Context: Genetic aberration in phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been detected in numerous and diverse human cancers. PIK3CA, which encodes for the catalytic subunit of p110␣ of PI3K, is amplified in some cases of papillary thyroid cancer (PTC). Mutations in the PIK3CA have also been identified in thyroid cancers and, although relatively common in anaplastic thyroid carcinoma, are uncommon in PTC.Objective: The objective of the study was to investigate genetic alterations like PIK3CA gene mutation, PIK3CA amplification, RAS, and RAF mutations and to further explore the relationship of these genetic alterations with various clinicopathological characteristics in Middle Eastern PTC. Design:We used the fluorescence in situ hybridization technique for analysis of PIK3CA amplification from 536 PTC cases, and selected amplified samples were further validated by real-time quantitative PCR. Mutation analysis was done by direct DNA sequencing of PIK3CA, N2-RAS, and BRAF genes.Results: PIK3CA amplification was seen in 265 of 499 PTC cases analyzed (53.1%); PIK3CA gene mutations in four of 207 PTC (1.9%); N2-RAS mutations in 16 of 265 PTC (6%); and BRAF mutations in 153 of 296 PTC (51.7%). N-RAS mutations were-associated with an early stage (P ϭ 0.0465) and lower incidence of extrathyroidal extension (P ϭ 0.027), whereas BRAF mutations were-associated with metastasis (P ϭ 0.0274) and poor disease-free survival (P ϭ 0.0121) in PTCs. P apillary thyroid carcinoma (PTC) is the most common malignant thyroid tumor, representing 80 -90% of all thyroid malignancies. PTC is usually well differentiated; however, the clinical behavior of PTC varies widely. For example, incidental microcarcinomas grow very slowly and are noninvasive or minimally invasive. On the other hand, invasive PTC with metastasis can be lethal. PTC often recurs many years after surgical removal. The prognosis for PTC is often favorable; however, approximately 20% of PTC tumors recur, and some reach advanced stages (1). Several clinicopathological variables including stage, cancer invasion, and distant metastasis are used for prognostication and treatment selection for PTC (2, 3). A better understanding of the factors and mechanisms determining the aggressive behavior of some papillary carcinomas is critical in developing new treatment. Conclusion

In an attempt to find genes that may be of importance in malignant progression of papillary thyroid carcinoma (PTC) in the Middle East, which therefore can be targeted in cancer therapy, we screened and validated the global gene expression in PTC using cDNA expression arrays and immunohistochemistry (IHC) on tumour tissue microarrays. Twenty-nine PTC tissue specimens were compared with seven non-cancerous thyroid specimens by use of cDNA microarray. Results for selected genes were confirmed by quantitative real-time PCR. Protein expression of selected genes was further studied using a tissue microarray consisting of 536 PTCs and compared with histologically non-cancerous tissue samples. One hundred and ninety-six genes were overexpressed in PTC tissues relative to non-cancerous thyroid tissues. The genes that were up-regulated in PTC were involved in cell cycle regulation, cell signaling, and oncogenesis. Among these genes, c-MET was identified by immunohistochemical methods as a protein that is overexpressed in 37% of PTCs and was significantly associated with more aggressive behaviour, eg higher stage, nodal involvement, and tall cell variant (p value = 0.01, 0.01 and 0.04, respectively). In this study, 55% of the PTC cases expressed activated AKT (P-AKT), which suggests that activated AKT may play an important role in PTC tumourigenesis. The fact that most of the PTC cases that had activated AKT showed overexpression of c-MET (p = 0.027) leads us to hypothesize that c-MET may be an alternative mechanism of AKT activation in Middle Eastern PTCs. Finally, our data suggest that c-MET dysregulation is associated with aggressive behaviour and may serve as a molecular biomarker and potential therapeutic target in this disease.

Genetic polymorphisms of DNA repair genes seem to determine the DNA repair capacity. We hypothesized that polymorphisms of genes responsible for DNA repair may be associated with risk of thyroid cancer. To evaluate the role of genetic polymorphisms of DNA repair genes in thyroid cancer, we conducted a hospital-based case-control study in Saudi population. Two hundred and twenty-three incident papillary thyroid cancer cases and 229 controls recruited from Saudi Arabian population were analyzed for 21 loci in 8 selected DNA repair genes by PCR-restriction fragment length polymorphism including non-homologous end joining pathway genes LIGIV (LIGlV ASP62HIS, PRO231SER, TRP46TER), XRCC4 Splice 33243301G>A and XRCC7 ILE3434THR; homologous recombination pathway genes XRCC3 ARG94HIS and THR241MET, RAD51 UTR 15452658T>C, 15455419A>G, RAD52 2259 and GLN221GLU, conserved DNA damage response gene Tp53 PRO47SER, PRO72ARG, Tp53 UTR 7178189A>C and base excision repair gene XRCC1 ARG194TRP, ARG280HIS, ARG399GLN, ARG559GLN. RAD52 GLN221GLU genotypes CG and variants carrying G allele showed statistical significance and very high risk of developing thyroid cancer compared to wild type [CG vs CC; p<0.001, odds ratio (OR)=15.57, 95% confidence interval (CI)=6.56-36.98, CG+GG vs CC; p<0.001, OR=17.58, 95% CI=7.44-41.58]. Similarly, RAD52 2259 genotypes CT and variant allele T showed a significant difference in terms of risk estimation (CT vs CC; p<0.05, OR=1.53, 95% CI=1.03-2.28, CT+TT vs CC; p<0.001, OR=1.922, 95% CI=1.31-2.82). Remaining loci demonstrated no significance with risk. Of the 21 loci screened, RAD52 2259 and RAD52 GLN221GLU may be of importance to disease process and may be associated with papillary thyroid cancer risk in Saudi Arabian population.

BackgroundThe xenobiotic enzyme system that enables us to detoxify carcinogens exhibits identifiable genetic polymorphisms that are highly race specific. We hypothesized that polymorphisms of these genes may be associated with risk of thyroid cancer. To evaluate the role of genetic polymorphisms of xenobiotic genes in thyroid cancer, we conducted a hospital-based case-control study in Saudi population.Methods223 incident papillary thyroid cancer cases and 513 controls recruited from Saudi Arabian population were analyzed for the association between polymorphisms in genes encoding folic acid metabolizing enzymes MTHFR and six xenobiotics-metabolizing enzymes including CYP1A1 T3801C, C4887A, GSTP1 A1578G, C2293T, GSTM1, GSTT1, NAT2 G590A, NQO*1 C609T, using PCR-RELP.ResultsAmong selected genes, CYP1A1 C4887A genotypes CA, AA and variant allele A demonstrated significant differences and greater risk of developing thyroid cancer comparing to wild type genotype CC (CA vs. CC; p < 0.0001, OR = 1.91, 95% CI = 1.36–2.70, AA vs. CC; p < 0.001, OR = 3.48, 95% CI = 1.74–6.96 and CA+AA vs. CC; p < 0.0001, OR = 2.07, 95% CI = 1.49–2.88). GSTT1 null showed 3.48 times higher risk of developing thyroid cancer (p < 0.0001, 95% CI = 2.48–4.88) while GSTM1 null showed protective effect (p < 0.05, OR = 0.72, 95% CI = 0.52–0.99). Remaining loci demonstrated no significance with risk.ConclusionOf the 9 polymorphisms screened, we identified GST, GSTM1 and CYP1A1 C4887A, may be of importance to disease process and may be associated with papillary thyroid cancer risk in Saudi Arabian population.

The chance of an intrathyroidal occurrence of a parathyroid gland is about 1–3%. Among the causes of hyperparathyroidism, parathyroid cases occur in less than 1% of patients. Here we present the case of a 63 year old Saudi female suffering from an intrathryroidal parathyroid carcinoma. The suspicion coming from the clinical investigations that the removed tumor tissue may be a parathyroid carcinoma could be confirmed by histology. Additionally non-radioactive in situ hybridization to localize mRNA transcripts for Cyclin D1 and immunohistochemical localization of Cyclin D1 was performed. Although parathyroid adenoma and carcinoma have disparate natural history, it can be difficult to differentiate between the two entities. Clinical presentation, operative findings may raise suspicion, but may not be conclusive especially if there is no evidence of invasion or metastasis, especially if the gland was intrathyroidal.