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.

Identification of novel candidate genes by exome sequencing in Tunisian familial male breast cancer patients.

Male Breast Cancer (MBC) is a rare and aggressive disease that is associated with genetic factors. Mutations in BRCA1 and BRCA2 account for 10% of all MBC cases suggesting that other genetic factors are involved. The aim of the present study is to screen whole BRCA1 and BRCA2 exons using the Ampliseq BRCA panel in Tunisian MBC patients with family history. Furthermore, we performed exome sequencing using the TruSight One sequencing panel on an early onset BRCA negative patient. We showed that among the 6 MBC patients, only one (MBC-F1) harbored a novel frameshift mutation in exon 2 of the BRCA2 gene (c.17-20delAAGA, p.Lys6Xfs) resulting in a short BRCA2 protein of only 6 amino-acids. We selected 9 rare variants after applying several filter steps on the exome sequencing data. Among these variants, and based on their role in breast carcinogenesis, we retained 6 candidate genes (MSH5, DCC, ERBB3, NOTCH3, DIAPH1, and DNAH11). Further studies are needed to confirm the association of the selected genes with family MBC.

CD155 expression in human breast cancer: Clinical significance and relevance to natural killer cell infiltration.

AIMS: CD155 is a ligand of the NK activating receptor DNAM-1, it has been described in a variety of human malignancies, but its expression in breast cancer remains unclear and poorly studied. MAIN METHODS: CD155 expression and NK cells infiltration were investigated in 158 patients with breast cancer by immunohistochemistry (IHC). Statistical analyses were performed to evaluate correlations of CD155 expression with clinical-pathological features, prognosis and tumor immunity. KEY FINDINGS: Tumor cytoplasmic CD155 (cyt-CD155) was associated with lymphovascular invasion (p = 0.011), and membranous CD155 (m-CD155) was strongly correlated with the presence of Tumor Infiltrating natural killer cells (NK-TILs) (p = 0.0003). Survival analysis demonstrated that patients with high cyt-CD155 had a significantly worse overall survival (p < 0.001) and death free survival (p = 0.014) than those with low expression, while high levels of m-CD155 correlated with a better prognosis (p = 0.037). Furthermore, we found that patients with m-CD155Low/NKLow tumors had a significantly reduced overall survival (p = 0.012). Multivariate analysis showed that positive tumor m-CD155 status was a significant independent marker of good prognosis. Meanwhile, high cyt-CD155 expression was identified as an independent poor prognostic predictor, suggesting a key role in this malignancy. SIGNIFICANCE: Altogether, our results revealed that cyt-CD155 was associated with invasiveness and poorer prognosis, but the concomitant presence of m-CD155 and NK-TILs had an opposite prognostic relevance in breast cancer. These results raised the importance of CD155 IHC analysis to elucidate biomarker localization, leading to better understand and design therapeutic molecule targeting CD155 in breast tumors.

Association of FOXA1 and EMT markers (Twist1 and E-cadherin) in breast cancer.

The transcription factor FOXA1 (forkhead box A1) plays key roles in tumor development and progression. In the present study, we analyzed the expression of FOXA1 in 52 breast tumors and 10 normal tissues, and investigated the relationship between FOXA1 and two EMT markers, namely Twist1 and E-cadherin by RT-PCR and IHC respectively. The expression level of FOXA1 was higher in tumor compared to normal tissues but the difference was not statistically significant (P = 0.138). FOXA1 expression correlated with less aggressive behavior as SBR grade I (P = 0.04), small tumors size (P = 0.05), and longer survival (P = 0.001). Furthermore, estrogen and progesterone positive tumors exhibit high level of FOXA1 (P = 0.002 and P = 0.038 respectively). Survival analysis showed that patients with ER positive/FOXA1 positive (P log rank = 0.001), PR positive/FOXA1 positive (P log rank = 0.044) and HER-2 negative/FOXA1 positive (P log rank = 0.002) tumors have a significant prolonged overall survival. On the other hand, the expression of E-cadherin positively correlated with FOXA1 (P = 0.028), whereas negative association was seen between the expression of Twist1 and FOXA1 (P = 0.016). Kaplan-Meier plots showed that patients with Twist1negative/FOXA1positive tumors have a significant prolonged overall survival (P log rank = 0.001) and FOXA1 appeared as independent predictors of patient survival in multivariate analyses. Overall, our results indicate that FOXA1 could be a useful biomarker to predict prognosis in breast cancer patients.

