Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 58 6 2020 08 19 266 270 Naghmeh Ahmadiankia School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran. AND Cancer Prevention Research Center, Shahroud University of Medical Sciences, Shahroud, Iran. Maryam Yarmohammadi Imam Hossein Center for Education, Research and Treatment, Shahroud University of Medical Sciences, Shahroud, Iran. Azam Hadi Student Research Committee, School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran Behnaz Jafari School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran. Mozhgan Fazli School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran. Zahra Shahmohammadi Student Research Committee, School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran. 2019 12 30 2020 04 28 The theory of platelet role in cancer progression was recently introduced. We investigated the association of extravasated platelets in colorectal cancer with clinicopathological features, and also the expression of epithelial-mesenchymal transition (EMT) markers. We retrospectively analyzed data from 33 patients with colorectal cancer who underwent surgery between 2013-2016. In formalin-fixed paraffin-embedded tissues, we evaluated the expression of a platelet-specific marker of CD42b and EMT markers using immunohistochemistry. The associations among the expression of the platelet‑specific marker in specimens, EMT, and clinicopathological futures were analyzed. The presence of platelets was observed in 15 out of 33 primary colorectal tumors (45%). According to multivariate analysis, CD42b expression was not correlated with clinical characteristics. Platelet-positive tumor cells did not show EMT marker expression. These data suggest that extravasated platelets may not have a central role in determining patient characteristics and clinical futures. https://acta.tums.ac.ir/index.php/acta/article/view/8255 https://acta.tums.ac.ir/index.php/acta/article/download/8255/5410