Estrogen Receptor-α Gene Codon 10 (T392C) Polymorphism in Iranian Women with Breast Cancer: A Case Study

Structural and functional analysis of KIT gene encoding receptor tyrosine kinase and its interaction with sunitinib and HDAC inhibitors: an in silico approach

KIT is a growth factor receptor, important for normal germ cell migration and development. The malfunction of KIT gene results in constitutive activation of the tyrosine kinase activity of c-KIT which is believed to be the major oncogenic event in stomach, small intestine mastocytosis, acute leukemias, melanomas and colon tumors. The genetics of these diseases could be better understood by knowing the functional relevance of their SNP variation. In this study, a computational analysis to detect the most deleterious nonsynonymous SNPs of KIT gene was performed and investigated its binding affinity to native and predicted mutant protein structure (D816V) with sunitinib and HDAC (Trichostatin A and Panobinostat) inhibitors was investigated. Out of 1,288 SNPs retrieved from dbSNP database against KIT gene, 11 non-synonymous SNPs were detected to be damaging and deleterious by SIFT, PolyPhen and I-Mutant2.0 servers. Further, we modeled the mutant protein based on the deleterious nsSNP (rs121913507) and showed that the mutation from Aspartic acid to Valine at 816 position exhibit greatest impact on stability. The RMSD values of mutant and native structures are found to be 0.40 and 1.9 A, respectively. Furthermore, the binding affinity of sunitinib and HDAC inhibitors were compared with native and mutant protein. In this regard, it was found that trichostatin A has a high binding efficacy towards the mutant protein with a binding energy of -35.274 kcal mol(-1), as compared to the native structure which has a binding energy of -25.996 kcal mol(-1). Also, the FastSNP tool suggested that 3 SNPs found to affect protein splicing site and splicing regulation. From present results, it was clear that the non-synonymous SNP rs121913507 (D816V) could be the most deleterious SNP for KIT gene and HDAC inhibitors can serve as a best drug for the mutant protein.

Expression of epidermal growth factor receptor tyrosine kinase family in fine needle aspiration and permanent specimens of invasive lobular and ductal breast cancers

Recently, the role of HER-2/Neu gene amplification has been enthusiastically investigated in breast cancer. Determining the HER-2/Neu status could be achieved by evaluating either histologic samples or cytologic specimens obtained by Fine Needle Aspiration (FNA). This study aimed at determining the concordance of HER-2/Neu expression in FNA and histologic sections. FNA samples, as well as their corresponding histologic sections of 90 cases with breast cancer were evaluated in Tabriz Sina Teaching Center in a 13-month period of time. The immunohistochemistry was employed for determining the HER-2/Neu amplification for both methods. The concordance rate and agreement were determined between the two methods. Ninety specimens of women with a mean age of 50.93 +/- 10.64 (29-84) years were assessed. There were 84 cases with invasive ductal carcinoma and 6 cases with invasive lobular carcinoma. Lymph nodes were involved in 50 cases and there were vascular and neural involvement in 40 and 35 cases, respectively. Her-2/Neu was not detected in 27 cases (30%) with weak and strong amplifications in 47 (52.2%) and 16 (17.8%) cases of FNA specimens, respectively. Her-2/Neu was not detected in 29 cases (32.2%) with weak and strong amplifications in 42 (46.7%) and 19 (21.1%) cases of histologic specimens, respectively. The concordance rate was 70% between the two methods. The agree ment was statistically significant between the two methods, as well (kappa = 0.51, p < 0.001). HER-2/neu gene amplification can be reliably estimated by immunohistochemistry on breast cancer FNAs and a good correlation has been found between this and results on histological sections.