Pemphigus herpetiformis in South Tunisia: a clinical expression of pemphigus foliaceus?

BACKGROUND: Pemphigus herpetiformis (PH) is a rare subtype of pemphigus combining clinical features of dermatitis herpetiformis and the immunopathologic characteristics of pemphigus. We aimed to analyze the epidemiological, clinical, and immunological presentation and management of the disease in a cohort of south Tunisian patients with a long-term follow-up. METHODS: We included all patients with confirmed PH followed from January 1987 to December 2015 in the dermatology department. RESULTS: We included 24 south Tunisian female patients with a mean age of 36 years (20-63), mainly from rural origin (84%). All patients had exclusive skin lesions. Clinical features combined erythematous, vesicular, or bullous lesions, with circinate borders mainly on the trunk and limbs associated with severe pruritus (91%). Peripheral hypereosinophilia was noted in 31% of cases. Histological examination demonstrated no intraepithelial (50%), suprabasal (35%), or subcorneal cleavage (15%). Eosinophilic spongiosis was seen in 42% of cases. On direct immunofluorescence, there was an intercellular staining in 96% of cases composed mainly of IgG and C3 (79%). Indirect immunofluorescence was positive in 71% of cases. Reactivity was mainly directed against Dsg1. Dapsone alone was inefficient. All patients received systemic corticosteroids. Most patients (64%) relapsed. Iatrogenic complications and cutaneous infections were noted in 40% and 16% of cases, respectively. CONCLUSION: PH is characterized by the occurrence of exclusive skin lesions in young women with a good response to corticosteroids but not to Dapsone. Reactivity mainly against Dsg1 suggests that PH in south Tunisia is a particular variant of nonendemic pemphigus foliaceus.

RIP140 and LCoR expression in gastrointestinal cancers.

The transcription coregulators RIP140 and LCoR are part of a same complex which controls the activity of various transcription factors and cancer cell proliferation. In this study, we have investigated the expression of these two genes in human colorectal and gastric cancers by immunohistochemistry. In both types of tumors, the levels of RIP140 and LCoR appeared highly correlated. Their expression tended to decrease in colorectal cancer as compared to adjacent normal tissues but was found higher in gastric cancer as compared to normal stomach. RIP140 and LCoR expression correlated with TNM and tumor differentiation. Significant correlations were observed with expression levels of key proteins involved in tumor progression and invasion namely E-cadherin and Cyclooxygenase-2. Survival analysis showed that patients with LCoRlow/RIP140high colorectal tumors have a significant prolonged overall and disease-free survival. In gastric cancer, high LCoR expression was identified as an independent marker of poor prognosis suggesting a key role in this malignancy. Altogether, these results demonstrate that RIP140 and LCoR have a prognostic relevance in gastrointestinal cancers and could represent new potential biomarkers in these tumors.

CpG methylation of APC promoter 1A in sporadic and familial breast cancer patients.

Tumour suppressor gene (TSG) silencing through promoter hypermethylation plays an important role in cancer initiation. The aim of this study was to assess the extent of methylation of APC gene promoter in 91 sporadic and 44 familial cases of Tunisian patients with breast cancer (BC) in. The frequency of APC promoter methylation is somewhat similar for sporadic and familial breast cancer cases, (52.1%, and 54.5% respectively). For sporadic breast cancer patients, there was a significant correlation of APC promoter hypermethylation with TNM stage (p = 0.024) and 3-year survival (p = 0.025). Regarding the hormonal status (HR), we found significant association between negativity to PR and unmethylated APC (p= 0.005) while ER and Her2/neu are not correlated. Moreover, unmethylated APC promoter is more frequent in tumours expressing at least one out the 3 proteins compared to triple negative cases (p= 0.053). On the other hand, aberrant methylation of APC was associated with tumour size (p = 0.036), lymph node (p = 0.028), distant metastasis (p = 0.031), and 3-year survival (p = 0.046) in the group of patients with familial breast cancer. Moreover, patients with sporadic breast cancer displaying the unmethylated profile have a significant prolonged overall survival compared to those with the methylated pattern of APC promoter (p log rank = 0.008). Epigenetic change at the CpG islands in the APC promoter was associated with the silence of its transcript and the loss of protein expression suggesting that this event is the main mechanism regulating the APC expression in breast cancer. In conclusion, our data showed that the loss of APC through aberrant methylation is associated with the aggressive behavior of both sporadic and familial breast cancer in Tunisian patients.

