Colorectal Cancer Tissue Collection and Analysis

Fresh tissues were collected from the resected tissues of four patients with colorectal cancer, preferably 10 mm × 8 mm × 6 mm in size. Excess fluid, such as blood, was aspirated using dust-free paper (Kimtech, Cat#: 0131-10, Texas, USA) to ensure that as many tissues as possible were of no liquid residue. The prepared tissues were put into the mold (Leica, Cat#:14702218313, 6mm×8mm, Hesse, Germany) after marking the direction from epithelial layer to serosal layer using forceps. A little pre-cooled OCT (pre-cooled at four °C for ≥30 min; Sakura, Cat#: 4583, CA, USA) was then injected into the mold to thoroughly cover the tissue. Finally, the embedded tissue was transferred to a -80°C freezer for storage.
We collected resected tissues from 45 CRC patients in the Second Affiliated Hospital of Chongqing Medical University. Immunohistochemical staining of PRL5, HLA-A, STC1, AKR1B1, and CD47 expression was performed on tumor tissue sections. The study was approved by the ethical review board of the Second Affiliated Hospital of Chongqing Medical University (Chongqing China; Project identification code: 2019.133) and all patients signed informed written consent.