal cancer (CRC) from Tunisian patients. We found that UCHL1 was methylated in 68.57 % and correlated significantly with lymph node metastasis (P = 0.029) and transcriptional silencing in tumor tissues (P = 0.013). Mutation screening of exons 5-9 of P53 showed that 42.85 % of cases harbor somatic mutation and are positively correlated with the methylated pattern of UCHL1 (P = 0.001). Furthermore, cytoplasmic accumulation of P53 was strongly associated with the unmethylated UCHL1 profile (P = 0.006), supporting the relationship between these two proteins in CRC.

Tunisian adult's Hodgkin lymphoma Study Group.

The Tunisian adult's Hodgkin lymphoma (HL) Study Group was created in 1999. It aimed to improve the management of this curable hematologic malignancy by standardizing the diagnosis, assessment of disease, treatment management and therapeutic evaluation in different Tunisian centers (Hematology, oncology and radiotherapy).Since 1998, four versions of the prospective national protocol for treating adult Hodgkin lymphoma have succeeded (MDH99, MDH2002, MDH2008, MDH2015). Each version was based on the results of the previous version and analyzed according to new data from the literature. Due to this national study group, the number of patients lost to follow decreased significantly (30% before the creation of the group and only 3% for patients treated with MDH2008), the complete and uncertain response rates have improved (75% before the creation of the group and 92% in patients treated with MDH2008) with dramatically improved rates of overall survival from 57% to 90%. On the other hand there was an improvement of toxic death rate (13% of toxic deaths in MDH2002 to 4.37% in the MDH2008) with a decrease of the respective rate of primary failure and relapse by 17% and 12.5% in MDH2002 against the 11.4% and 7.8% in the MDH2008. This resulted in an improvement in overall survival (90%) and event-free survival at 5 years (75%). Now with the introduction of positron emission tomography in Tunisia, we hope yet to finalize the assessment of response and thus better adapt the treatment of this disease. Our objective remains the improvement of event-free survival rate to reach 80%.

Over-expression of miR-10b in NPC patients: correlation with LMP1 and Twist1.

Aberrant expression of miR-10b has been described in many cancers but remains unexplored in nasopharyngeal carcinoma (NPC). Therefore, we aimed to study the miR-10b expression level in 43 NPC biopsies collected from Tunisian patients and three NPC xenografts. Then, we investigated the correlation between miR-10b expression and its upstream regulators LMP1/Twist1 as well as its adjacent gene HoxD4. We showed that miR-10b was significantly up-regulated in NPC biopsies compared to non-tumor nasopharyngeal tissues (fold change 153; p = 0.004) and associated with advanced clinical stage and young age at diagnosis (p = 0.005 and p = 0.011, respectively). In addition, over-expression of miR-10b was positively associated with the transcription factor Twist1 as well as the EBV oncoprotein LMP1 (fold change 6.32; p = 0.014, fold change 6.58; p = 0.01 respectively). Furthermore, higher level of miR-10b was observed in tumors with simultaneous expression of LMP1 and Twist1, compared to those expressing only Twist1 (fold change 2.49; p = 0.033). Meanwhile, the analysis of the link between miR-10b and its neighbor gene HoxD4 did not show any significant correlation (Fisher test p = 0.205; Mann-Whitney test p = 0.676). This study reports the first evidence of miR-10b over-expression in NPC patients. Furthermore, our findings can support hsa-miR-10b gene regulation through LMP1/Twist1 in NPC malignancy.

[Adjuvant chemotherapy in colon cancer. About 119 cases]. / Chimiothérapie adjuvante dans les cancers coliques. A propos de 119 cas.

BACKGROUND: colon cancer is a public health problem worldwide and in Tunisia. The prognosis of patients with unresectable colorectal cancer varies according to the stage. The indication for adjuvant chemotherapy is well established in the colon cancer stage III, while it remains a matter of controversy for stage II. The aim of this work is to identify the epidemiological and anatomoclinical assess therapeutic outcomes in terms of overall survival of patients with high-risk stage II and stage III colon cancer treated with surgery and adjuvant chemotherapy. METHODS: DS: It's a retrospective study based on 119 patients with colon adenocarcinoma from 1996 to 2010. This patients suffering from colon cancer classified stage II and III having them all radical surgery and adjuvant chemotherapy. RESULTS: The average age of our patients was 53 years. The surgery was performed in an emergency situation in 53 patients (44%). Stages II and III, respectively, were observed in 47% and 53% of cases. Three regimens of chemotherapy were used: protocol FUFOL (50%), followed by FOLFOX (34%) and the protocol LV5FU2 (16%). Overall survival of patients all stages combined was 73.4% at 5 years. Stage III of the TNM classification (p = 0.03) and the number of cycles of chemotherapy <6 (p=0.02) were a negative prognostic factors influencing overall survival. Patients stage III treated with FOLFOX chemotherapy type had a better survival than those treated with chemotherapy type LV5FU2 or FUFOL with a significant difference (p= 0.05). CONCLUSION: Our results are consistent with those in the literature. The prognosis of colon cancer is improving thanks to recent advances that have enabled the integration of new cytogenetic factors in the therapeutic decision.

[Chemotherapy-induced febrile neutropenia: About 186 episodes. Clinical, microbiological and therapeutic characteristics]. / Les neutropénies fébriles chimio-induites: A propos de 186 épisodes Aspects épidémiologiques, diagnostiques et thérapeutiques.

BACKGROUND: One of the major side effects of anti-proliferative treatment is their medullar toxicity. This toxicity is particularly important in neutrophils and leads to a neutropenia. Fever during these episodes of neutropenia is a frequent complication but remains of indeterminate origin in 60% of cases. It's a medical emergency because of rapid evolution and a significant increase in mortality up to 10%. Thus, these episodes should be prevented and treated in priority with un empiric and large spectrum antibiotherapy, taking into account the bacterial ecology of each hospital. AIM: The aim of this study was to determinate the clinical, therapeutic and evolutive characteristics of febrile neutropenia (FN). METHODS: This retrospective study concerned 186 episodes of FN in 136 patients treated for solid tumors and lymphoma in the department of medical oncology of Sfax from january 2006 to December 2010. RESULTS: Mean age was 40 years (1 to 81) and sex ratio at 0.97. They were trated mainly solid tumors in 86.02%. Median time to onset of FN was 11 days and the mean duration of neutropenia was 5 days. 24.2% had a neutrophil count (ANC) <100 / mm3. Fever was clinically documented in 33.87%. Patients have mainly ORL clinical manifestations (38.46%) and specially mucositis (50%). Only 17.2% of cases were microbiologically documented and a bacteria was isolated in 76.46% of them in blood cultures, Gram-negative bacilli (GNB) accounted for the majority of organisms isolated in different samples in 66.66% of cases. Enterobacteriaceae were the most frequent dominated by Klebsiella spp, followed by Escherichia coli. Pseudomonas aeruginosa ranked second after the Enterobacteriaceae (21.21%). The Gram-positive cocci (GPC) were found in 24.24% mainly Staphylococcus aureus. The first line of empirical antibiotic therapy was associated in 88.7% of ceftazidime and amikacin or a fluoroquinolone that has to have an efficiency of 72.12%. The rate of death due to infection in our series was 9.14%. CONCLUSION: Our results are consistent with data in the literature concerning the short duration of neutropenia, causing fever and mortality, but our bacterial epidemiology is different from the current literature, where there is a predominance of CGP unlike our predominantly the BGN. And prescribing empiric antibiotic therapy must take into account the epidemiological and ecological particularities of each country, each hospital or each department.

Breast cancer in young women in southern Tunisia: Anatomical study and clinical prognostic factors: About a series of 83 patients.

PURPOSE: To define epidemiological, clinical, therapeutic and prognostic factors influencing survival of breast cancer in young women younger than 35 in southern Tunisia. MATERIAL AND METHODS: This is a retrospective study of 83 patients younger than 35 years and treated within tumors mammary committee of Sfax. RESULTS: The mean age was 31.7 years. T2 stage, high grade with positive node tumors were frequent. Breast surgery was performed for 73 patients. Chemotherapy was neo-adjuvant, adjuvant and palliative for respectively 10, 62 and 13 patients. Radiotherapy was delivered for 65 patients with curative intent and for 8 metastatic patients. Endocrine therapy was adjuvant in 38 patients and palliative in 6 cases. The overall survival (OS) at 5 years was 66.8%. Pejorative prognostic factors in uni-variate analysis were clinical T stage (T3, T4), and the number of involved lymph nodes. CONCLUSION: Despite adequate treatment, the prognosis of breast cancer in young women remains worse. Early diagnosis is necessary to promote outcome.

Downregulation of WIF-1 and Wnt5a in patients with colorectal carcinoma: clinical significance.

Activation of the wingless-type (Wnt) signaling pathway is common in various human cancers including colorectal cancer (CRC). Wnt inhibitory factor-1 (WIF-1) is a secreted antagonist that can bind Wnt ligands and therefore inhibits the Wnt signaling pathway. In this study, we aimed to analyze the expression of two members of Wnt signaling (WIF-1 and Wnt5a) in Tunisian patients with sporadic CRC. WIF-1 was frequently methylated in tumor tissues (87.95 %) compared to normal mucosa (39.54 %) and correlated with distant metastasis and vascular invasion (P = 0.001 and 0.037, respectively). The unmethylated profile of the WIF-1 promoter conferred a benefit to patients in terms of overall survival (P log rank = 0.024). In addition, in the group of patients with methylated WIF-1 promoter, the overall survival rate was significantly prolonged for those with small tumor size (<5 cm) and absence of distant metastasis (P log rank = 0.007 and 0.036, respectively). Aberrant CpG methylation of the WIF-1 promoter leads to transcriptional silencing of this tumor suppressor gene in tumor tissues (P = 0.001). Furthermore, we showed that the level of Wnt5a mRNA was significantly lower in tumor compared to normal tissues (P = 0.031) and lower still in those showing more aggressive behavior (presence of lymph nodes and advanced TNM stage). Our finding supports that WIF-1 is frequently methylated and that Wnt5a acts as a tumor suppressor gene in CRC. Loss of WIF-1 and Wnt5a functions results in more aggressive behavior of the disease.

Impact of breast cancer stage, time from diagnosis and chemotherapy on plasma and cellular biomarkers of hypercoagulability.

BACKGROUND: In breast cancer patients routine thromboprophylaxis is not recommended but individualized risk assessment is encouraged. The incorporation of hypercoagulability biomarkers could increase the sensitivity of risk assessment models (RAM) to identify patients at VTE risk. To this aim we investigated the impact of cancer-related characteristics on hypercoagulability biomarkers. METHODS: Thrombin generation (TG) assessed with the Thrombogramme-Thrombinoscope®, levels of platelet derived microparticles (Pd-MP) assessed with flow cytometry, procoagulant phospholid dependent clotting time (PPL-ct) measured with a clotting assay and D-Dimers (were assessed in a cohort of 62 women with breast cancer and in 30 age matched healthy women. RESULTS: Patients showed significantly higher TG, Pd-MP, D-Dimers levels and shortened PPL-ct compared to the controls. The PPL-ct was inversely correlated with the levels of Pd-MP, which were increased in 97% of patients. TG and D-Dimers were increased in 76% and 59% of patients respectively. In any stage of the disease TG was significantly increased as compared to the controls. There was no significant difference of TG in patients with local, regional of metastatic stage. There was no significant difference in Pd-MP or Pd-MP/PS+ between the subgroups of patients with local or regional stage of cancer. Patients with metastatic disease had significantly higher levels of Pd-MP and Pd-MP/PS+ compared to those with regional stage. The D-Dimers increased in patients with metastatic stage. In patients on chemotherapy with less than 6 months since diagnosis TG was significantly higher compared to those on chemotherapy who diagnosed in interval > 6 months. Patients with metastatic disease had significantly higher levels of Pd-MP and D-Dimers compared to those with non-metastatic disease. CONCLUSION: In breast cancer patients the stage, the time elapsed since the diagnosis and the administration of chemotherapy are determinants of cellular and plasma hypercoagulability. The levels and the procoagulant activity of Pd-MP are interconnected with the biological activity and the overall burden of cancer. TG reflects the procoagulant properties of both breast cancer and chemotherapy in the initial period of cancer diagnosis. Thus the weighted incorporation of the biomarkers of cellular and plasma hypercoagulabilty in RAM for VTE might improve their predictive value.