Clinical and prognosis relevance of COX-2 expression in Tunisian patients with primary gastric adenocarcinoma.

BACKGROUND: Inflammation and hormonal signalling induce the cyclooxygenase-2 (COX-2) expression in various human cancers including Gastric Cancer (GC). GC remains among the human malignancies diagnosticated at advanced tumor stage and thus having a poor prognosis. COX-2 is a key protein in cancer progression which is involved in proliferation, invasion, and metastasis of tumor cells. OBJECTIVE: The aim of this study was to investigate the expression of COX-2 and its association with clinico-patholocigal parameters and survival in Tunisian GC patients and to correlate COX-2 expression with others cancer-related proteins. METHODS: The immunohistochemistry was used to study the expression of COX-2 on 93 patients with gastric adenocarcinoma. RESULTS: Our results show that COX-2 immunostaining is negative to weak in 51.6%, moderate in 33.3%, and intense in 15.1% of tumor tissues. The expression of COX-2 associated significantly with tumor differentiation (p = 0.003), and histological type (p = 0.039). Furthermore, lack of COX-2 expression is significantly associated with 1-year (p= 0.005), 2-years (p= 0.000), and 5-years (p= 0.042) relapse free survival. In addition, Cox regression model, revealed that metastasis (p= 0.014), tumor site (p= 0.013), histotype (p = 0.02), and COX-2 expression (p = 0.003) are independent factors for prognosis. Regarding the relationship between COX-2 and cancer related proteins, we found that COX-2 expression is positively associated with APC (p = 0.006), and P53 (p = 0.026), supporting a cross link between these proteins in gastric carcinogenesis. CONCLUSION: Our findings emphasize the importance of COX-2 as a potential marker of tumor progression and prognosis in GC, and that the inhibition of COX-2 activity may have a therapeutic benefit in GC.

Quantitative measurement of iNOS expression in melanoma, nasopharyngeal, colorectal, and breast tumors of Tunisian patients: comparative study and clinical significance.

Chronic inflammation increases the risk of development of human malignancies. iNOS is an enzyme dominantly expressed during inflammatory reactions and seems to play a critical role in tumorigenesis. Our aim was to assess the iNOS expression in four types of human tumors: breast, colorectal, nasopharyngeal, and melanoma, of Tunisian patients. The level of iNOS was measured by RT-QPCR in tumor specimens. We showed that the expression of iNOS was higher in breast compared to colorectal and nasopharyngeal tumors, whereas in melanoma, the level of iNOS expression was low. Significant associations were found when comparing the iNOS expression in cancers pairs such as melanoma versus colorectal (p < 0.0001), colorectal versus nasopharyngeal (p = 0.0072), and melanoma versus breast (p < 0.0001). Furthermore, iNOS expression correlated with the Breslow thickness, Clark level, and histological subtype in melanoma, while in nasopharyngeal carcinoma, significant association was seen with age at diagnosis, TNM, metastasis, response to treatment, and expression of COX-2. Furthermore, the expression of iNOS correlated with tumor size, TNM, tumor location, and histological type in colorectal cancer, and with tumor size, tumor stage, SBR grade, and triple negative cases in breast cancer. On the other hand, immunohistochemistry analysis shows that the expression of iNOS is observed in the stroma and tumor cells as well. Overall, our results highlight that iNOS is a reliable marker for advanced stage and aggressive behavior for the four types of cancer and might be a potential promising therapeutic target.

Expression and mutation pattern of ß-catenin and adenomatous polyposis coli in colorectal cancer patients.

