en Oncology Oncology Original Article Original Article <span style="font-size: 14px;"><span style="font-family: times new roman;"><span style="color: rgb(0, 0, 255);"><strong><em>Background</em></strong><em>:</em> </span>To determine the expression of cancer stem cell marker Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5) in colorectal carcinoma samples compared to normal adjacent tissue and any possible association with clinicopathological findings.<br> <span style="color: rgb(0, 0, 255);"><strong><em>Methods</em></strong><em>:</em></span> This study was performed on forty samples of cancerous colorectal tissues (case group) and their adjacent normal mucosa (control group) in Imam Khomeini Hospital (Sari, Mazandaran, Iran). Expression of Lgr5 in tissue sections was done by immunohistochemistry. Statistical analysis was carried out using SPSS software.<br> <span style="color: rgb(0, 0, 255);"><strong><em>Results</em></strong><em>:</em></span> Forty colorectal cancer patients including 21 males (57.8&plusmn;11.6 years) and 19 females (58.4&plusmn;12.77 years) were enrolled. Lgr5 was overexpressed in tumoral samples than normal adjacent tissues (77.5% vs 27.5%, p<0.001). Also, no association was found between primary tumor, regional lymph nodes, invasion, histological type, grade, distant metastasis and IHC results. Patients with low Lgr5 expression had a better survival rate than patients with high expression but this was not statistically significant (p=0.121).<br> <span style="color: rgb(0, 0, 255);"><strong><em>Conclusion</em></strong><em>:</em></span>The higher immunoreactivity of Lgr5 in colorectal cancer tissues may indicate its role as a cancer stem cell marker in tumor carcinogenesis and patient&rsquo;s survival however; Lgr5 is not associated with pathological prognostic variables.</span></span> cancer stem cell, Lgr5, colorectal cancer 411 416 http://caspjim.com/browse.php?a_code=A-10-250-4&slc_lang=en&sid=1 Ramin Shekarriz drraminshekarriz@yahoo.com 100319475328460019257 100319475328460019257 No Department of hematology and oncology, gastrointestinal cancer research center, Mazandaran University of medical science, Sari, Iran. Fatemeh Montazer montazer.f@iums.ac.ir 100319475328460019258 100319475328460019258 Yes Department of pathology, Iran University of medical science, Tehran, Iran Reza Alizadeh-Navaei reza_nava@yahoo.com 100319475328460019259 100319475328460019259 No Gastrointestinal cancer research center, Mazandaran University of medical science, Sari, Iran