en Internal Internal Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> <span style="color:black">Colorectal cancer </span>could be developed from adenomatous polyp.&nbsp; The study aimed to evaluate the diagnostic significance of stromal and epithelial CD10 (Neprilysin) expression in patients with colorectal adenocarcinoma and adenomatous polyps.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods:</span></i></b> This cross-sectional study was conducted on 141 patients with colorectal adenocarcinoma and adenomatous polyps referred to Ayatollah Rouhani Hospital from March 2020 to March 2021. Differential diagnoses of colorectal adenocarcinoma and adenomatous polyps were made colonoscopically, and then samples were taken from the lesions. The pathologists confirmed the final diagnosis as colorectal adenocarcinoma, high-grade or low-grade adenomatous polyps. The stromal and epithelial CD10 expression was evaluated by immunohistochemistry. The data was analyzed by SPSS 22 software (p<0.05). </span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results:</span></i></b> Sixty-five (46.1%) of the cases were low-grade polyps that were included<b> </b>positive (4 cases; 6.20%) and negative (61 cases; 93.80%)<b> </b>CD10 expression (P=0.001), also 76 (53.9%) of them were either high-grade polyps (21 cases) or adenocarcinomas (21 cases). Also, epithelial CD10 expression was significantly higher in the well-differentiated adenocarcinoma (38 cases) group than moderate (13 cases) and poor (4 cases) groups (P =0.001). Moreover, the CD10 expression level in the adenomatous polyps (10 positive cases and 76 negative cases) was correlated with the degree of dysplasia (P = 0.001) and the presence of tumor invasion (8 positive cases and 133 negative cases) (P = 0.001).</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> The CD10 expression is associated with an increased degree of dysplasia and the presence of tumor invasion in patients with pre-neoplastic lesions and colorectal adenocarcinoma.</span></span></span><br> &nbsp; Immunohistochemistry, Colorectal neoplasms, Neprilysin, Adenomatous polyps. 228 233 http://caspjim.com/browse.php?a_code=A-10-2423-3&slc_lang=en&sid=1 Ghasem Dehini ghasem.dehini@gmail.com 100319475328460047686 100319475328460047686 Yes Clinical Research Development Unit of Rouhani Hospital, Babol University of Medical Sciences, Babol, Iran Hossein Ghorbani ghorbani@yahoo.com 100319475328460047687 100319475328460047687 No Clinical Research Development Unit of Rouhani Hospital, Babol University of Medical Sciences, Babol, Iran Soraya Khafri khafri@yahoo.com 100319475328460047688 100319475328460047688 No Social Determinants of Health Research Center, Health Research Institute, Babol University of Medical. Sciences, Babol, Iran Javad Shokri Shirvani javadshokry@gmail.com 100319475328460047689 100319475328460047689 No Department of Gastroenterology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran Akramossadat Hosseini dr_hosseini_2006@yahoo.com 100319475328460047690 100319475328460047690 No Department of Pathology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran Sahar Sadr Mohararpur drsaharsadr@gmail.com 100319475328460047691 100319475328460047691 No Non-Communicable Pediatric Diseases Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Tina Rouhi Rouhitina0@gmail.com 100319475328460047692 100319475328460047692 No Department of Pathology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran