Background: Recent epidemiological studies have suggested that obesity is associated with ovarian cancer. Obesity hormone leptin and its receptor (Ob-R) contribute to tumor development by enhancing cell growth and survival. This study was design to investigate the prevalence of leptin and Ob-R in Middle Eastern epithelial ovarian cancer (EOC) and to analyze the role of leptin and the mechanisms under its action in EOC tissue sample and cell lines.

The putative role of leptin and its receptor (Ob-R) in the pathogenesis of various primary human malignancies has been reported; however, their role in papillary thyroid cancer (PTC) has not yet been evaluated. We investigated the role of Ob-R in a large tissue microarray cohort of PTC followed by in vitro studies using a panel of PTC cell lines. Ob-R overexpression was seen in 80% PTCs and was significantly associated with poor disease-free survival (PZ0.0235). PTCs that overexpressed Ob-R showed a aggressive phenotype characterized by older age, extrathyroid extension, larger tumor size, nodal metastasis, advanced stage, tall cell variant histological subtype, and a poor disease-free survival (PZ0.0005, PZ0.0006, PZ0.0398, PZ0.0004, PZ0.0111, PZ0.0003, and PZ0.0235 respectively). However, Ob-R expression was not an independent prognostic marker to predict disease-free survival in multivariate analysis. PTCs with overexpression of Ob-R showed a significant direct association with overexpression of XIAP (P!0.0001) and Bcl-XL (P!0.0001). In vitro analysis showed that leptin stimulated cell proliferation and inhibited apoptosis via activation of phosphatidylinisitol 3 0 kinase (PI3K)/protein kinase B (AKT) signaling pathway. Inhibition of PI3K activity by its inhibitor LY294002 abrogated leptin-mediated PI3K/AKT signaling. Gene silencing of Ob-R in PTC cells resulted in downregulation of phospho-AKT, Bcl-XL, and XIAP expression suggesting that leptin-mediated pathogenesis of PTC occurs via involvement of these downstream targets. Altogether, these data show that leptin plays an important role in PTC pathogenesis through PI3K/AKT pathway via Ob-R and is a potential prognostic marker associated with an aggressive phenotype and poor diseasefree survival.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Tumor recurrence occurs in ∼20% of PTCs and some reach advanced stages. Promoter mutation in the telomerase reverse transcriptase (TERT) gene is identified to be a prognostic marker in PTC. However, the contribution of TERT promoter mutation to cancer progression in PTC patients is still not fully understood. In this study, we investigated the incidence of TERT promoter mutations and TERT protein expression and their association with clinicopathological outcomes in a large cohort of PTC samples using direct sequencing technology and immunohistochemistry. Furthermore, two PTC cell lines were utilized to investigate role of TERT mutations in mediating metastasis. Two promoter hotspot mutations C228T and C250T were identified in 18.0% (167/927) of our cohort and were significantly associated with poor 5 years disease-free survival and distant metastasis of PTC. TERT protein overexpression was noted in 20.1% of our PTC cohort and was significantly associated with poor prognostic markers such as older age, extrathyroidal extension and Stage IV tumors. A significant association was also found between TERT overexpression and epithelial-mesenchymal transition (EMT) markers. Functional analysis showed that TERT inhibition reduced cell growth, invasion, migration and angiogenesis in PTC via suppression of EMT in PTC cells. Our results suggest that TERT promoter mutation is an independent predictor of disease-free survival and might drive the metastasis, and downregulation of TERT could potentiate antitumor and antimetastatic activities in PTC.

Our results suggest that FASN and activated AKT pathway may be a potential target for therapeutic intervention for the treatment of PTC.

Ethnic differences of breast cancer genomics have prompted us to investigate the spectra of BRCA1 and BRCA2 mutations in different populations. The prevalence and effect of BRCA 1 and BRCA 2 mutations in Middle Eastern population is not fully explored. To characterize the prevalence of BRCA mutations in Middle Eastern breast cancer patients, BRCA mutation screening was performed in 818 unselected breast cancer patients using Capture and/or Sanger sequencing. 19 short tandem repeat (STR) markers were used for founder mutation analysis. In our study, nine different types of deleterious mutation were identified in 28 (3.4%) cases, 25 (89.3%) cases in BRCA 1 and 3 (10.7%) cases in BRCA 2. Seven recurrent mutations identified accounted for 92.9% (26/28) of all the mutant cases. Haplotype analysis was performed to confirm c.1140 dupG and c.4136_4137delCT mutations as novel putative founder mutation, accounting for 46.4% (13/28) of all BRCA mutant cases and 1.6% (13/818) of all the breast cancer cases, respectively. Moreover, BRCA 1 mutation was significantly associated with BRCA 1 protein expression loss (p = 0.0005). Our finding revealed that a substantial number of BRCA mutations were identified in clinically high risk breast cancer from Middle East region. Identification of the mutation spectrum, prevalence and founder effect in Middle Eastern population facilitates genetic counseling, risk assessment and development of cost‐effective screening strategy.