COL5A2 and urinary bladder carcinoma: COL5A2, also known as collagen type V alpha 2, is located at 2q32.2 in the human genome and encodes an alpha chain of fibrillar collagen type V. COL5A2 functions as an oncogene in multiple tumor types, and higher COL5A2 expression indicates poor prognosis in patients with colorectal cancer (Wang et al., 2021a), gastric cancer (Ding et al., 2021), and bladder cancer (Zeng et al., 2018).