en Cancer Cancer Original Article Original Article One of the most prevalent malignancies, which have severe effects on women&#39;s health, is breast cancer. Quercetin, a flavonoid found in vegetables, tea, and fruits, is known to have bioactive properties, such as anti-inflammatory, anti-oxidant, as well as anti-cancer. Long non-coding RNAs (lncRNAs) have been recognized to function as primary regulators of diverse cellular processes, including differentiation, development, and cell fate. <em>INXS</em> and <em>UCA1</em> are lncRNAs that are upregulated and downregulated, respectively in cancer cells. This research aimed to assess the impact of quercetin on the expression of <em>INXS</em> and <em>UCA1</em> genes in MCF-7 cells. Various quercetin concentrations at different times were used to treat MCF-7 cells. The cell viability and IC₅₀ values were determined using MTT assay. Then, MCF-7 cells were incubated with various quercetin concentrations for 24, 48, and 72 h. Cell cycle analyzes were evaluated by flow cytometry. The levels of <em>INXS</em> and <em>UCA1</em> genes expression compared with the <em>GAPDH</em> gene at different concentrations of quercetin were quantified using real-time PCR method. Based on the results, quercetin exerted a dose- and time-dependent inhibitory impact on the viability of MCF-7 cells. Furthermore, quercetin induced cell cycle arrest at the G2 phase in MCF-7 cells. Also, quercetin induced <em>INXS</em> upregulation and <em>UCA1</em> downregulation in the MCF-7 cell line. These data suggest that quercetin might increase cell death by upregulating <em>INXS</em> and downregulating <em>UCA1</em> lncRNAs in MCF-7 cells. Breast cancer, quercetin, MCF-7 cells, INXS, UCA1 207 217 http://ijmcmed.org/browse.php?a_code=A-10-1900-2&slc_lang=en&sid=1 Fatemeh Rezaie sara.re3731@gmail.com 100319475328460022148 100319475328460022148 No Department of Biology, Zarghan Branch, Islamic Azad University, Zarghan, Iran. Mohammad Javad Mokhtari Mj.mokhtari@gmail.com 100319475328460022149 100319475328460022149 Yes Department of Biology, Zarghan Branch, Islamic Azad University, Zarghan, Iran. Mehdi Kalani mkalani2008@gmail.com 100319475328460022150 100319475328460022150 No Department of Immunology, Prof. Alborzi Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.