COL11A1 and neoplasm: <h4>Background</h4>Collagen XIα1, encoded by the <i>COL11A1</i> gene, is a minor fibrillar collagen that is overexpressed in various human cancers, in which its presence correlates with tumor aggressiveness and progression.<h4>Methods</h4>In this study, we developed two novel mouse monoclonal antibodies (mAbs)-anti-colXIα1 clone 3 and anti-colXIα1 clone 9-that target the putative C-telopeptide of human collagen XIα1.