High frequency and strong prognostic relevance of O6-methylguanine DNA methyltransferase silencing in diffuse large B-cell lymphomas from the Middle East.

Several clinically relevant molecular classifiers of diffuse large B-cell lymphoma (DLBCL) have recently been demonstrated in Western populations. However, substantial molecular differences have recently been shown between tumors derived from different ethnic groups. To investigate prevalence and interrelationship of recently suggested molecular prognostic markers in Middle East DLBCL, we analyzed coexpression of CD10/Bcl6 (by immunohistochemistry), t(14;18) translocations (by fluorescence in situ hybridization), and methylation of the gene encoding the DNA repair enzyme O(6)-methylguanine DNA methyltransferase (MGMT) in a series of 190 DLBCL patients from Saudi Arabia with clinical follow-up data.

High epidermal growth factor receptor amplification rate but low mutation frequency in Middle East lung cancer population.

Epidermal growth factor receptor (EGFR) exon 18-21 mutations were shown to be highly predictive of response to gefitinib (Iressa) therapy in lung cancer. Studies on Western and Japanese lung cancers have indicated substantial differences in the EGFR mutation frequency between these populations. To investigate the prevalence of EGFR in another distinct ethnic group, EGFR alterations were studied in 47 consecutive non small cell lung cancers from Saudi Arabia by immunohistochemistry, fluorescence in situ hybridization, and DNA sequencing.

Epigenetic changes and their clinical relevance in Saudi diffuse large B-cell lymphoma. A molecular and tissue microarray analysis of 100 cases.

Objective: The gene encoding the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) is transcriptionally silenced by promoter hypermethylation in several human cancers including diffuse large B-cell lymphoma (DLBCL). We explored the aberrant promoter methylation of MGMT in Saudi diffuse large B-cell lymphoma and to investigate MGMT hypermethylation has an effect on patient's overall survival.

Methods: In a retrospective cohort study, 100 cases of DLBCL were collected from the Department of Pathology at King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia.