Jorjani Biomedicine Journal

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Background & Objective: Deafness is the most common sensory disorder in humans which is highly heterogeneous. Among its various types, autosomal recessive non-syndromic hearing loss (ARNSHL) is responsible for 80% of pre-speech congenital cases of hearing loss. The purpose of this study was to investigate the genetic linkage of DFNB4 locus in hearing impaired families in Hormozgan. Method: Ten deaf large families in the Hormozgan province were selected. A hearing impaired person was selected from each family tree and sequence of the GJB2 gene in regards of coding regions' mutations was investigated using sequencing method. STR markers of DFNB4 locus in families with no mutation in GJB2 were amplified using PCR and after determining the type alleles, they were analyzed for linkage. Results: In one among the ten studied families, GJB2 mutation was observed. The nine other families were entered for linkage studies and no linkage was found in the said families. Conclusion: Due to the high heterogeneity of loci associated with ARNSHL, other factors may be involved in the cause of deafness in families, without mutations in the GJB2 gene and the investigated locus. Therefore it is recommended to study other loci and more families in this matter.

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Background & Objectives: Breast cancer is the most common cancer among women and the second most common cause of cancer death. Genetic factors play an important role in the development of breast cancer. Among these genetic factors, CHEk2 (checkpoint kinase 2) gene, as a tumor suppressor gene, plays a critical role in DNA repair. Germline mutations in CEHK2 result in the loss of this feature. One of the mutations in CHEK2 gene is a 5395 bp deletion mutation which has been associated with the increasing risk of Breast Cancer in some populations in the world.  In the present study, we investigated the association between a 5395 bp deletion mutation in CHEK2 gene and the risk of Breast Cancer in the women of an Iranian population.

Methods: Pathologic information of 38 cases under the age of 45 and 62 cases over the age of 45 referring to surgery ward of Milad Hospital in Tehran were extracted. 100 healthy controls were included in the study as well. After obtaining informed consent, 5 mL whole blood was taken DNA was successfully isolated. Multiplex PCR was used to investigate the association between a 5395bp deletion mutation in CHEK2 gene and increasing risk of Breast Cancer among patients.

Results: The 5395bp deletion mutation in CHEK2 gene was not found in any of the participating groups of patients or heathy controls.

Conclusion: The present study revealed that there is no significant relation between increasing the risk of Breast Cancer and bearing large deletion mutation in exon 9 and exon 10 of CHECK2 gene.

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Background and objectives: Deregulation in the expression of microRNAs is involved in the pathogenesis of various malignancies. Impaired microRNAs processing pathway is one possible mechanism for global deregulation of the miRNAs. Exportin 5 (XPO5) is a key member of this pathway that links nuclear and cytoplasmic steps of miRNAs biogenesis together. XPO5 deregulation has been reported in some cancers but very little is known about its role in breast cancer. Therefore, this study aimed to evaluate the mRNA expression of XPO5 in breast cancer in an Iranian population.

Methods: In this case-control study, 30 tumoral tissues and 30 tumor-free margins were collected from breast cancer patients. After RNA extraction and cDNA synthesis, XPO5 mRNA expression level was assessed using quantitative Real-Time PCR.

Results: Our results showed that XPO5 was overexpressed in 53.3% of tumoral tissues but the difference in the gene expression level between tumoral tissues and tumor-free margins was not statistically significant (P-value=0.834). XPO5 expression level showed no statistically significant correlation and association with clinical and pathological parameters.

Conclusion: Overexpression of XPO5 in large percent of patients indicates that high level of XPO5 expression may be a tumorigenic factor for breast cancer which needs to be investigated more deeply.