Loss of WIF-1 and Wnt5a expression is related to aggressiveness of sporadic breast cancer in Tunisian patients.

Activation of the Wnt/ß-catenin signaling pathway is common in various human cancers. The aim of this study was to investigate the expression of 2 members of the Wnt family (WIF-1 and Wnt5a) in sporadic and hereditary breast cancer tissues. WIF-1, is a secreted antagonist that binds Wnt ligands, and therefore inhibits the canonical Wnt/ß-catenin pathway. Wnt5a is one of the members of the noncanonical Wnt family that mainly acts through calcium signaling pathway. The expression of WIF-1 was analyzed by methylation-specific PCR and RT-PCR, and the level of Wnt5a ligand was quantified by RT-QPCR in breast cancer tissues. Methylation of WIF-1 was detected in 71.3 % and 81.8 % of sporadic and hereditary cases, respectively. Aberrant methylation of WIF-1 was associated with advanced TNM stage and triple negative cases in sporadic breast carcinoma (p=0.001 and p=0.037, respectively). In hereditary cases, methylation of WIF-1 correlated with age at diagnosis (p=0.027) and p53 status (p=0.035). Regarding patients' survival, WIF-1 methylated promoter conferred a reduced overall survival rate, and particularly in a group of patients with advanced TNM stage (p log rank=0.006). Furthermore, aberrant CpG methylation of the WIF-1 promoter was significantly associated with transcriptional silencing of this tumor suppressor gene in sporadic breast cancer tissues (p=0.036). On the other hand, in sporadic tumor tissues, the level of Wnt5a mRNA was significantly lower compared to normal tissues (p=0.031) and lower still in those showing more aggressive behavior, suggesting that Wnt5a, a ligand involved in the noncanonical Wnt/ß-catenin pathway, could act as a tumor suppressor gene in breast cancer.

Secreted recombinant P53 protein from Pichia pastoris is a useful antigen for detection of serum p53: autoantibody in patients with advanced colorectal adenocarcinoma.

The detection of P53 alteration by serological method is easier to perform, does not require tumor tissues and is of interest for patients monitoring. In this study, we described the development of a home made ELISA test based on recombinant human P53 protein produced in Pichia pastoris and used as antigen for the detection of serum p53-Abs in colorectal carcinoma patients. The human P53 was secreted as a His-tagged protein by recombinant KM71 strain (Kα21) via the peptide signal α of the Saccharomyces cerevisiae mating type gene. The recombinant P53-His was able to detect p53-Abs in 23.4% of patients. Serum p53-Abs correlated significantly with surgical treatment (P = 0.007), relapse during follow-up (P = 0.036), depth of invasion (P = 0.036) and the level of CA19-9 (P = 0.034). Survival analysis showed that patients negative for serum p53-Abs exhibited a prolonged disease free survival period (P log rank = 0.012). In conclusion, the secreted recombinant human P53-His produced in P. pastoris seems to be a useful antigen for detection of serum p53 Abs in patients with colorectal carcinoma.

Prognostic factors and survival in metastatic breast cancer: A single institution experience.

BACKGROUND: The current retrospective study aims to identify some determinants of survival in metastatic breast cancer. METHODS: The study concerned 332 patients with synchronous (SM) or metachronous (MM) metastatic breast cancer treated between January 2000 and December 2007. Statistical comparison between subgroups of patients concerning survival was carried out employing log-rank test for the invariable analysis and Cox model for the multivariable analysis. Factors included: age group (≤50 years vs. >50; ≤70 years vs. >70; ≤35 years vs. >35), menopausal status, presentation of metastatic disease (SM vs. MM), disease free interval (DFI) (≤24 months vs. >24 months; ≤60 months vs. >60 months), performance status at diagnosis of metastatic disease (PS) (0-1 vs. >1), hormone receptors (HR), number of metastatic sites (1 site vs. >1), nature of the metastatic site (visceral vs. non visceral), first line therapy, surgery of the primary tumor (SPT), locoregional radiotherapy (LRRT) and use or not of bisphosphonates. RESULTS: Overall survival at 5 years was 12%. Positive prognostic factors in univariate analysis were: age ≤ 70 years, hormono-dependence of the tumor, good PS (PS 0-1), less than two metastatic sites, no visceral metastases, DFI ≥ 24 months, SPT or LRRT. In multivariate analysis, favorable independent prognostic factors included: good PS (PS 0-1), absence of visceral metastases (liver, lung, brain) and age ≤ 70 years. CONCLUSION: Many of the prognostic factors in metastatic breast cancer found in our study are known in the literature but some of them, like the application of locoregional treatment (radiotherapy or surgery) and the use of bisphosphonates, need to be further investigated in randomized clinical trials.

EGFR overexpression relates to triple negative profile and poor prognosis in breast cancer patients in Tunisia.

BACKGROUND: The prognosis of breast carcinoma is related to a large variety of clinical and pathological factors. Currently, only oestrogen (ER) and progesterone (PR) receptors and human epidermal growth factor receptor 2 (HER2) are used in routine pathological assessment as biomarkers. The aim of this study was to evaluate the prognostic impact of epidermal growth factor receptor (EGFR) expression individually and in combination to classical biomarkers (HER2, ER, and PR), and its relation to tumors with triple negative profile in Tunisian breast carcinoma. METHODS: Immunohistochemistry was used to estimate the rate expression of these receptors. Univariate and multivariate analyses were used to explore the prognostic significance of EGFR in this study. RESULTS: The expression rate of EGFR was 28.6%. EGFR expression was inversely correlated to that of ER (P < 0.001). Significant correlations between the expression of EGFR and the high histological Scarff-Bloom-Richardson (SBR) grade (P = 0.038) and also with tumors size (P = 0.041) were observed. The triple negative profile (TN: ER-/PR-/HER2-) was present in 17.3% of cases. EGFR overexpression was positively associated with this clinical aggressive profile (P < 0.001). Survival analysis showed that EGFR expression was associated with poor survival of patients (P = 0.004). In multivariate analysis, EGFR expression (P = 0.035) was found to be independent prognostic factors (significantly correlated to survival). CONCLUSION: EGFR overexpression was observed in 28.6% of Tunisian breast carcinoma, associated with unfavorable prognosis and with triple negative tumors. Systemically evaluation of EGFR in breast carcinoma could benefit especially to TN subgroup from EGFR targeting agents.

Methylation status and overexpression of COX-2 in Tunisian patients with ductal invasive breast carcinoma.

Inflammation and hormonal signalling induce the cyclooxygenase-2 (COX-2) expression in solid tumours including breast cancer, which in turn affects cell proliferation, apoptosis and metastasis. The aim of this study was to investigate the expression of COX-2 and its association with clinical parameters, patient's survival, hormones receptors (oestrogen, progesterone), ERBB2 and TP53 expression in 83 cases of infiltrating ductal breast carcinomas. Moreover, the methylation status at the CpG islands of the COX-2 gene promoter was also explored in 70 specimens. We showed that tumours exhibiting moderate to intense COX-2 immunostaining were significantly more frequent in patients over 45 years old (p = 0.027). Moreover, a high level of COX-2 expression correlated with a shorter survival time (p log-rank = 0.04) and was an independent prognostic factor (p = 0.022; HR 6.4; 95% CI = 1.3-31.4). On the other hand, hypermethylation of the COX-2 gene promoter was observed in 27% of cases and strongly associated with smaller tumours (<5 cm, p = 0.011). Furthermore, patients with methylated COX-2 pattern have a better 4-year disease-free survival (p = 0.022) as well as a prolonged overall survival (p log-rank test = 0.034). In conclusion, we showed that high COX-2 expression was associated with reduced survival and was an independent prognostic factor. However, hypermethylation of the COX-2 promoter correlated with a better overall survival in Tunisian patients with breast carcinoma.

Hypermethylation of RARß2 correlates with high COX-2 expression and poor prognosis in patients with colorectal carcinoma.

Silencing of gene expression by aberrant methylation at the CpG islands is common in human tumors, including colorectal cancer. This epigenetic alteration affects promoter of genes having crucial cellular functions such as tumor suppressor, DNA repair, apoptosis, cell adhesion, etc. We investigated the methylation status in the promoter regions of the RARß2, RASSF1A, DAPKinase, and CDH1 genes in 73 colorectal carcinoma and 43 paired normal tissues of Tunisian patients using methylation-specific PCR assays. The association between methylation status and the clinicopathological features was evaluated. To determine whether aberrant methylation affects gene expression, we performed immunohistochemistry analysis for E-cadherin and COX-2, a target gene of RARß2. The methylation frequencies vary from 80.8% for RARß2 to 35.6% for RASSF1A while in non-tumor-paired samples; the frequencies of methylation are significantly lower for all the fourth genes tested. The methylation status did not correlate with any of the clinical features considered; however, aberrant methylation of RARß2 was associated with a shortened overall patients' survival (p log rank = 0.026); nevertheless, it needs to be confirmed on larger sample size. Moreover, a significant inverse association was observed between methylation status of RARß2 and COX-2 protein expression in tumor specimen (p = 0.014). On the other hand, we found that loss of E-cadherin expression was significantly associated with aberrant methylation of the CDH1 promoter (p = 0.005). Our findings showed that RARß2 was frequently methylated in colorectal cancer and correlated with a worse prognosis and high expression of COX-2 suggesting a link between these two proteins in colorectal carcinogenesis. We also showed that epigenetic alteration of CDH1 is a major mechanism of the loss of E-cadherin protein expression in primary colorectal tumors.

Epigenetic alteration of the Wnt inhibitory factor-1 promoter is common and occurs in advanced stage of Tunisian nasopharyngeal carcinoma.

Activation of the wingless-type (Wnt) signaling pathway is common in cancers. The Wnt inhibitory factor-1 (WIF-1) is a secreted antagonist that acts by binding to Wnt ligands. We examined by methylation-specific PCR (MSP), whether WIF-1 is inactivated in 68 nasopharyngeal carcinomas (NPC), and 10 normal mucosa. We showed that the WIF-1 promoter was methylated in 89.7% of tumors, whereas all normal mucosa were unmethylated. The WIF-1 methylation was associated with the tumor, node, and metastasis (TNM) (p = .003) and the age (p = .014). The Wnt-5a mRNA was higher in tumors and correlated with TNM (p = .012). The methylation of WIF-1 contributes to the activation of the Wnt pathway in NPC.