The association of p21, inhibin, and Tob-1 expression with the clinicopathological characteristics of benign and malignant colorectal lesions

Background Worldwide, colorectal cancer (CRC) is the third most common cancer and the second most common cause of cancer-related deaths. p21, inhibin, and Tob-1 are tumor suppressors that play a role in the development and progression of several cancers, however, their role in CRC is not well-established. This study aims to evaluate the expression of these proteins by immunohistochemistry and correlate their expression with the clinicopathological characteristics of CRCs and preneoplastic lesions [adenomas and ulcerative colitis] to study the potential for their use as targeted therapies. The study was performed on sections of 30 CRCs, 30 adenomas, 30 UC, 30 chronic colitis, and 20 controls. Results p21 expression was lower in CRCs and adenomas compared to inflammatory lesions (chronic colitis and UC). High-grade CRCs, adenomas with high-grade dysplasia, and UC with dysplasia showed insignificantly lower expression compared to their counterparts. Inhibin expression was absent in CRCs; however, its expression was higher in chronic colitis than in UC and adenomas. Adenomas with high-grade dysplasia and UC with dysplasia showed insignificantly higher expression than their counterparts. Tob-1 expression increased significantly from chronic colitis to UC to adenomas to CRCs. High-grade CRCs, adenomas with high-grade dysplasia, and UC with dysplasia showed higher expression compared to their counterparts. Conclusions Decreased p21 and increased inhibin and Tob-1 expressions are associated with the progression of adenomas and UC to more dysplastic lesions, then possibly to CRC. Despite being tumor suppressors, the studied proteins may potentially have tumor-promoting properties. They can be useful targets for therapeutic intervention.