BACKGROUND AND AIMS: ß-Catenin and adenomatous polyposis coli (APC) are major components of the Wnt pathway. This study aimed to investigate the expression of ß-catenin and APC in tumors and lymph nodes in colorectal cancer (CRC) patients and the mutational spectrum of the genes coding these proteins. METHODS: Expression of APC and ß-catenin was examined in 124 tumors and 41 lymph nodes. Exon 3 of CTNNB1 and the mutation cluster region (MCR) in exon 15 of the APC gene were screened for mutation by PCR-sequencing. RESULTS: Nuclear/cytoplasmic immunostaining of ß-catenin was detected in 58.1 and 48.8% in tumors and lymph nodes, respectively. In tumors, abnormal expression of ß-catenin correlated with tumor size and with those in lymph nodes. Membranous ß-catenin expression occurred in 41.9 and 14.6% of tumors and lymph nodes, respectively. In tumors, lack of membranous ß-catenin correlated with high invasiveness and metastatic potential. Positive immunostaining for APC was observed in 2 and 14% of tumors and lymph nodes, respectively. Overexpression in nucleus/cytoplasm and lack of membranous ß-catenin significantly correlated with a reduced overall survival. Among 25 tumors, four harbour mutation in Ser33 and Ser47 and overexpress the ß-catenin in the nucleus/cytoplasm. Mutations were identified in the APC gene in 13 tumors and six mutations were novel. CONCLUSIONS: Positive association between aberrant expression of ß-catenin in the nucleus/cytoplasm of tumors and lymph nodes was observed. Nucleus/cytoplasmic accumulation of ß-catenin and loss of membranous expression are related to reduced survival and could serve as a candidate prognostic predictor.

Clinicopathological and prognostic significance of p53, Ki-67, and Bcl-2 expression in Tunisian gastric adenocarcinomas.

Gastric carcinoma (GC) is a highly aggressive malignancy with poor prognosis. It is widely accepted that malignancy results from abnormal cell growth due to dysregulation of the balance between cell proliferation and apoptosis. Our study aimed to investigate the clinicopathological and prognostic significance of p53, Ki-67, and Bcl-2 in Tunisian GC patients by immunohistochemistry. It was observed that the older patients showed p53 overexpression compared with the younger patients (p<0.05). There was higher p53 expression in the intestinal-type compared with the diffuse-type (p<0.05), and in well/moderate differentiated than in poor differentiated tumors. The expression of Ki-67 was positively associated with tumor size and venous invasion (p<0.05). Bcl2 expression occurred in male patients and correlated with depth of invasion (p=0.02). A Kaplan-Meier analysis indicated an inverse correlation between p53 and Ki-67 expression and the overall survival. Multivariate analysis revealed that the tumor site, Ki-67 and p53 expression were independent prognostic factors for gastric carcinomas (p<0.05). Finally, combined expression of p53, Ki-67 and Bcl-2 showed that the group of patients with tumors p53+/Ki-67+/Bcl2- had aggressive behavior and poor prognosis (p log rank=0.000). In summary, our data indicated that the expression of p53, Ki-67, and Bcl-2 may provide useful information for identifying patients with aggressive behavior and poor prognosis of GC.

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.

Expression of APC, ß-catenin and E-cadherin in Tunisian patients with gastric adenocarcinoma: clinical significance.

Aberrant activation of the Wnt signalling pathway is a key feature of many cancers. ß-Catenin, adenomatous polyposis coli (APC) and E-cadherin are major players in this pathway. The aim of this study is to examine the expression of ß-catenin, APC and E-cadherin in tumour tissues of 80 Tunisian patients with gastric carcinoma and to determine the methylation status of the APC promoter in tumour tissues. Associations between protein expression and clinico-pathological parameters, including prognosis, were performed. Positive expression of ß-catenin, APC and E-cadherin was observed in 77.5, 68.7 and 60% of cases, respectively. Tumours lacking membranous expression of ß-catenin had greater extent of lymph node metastasis, poor differentiation and advanced T-stage. The expression of E-cadherin correlated with poor differentiation (P = 0.05) and ß-catenin expression (P = 0.004). With regards to prognosis, the overall survival time was significantly prolonged for patients showing normal ß-catenin expression (exclusively or predominantly membranous staining) alone or combined with positive APC expression (P log rank = 0.008 and 0.003, respectively). The methylated pattern of APC promoter 1A was detected in 43.8% of cases and correlated with T-stage (P = 0.046) and distant metastasis (P = 0.037). No correlation was found between the methylated profile of APC promoter 1A and the expression of APC protein in tumour tissues. Our findings suggest that deregulation of the Wnt pathway via abnormal expression of ß-catenin and E-cadherin occurred frequently in gastric carcinoma and correlated with worse clinical behaviour.

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.

Frequent CpG methylation of ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) in sporadic and hereditary Tunisian breast cancer patients: clinical significance.

Aberrant methylation of the CpG islands in promoter regions is one of the mechanisms for inactivation of tumor suppressor genes in many human cancers including breast carcinoma. In this study, we aimed to assess, by methylation-specific PCR, the CpG methylation pattern of the UCHL1 promoter in 94 sporadic and 44 hereditary breast cancers from Tunisian patients. The percentage of UCHL1 methylation was 67 % in sporadic and 82 % in hereditary breast cancer cases. In sporadic cases, UCHL1 methylation correlated with poor response to treatment (P = 0.042) and progesterone receptor status (P = 0.036), whereas in patients with hereditary predisposition, the only significant association was found with Her2 expression (P = 0.024). Moreover, in patients with sporadic breast cancer, the UCHL1 unmethylated pattern conferred a prolonged overall survival time in particular in the group of patients with advanced TNM stage of the disease (P log rank = 0.04). Aberrant CpG methylation of the UCHL1 promoter was significantly associated with transcriptional silencing of this tumor suppressor gene in sporadic breast cancer tissues (P = 0.001). On the other hand, the UCHL1 unmethylated pattern correlated with P53 positivity in primary sporadic tumors (P = 0.032), supporting the functional link between the two tumor suppressors in breast tumorigenesis.

Leydig Cell Tumor Associated with Testicular Adrenal Rest Tumors in a Patient with Congenital Adrenal Hyperplasia due to 11ß-Hydroxylase Deficiency.

Congenital adrenal hyperplasia (CAH) describes a group of inherited autosomal recessive disorders characterized by enzyme defects in the steroidogenic pathways that lead to the biosynthesis of cortisol, aldosterone, and androgens. Chronic excessive adrenocorticotropic hormone (ACTH) stimulation may result in hyperplasia of ACTH-sensitive tissues in adrenal glands and other sites such as the testes, causing testicular masses known as testicular adrenal rest tumors (TARTs). Leydig cell tumors (LCTs) are make up a very small number of all testicular tumors and can be difficult to distinguish from TARTs. This distinction is interesting because LCTs and TARTs require different therapeutic approaches. Hereby, we present an unusual case of a 19-year-old patient with CAH due to 11ß-hydroxylase deficiency, who presented with TARTs and an epididymal Leydig cell tumor.

Negative/low HER2 expression alone or combined with E-cadherin positivity is predictive of better prognosis in patients with breast carcinoma.

The loss of E-cadherin expression leads to absence of tissue integrity, an essential step in tumor progression. Methylation of CpG islands in the promoter region of the CDH1 gene coding E-cadherin might be an alternative for gene silencing. In the present study, we investigate the expression of E-cadherin and hormone receptors in invasive ductal breast carcinoma (IDCs). Protein expression was analysed immunohistochemically in 87 cases, including 26 familial tumors. The most interesting results revealed a significantly reduced E-cadherin expression in cases with familial history compared to sporadic tumors (p=0.009), as well as with tumors ≤5 cm (p=0.022). Moreover, HER2 over-expression was associated with distant metastasis (p=0.011) and overall survival (p log rank=0.028). Tumors displaying negative/low HER2 expression combined with E-cadherin positivity confer better patient survival (p=0.052). Triple Negative tumors (TN) were more frequently found in patients with advanced grade (GIII) (p=0.001) and TNM (III+IV) (p=0.018) which supports the aggressive behavior of TN tumors. On the other hand, hypermethylation of CDH1 gene promoter was observed in 46% of hereditary cases and strongly associated with loss of E-cadherin expression (p=0.002). Furthermore, patients with unmethylated CDH1 pattern have a better 5-year disease free survival (p=0.021). In conclusion, in patients with hereditary breast cancer, the CpG methylation event contributes to the loss of E-cadherin expression. On the other hand, HER2 over-expression is predictive of worse prognosis, either alone or combined with loss of E-cadherin expression in Tunisian patients with breast cancer.

Expression of COX-2 and E-cadherin in Tunisian patients with colorectal adenocarcinoma.

Cyclo-oxygenase 2 (COX-2) and E-cadherin are promising biomarkers for cancer diagnosis and therapy. The aim of this study was to examine the expression of these two proteins in primary colorectal adenocarcinomas and to investigate their association with clinicopathological characteristics including survival of patients. Immunostaining of E-cadherin and COX-2 was assessed in 70 primary colorectal adenocarcinomas from Tunisian patients. Membranous E-cadherin immunostaining and cytoplasmic COX-2 expression were observed in 74.3% and 68.6% of cases respectively. A significant association was found between COX-2 expression and age at diagnosis (P=0.02), and vessel invasion (P=0.037). The expression of E-cadherin correlated with age at diagnosis (P=0.01), and tumor size (P=0.02). In addition, by multivariate analysis, we revealed a significant association with 1-year disease free survival and a tendency with distant metastasis (P=0.017 and P=0.065 respectively). On the other hand, tumors exhibiting COX-2+/E-cadherin-profile were larger (P=0.006), and in an advanced stage (P=0.001). Survival analysis showed that COX-2 over-expression confers a reduced overall survival rate (Plog rank=0.036) and is an independent factor predictive for prognosis.

Characteristics of epstein barr virus variants associated with gastric carcinoma in Southern Tunisia.

BACKGROUND: EBV-associated Gastric Carcinoma (EBVaGC) has a distinct clinical features and its prevalence is variable worldwide. RESULTS: To determine the prevalence of EBVaGC in Tunisia, EBV-encoded small RNA (EBER) expression was assessed in 81 gastric carcinoma (GC) specimens. The nuclear EBER expression was detected in 12 out of 81 GC cases (14.81%) and concordance between the score range of EBER staining and the number of EBV DNA copies as estimate by QPCR is observed. On the other hand, we found that EBVaGC strongly correlated with age at diagnosis, and weakly with tumor differentiation and venous invasion.Furthermore, the EBVaGC specimens were subjected to determine the EBV DNA polymorphisms. Our results show a unique genetic profile of the EBV strains regarding the A and D types, the F prototype, the retention of XhoI restriction site and the 30 bp del-LMP1 variant. According to our previous studies on nasopharyngeal carcinoma (NPC), we suggested that EBV strains associated to GC and NPC shared some similarities in Tunisian patients. CONCLUSION: The prevalence of EBVaGC is of 14.81% in the southern Tunisia and that common EBV strain are associated with both NPC and GC which are likely to differ from Asian strains. Our findings support therefore a certain geographical distribution of EBV strains which is not restricted to EBV-associated malignancies.

Expression of p16INK4a, alone or combined with p53, is predictive of better prognosis in colorectal adenocarcinoma in Tunisian patients.

INTRODUCTION: Alterations in different signaling pathways are involved in initiation and progression of colorectal carcinoma, such as those related to p53, MLH1, p16INK4a, Kras, etc. AIM: This study was conducted with the aim to investigate the expression of p16INK4a and p53 in colorectal cancer (CRC) and evaluated their correlation with major clinicopathologic features and patients' survival. MATERIALS AND METHODS: The expression of p16INK4a and p53 were analyzed by immunohistochemistry on 70 paraffin specimens of CRC. RESULTS: Positive immunostaining for p16INK4a and p53 was observed in 27 (38.6%) and 53 (80%) cases, respectively. Significant correlation between loss of p16INK4a expression and tumor size was found (P=0.008), whereas overexpression of p16INK4a correlated with favorable prognosis parameters, such as absence of lymph node metastasis (P=0.029) and early stage of CRC (P=0.027). Furthermore, p53 overexpression significantly correlated with distal tumor location (P=0.022) and was related to a better overall survival in the group of patients with distal colon carcinomas (P=0.002). Patients with p16INK4a-positive tumors had a significant longer overall survival time than patients with p16INK4a-negative carcinomas (P=0.033). In addition, Cox regression model showed that overexpression of p16INK4a is an independent factor for prognosis with depth of invasion, p53 accumulation, and coincident abnormal expression of p16INK4a or p53. CONCLUSION: Our data suggest that the assessment of both p53 and p16INK4a expression might be helpful in predicting prognosis in patients with colorectal cancer.