en Materials Science and Nanomedicine Original/Research Article <div style="text-align: justify;"><strong>Int</strong><strong>r</strong><strong>oduction</strong><strong>: </strong>Mutations in the <em>BRCA1 </em>gene are major risk factors for breast and ovarian cancers. However, the relationship between some <em>BRCA1 </em>mutations and cancer risk remains largely unknown<strong>. </strong>Cancer risk predictions could be improved by evaluation of the impairment degree in the <em>BRCA1 </em>functions due to a specific mutation. This study aimed to assess the functional effect of a novel variant (Glu1661Gly) by a combination of in silico tools, structural analysis, and also experimental functional assay based on yeast transcription activation.<br> <strong>Methods</strong><strong>: </strong>Computational tools including PROVEAN, PolyPhen2, Align-GVGD, Mutation Taster, and also structural analysis were used for prediction of the impact of Glu1661Gly on protein function. To perform the yeast functional assay, the <em>BRCA1 </em>C-terminal (BRCT domain) was cloned into pLexA plasmid in-frame with the DNA-binding domain of LexA to generate a functional transcription activator. The resulted construct was transformed into EGY48/ pRB1840 yeast and positive colonies were assayed for &beta;-galactosidase activity. Wild-type <em>BRCA</em><em>1 </em>and Ser1613Gly were used as positive controls and Met1775Arg as negative control.<br> <strong>Results</strong><strong>: &nbsp;</strong>The &nbsp;Glu1661Gly &nbsp;variant &nbsp;was &nbsp;predicted &nbsp;to &nbsp;be &nbsp;neutral &nbsp;by &nbsp;PROVEAN, &nbsp;disease- causing by Mutation Taster, probably damaging by Polyphen2, and intermediate effect by Align-GVGD. The yeast functional assay revealed that Glu1661Gly activity was comparable to wild-type <em>BRCA1</em><br> <strong>Conclusions</strong><strong>: </strong>Observed discrepancies between in silico tools make it difficult to interpret the results. Based on structural analysis, the Glu1661Gly on &alpha;1 helix of the C-terminal domain does not seem to impair function due to &alpha;1 helix is far from the BRCT-BRCT interface and phosphopeptide-binding site. This variant was also classified as neutral; using yeast functional assay.</div> Susceptibility Genes, BRCA1, VUS, Glu1661Gly, Transcriptional Activation 20 26 http://mcijournal.com/browse.php?a_code=A-10-286-1&slc_lang=en&sid=1 Fatemeh Yadegari yadegari1985@gmail.com 10031947532846003658 10031947532846003658 No Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran Leila Farahmand laylafarahmand@gmail.com 10031947532846003659 10031947532846003659 No 2 Recombinant Proteins Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran Rezvan Esmaeili esmaeili.rezvan@gmail.com 10031947532846003660 10031947532846003660 No Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran Shiva Zarinfam sh.zarinfam@gmail.com 10031947532846003661 10031947532846003661 No Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran Keivan Majidzadeh-A kmajidzadeh@razi.tums.ac.ir 10031947532846003662 10031947532846003662 Yes Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran