EBV-Associated Gastric Cancer; An In Situ Hybridization Assay on Tissue Microarray: A Multi-Region Study from Four Major Provinces of Iran.

BACKGROUND: Gastric cancer is the fourth leading cause of cancer-related deaths in the world. The identification of gastric cancer subtypes related to recognizable microbial agents may play a pivotal role in the targeted prevention and treatment of this cancer. The current study is conducted to define the frequency of Epstein-Barr virus (EBV) infection in gastric cancers of four major provinces, with different incidence rates of gastric cancers, in Iran. METHODS: Paraffin blocks of 682 cases of various types of gastric cancer from Tehran, South and North areas of Iran were collected. Twelve tissue microarray (TMA) blocks were constructed from these blocks. Localization of EBV in tumors was assessed by in situ hybridization (ISH) for EBV-encoded RNA (EBER). Chi-squared test was used to evaluate the statistical significance between EBV-associated gastric cancer (EBVaGC) and clinicopathologic tumor characteristics. RESULTS: Fourteen out of 682 cases (2.1%) of gastric adenocarcinoma were EBER-positive. EBER was positive in 8 out of 22 (36.4%) of medullary carcinomas and 6 out of 660 (0.9%) of non-medullary type, which was a statistically significant difference (P<0.001). The EBVaGCs were more frequent in younger age (P=0.009) and also showed a trend toward the lower stage of the tumor (P=0.075). CONCLUSION: EBV-associated gastric adenocarcinoma has a low prevalence in Iran. This finding can be due to epidemiologic differences in risk factors and exposures, and the low number of gastric medullary carcinomas in the population. It may also be related to gastric tumor heterogeneity not detected with the TMA technique.

Quantitative and qualitative analysis of argyrophilic nuclear organizer regions in follicular cyst, keratocystic odontogenic tumor and ameloblastoma.

BACKGROUND: Multicystic ameloblastoma is a benign odontogenic tumor that exhibits a more aggressive behavior than keratocystic odontogenic tumor (KCOT) and follicular cyst. AIM: The purpose of the study was to evaluate the proliferation index nuclear organizer regions (NORs) and their distribution among the four odontogenic lesions with known different clinical invasive behavior. STUDY AND DESIGN: In a descriptive-analytical cross-sectional study, 60 paraffin blocks of odontogenic lesions were prepared for silver nitrate staining. MATERIALS AND METHODS: For the quantitative analysis, 100 cells were counted at ×100 and the mean value was calculated. The morphometric analysis of NORs showed that they can be distributed into normal (round to oval-shaped) and abnormal (large, bean-shaped and cluster-shaped) groups. One-way analysis of variance (ANOVA) and multiple comparison with Tukey test were used for the statistical analysis of the results. RESULTS: The argyrophilic NOR (AgNOR) numbers in multicystic ameloblastoma, unicystic ameloblastoma, KCOT, and follicular cyst were 7.4 ± 2.7, 6.1 ± 2.56, 4.7 ± 1.84, and 2.82 ± 1.052, respectively. The difference between ameloblastoma (unicystic and multicystic types) and either_KCOT, or follicular cyst was statistically significant (P<0.001) and, (P=0.001), respectively. In follicular cysts, normal AgNOR dots were not detected outside the nuclei. NOR histological patterns of KCOT were large, bean shaped and rarely cluster shaped and it was cluster-shaped in multicystic and unicystic ameloblastoma. CONCLUSION: The current study suggests that determination of clinical behavior of ameloblastoma in comparison with KCOT and follicular cyst in silver nitrate staining is related to higher proliferation activity and different NORs' distribution pattern. However, further clinical follow-up studies must be performed to prove this.

p63 expression in randomized odontogenic cysts.

OBJECTIVE: To find out the immunohistochemical assessment of p63 expression in odontogenic cysts based on the differences among their clinical behaviors. METHODS: This study was carried out on 34 archival paraffin-embedded specimens of odontogenic cysts. We obtained the specimens from the Pathology Department of Babol University of Medical Sciences, Babol, Iran from March 2003 to February 2008. The specimens comprised 12 dentigerous cysts, 9 radicular cysts, and 13 keratocystic odontogenic tumors (KCOTs). The immunohistochemical technique was performed using the Envision system for evaluation of p63 expression. RESULTS: The KCOT revealed the highest p63 expression and the differences between the 3 groups was statistically significant. CONCLUSION: P63 expression might be helpful when identifying cyst types with more aggressive and invasive phenotype.

Myofibroblast stromal presence and distribution in squamous epithelial carcinomas, oral dysplasia and hyperkeratosis.

PURPOSE: Stromal elements play a key role in growth and development of different neoplasms. Myofibroblasts are the major components and occur in stromal tissue during carcinogenesis processes. The purpose of this study was to review the frequency and the distribution pattern of myofibroblasts(αSMA-positive) in the stroma of squamous epithelial carcinoma and to compare values with those for with oral dysplasia and hyperkeratosis. METHODS: we evaluated αSMA protein frequency in hyperkeratosis (N =18), oral epithelial dysplasia (N=18) and oral squamous cell carcinoma (N=18) using immunohistochemistry. RESULTS: αSMA-positive expression was observed in 67% of OSCC tissue samples with network and spindle patterns, whereas it was seen in 22% with a focal pattern in dysplasia and in 6% with a scanty pattern in hyperkeratosis cases. CONCLUSION: These findings suggest that an increase in number of myofibroblasts and change in their distribution pattern occurs during carcinogenesis which can be an expression of their role in tumor invasive characteristics.